зеркало из https://github.com/mozilla/pjs.git
Added make-and-compile-grammar cache
This commit is contained in:
waldemar%netscape.com
Родитель
12ec735bd9
Коммит
d5f1e7556c
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@ -1,543 +0,0 @@
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;;; The contents of this file are subject to the Mozilla Public
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;;; License Version 1.1 (the "License"); you may not use this file
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;;; except in compliance with the License. You may obtain a copy of
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;;; the License at http://www.mozilla.org/MPL/
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;;;
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;;; Software distributed under the License is distributed on an "AS
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;;; IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
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;;; implied. See the License for the specific language governing
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;;; rights and limitations under the License.
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;;;
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;;; The Original Code is the Language Design and Prototyping Environment.
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;;;
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;;; The Initial Developer of the Original Code is Netscape Communications
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;;; Corporation. Portions created by Netscape Communications Corporation are
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;;; Copyright (C) 1999 Netscape Communications Corporation. All
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;;; Rights Reserved.
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;;;
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;;; Contributor(s): Waldemar Horwat <waldemar@acm.org>
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;;;
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;;; LALR(1) and LR(1) parametrized grammar utilities
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;;;
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;;; Waldemar Horwat (waldemar@acm.org)
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;;;
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;;; ------------------------------------------------------------------------------------------------------
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;;; UTILITIES
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(declaim (inline identifier?))
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(defun identifier? (form)
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(and form (symbolp form) (not (keywordp form))))
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(deftype identifier () '(satisfies identifier?))
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; Make sure that form is one of the following:
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; A symbol
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; An integer
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; A float
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; A character
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; A string
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; A list of zero or more forms that also satisfy ensure-proper-form;
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; the list cannot be dotted.
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; Return the form.
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(defun ensure-proper-form (form)
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(labels
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((ensure-list-form (form)
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(or (null form)
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(and (consp form)
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(progn
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(ensure-proper-form (car form))
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(ensure-list-form (cdr form)))))))
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(unless
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(or (symbolp form)
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(integerp form)
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(floatp form)
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(characterp form)
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(stringp form)
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(ensure-list-form form))
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(error "Bad form: ~S" form))
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form))
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;;; ------------------------------------------------------------------------------------------------------
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;;; TERMINALS
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; A terminal is any of the following:
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; A symbol that is neither nil nor a keyword
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; A string;
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; A character;
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; An integer.
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(defun terminal? (x)
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(and x
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(or (and (symbolp x) (not (keywordp x)))
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(stringp x)
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(characterp x)
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(integerp x))))
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; The following terminals are reserved and may not be used in user input:
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; $$ Marker for end of token stream
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(defconstant *end-marker* '$$)
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(defconstant *end-marker-terminal-number* 0)
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(deftype terminal () '(satisfies terminal?))
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(deftype user-terminal () `(and terminal (not (eql ,*end-marker*))))
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; Emit markup for a terminal. subscript is an optional integer.
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(defun depict-terminal (markup-stream terminal &optional subscript)
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(cond
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((characterp terminal)
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(depict-char-style (markup-stream ':character-literal)
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(depict-character markup-stream terminal)
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(when subscript
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(depict-char-style (markup-stream ':plain-subscript)
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(depict-integer markup-stream subscript)))))
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((and terminal (symbolp terminal))
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(let ((name (symbol-name terminal)))
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(if (and (> (length name) 0) (char= (char name 0) #\$))
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(depict-char-style (markup-stream ':terminal)
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(depict markup-stream (subseq (symbol-upper-mixed-case-name terminal) 1))
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(when subscript
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(depict-char-style (markup-stream ':plain-subscript)
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(depict-integer markup-stream subscript))))
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(progn
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(depict-char-style (markup-stream ':terminal-keyword)
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(depict markup-stream (string-downcase name)))
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(when subscript
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(depict-char-style (markup-stream ':terminal)
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(depict-char-style (markup-stream ':plain-subscript)
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(depict-integer markup-stream subscript))))))))
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(t (error "Don't know how to emit markup for terminal ~S" terminal))))
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;;; ------------------------------------------------------------------------------------------------------
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;;; NONTERMINAL PARAMETERS
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(declaim (inline nonterminal-parameter?))
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(defun nonterminal-parameter? (x)
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(symbolp x))
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(deftype nonterminal-parameter () 'symbol)
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; Return true if this nonterminal parameter is a constant.
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(declaim (inline nonterminal-attribute?))
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(defun nonterminal-attribute? (parameter)
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(and (symbolp parameter) (not (keywordp parameter))))
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(deftype nonterminal-attribute () '(and symbol (not keyword)))
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(defun depict-nonterminal-attribute (markup-stream attribute)
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(depict-char-style (markup-stream ':nonterminal)
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(depict-char-style (markup-stream ':nonterminal-attribute)
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(depict markup-stream (symbol-lower-mixed-case-name attribute)))))
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; Return true if this nonterminal parameter is a variable.
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(declaim (inline nonterminal-argument?))
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(defun nonterminal-argument? (parameter)
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(keywordp parameter))
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(deftype nonterminal-argument () 'keyword)
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(defparameter *special-nonterminal-arguments*
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'(:alpha :beta :gamma :delta :epsilon :zeta :eta :theta :iota :kappa :lambda :mu :nu
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:xi :omicron :pi :rho :sigma :tau :upsilon :phi :chi :psi :omega))
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(defun depict-nonterminal-argument-symbol (markup-stream argument)
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(depict-char-style (markup-stream ':nonterminal-argument)
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(let ((argument (symbol-abbreviation argument)))
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(depict markup-stream
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(if (member argument *special-nonterminal-arguments*)
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argument
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(symbol-upper-mixed-case-name argument))))))
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(defun depict-nonterminal-argument (markup-stream argument)
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(depict-char-style (markup-stream ':nonterminal)
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(depict-nonterminal-argument-symbol markup-stream argument)))
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;;; ------------------------------------------------------------------------------------------------------
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;;; ATTRIBUTED NONTERMINALS
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; An attributed-nonterminal is a specific instantiation of a generic-nonterminal.
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(defstruct (attributed-nonterminal (:constructor allocate-attributed-nonterminal (symbol attributes))
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(:copier nil)
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(:predicate attributed-nonterminal?))
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(symbol nil :type keyword :read-only t) ;The name of the attributed nonterminal
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(attributes nil :type list :read-only t)) ;Ordered list of nonterminal attributes
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; Make an attributed nonterminal with the given symbol and attributes. If there
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; are no attributes, return the symbol as a plain nonterminal.
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; Nonterminals are eq whenever they have identical symbols and attribute lists.
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(defun make-attributed-nonterminal (symbol attributes)
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(assert-type symbol keyword)
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(assert-type attributes (list nonterminal-attribute))
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(if attributes
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(let ((generic-nonterminals (get symbol 'generic-nonterminals)))
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(or (cdr (assoc attributes generic-nonterminals :test #'equal))
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(let ((attributed-nonterminal (allocate-attributed-nonterminal symbol attributes)))
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(setf (get symbol 'generic-nonterminals)
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(acons attributes attributed-nonterminal generic-nonterminals))
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attributed-nonterminal)))
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symbol))
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(defmethod print-object ((attributed-nonterminal attributed-nonterminal) stream)
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(print-unreadable-object (attributed-nonterminal stream)
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(format stream "a ~@_~W~{ ~:_~W~}"
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(attributed-nonterminal-symbol attributed-nonterminal)
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(attributed-nonterminal-attributes attributed-nonterminal))))
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;;; ------------------------------------------------------------------------------------------------------
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;;; GENERIC NONTERMINALS
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; A generic-nonterminal is a parametrized nonterminal that can expand into two or more
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; attributed-nonterminals.
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(defstruct (generic-nonterminal (:constructor allocate-generic-nonterminal (symbol parameters))
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(:copier nil)
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(:predicate generic-nonterminal?))
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(symbol nil :type keyword :read-only t) ;The name of the generic nonterminal
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(parameters nil :type list :read-only t)) ;Ordered list of nonterminal attributes or arguments
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; Make a generic nonterminal with the given symbol and parameters. If none of
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; the parameters is an argument, make an attributed nonterminal instead. If there
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; are no parameters, return the symbol as a plain nonterminal.
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; Nonterminals are eq whenever they have identical symbols and parameter lists.
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(defun make-generic-nonterminal (symbol parameters)
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(assert-type symbol keyword)
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(if parameters
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(let ((generic-nonterminals (get symbol 'generic-nonterminals)))
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(or (cdr (assoc parameters generic-nonterminals :test #'equal))
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(progn
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(assert-type parameters (list nonterminal-parameter))
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(let ((generic-nonterminal (if (every #'nonterminal-attribute? parameters)
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(allocate-attributed-nonterminal symbol parameters)
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(allocate-generic-nonterminal symbol parameters))))
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(setf (get symbol 'generic-nonterminals)
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(acons parameters generic-nonterminal generic-nonterminals))
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generic-nonterminal))))
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symbol))
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(defmethod print-object ((generic-nonterminal generic-nonterminal) stream)
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(print-unreadable-object (generic-nonterminal stream)
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(format stream "g ~@_~W~{ ~:_~W~}"
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(generic-nonterminal-symbol generic-nonterminal)
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(generic-nonterminal-parameters generic-nonterminal))))
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;;; ------------------------------------------------------------------------------------------------------
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;;; NONTERMINALS
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;;; A nonterminal is a keyword or an attributed-nonterminal.
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(declaim (inline nonterminal?))
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(defun nonterminal? (x)
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(or (keywordp x) (attributed-nonterminal? x)))
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; The following nonterminals are reserved and may not be used in user input:
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; :% Nonterminal that expands to the start nonterminal
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(defconstant *start-nonterminal* :%)
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(deftype nonterminal () '(or keyword attributed-nonterminal))
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(deftype user-nonterminal () `(and nonterminal (not (eql ,*start-nonterminal*))))
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;;; ------------------------------------------------------------------------------------------------------
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;;; GENERAL NONTERMINALS
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;;; A general-nonterminal is a nonterminal or a generic-nonterminal.
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(declaim (inline general-nonterminal?))
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(defun general-nonterminal? (x)
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(or (nonterminal? x) (generic-nonterminal? x)))
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(deftype general-nonterminal () '(or nonterminal generic-nonterminal))
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; Return the list of parameters in the general-nonterminal. The list is empty if the
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; general-nonterminal is a plain nonterminal.
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(defun general-nonterminal-parameters (general-nonterminal)
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(cond
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((attributed-nonterminal? general-nonterminal) (attributed-nonterminal-attributes general-nonterminal))
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((generic-nonterminal? general-nonterminal) (generic-nonterminal-parameters general-nonterminal))
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(t (progn
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(assert-true (keywordp general-nonterminal))
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nil))))
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; Emit markup for a general-nonterminal. subscript is an optional integer.
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; link should be one of:
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; :reference if this is a reference of this general-nonterminal;
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; :external if this is an external reference of this general-nonterminal;
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; :definition if this is a definition of this general-nonterminal;
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; nil if this use of the general-nonterminal should not be cross-referenced.
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(defun depict-general-nonterminal (markup-stream general-nonterminal link &optional subscript)
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(labels
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((depict-nonterminal-name (markup-stream symbol)
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(let ((name (symbol-upper-mixed-case-name symbol)))
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(depict-link (markup-stream link "N-" name t)
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(depict markup-stream name))))
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(depict-nonterminal-parameter (markup-stream parameter)
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(if (nonterminal-attribute? parameter)
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(depict-char-style (markup-stream ':nonterminal-attribute)
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(depict markup-stream (symbol-lower-mixed-case-name parameter)))
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(depict-nonterminal-argument-symbol markup-stream parameter)))
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(depict-parametrized-nonterminal (markup-stream symbol parameters)
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(depict-nonterminal-name markup-stream symbol)
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(depict-char-style (markup-stream ':superscript)
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(depict-list markup-stream #'depict-nonterminal-parameter parameters
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:separator ",")))
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(depict-general (markup-stream)
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(depict-char-style (markup-stream ':nonterminal)
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(cond
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((keywordp general-nonterminal)
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(depict-nonterminal-name markup-stream general-nonterminal))
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((attributed-nonterminal? general-nonterminal)
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(depict-parametrized-nonterminal markup-stream
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(attributed-nonterminal-symbol general-nonterminal)
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(attributed-nonterminal-attributes general-nonterminal)))
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((generic-nonterminal? general-nonterminal)
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(depict-parametrized-nonterminal markup-stream
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(generic-nonterminal-symbol general-nonterminal)
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(generic-nonterminal-parameters general-nonterminal)))
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(t (error "Bad nonterminal ~S" general-nonterminal)))
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(when subscript
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(depict-char-style (markup-stream ':plain-subscript)
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(depict-integer markup-stream subscript))))))
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(if (or (eq link :definition)
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(and (or (eq link :reference) (eq link :external))
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(keywordp general-nonterminal)
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(null subscript)))
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(depict-link (markup-stream link "N-" (symbol-upper-mixed-case-name (general-grammar-symbol-symbol general-nonterminal)) t)
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(setq link nil)
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(depict-general markup-stream))
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(depict-general markup-stream))))
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;;; ------------------------------------------------------------------------------------------------------
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;;; GRAMMAR SYMBOLS
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;;; A grammar-symbol is either a terminal or a nonterminal.
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(deftype grammar-symbol () '(or terminal nonterminal))
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(deftype user-grammar-symbol () '(or user-terminal user-nonterminal))
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;;; A general-grammar-symbol is either a terminal or a general-nonterminal.
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(deftype general-grammar-symbol () '(or terminal general-nonterminal))
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; Return true if x is a general-grammar-symbol. x can be any object.
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(defun general-grammar-symbol? (x)
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(or (terminal? x) (general-nonterminal? x)))
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; Return true if the two grammar symbols are the same symbol.
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(declaim (inline grammar-symbol-=))
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(defun grammar-symbol-= (grammar-symbol1 grammar-symbol2)
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(eql grammar-symbol1 grammar-symbol2))
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; A version of grammar-symbol-= suitable for being the test function for hash tables.
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(defparameter *grammar-symbol-=* #'eql)
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; Return the general-grammar-symbol's symbol. Return it unchanged if it is not
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; an attributed or generic nonterminal.
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(defun general-grammar-symbol-symbol (general-grammar-symbol)
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(cond
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((attributed-nonterminal? general-grammar-symbol) (attributed-nonterminal-symbol general-grammar-symbol))
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((generic-nonterminal? general-grammar-symbol) (generic-nonterminal-symbol general-grammar-symbol))
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(t (assert-type general-grammar-symbol (or keyword terminal)))))
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; Return the list of arguments in the general-grammar-symbol. The list is empty if the
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; general-grammar-symbol is not a generic nonterminal.
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(defun general-grammar-symbol-arguments (general-grammar-symbol)
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(and (generic-nonterminal? general-grammar-symbol)
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(remove-if (complement #'nonterminal-argument?) (generic-nonterminal-parameters general-grammar-symbol))))
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|
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; Return the general-grammar-symbol expanded into source form that can be interned to yield the same
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; general-grammar-symbol.
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(defun general-grammar-symbol-source (general-grammar-symbol)
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(cond
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((attributed-nonterminal? general-grammar-symbol)
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(cons (attributed-nonterminal-symbol general-grammar-symbol) (attributed-nonterminal-attributes general-grammar-symbol)))
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((generic-nonterminal? general-grammar-symbol)
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(cons (generic-nonterminal-symbol general-grammar-symbol) (generic-nonterminal-parameters general-grammar-symbol)))
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(t (assert-type general-grammar-symbol (or keyword terminal)))))
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|
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|
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; Emit markup for a general-grammar-symbol. subscript is an optional integer.
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||||
; link should be one of:
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||||
; :reference if this is a reference of this general-grammar-symbol;
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||||
; :external if this is an external reference of this general-grammar-symbol;
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||||
; :definition if this is a definition of this general-grammar-symbol;
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; nil if this use of the general-grammar-symbol should not be cross-referenced.
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(defun depict-general-grammar-symbol (markup-stream general-grammar-symbol link &optional subscript)
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(if (general-nonterminal? general-grammar-symbol)
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(depict-general-nonterminal markup-stream general-grammar-symbol link subscript)
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(depict-terminal markup-stream general-grammar-symbol subscript)))
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||||
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||||
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; Styled text can include (:grammar-symbol <grammar-symbol-source> [<subscript>]) as long as
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; *styled-text-grammar-parametrization* is bound around the call to depict-styled-text.
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(defvar *styled-text-grammar-parametrization*)
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||||
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(defun depict-grammar-symbol-styled-text (markup-stream grammar-symbol-source &optional subscript)
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(depict-general-grammar-symbol markup-stream
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(grammar-parametrization-intern *styled-text-grammar-parametrization* grammar-symbol-source)
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||||
:reference
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||||
subscript))
|
||||
|
||||
(setf (styled-text-depictor :grammar-symbol) #'depict-grammar-symbol-styled-text)
|
||||
|
||||
|
||||
;;; ------------------------------------------------------------------------------------------------------
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||||
;;; GRAMMAR PARAMETRIZATIONS
|
||||
|
||||
; A grammar parametrization holds the rules for converting nonterminal arguments into nonterminal attributes.
|
||||
(defstruct (grammar-parametrization (:constructor allocate-grammar-parametrization (argument-attributes))
|
||||
(:predicate grammar-parametrization?))
|
||||
(argument-attributes nil :type hash-table :read-only t)) ;Hash table of nonterminal-argument -> list of nonterminal-attributes
|
||||
|
||||
|
||||
(defun make-grammar-parametrization ()
|
||||
(allocate-grammar-parametrization (make-hash-table :test #'eq)))
|
||||
|
||||
|
||||
; Declare that nonterminal arguments with the given name can hold any of the
|
||||
; given nonterminal attributes given. At least one attribute must be provided.
|
||||
(defun grammar-parametrization-declare-argument (grammar-parametrization argument attributes)
|
||||
(assert-type argument nonterminal-argument)
|
||||
(assert-type attributes (list nonterminal-attribute))
|
||||
(assert-true attributes)
|
||||
(when (gethash argument (grammar-parametrization-argument-attributes grammar-parametrization))
|
||||
(error "Duplicate parametrized grammar argument ~S" argument))
|
||||
(setf (gethash argument (grammar-parametrization-argument-attributes grammar-parametrization)) attributes))
|
||||
|
||||
|
||||
; Return the attributes to which the given argument may expand.
|
||||
(defun grammar-parametrization-lookup-argument (grammar-parametrization argument)
|
||||
(assert-non-null (gethash argument (grammar-parametrization-argument-attributes grammar-parametrization))))
|
||||
|
||||
|
||||
; Create a plain, attributed, or generic grammar symbol from the specification in grammar-symbol-source.
|
||||
; If grammar-symbol-source is not a cons, it is a plain grammar symbol. If it is a list, its first element
|
||||
; must be a keyword that is a nonterminal's symbol and the other elements must be nonterminal
|
||||
; parameters.
|
||||
; Return two values:
|
||||
; the grammar symbol
|
||||
; a list of arguments used in the grammar symbol.
|
||||
; If allowed-arguments is given, check that each argument is in the allowed-arguments list;
|
||||
; if not, allow any arguments declared in grammar-parametrization but do not allow duplicates.
|
||||
(defun grammar-parametrization-intern (grammar-parametrization grammar-symbol-source &optional (allowed-arguments nil allow-duplicates))
|
||||
(if (consp grammar-symbol-source)
|
||||
(progn
|
||||
(assert-type grammar-symbol-source (cons keyword (list nonterminal-parameter)))
|
||||
(let* ((symbol (car grammar-symbol-source))
|
||||
(parameters (cdr grammar-symbol-source))
|
||||
(arguments (remove-if (complement #'nonterminal-argument?) parameters)))
|
||||
(mapl #'(lambda (arguments)
|
||||
(let ((argument (car arguments)))
|
||||
(if allow-duplicates
|
||||
(unless (member argument allowed-arguments :test #'eq)
|
||||
(error "Undefined nonterminal argument ~S" argument))
|
||||
(progn
|
||||
(unless (gethash argument (grammar-parametrization-argument-attributes grammar-parametrization))
|
||||
(error "Undeclared nonterminal argument ~S" argument))
|
||||
(when (member argument (cdr arguments) :test #'eq)
|
||||
(error "Duplicate nonterminal argument ~S" argument))))))
|
||||
arguments)
|
||||
(values (make-generic-nonterminal symbol parameters) arguments)))
|
||||
(values (assert-type grammar-symbol-source (or keyword terminal)) nil)))
|
||||
|
||||
|
||||
; Call f on each possible binding permutation of the given arguments concatenated with the bindings in
|
||||
; bound-argument-alist. f takes one argument, an association list that maps arguments to attributes.
|
||||
(defun grammar-parametrization-each-permutation (grammar-parametrization f arguments &optional bound-argument-alist)
|
||||
(if arguments
|
||||
(let ((argument (car arguments))
|
||||
(rest-arguments (cdr arguments)))
|
||||
(dolist (attribute (grammar-parametrization-lookup-argument grammar-parametrization argument))
|
||||
(grammar-parametrization-each-permutation grammar-parametrization f rest-arguments (acons argument attribute bound-argument-alist))))
|
||||
(funcall f bound-argument-alist)))
|
||||
|
||||
|
||||
; If general-grammar-symbol is a generic-nonterminal, return one possible binding permutation of its arguments;
|
||||
; otherwise return nil.
|
||||
(defun nonterminal-sample-bound-argument-alist (grammar-parametrization general-grammar-symbol)
|
||||
(when (generic-nonterminal? general-grammar-symbol)
|
||||
(grammar-parametrization-each-permutation
|
||||
grammar-parametrization
|
||||
#'(lambda (bound-argument-alist) (return-from nonterminal-sample-bound-argument-alist bound-argument-alist))
|
||||
(general-grammar-symbol-arguments general-grammar-symbol))))
|
||||
|
||||
|
||||
; If the grammar symbol is a generic nonterminal, convert it into an attributed nonterminal
|
||||
; by instantiating its arguments with the corresponding attributes from the bound-argument-alist.
|
||||
; If the grammar symbol is already an attributed or plain nonterminal, return it unchanged.
|
||||
(defun instantiate-general-grammar-symbol (bound-argument-alist general-grammar-symbol)
|
||||
(if (generic-nonterminal? general-grammar-symbol)
|
||||
(make-attributed-nonterminal
|
||||
(generic-nonterminal-symbol general-grammar-symbol)
|
||||
(mapcar #'(lambda (parameter)
|
||||
(if (nonterminal-argument? parameter)
|
||||
(let ((binding (assoc parameter bound-argument-alist :test #'eq)))
|
||||
(if binding
|
||||
(cdr binding)
|
||||
(error "Unbound nonterminal argument ~S" parameter)))
|
||||
parameter))
|
||||
(generic-nonterminal-parameters general-grammar-symbol)))
|
||||
(assert-type general-grammar-symbol grammar-symbol)))
|
||||
|
||||
|
||||
; If the grammar symbol is a generic nonterminal parametrized on argument, substitute
|
||||
; attribute for argument in it and return the modified grammar symbol. Otherwise, return it unchanged.
|
||||
(defun general-grammar-symbol-substitute (attribute argument general-grammar-symbol)
|
||||
(assert-type attribute nonterminal-attribute)
|
||||
(assert-type argument nonterminal-argument)
|
||||
(if (and (generic-nonterminal? general-grammar-symbol)
|
||||
(member argument (generic-nonterminal-parameters general-grammar-symbol) :test #'eq))
|
||||
(make-generic-nonterminal
|
||||
(generic-nonterminal-symbol general-grammar-symbol)
|
||||
(substitute attribute argument (generic-nonterminal-parameters general-grammar-symbol) :test #'eq))
|
||||
(assert-type general-grammar-symbol general-grammar-symbol)))
|
||||
|
||||
|
||||
; If the general grammar symbol is a generic nonterminal, return a list of all possible attributed nonterminals
|
||||
; that can be instantiated from it; otherwise, return a one-element list containing the given general grammar symbol.
|
||||
(defun general-grammar-symbol-instances (grammar-parametrization general-grammar-symbol)
|
||||
(if (generic-nonterminal? general-grammar-symbol)
|
||||
(let ((instances nil))
|
||||
(grammar-parametrization-each-permutation
|
||||
grammar-parametrization
|
||||
#'(lambda (bound-argument-alist)
|
||||
(push (instantiate-general-grammar-symbol bound-argument-alist general-grammar-symbol) instances))
|
||||
(general-grammar-symbol-arguments general-grammar-symbol))
|
||||
(nreverse instances))
|
||||
(list (assert-type general-grammar-symbol grammar-symbol))))
|
||||
|
||||
|
||||
; Return true if grammar-symbol can be obtained by calling instantiate-general-grammar-symbol on
|
||||
; general-grammar-symbol.
|
||||
(defun general-nonterminal-is-instance? (grammar-parametrization general-grammar-symbol grammar-symbol)
|
||||
(or (grammar-symbol-= general-grammar-symbol grammar-symbol)
|
||||
(and (generic-nonterminal? general-grammar-symbol)
|
||||
(attributed-nonterminal? grammar-symbol)
|
||||
(let ((parameters (generic-nonterminal-parameters general-grammar-symbol))
|
||||
(attributes (attributed-nonterminal-attributes grammar-symbol)))
|
||||
(and (= (length parameters) (length attributes))
|
||||
(every #'(lambda (parameter attribute)
|
||||
(or (eq parameter attribute)
|
||||
(and (nonterminal-argument? parameter)
|
||||
(member attribute (grammar-parametrization-lookup-argument grammar-parametrization parameter) :test #'eq))))
|
||||
parameters
|
||||
attributes))))))
|
||||
|
|
@ -1,820 +0,0 @@
|
|||
;;; The contents of this file are subject to the Mozilla Public
|
||||
;;; License Version 1.1 (the "License"); you may not use this file
|
||||
;;; except in compliance with the License. You may obtain a copy of
|
||||
;;; the License at http://www.mozilla.org/MPL/
|
||||
;;;
|
||||
;;; Software distributed under the License is distributed on an "AS
|
||||
;;; IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
|
||||
;;; implied. See the License for the specific language governing
|
||||
;;; rights and limitations under the License.
|
||||
;;;
|
||||
;;; The Original Code is the Language Design and Prototyping Environment.
|
||||
;;;
|
||||
;;; The Initial Developer of the Original Code is Netscape Communications
|
||||
;;; Corporation. Portions created by Netscape Communications Corporation are
|
||||
;;; Copyright (C) 1999 Netscape Communications Corporation. All
|
||||
;;; Rights Reserved.
|
||||
;;;
|
||||
;;; Contributor(s): Waldemar Horwat <waldemar@acm.org>
|
||||
|
||||
;;;
|
||||
;;; LALR(1) and LR(1) grammar generator
|
||||
;;;
|
||||
;;; Waldemar Horwat (waldemar@acm.org)
|
||||
;;;
|
||||
|
||||
|
||||
;;; ------------------------------------------------------------------------------------------------------
|
||||
|
||||
; kernel-item-alist is a list of pairs (item . prev), where item is a kernel item
|
||||
; and prev is either nil or a laitem. kernel is a list of the kernel items in a canonical order.
|
||||
; Return a new state with the given list of kernel items and state number.
|
||||
; If mode is :lalr-1, for each non-null prev in kernel-item-alist, update
|
||||
; (laitem-propagates prev) to include the corresponding laitem in the new state. Do this anyway
|
||||
; for internal lookaheads, regardless of mode.
|
||||
;
|
||||
; If mode is :canonical-lr-1, kernel-item-alist is a list of pairs (item . lookaheads), where
|
||||
; lookaheads is a terminalset of lookaheads for that item. Use these lookaheads instead of
|
||||
; initial-lookaheads.
|
||||
(defun make-state (grammar kernel kernel-item-alist mode number initial-lookaheads)
|
||||
(let ((laitems nil)
|
||||
(laitems-hash (make-hash-table :test #'eq))
|
||||
(laitems-maybe-forbidden nil)) ;Association list of: laitem -> terminalset of potentially forbidden terminals; missing means *empty-terminalset*
|
||||
(labels
|
||||
;Create a laitem for this item and add the association item->laitem to the laitems-hash
|
||||
;hash table if it's not there already. Regardless of whether a new laitem was created,
|
||||
;update the laitem's lookaheads to also include the given lookaheads.
|
||||
;forbidden is a terminalset of terminals that must not occur immediately after the dot in this
|
||||
;laitem. The forbidden set is inherited from constraints in parent laitems in the same state.
|
||||
;maybe-forbidden is an upper bounds on the forbidden lookaheads in this laitem.
|
||||
;If prev is non-null, update (laitem-propagates prev) to include the laitem and the given
|
||||
;passthrough terminalset if it's not already included there.
|
||||
;If a new laitem was created and its first symbol after the dot exists and is a
|
||||
;nonterminal A, recursively close items A->.rhs corresponding to all rhs's in the
|
||||
;grammar's rule for A.
|
||||
((close-item (item forbidden maybe-forbidden lookaheads prev passthroughs)
|
||||
(let ((production (item-production item))
|
||||
(dot (item-dot item))
|
||||
(laitem (gethash item laitems-hash)))
|
||||
(let ((extra-forbidden (terminalset-complement (general-production-constraint production dot))))
|
||||
(terminalset-union-f forbidden extra-forbidden)
|
||||
(terminalset-union-f maybe-forbidden extra-forbidden))
|
||||
(unless (terminalset-empty? forbidden)
|
||||
(multiple-value-bind (dot-lookaheads dot-passthroughs)
|
||||
(string-initial-terminals grammar (item-unseen item) (production-constraints production) (item-dot item) t)
|
||||
(let ((dot-initial (terminalset-union dot-lookaheads dot-passthroughs)))
|
||||
;Check whether any terminal can start this item. If not, skip this item altogether.
|
||||
(when (terminalset-empty? (terminalset-difference dot-initial forbidden))
|
||||
;Mark skipped items in the laitems-hash table.
|
||||
(when (and laitem (not (eq laitem 'forbidden)))
|
||||
(error "Two laitems in the same state differing only in forbidden initial terminal constraints: ~S" laitem))
|
||||
(setf (gethash item laitems-hash) 'forbidden)
|
||||
(return-from close-item))
|
||||
;Convert forbidden into a canonical format by removing terminals that cannot begin this item's expansion anyway.
|
||||
(terminalset-intersection-f forbidden dot-initial))))
|
||||
(if laitem
|
||||
(let ((laitem-maybe-forbidden-entry (assoc laitem laitems-maybe-forbidden))
|
||||
(new-forbidden (terminalset-union forbidden (laitem-forbidden laitem))))
|
||||
(when laitem-maybe-forbidden-entry
|
||||
(terminalset-intersection-f (cdr laitem-maybe-forbidden-entry) maybe-forbidden))
|
||||
(unless (terminalset-<= new-forbidden (or (cdr laitem-maybe-forbidden-entry) *empty-terminalset*))
|
||||
(error "Two laitems in the same state differing only in forbidden initial terminal constraints: ~S ~%old forbidden: ~S ~%new forbidden: ~S~%maybe forbidden: ~S"
|
||||
laitem
|
||||
(terminalset-list grammar (laitem-forbidden laitem))
|
||||
(terminalset-list grammar forbidden)
|
||||
(and laitem-maybe-forbidden-entry (terminalset-list grammar (cdr laitem-maybe-forbidden-entry)))))
|
||||
(setf (laitem-forbidden laitem) new-forbidden)
|
||||
(terminalset-union-f (laitem-lookaheads laitem) lookaheads))
|
||||
(let ((item-next-symbol (item-next-symbol item)))
|
||||
(setq laitem (allocate-laitem grammar item forbidden lookaheads))
|
||||
(push laitem laitems)
|
||||
(setf (gethash item laitems-hash) laitem)
|
||||
(unless (terminalset-empty? maybe-forbidden)
|
||||
(push (cons laitem maybe-forbidden) laitems-maybe-forbidden))
|
||||
(when (nonterminal? item-next-symbol)
|
||||
(multiple-value-bind (next-lookaheads next-passthroughs)
|
||||
(string-initial-terminals grammar (rest (item-unseen item)) (production-constraints production) (1+ dot) nil)
|
||||
(let ((next-prev (and (not (terminalset-empty? next-passthroughs)) laitem)))
|
||||
(dolist (production (rule-productions (grammar-rule grammar item-next-symbol)))
|
||||
(close-item (make-item grammar production 0) forbidden maybe-forbidden next-lookaheads next-prev next-passthroughs)))))))
|
||||
(when prev
|
||||
(laitem-add-propagation prev laitem passthroughs)))))
|
||||
|
||||
(dolist (acons kernel-item-alist)
|
||||
(close-item (car acons)
|
||||
*empty-terminalset*
|
||||
*empty-terminalset*
|
||||
(if (eq mode :canonical-lr-1) (cdr acons) initial-lookaheads)
|
||||
(and (eq mode :lalr-1) (cdr acons))
|
||||
*full-terminalset*))
|
||||
(allocate-state number kernel (nreverse laitems)))))
|
||||
|
||||
|
||||
; f is a function that takes three arguments:
|
||||
; a grammar symbol;
|
||||
; a list of kernel items in order of increasing item number [list of (item . lookahead) when mode is :canonical-lr-1];
|
||||
; a list of pairs (item . prev), where item is a kernel item and prev is a laitem.
|
||||
; For each possible symbol X that can be shifted while in the given state S, call
|
||||
; f giving it S and the list of items that constitute the kernel of that shift's destination
|
||||
; state. The prev's are the sources of the corresponding shifted items.
|
||||
(defun state-each-shift-item-alist (f state mode)
|
||||
(let ((shift-symbols-hash (make-hash-table :test *grammar-symbol-=*)))
|
||||
(dolist (source-laitem (state-laitems state))
|
||||
(let* ((source-item (laitem-item source-laitem))
|
||||
(shift-symbol (item-next-symbol source-item)))
|
||||
(when shift-symbol
|
||||
(push (cons (item-next source-item) source-laitem)
|
||||
(gethash shift-symbol shift-symbols-hash)))))
|
||||
;Use dolist/gethash instead of maphash to make state assignments deterministic.
|
||||
(dolist (shift-symbol (sorted-hash-table-keys shift-symbols-hash))
|
||||
(let* ((kernel-item-alist (gethash shift-symbol shift-symbols-hash))
|
||||
(kernel (if (eq mode :canonical-lr-1)
|
||||
(sort (mapcar #'(lambda (acons)
|
||||
(cons (car acons) (laitem-lookaheads (cdr acons))))
|
||||
kernel-item-alist)
|
||||
#'<
|
||||
:key #'(lambda (acons) (item-number (car acons))))
|
||||
(sort (mapcar #'car kernel-item-alist) #'< :key #'item-number))))
|
||||
(funcall f shift-symbol kernel kernel-item-alist)))))
|
||||
|
||||
|
||||
; f is a function that takes a terminal variant as an argument.
|
||||
; For each variant of the given terminal (which, along with kernel-item-alist, was obtained from
|
||||
; state-each-shift-item-alist's callback), determine whether that variant can actually occur at the
|
||||
; current position or whether it is forbidden by constraints. If it can occur, call f with that variant.
|
||||
; Signal an error if some laitems in kernel-item-alist indicate that a variant can occur while others
|
||||
; indicate that the same variant cannot occur. Also signal an internal error if no variant can occur, as
|
||||
; make-state should have filtered such shift items out.
|
||||
(defun each-shift-symbol-variant (f grammar terminal kernel-item-alist)
|
||||
(let ((n-applicable-variants 0))
|
||||
(dolist (variant (terminal-variants grammar terminal))
|
||||
(let ((allowed nil)
|
||||
(forbidden nil))
|
||||
(dolist (acons kernel-item-alist)
|
||||
(if (terminal-in-terminalset grammar variant (laitem-forbidden (cdr acons)))
|
||||
(setq forbidden t)
|
||||
(setq allowed t)))
|
||||
(when (eq allowed forbidden)
|
||||
(error "Symbol ~S ~A" variant
|
||||
(if allowed "both allowed and forbidden" "neither allowed nor forbidden")))
|
||||
(unless forbidden
|
||||
(incf n-applicable-variants)
|
||||
(funcall f variant))))
|
||||
(when (zerop n-applicable-variants)
|
||||
(error "Internal parser error"))))
|
||||
|
||||
|
||||
;;; ------------------------------------------------------------------------------------------------------
|
||||
;;; CANONICAL LR(1)
|
||||
;;;
|
||||
;;; Canonical LR(1) is accepts the same set of languages as LR(1) except that it produces vastly larger,
|
||||
;;; unoptimizied state tables. The only advantage to using Canonical LR(1) instead of LR(1) is that
|
||||
;;; a Canonical LR(1) parser will not make any reductions from an error state, whereas a LR(1) or LALR(1)
|
||||
;;; parser might make reductions (but not shifts). In other words, a Canonical LR(1) parser's shift and
|
||||
;;; reduce tables are fully accurate rather than conservative approximations based on merged states.
|
||||
|
||||
|
||||
; Make all states in the grammar and return the initial state.
|
||||
; Initialize the grammar's list of states.
|
||||
; Initialize the states' gotos lists.
|
||||
; Initialize the states' shift (but not reduce or accept) transitions in the transitions lists.
|
||||
(defun add-all-canonical-lr-states (grammar)
|
||||
(let* ((initial-item (make-item grammar (grammar-start-production grammar) 0))
|
||||
(lr-states-hash (make-hash-table :test #'equal)) ;canonical kernel -> state
|
||||
(initial-kernel (list (cons initial-item (make-terminalset grammar *end-marker*))))
|
||||
(initial-state (make-state grammar initial-kernel initial-kernel :canonical-lr-1 0 nil))
|
||||
(states (list initial-state))
|
||||
(next-state-number 1))
|
||||
(setf (gethash initial-kernel lr-states-hash) initial-state)
|
||||
(do ((source-states (list initial-state)))
|
||||
((endp source-states))
|
||||
(let ((source-state (pop source-states)))
|
||||
;Propagate the source state's internal lookaheads and then erase the propagates chains.
|
||||
(propagate-internal-lookaheads source-state)
|
||||
(dolist (laitem (state-laitems source-state))
|
||||
(setf (laitem-propagates laitem) nil))
|
||||
|
||||
(state-each-shift-item-alist
|
||||
#'(lambda (shift-symbol kernel kernel-item-alist)
|
||||
(let ((destination-state (gethash kernel lr-states-hash)))
|
||||
(unless destination-state
|
||||
(setq destination-state (make-state grammar kernel kernel :canonical-lr-1 next-state-number nil))
|
||||
(setf (gethash kernel lr-states-hash) destination-state)
|
||||
(incf next-state-number)
|
||||
(push destination-state states)
|
||||
(push destination-state source-states))
|
||||
(if (nonterminal? shift-symbol)
|
||||
(push (cons shift-symbol destination-state)
|
||||
(state-gotos source-state))
|
||||
(each-shift-symbol-variant
|
||||
#'(lambda (shift-symbol-variant)
|
||||
(push (cons shift-symbol-variant (make-shift-transition destination-state))
|
||||
(state-transitions source-state)))
|
||||
grammar shift-symbol kernel-item-alist))))
|
||||
source-state :canonical-lr-1)))
|
||||
(setf (grammar-states grammar) (nreverse states))
|
||||
initial-state))
|
||||
|
||||
|
||||
;;; ------------------------------------------------------------------------------------------------------
|
||||
;;; LR(1)
|
||||
|
||||
|
||||
; kernel-item-alist should have the same kernel items as state.
|
||||
; Return true if the prev lookaheads in kernel-item-alist are the same as or subsets of
|
||||
; the corresponding lookaheads in the state's kernel laitems.
|
||||
(defun state-subsumes-lookaheads (state kernel-item-alist)
|
||||
(every
|
||||
#'(lambda (acons)
|
||||
(terminalset-<= (laitem-lookaheads (cdr acons))
|
||||
(laitem-lookaheads (state-laitem state (car acons)))))
|
||||
kernel-item-alist))
|
||||
|
||||
|
||||
; kernel-item-alist should have the same kernel items as state.
|
||||
; Return true if the prev lookaheads in kernel-item-alist are weakly compatible
|
||||
; with the lookaheads in the state's kernel laitems.
|
||||
(defun state-weakly-compatible (state kernel-item-alist)
|
||||
(labels
|
||||
((lookahead-weakly-compatible (lookahead1a lookahead1b lookahead2a lookahead2b)
|
||||
(or (and (terminalsets-disjoint lookahead1a lookahead2b)
|
||||
(terminalsets-disjoint lookahead1b lookahead2a))
|
||||
(not (terminalsets-disjoint lookahead1a lookahead1b))
|
||||
(not (terminalsets-disjoint lookahead2a lookahead2b))))
|
||||
|
||||
(lookahead-list-weakly-compatible (lookahead1a lookaheads1 lookahead2a lookaheads2)
|
||||
(or (endp lookaheads1)
|
||||
(and (lookahead-weakly-compatible lookahead1a (first lookaheads1) lookahead2a (first lookaheads2))
|
||||
(lookahead-list-weakly-compatible lookahead1a (rest lookaheads1) lookahead2a (rest lookaheads2)))))
|
||||
|
||||
(lookahead-lists-weakly-compatible (lookaheads1 lookaheads2)
|
||||
(or (endp lookaheads1)
|
||||
(and (lookahead-list-weakly-compatible (first lookaheads1) (rest lookaheads1) (first lookaheads2) (rest lookaheads2))
|
||||
(lookahead-lists-weakly-compatible (rest lookaheads1) (rest lookaheads2))))))
|
||||
|
||||
(or (= (length kernel-item-alist) 1)
|
||||
(lookahead-lists-weakly-compatible
|
||||
(mapcar #'(lambda (acons) (laitem-lookaheads (state-laitem state (car acons)))) kernel-item-alist)
|
||||
(mapcar #'(lambda (acons) (laitem-lookaheads (cdr acons))) kernel-item-alist)))))
|
||||
|
||||
|
||||
; Propagate all lookaheads in the state.
|
||||
(defun propagate-internal-lookaheads (state)
|
||||
(do ((changed t))
|
||||
((not changed))
|
||||
(setq changed nil)
|
||||
(dolist (src-laitem (state-laitems state))
|
||||
(let ((src-lookaheads (laitem-lookaheads src-laitem)))
|
||||
(dolist (propagation (laitem-propagates src-laitem))
|
||||
(let* ((dst-laitem (car propagation))
|
||||
(mask (cdr propagation))
|
||||
(old-dst-lookaheads (laitem-lookaheads dst-laitem))
|
||||
(new-dst-lookaheads (terminalset-union old-dst-lookaheads (terminalset-intersection src-lookaheads mask))))
|
||||
(setf (laitem-lookaheads dst-laitem) new-dst-lookaheads)
|
||||
(unless (terminalset-= old-dst-lookaheads new-dst-lookaheads)
|
||||
(setq changed t))))))))
|
||||
|
||||
|
||||
; Propagate all lookaheads in kernel-item-alist, which must target destination-state.
|
||||
; Mark destination-state as dirty in the dirty-states hash table.
|
||||
(defun propagate-external-lookaheads (kernel-item-alist destination-state dirty-states)
|
||||
(dolist (acons kernel-item-alist)
|
||||
(let ((dest-laitem (state-laitem destination-state (car acons)))
|
||||
(src-laitem (cdr acons)))
|
||||
(terminalset-union-f (laitem-lookaheads dest-laitem) (laitem-lookaheads src-laitem))))
|
||||
(setf (gethash destination-state dirty-states) t))
|
||||
|
||||
|
||||
; Make all states in the grammar and return the initial state.
|
||||
; Initialize the grammar's list of states.
|
||||
; Initialize the states' gotos lists.
|
||||
; Initialize the states' shift (but not reduce or accept) transitions in the transitions lists.
|
||||
(defun add-all-lr-states (grammar)
|
||||
(let* ((initial-item (make-item grammar (grammar-start-production grammar) 0))
|
||||
(lr-states-hash (make-hash-table :test #'equal)) ;kernel -> list of states with that kernel
|
||||
(initial-kernel (list initial-item))
|
||||
(initial-state (make-state grammar initial-kernel (list (cons initial-item nil)) :lr-1 0 (make-terminalset grammar *end-marker*)))
|
||||
(states (list initial-state))
|
||||
(next-state-number 1))
|
||||
(setf (gethash initial-kernel lr-states-hash) (list initial-state))
|
||||
(do ((source-states (list initial-state))
|
||||
(dirty-states (make-hash-table :test #'eq))) ;Set of states whose kernel lookaheads changed and haven't been propagated yet
|
||||
((and (endp source-states) (zerop (hash-table-count dirty-states))))
|
||||
(labels
|
||||
((make-destination-state (kernel kernel-item-alist)
|
||||
(let* ((possible-destination-states (gethash kernel lr-states-hash))
|
||||
(destination-state (find-if #'(lambda (possible-destination-state)
|
||||
(state-subsumes-lookaheads possible-destination-state kernel-item-alist))
|
||||
possible-destination-states)))
|
||||
(cond
|
||||
(destination-state)
|
||||
((setq destination-state (find-if #'(lambda (possible-destination-state)
|
||||
(state-weakly-compatible possible-destination-state kernel-item-alist))
|
||||
possible-destination-states))
|
||||
(propagate-external-lookaheads kernel-item-alist destination-state dirty-states))
|
||||
(t
|
||||
(setq destination-state (make-state grammar kernel kernel-item-alist :lr-1 next-state-number *empty-terminalset*))
|
||||
(propagate-external-lookaheads kernel-item-alist destination-state dirty-states)
|
||||
(push destination-state (gethash kernel lr-states-hash))
|
||||
(incf next-state-number)
|
||||
(push destination-state states)
|
||||
(push destination-state source-states)))
|
||||
destination-state))
|
||||
|
||||
(update-destination-state (destination-state kernel-item-alist)
|
||||
(cond
|
||||
((state-subsumes-lookaheads destination-state kernel-item-alist)
|
||||
destination-state)
|
||||
((state-weakly-compatible destination-state kernel-item-alist)
|
||||
(propagate-external-lookaheads kernel-item-alist destination-state dirty-states)
|
||||
destination-state)
|
||||
(t (make-destination-state (state-kernel destination-state) kernel-item-alist)))))
|
||||
|
||||
(if source-states
|
||||
(let ((source-state (pop source-states)))
|
||||
(remhash source-state dirty-states)
|
||||
(propagate-internal-lookaheads source-state)
|
||||
(state-each-shift-item-alist
|
||||
#'(lambda (shift-symbol kernel kernel-item-alist)
|
||||
(let ((destination-state (make-destination-state kernel kernel-item-alist)))
|
||||
(if (nonterminal? shift-symbol)
|
||||
(push (cons shift-symbol destination-state)
|
||||
(state-gotos source-state))
|
||||
(each-shift-symbol-variant
|
||||
#'(lambda (shift-symbol-variant)
|
||||
(push (cons shift-symbol-variant (make-shift-transition destination-state))
|
||||
(state-transitions source-state)))
|
||||
grammar shift-symbol kernel-item-alist))))
|
||||
source-state :lr-1))
|
||||
(dolist (dirty-state (sort (hash-table-keys dirty-states) #'< :key #'state-number))
|
||||
(when (remhash dirty-state dirty-states)
|
||||
(propagate-internal-lookaheads dirty-state)
|
||||
(state-each-shift-item-alist
|
||||
#'(lambda (shift-symbol kernel kernel-item-alist)
|
||||
(declare (ignore kernel))
|
||||
(if (nonterminal? shift-symbol)
|
||||
(let* ((destination-binding (assoc shift-symbol (state-gotos dirty-state) :test *grammar-symbol-=*))
|
||||
(destination-state (assert-non-null (cdr destination-binding))))
|
||||
(setf (cdr destination-binding) (update-destination-state destination-state kernel-item-alist)))
|
||||
(each-shift-symbol-variant
|
||||
#'(lambda (shift-symbol-variant)
|
||||
(let* ((destination-transition (state-transition dirty-state shift-symbol-variant))
|
||||
(destination-state (assert-non-null (transition-state destination-transition))))
|
||||
(setf (transition-state destination-transition)
|
||||
(update-destination-state destination-state kernel-item-alist))))
|
||||
grammar shift-symbol kernel-item-alist)))
|
||||
dirty-state :lr-1))))))
|
||||
(setf (grammar-states grammar) (nreverse states))
|
||||
initial-state))
|
||||
|
||||
|
||||
;;; ------------------------------------------------------------------------------------------------------
|
||||
;;; LALR(1)
|
||||
|
||||
|
||||
; Make all states in the grammar and return the initial state.
|
||||
; Initialize the grammar's list of states.
|
||||
; Set up the laitems' propagate lists but do not propagate lookaheads yet.
|
||||
; Initialize the states' gotos lists.
|
||||
; Initialize the states' shift (but not reduce or accept) transitions in the transitions lists.
|
||||
(defun add-all-lalr-states (grammar)
|
||||
(let* ((initial-item (make-item grammar (grammar-start-production grammar) 0))
|
||||
(lalr-states-hash (make-hash-table :test #'equal)) ;kernel -> state
|
||||
(initial-kernel (list initial-item))
|
||||
(initial-state (make-state grammar initial-kernel (list (cons initial-item nil)) :lalr-1 0 (make-terminalset grammar *end-marker*)))
|
||||
(states (list initial-state))
|
||||
(next-state-number 1))
|
||||
(setf (gethash initial-kernel lalr-states-hash) initial-state)
|
||||
(do ((source-states (list initial-state)))
|
||||
((endp source-states))
|
||||
(let ((source-state (pop source-states)))
|
||||
(state-each-shift-item-alist
|
||||
#'(lambda (shift-symbol kernel kernel-item-alist)
|
||||
(let ((destination-state (gethash kernel lalr-states-hash)))
|
||||
(if destination-state
|
||||
(dolist (acons kernel-item-alist)
|
||||
(laitem-add-propagation (cdr acons) (state-laitem destination-state (car acons)) *full-terminalset*))
|
||||
(progn
|
||||
(setq destination-state (make-state grammar kernel kernel-item-alist :lalr-1 next-state-number *empty-terminalset*))
|
||||
(setf (gethash kernel lalr-states-hash) destination-state)
|
||||
(incf next-state-number)
|
||||
(push destination-state states)
|
||||
(push destination-state source-states)))
|
||||
(if (nonterminal? shift-symbol)
|
||||
(push (cons shift-symbol destination-state)
|
||||
(state-gotos source-state))
|
||||
(each-shift-symbol-variant
|
||||
#'(lambda (shift-symbol-variant)
|
||||
(push (cons shift-symbol-variant (make-shift-transition destination-state))
|
||||
(state-transitions source-state)))
|
||||
grammar shift-symbol kernel-item-alist))))
|
||||
source-state :lalr-1)))
|
||||
(setf (grammar-states grammar) (nreverse states))
|
||||
initial-state))
|
||||
|
||||
|
||||
; Propagate the lookaheads in the LALR(1) grammar.
|
||||
(defun propagate-lalr-lookaheads (grammar)
|
||||
(let ((dirty-laitems (make-hash-table :test #'eq)))
|
||||
(dolist (state (grammar-states grammar))
|
||||
(dolist (laitem (state-laitems state))
|
||||
(when (and (laitem-propagates laitem) (not (terminalset-empty? (laitem-lookaheads laitem))))
|
||||
(setf (gethash laitem dirty-laitems) t))))
|
||||
(do ()
|
||||
((zerop (hash-table-count dirty-laitems)))
|
||||
(dolist (dirty-laitem (hash-table-keys dirty-laitems))
|
||||
(remhash dirty-laitem dirty-laitems)
|
||||
(let ((src-lookaheads (laitem-lookaheads dirty-laitem)))
|
||||
(dolist (propagation (laitem-propagates dirty-laitem))
|
||||
(let ((dst-laitem (car propagation))
|
||||
(mask (cdr propagation)))
|
||||
(let* ((old-dst-lookaheads (laitem-lookaheads dst-laitem))
|
||||
(new-dst-lookaheads (terminalset-union old-dst-lookaheads (terminalset-intersection src-lookaheads mask))))
|
||||
(unless (terminalset-= old-dst-lookaheads new-dst-lookaheads)
|
||||
(setf (laitem-lookaheads dst-laitem) new-dst-lookaheads)
|
||||
(setf (gethash dst-laitem dirty-laitems) t))))))))
|
||||
|
||||
;Erase the propagates chains in all laitems.
|
||||
(dolist (state (grammar-states grammar))
|
||||
(dolist (laitem (state-laitems state))
|
||||
(setf (laitem-propagates laitem) nil)))))
|
||||
|
||||
|
||||
;;; ------------------------------------------------------------------------------------------------------
|
||||
|
||||
|
||||
; Calculate the reduce and accept transitions in the grammar.
|
||||
; Also sort all transitions by their terminal numbers and gotos by their nonterminal numbers.
|
||||
; Conflicting transitions are sorted as follows:
|
||||
; shifts come before reduces and accepts
|
||||
; accepts come before reduces
|
||||
; reduces with lower production numbers come before reduces with higher production numbers
|
||||
; Disambiguation will choose the first member of a sorted list of conflicting transitions.
|
||||
(defun finish-transitions (grammar)
|
||||
(dolist (state (grammar-states grammar))
|
||||
(dolist (laitem (state-laitems state))
|
||||
(let ((item (laitem-item laitem)))
|
||||
(unless (item-next-symbol item)
|
||||
(let ((lookaheads (terminalset-difference
|
||||
(terminalset-intersection
|
||||
(laitem-lookaheads laitem)
|
||||
(general-production-constraint (item-production item) (item-dot item)))
|
||||
(laitem-forbidden laitem))))
|
||||
(if (grammar-symbol-= (item-lhs item) *start-nonterminal*)
|
||||
(when (terminal-in-terminalset grammar *end-marker* lookaheads)
|
||||
(push (cons *end-marker* (make-accept-transition))
|
||||
(state-transitions state)))
|
||||
(map-terminalset-reverse
|
||||
#'(lambda (lookahead)
|
||||
(push (cons lookahead (make-reduce-transition (item-production item)))
|
||||
(state-transitions state)))
|
||||
grammar
|
||||
lookaheads))))))
|
||||
(setf (state-gotos state)
|
||||
(sort (state-gotos state) #'< :key #'(lambda (goto-cons) (state-number (cdr goto-cons)))))
|
||||
(setf (state-transitions state)
|
||||
(sort (state-transitions state)
|
||||
#'(lambda (transition-cons-1 transition-cons-2)
|
||||
(let ((terminal-number-1 (terminal-number grammar (car transition-cons-1)))
|
||||
(terminal-number-2 (terminal-number grammar (car transition-cons-2))))
|
||||
(cond
|
||||
((< terminal-number-1 terminal-number-2) t)
|
||||
((> terminal-number-1 terminal-number-2) nil)
|
||||
(t (let* ((transition1 (cdr transition-cons-1))
|
||||
(transition2 (cdr transition-cons-2))
|
||||
(transition-kind-1 (transition-kind transition1))
|
||||
(transition-kind-2 (transition-kind transition2)))
|
||||
(cond
|
||||
((eq transition-kind-2 :shift) nil)
|
||||
((eq transition-kind-1 :shift) t)
|
||||
((eq transition-kind-2 :accept) nil)
|
||||
((eq transition-kind-1 :accept) t)
|
||||
(t (let ((production-number-1 (production-number (transition-production transition1)))
|
||||
(production-number-2 (production-number (transition-production transition2))))
|
||||
(< production-number-1 production-number-2)))))))))))))
|
||||
|
||||
|
||||
; Find ambiguities, if any, in the grammar. Report them on the given stream.
|
||||
; Fix all ambiguities in favor of the first transition listed
|
||||
; (the transitions were ordered by finish-transitions).
|
||||
(defun report-and-fix-ambiguities (grammar stream)
|
||||
(let ((found-ambiguities nil))
|
||||
(dolist (state (grammar-states grammar))
|
||||
(labels
|
||||
|
||||
((report-ambiguity (transition-cons other-transition-conses)
|
||||
(unless found-ambiguities
|
||||
(setq found-ambiguities t)
|
||||
(format stream "~&Ambiguities:"))
|
||||
(write-char #\newline stream)
|
||||
(pprint-logical-block (stream nil)
|
||||
(format stream "S~D: ~W => " (state-number state) (car transition-cons))
|
||||
(pprint-logical-block (stream nil)
|
||||
(dolist (a (cons transition-cons other-transition-conses))
|
||||
(print-transition (cdr a) stream)
|
||||
(format stream " ~:_")))))
|
||||
|
||||
; Check the list of transition-conses and report ambiguities.
|
||||
; start is the start of a possibly larger list of transition-conses whose tail
|
||||
; is the given list. If ambiguities exist, return a copy of start up to the
|
||||
; position of list in it followed by list with ambiguities removed. If not,
|
||||
; return start unchanged.
|
||||
(check (transition-conses start)
|
||||
(if transition-conses
|
||||
(let* ((transition-cons (first transition-conses))
|
||||
(transition-terminal (car transition-cons))
|
||||
(transition-conses-rest (rest transition-conses)))
|
||||
(if transition-conses-rest
|
||||
(if (grammar-symbol-= transition-terminal (car (first transition-conses-rest)))
|
||||
(let ((unrelated-transitions
|
||||
(member-if #'(lambda (a) (not (grammar-symbol-= transition-terminal (car a))))
|
||||
transition-conses-rest)))
|
||||
(report-ambiguity transition-cons (ldiff transition-conses-rest unrelated-transitions))
|
||||
(check unrelated-transitions (append (ldiff start transition-conses-rest) unrelated-transitions)))
|
||||
(check transition-conses-rest start))
|
||||
start))
|
||||
start)))
|
||||
|
||||
(let ((transition-conses (state-transitions state)))
|
||||
(setf (state-transitions state) (check transition-conses transition-conses)))))
|
||||
(when found-ambiguities
|
||||
(write-char #\newline stream))))
|
||||
|
||||
|
||||
; Remove the temporary item and laitem lists from the grammar's states. This reduces the grammar's lisp
|
||||
; heap usage but prevents it from being printed.
|
||||
(defun clean-grammar (grammar)
|
||||
(when (grammar-items-hash grammar)
|
||||
(setf (grammar-items-hash grammar) nil)
|
||||
(dolist (state (grammar-states grammar))
|
||||
(setf (state-kernel state) nil)
|
||||
(setf (state-laitems state) nil))))
|
||||
|
||||
|
||||
; Erase the existing parser, if any, for the given grammar.
|
||||
(defun clear-parser (grammar)
|
||||
(setf (grammar-items-hash grammar) nil)
|
||||
(setf (grammar-states grammar) nil))
|
||||
|
||||
|
||||
; Construct a LR or LALR parser in the given grammar. kind should be :lalr-1, :lr-1, or :canonical-lr-1.
|
||||
; Return the grammar.
|
||||
(defun compile-parser (grammar kind)
|
||||
(clear-parser grammar)
|
||||
(setf (grammar-items-hash grammar) (make-hash-table :test #'equal))
|
||||
(ecase kind
|
||||
(:lalr-1
|
||||
(add-all-lalr-states grammar)
|
||||
(propagate-lalr-lookaheads grammar))
|
||||
(:lr-1
|
||||
(add-all-lr-states grammar))
|
||||
(:canonical-lr-1
|
||||
(add-all-canonical-lr-states grammar)))
|
||||
(finish-transitions grammar)
|
||||
(report-and-fix-ambiguities grammar *error-output*)
|
||||
grammar)
|
||||
|
||||
|
||||
; Make the grammar and compile its parser. kind should be :lalr-1, :lr-1, or :canonical-lr-1.
|
||||
(defun make-and-compile-grammar (kind parametrization start-symbol grammar-source &rest grammar-options)
|
||||
(compile-parser (apply #'make-grammar parametrization start-symbol grammar-source grammar-options)
|
||||
kind))
|
||||
|
||||
|
||||
; Collapse states that have at most one possible reduction into forwarding states.
|
||||
; DON'T DO THIS ON GRAMMARS THAT HAVE CONSTRAINTS AT THE TAIL END OF A PRODUCTION.
|
||||
; Return the number of states optimized.
|
||||
(defun forward-parser-states (grammar)
|
||||
(let ((n-forwarded-states 0))
|
||||
(dolist (state (grammar-states grammar))
|
||||
(let ((production (forwarding-state-production state)))
|
||||
(when production
|
||||
(setf (state-transitions state) (list (cons nil (make-reduce-transition production))))
|
||||
(incf n-forwarded-states))))
|
||||
n-forwarded-states))
|
||||
|
||||
|
||||
;;; ------------------------------------------------------------------------------------------------------
|
||||
|
||||
; Parse the input list of tokens to produce a parse tree.
|
||||
; token-terminal is a function that returns a terminal symbol when given an input token.
|
||||
(defun parse (grammar token-terminal input)
|
||||
(labels
|
||||
(;Continue the parse with the given parser stack and remainder of input.
|
||||
(parse-step (stack input)
|
||||
(if (endp input)
|
||||
(parse-step-1 stack *end-marker* nil nil)
|
||||
(let ((token (first input)))
|
||||
(parse-step-1 stack (funcall token-terminal token) token (rest input)))))
|
||||
|
||||
;Same as parse-step except that the next input terminal has been determined already.
|
||||
;input-rest contains the input tokens after the next token.
|
||||
(parse-step-1 (stack terminal token input-rest)
|
||||
(let* ((state (caar stack))
|
||||
(transition (state-transition state terminal)))
|
||||
(if transition
|
||||
(case (transition-kind transition)
|
||||
(:shift (parse-step (acons (transition-state transition) token stack) input-rest))
|
||||
(:reduce (let ((production (transition-production transition))
|
||||
(expansion nil))
|
||||
(dotimes (i (production-rhs-length production))
|
||||
(push (cdr (pop stack)) expansion))
|
||||
(let* ((state (caar stack))
|
||||
(dst-state (assert-non-null
|
||||
(cdr (assoc (production-lhs production) (state-gotos state) :test *grammar-symbol-=*))))
|
||||
(named-expansion (cons (production-name production) expansion)))
|
||||
(parse-step-1 (acons dst-state named-expansion stack) terminal token input-rest))))
|
||||
(:accept (cdar stack))
|
||||
(t (error "Bad transition: ~S" transition)))
|
||||
(error "Parse error on ~S followed by ~S ..." token (ldiff input-rest (nthcdr 10 input-rest)))))))
|
||||
|
||||
(parse-step (list (cons (grammar-start-state grammar) nil)) input)))
|
||||
|
||||
|
||||
;;; ------------------------------------------------------------------------------------------------------
|
||||
;;; ACTIONS
|
||||
|
||||
; Initialize the action-signatures hash table, setting each grammar symbol's signature
|
||||
; to null for now. Also clear all production actions in the grammar.
|
||||
(defun clear-actions (grammar)
|
||||
(let ((action-signatures (make-hash-table :test *grammar-symbol-=*))
|
||||
(terminals (grammar-terminals grammar))
|
||||
(nonterminals (grammar-nonterminals grammar)))
|
||||
(dotimes (i (length terminals))
|
||||
(setf (gethash (svref terminals i) action-signatures) nil))
|
||||
(dotimes (i (length nonterminals))
|
||||
(setf (gethash (svref nonterminals i) action-signatures) nil))
|
||||
(setf (grammar-action-signatures grammar) action-signatures)
|
||||
(each-grammar-production
|
||||
grammar
|
||||
#'(lambda (production)
|
||||
(setf (production-actions production) nil)
|
||||
(setf (production-n-action-args production) nil)
|
||||
(setf (production-evaluator-code production) nil)
|
||||
(setf (production-evaluator production) nil)))
|
||||
(clrhash (grammar-terminal-actions grammar))))
|
||||
|
||||
|
||||
; Declare the type of action action-symbol, when called on general-grammar-symbol, to be type-expr.
|
||||
; Signal an error on duplicate actions.
|
||||
; It's OK if some of the symbol instances don't exist, as long as at least one does.
|
||||
(defun declare-action (grammar general-grammar-symbol action-symbol type-expr)
|
||||
(unless (and action-symbol (symbolp action-symbol))
|
||||
(error "Bad action name ~S" action-symbol))
|
||||
(let ((action-signatures (grammar-action-signatures grammar))
|
||||
(grammar-symbols (general-grammar-symbol-instances grammar general-grammar-symbol))
|
||||
(symbol-exists nil))
|
||||
(dolist (grammar-symbol grammar-symbols)
|
||||
(let ((signature (gethash grammar-symbol action-signatures :undefined)))
|
||||
(unless (eq signature :undefined)
|
||||
(setq symbol-exists t)
|
||||
(when (assoc action-symbol signature :test #'eq)
|
||||
(error "Attempt to redefine the type of action ~S on ~S" action-symbol grammar-symbol))
|
||||
(setf (gethash grammar-symbol action-signatures)
|
||||
(nconc signature (list (cons action-symbol type-expr))))
|
||||
(if (nonterminal? grammar-symbol)
|
||||
(dolist (production (rule-productions (grammar-rule grammar grammar-symbol)))
|
||||
(setf (production-actions production)
|
||||
(nconc (production-actions production) (list (cons action-symbol nil)))))
|
||||
(let ((terminal-actions (grammar-terminal-actions grammar)))
|
||||
(assert-type grammar-symbol terminal)
|
||||
(setf (gethash grammar-symbol terminal-actions)
|
||||
(nconc (gethash grammar-symbol terminal-actions) (list (cons action-symbol nil)))))))))
|
||||
(unless symbol-exists
|
||||
(error "Bad action grammar symbol ~S" grammar-symbols))))
|
||||
|
||||
|
||||
; Return the list of pairs (action-symbol . type-or-type-expr) for this grammar-symbol.
|
||||
; The pairs are in order from oldest to newest action-symbols added to this grammar-symbol.
|
||||
(declaim (inline grammar-symbol-signature))
|
||||
(defun grammar-symbol-signature (grammar grammar-symbol)
|
||||
(gethash grammar-symbol (grammar-action-signatures grammar)))
|
||||
|
||||
|
||||
; Return the list of action types of the grammar's user start-symbol.
|
||||
(defun grammar-user-start-action-types (grammar)
|
||||
(mapcar #'cdr (grammar-symbol-signature grammar (gramar-user-start-symbol grammar))))
|
||||
|
||||
|
||||
; If action action-symbol is declared on grammar-symbol, return two values:
|
||||
; t, and
|
||||
; the action's type-expr;
|
||||
; If not, return nil.
|
||||
(defun action-declaration (grammar grammar-symbol action-symbol)
|
||||
(let ((declaration (assoc action-symbol (grammar-symbol-signature grammar grammar-symbol) :test #'eq)))
|
||||
(and declaration
|
||||
(values t (cdr declaration)))))
|
||||
|
||||
|
||||
; Call f on every action declaration, passing it two arguments:
|
||||
; the grammar-symbol;
|
||||
; a pair (action-symbol . type-expr).
|
||||
; f may modify the action's type-expr.
|
||||
(defun each-action-declaration (grammar f)
|
||||
(maphash #'(lambda (grammar-symbol signature)
|
||||
(dolist (action-declaration signature)
|
||||
(funcall f grammar-symbol action-declaration)))
|
||||
(grammar-action-signatures grammar)))
|
||||
|
||||
|
||||
; Define action action-symbol, when called on the production with the given name,
|
||||
; to be action-expr. The action should have been declared already.
|
||||
(defun define-action (grammar production-name action-symbol action-expr)
|
||||
(dolist (production (general-production-productions (grammar-general-production grammar production-name)))
|
||||
(let ((definition (assoc action-symbol (production-actions production) :test #'eq)))
|
||||
(cond
|
||||
((null definition)
|
||||
(error "Attempt to define action ~S on ~S, which hasn't been declared yet" action-symbol production-name))
|
||||
((cdr definition)
|
||||
(error "Duplicate definition of action ~S on ~S" action-symbol production-name))
|
||||
(t (setf (cdr definition) (make-action action-expr)))))))
|
||||
|
||||
|
||||
; Define action action-symbol, when called on the given terminal,
|
||||
; to execute the given function, which should take a token as an input and
|
||||
; produce a value of the proper type as output.
|
||||
; The action should have been declared already.
|
||||
(defun define-terminal-action (grammar terminal action-symbol action-function)
|
||||
(assert-type action-function function)
|
||||
(let ((definition (assoc action-symbol (gethash terminal (grammar-terminal-actions grammar)) :test #'eq)))
|
||||
(cond
|
||||
((null definition)
|
||||
(error "Attempt to define action ~S on ~S, which hasn't been declared yet" action-symbol terminal))
|
||||
((cdr definition)
|
||||
(error "Duplicate definition of action ~S on ~S" action-symbol terminal))
|
||||
(t (setf (cdr definition) action-function)))))
|
||||
|
||||
|
||||
|
||||
; Parse the input list of tokens to produce a list of action results.
|
||||
; token-terminal is a function that returns a terminal symbol when given an input token.
|
||||
; If trace is:
|
||||
; nil, don't print trace information
|
||||
; :code, print trace information, including action code
|
||||
; other print trace information
|
||||
; Return two values:
|
||||
; the list of action results;
|
||||
; the list of action results' types.
|
||||
(defun action-parse (grammar token-terminal input &key trace)
|
||||
(labels
|
||||
(;Continue the parse with the given stacks and remainder of input.
|
||||
;When trace is non-null, type-stack contains the types of corresponding value-stack entries.
|
||||
(parse-step (state-stack value-stack type-stack input)
|
||||
(if (endp input)
|
||||
(parse-step-1 state-stack value-stack type-stack *end-marker* nil nil)
|
||||
(let ((token (first input)))
|
||||
(parse-step-1 state-stack value-stack type-stack (funcall token-terminal token) token (rest input)))))
|
||||
|
||||
;Same as parse-step except that the next input terminal has been determined already.
|
||||
;input-rest contains the input tokens after the next token.
|
||||
(parse-step-1 (state-stack value-stack type-stack terminal token input-rest)
|
||||
(let* ((state (car state-stack))
|
||||
(transition (state-transition state terminal)))
|
||||
(when trace
|
||||
(format *trace-output* "S~D: ~@_" (state-number state))
|
||||
(print-values (reverse value-stack) (reverse type-stack) *trace-output*)
|
||||
(pprint-newline :mandatory *trace-output*))
|
||||
(if transition
|
||||
(case (transition-kind transition)
|
||||
(:shift
|
||||
(when trace
|
||||
(format *trace-output* " shift ~W~:@_" terminal)
|
||||
(dolist (action-signature (grammar-symbol-signature grammar terminal))
|
||||
(push (cdr action-signature) type-stack)))
|
||||
(dolist (action-function-binding (gethash terminal (grammar-terminal-actions grammar)))
|
||||
(push (funcall (cdr action-function-binding) token) value-stack))
|
||||
(parse-step (cons (transition-state transition) state-stack) value-stack type-stack input-rest))
|
||||
|
||||
(:reduce
|
||||
(let ((production (transition-production transition)))
|
||||
(when trace
|
||||
(write-string " reduce " *trace-output*)
|
||||
(if (eq trace :code)
|
||||
(write production :stream *trace-output* :pretty t)
|
||||
(print-production production *trace-output*))
|
||||
(pprint-newline :mandatory *trace-output*))
|
||||
(let* ((state-stack (nthcdr (production-rhs-length production) state-stack))
|
||||
(state (car state-stack))
|
||||
(dst-state (assert-non-null
|
||||
(cdr (assoc (production-lhs production) (state-gotos state) :test *grammar-symbol-=*))))
|
||||
(value-stack (funcall (production-evaluator production) value-stack)))
|
||||
(when trace
|
||||
(setq type-stack (nthcdr (production-n-action-args production) type-stack))
|
||||
(dolist (action-signature (grammar-symbol-signature grammar (production-lhs production)))
|
||||
(push (cdr action-signature) type-stack)))
|
||||
(parse-step-1 (cons dst-state state-stack) value-stack type-stack terminal token input-rest))))
|
||||
|
||||
(:accept
|
||||
(when trace
|
||||
(format *trace-output* " accept~:@_"))
|
||||
(values
|
||||
(nreverse value-stack)
|
||||
(if trace
|
||||
(nreverse type-stack)
|
||||
(grammar-user-start-action-types grammar))))
|
||||
|
||||
(t (error "Bad transition: ~S" transition)))
|
||||
(error "Parse error on ~S followed by ~S ..." token (ldiff input-rest (nthcdr 10 input-rest)))))))
|
||||
|
||||
(parse-step (list (grammar-start-state grammar)) nil nil input)))
|
||||
|
||||
|
|
@ -413,6 +413,13 @@
|
|||
(allocate-grammar-parametrization (make-hash-table :test #'eq)))
|
||||
|
||||
|
||||
; Return true if the two grammar-parametrizations are the same.
|
||||
(defun grammar-parametrization-= (grammar-parametrization1 grammar-parametrization2)
|
||||
(hash-table-= (grammar-parametrization-argument-attributes grammar-parametrization1)
|
||||
(grammar-parametrization-argument-attributes grammar-parametrization2)
|
||||
:test #'equal))
|
||||
|
||||
|
||||
; Declare that nonterminal arguments with the given name can hold any of the
|
||||
; given nonterminal attributes given. At least one attribute must be provided.
|
||||
(defun grammar-parametrization-declare-argument (grammar-parametrization argument attributes)
|
||||
|
|
|
|||
|
|
@ -497,6 +497,7 @@
|
|||
; Find ambiguities, if any, in the grammar. Report them on the given stream.
|
||||
; Fix all ambiguities in favor of the first transition listed
|
||||
; (the transitions were ordered by finish-transitions).
|
||||
; Return true if ambiguities were found.
|
||||
(defun report-and-fix-ambiguities (grammar stream)
|
||||
(let ((found-ambiguities nil))
|
||||
(dolist (state (grammar-states grammar))
|
||||
|
|
@ -538,7 +539,8 @@
|
|||
(let ((transition-conses (state-transitions state)))
|
||||
(setf (state-transitions state) (check transition-conses transition-conses)))))
|
||||
(when found-ambiguities
|
||||
(write-char #\newline stream))))
|
||||
(write-char #\newline stream))
|
||||
found-ambiguities))
|
||||
|
||||
|
||||
; Remove the temporary item and laitem lists from the grammar's states. This reduces the grammar's lisp
|
||||
|
|
@ -558,7 +560,7 @@
|
|||
|
||||
|
||||
; Construct a LR or LALR parser in the given grammar. kind should be :lalr-1, :lr-1, or :canonical-lr-1.
|
||||
; Return the grammar.
|
||||
; Return true if ambiguities were found.
|
||||
(defun compile-parser (grammar kind)
|
||||
(clear-parser grammar)
|
||||
(setf (grammar-items-hash grammar) (make-hash-table :test #'equal))
|
||||
|
|
@ -571,14 +573,29 @@
|
|||
(:canonical-lr-1
|
||||
(add-all-canonical-lr-states grammar)))
|
||||
(finish-transitions grammar)
|
||||
(report-and-fix-ambiguities grammar *error-output*)
|
||||
grammar)
|
||||
(report-and-fix-ambiguities grammar *error-output*))
|
||||
|
||||
|
||||
|
||||
; (cons (list <kind> <start-symbol> <grammar-source> <grammar-options>) <grammar>)
|
||||
(defvar *make-and-compile-grammar-cache* (cons nil nil))
|
||||
|
||||
; Make the grammar and compile its parser. kind should be :lalr-1, :lr-1, or :canonical-lr-1.
|
||||
(defun make-and-compile-grammar (kind parametrization start-symbol grammar-source &rest grammar-options)
|
||||
(compile-parser (apply #'make-grammar parametrization start-symbol grammar-source grammar-options)
|
||||
kind))
|
||||
(let ((key (list kind start-symbol grammar-source grammar-options))
|
||||
(cached-grammar (cdr *make-and-compile-grammar-cache*)))
|
||||
(if (and (equal key (car *make-and-compile-grammar-cache*))
|
||||
(grammar-parametrization-= parametrization cached-grammar))
|
||||
(progn
|
||||
(format *trace-output* "Re-using grammar ~S ~S ~S~%" kind start-symbol grammar-options)
|
||||
cached-grammar)
|
||||
(let* ((grammar (apply #'make-grammar parametrization start-symbol grammar-source grammar-options))
|
||||
(found-ambiguities (compile-parser grammar kind)))
|
||||
(setq *make-and-compile-grammar-cache*
|
||||
(if found-ambiguities
|
||||
(cons nil nil)
|
||||
(cons key grammar)))
|
||||
grammar))))
|
||||
|
||||
|
||||
; Collapse states that have at most one possible reduction into forwarding states.
|
||||
|
|
|
|||
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