ruby/lib/irb.rb

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Ruby

# frozen_string_literal: true
# :markup: markdown
# irb.rb - irb main module
# by Keiju ISHITSUKA(keiju@ruby-lang.org)
#
require "ripper"
require "reline"
require_relative "irb/init"
require_relative "irb/context"
require_relative "irb/default_commands"
require_relative "irb/ruby-lex"
require_relative "irb/statement"
require_relative "irb/input-method"
require_relative "irb/locale"
require_relative "irb/color"
require_relative "irb/version"
require_relative "irb/easter-egg"
require_relative "irb/debug"
require_relative "irb/pager"
# ## IRB
#
# Module IRB ("Interactive Ruby") provides a shell-like interface that supports
# user interaction with the Ruby interpreter.
#
# It operates as a *read-eval-print loop*
# ([REPL](https://en.wikipedia.org/wiki/Read%E2%80%93eval%E2%80%93print_loop))
# that:
#
# * ***Reads*** each character as you type. You can modify the IRB context to
# change the way input works. See [Input](rdoc-ref:IRB@Input).
# * ***Evaluates*** the code each time it has read a syntactically complete
# passage.
# * ***Prints*** after evaluating. You can modify the IRB context to change
# the way output works. See [Output](rdoc-ref:IRB@Output).
#
#
# Example:
#
# $ irb
# irb(main):001> File.basename(Dir.pwd)
# => "irb"
# irb(main):002> Dir.entries('.').size
# => 25
# irb(main):003* Dir.entries('.').select do |entry|
# irb(main):004* entry.start_with?('R')
# irb(main):005> end
# => ["README.md", "Rakefile"]
#
# The typed input may also include [\IRB-specific
# commands](rdoc-ref:IRB@IRB-Specific+Commands).
#
# As seen above, you can start IRB by using the shell command `irb`.
#
# You can stop an IRB session by typing command `exit`:
#
# irb(main):006> exit
# $
#
# At that point, IRB calls any hooks found in array `IRB.conf[:AT_EXIT]`, then
# exits.
#
# ## Startup
#
# At startup, IRB:
#
# 1. Interprets (as Ruby code) the content of the [configuration
# file](rdoc-ref:IRB@Configuration+File) (if given).
# 2. Constructs the initial session context from [hash
# IRB.conf](rdoc-ref:IRB@Hash+IRB.conf) and from default values; the hash
# content may have been affected by [command-line
# options](rdoc-ref:IB@Command-Line+Options), and by direct assignments in
# the configuration file.
# 3. Assigns the context to variable `conf`.
# 4. Assigns command-line arguments to variable `ARGV`.
# 5. Prints the [prompt](rdoc-ref:IRB@Prompt+and+Return+Formats).
# 6. Puts the content of the [initialization
# script](rdoc-ref:IRB@Initialization+Script) onto the IRB shell, just as if
# it were user-typed commands.
#
#
# ### The Command Line
#
# On the command line, all options precede all arguments; the first item that is
# not recognized as an option is treated as an argument, as are all items that
# follow.
#
# #### Command-Line Options
#
# Many command-line options affect entries in hash `IRB.conf`, which in turn
# affect the initial configuration of the IRB session.
#
# Details of the options are described in the relevant subsections below.
#
# A cursory list of the IRB command-line options may be seen in the [help
# message](https://raw.githubusercontent.com/ruby/irb/master/lib/irb/lc/help-message),
# which is also displayed if you use command-line option `--help`.
#
# If you are interested in a specific option, consult the
# [index](rdoc-ref:doc/irb/indexes.md@Index+of+Command-Line+Options).
#
# #### Command-Line Arguments
#
# Command-line arguments are passed to IRB in array `ARGV`:
#
# $ irb --noscript Foo Bar Baz
# irb(main):001> ARGV
# => ["Foo", "Bar", "Baz"]
# irb(main):002> exit
# $
#
# Command-line option `--` causes everything that follows to be treated as
# arguments, even those that look like options:
#
# $ irb --noscript -- --noscript -- Foo Bar Baz
# irb(main):001> ARGV
# => ["--noscript", "--", "Foo", "Bar", "Baz"]
# irb(main):002> exit
# $
#
# ### Configuration File
#
# You can initialize IRB via a *configuration file*.
#
# If command-line option `-f` is given, no configuration file is looked for.
#
# Otherwise, IRB reads and interprets a configuration file if one is available.
#
# The configuration file can contain any Ruby code, and can usefully include
# user code that:
#
# * Can then be debugged in IRB.
# * Configures IRB itself.
# * Requires or loads files.
#
#
# The path to the configuration file is the first found among:
#
# * The value of variable `$IRBRC`, if defined.
# * The value of variable `$XDG_CONFIG_HOME/irb/irbrc`, if defined.
# * File `$HOME/.irbrc`, if it exists.
# * File `$HOME/.config/irb/irbrc`, if it exists.
# * File `.irbrc` in the current directory, if it exists.
# * File `irb.rc` in the current directory, if it exists.
# * File `_irbrc` in the current directory, if it exists.
# * File `$irbrc` in the current directory, if it exists.
#
#
# If the search fails, there is no configuration file.
#
# If the search succeeds, the configuration file is read as Ruby code, and so
# can contain any Ruby programming you like.
#
# Method `conf.rc?` returns `true` if a configuration file was read, `false`
# otherwise. Hash entry `IRB.conf[:RC]` also contains that value.
#
# ### Hash `IRB.conf`
#
# The initial entries in hash `IRB.conf` are determined by:
#
# * Default values.
# * Command-line options, which may override defaults.
# * Direct assignments in the configuration file.
#
#
# You can see the hash by typing `IRB.conf`.
#
# Details of the entries' meanings are described in the relevant subsections
# below.
#
# If you are interested in a specific entry, consult the
# [index](rdoc-ref:doc/irb/indexes.md@Index+of+IRB.conf+Entries).
#
# ### Notes on Initialization Precedence
#
# * Any conflict between an entry in hash `IRB.conf` and a command-line option
# is resolved in favor of the hash entry.
# * Hash `IRB.conf` affects the context only once, when the configuration file
# is interpreted; any subsequent changes to it do not affect the context and
# are therefore essentially meaningless.
#
#
# ### Initialization Script
#
# By default, the first command-line argument (after any options) is the path to
# a Ruby initialization script.
#
# IRB reads the initialization script and puts its content onto the IRB shell,
# just as if it were user-typed commands.
#
# Command-line option `--noscript` causes the first command-line argument to be
# treated as an ordinary argument (instead of an initialization script);
# `--script` is the default.
#
# ## Input
#
# This section describes the features that allow you to change the way IRB input
# works; see also [Input and Output](rdoc-ref:IRB@Input+and+Output).
#
# ### Input Command History
#
# By default, IRB stores a history of up to 1000 input commands in a file named
# `.irb_history`. The history file will be in the same directory as the
# [configuration file](rdoc-ref:IRB@Configuration+File) if one is found, or in
# `~/` otherwise.
#
# A new IRB session creates the history file if it does not exist, and appends
# to the file if it does exist.
#
# You can change the filepath by adding to your configuration file:
# `IRB.conf[:HISTORY_FILE] = *filepath*`, where *filepath* is a string filepath.
#
# During the session, method `conf.history_file` returns the filepath, and
# method `conf.history_file = *new_filepath*` copies the history to the file at
# *new_filepath*, which becomes the history file for the session.
#
# You can change the number of commands saved by adding to your configuration
# file: `IRB.conf[:SAVE_HISTORY] = *n*`, wheHISTORY_FILEre *n* is one of:
#
# * Positive integer: the number of commands to be saved,
# * Zero: all commands are to be saved.
# * `nil`: no commands are to be saved,.
#
#
# During the session, you can use methods `conf.save_history` or
# `conf.save_history=` to retrieve or change the count.
#
# ### Command Aliases
#
# By default, IRB defines several command aliases:
#
# irb(main):001> conf.command_aliases
# => {:"$"=>:show_source, :"@"=>:whereami}
#
# You can change the initial aliases in the configuration file with:
#
# IRB.conf[:COMMAND_ALIASES] = {foo: :show_source, bar: :whereami}
#
# You can replace the current aliases at any time with configuration method
# `conf.command_aliases=`; Because `conf.command_aliases` is a hash, you can
# modify it.
#
# ### End-of-File
#
# By default, `IRB.conf[:IGNORE_EOF]` is `false`, which means that typing the
# end-of-file character `Ctrl-D` causes the session to exit.
#
# You can reverse that behavior by adding `IRB.conf[:IGNORE_EOF] = true` to the
# configuration file.
#
# During the session, method `conf.ignore_eof?` returns the setting, and method
# `conf.ignore_eof = *boolean*` sets it.
#
# ### SIGINT
#
# By default, `IRB.conf[:IGNORE_SIGINT]` is `true`, which means that typing the
# interrupt character `Ctrl-C` causes the session to exit.
#
# You can reverse that behavior by adding `IRB.conf[:IGNORE_SIGING] = false` to
# the configuration file.
#
# During the session, method `conf.ignore_siging?` returns the setting, and
# method `conf.ignore_sigint = *boolean*` sets it.
#
# ### Automatic Completion
#
# By default, IRB enables [automatic
# completion](https://en.wikipedia.org/wiki/Autocomplete#In_command-line_interpr
# eters):
#
# You can disable it by either of these:
#
# * Adding `IRB.conf[:USE_AUTOCOMPLETE] = false` to the configuration file.
# * Giving command-line option `--noautocomplete` (`--autocomplete` is the
# default).
#
#
# Method `conf.use_autocomplete?` returns `true` if automatic completion is
# enabled, `false` otherwise.
#
# The setting may not be changed during the session.
#
# ### Automatic Indentation
#
# By default, IRB automatically indents lines of code to show structure (e.g.,
# it indent the contents of a block).
#
# The current setting is returned by the configuration method
# `conf.auto_indent_mode`.
#
# The default initial setting is `true`:
#
# irb(main):001> conf.auto_indent_mode
# => true
# irb(main):002* Dir.entries('.').select do |entry|
# irb(main):003* entry.start_with?('R')
# irb(main):004> end
# => ["README.md", "Rakefile"]
#
# You can change the initial setting in the configuration file with:
#
# IRB.conf[:AUTO_INDENT] = false
#
# Note that the *current* setting *may not* be changed in the IRB session.
#
# ### Input Method
#
# The IRB input method determines how command input is to be read; by default,
# the input method for a session is IRB::RelineInputMethod. Unless the
# value of the TERM environment variable is 'dumb', in which case the
# most simplistic input method is used.
#
# You can set the input method by:
#
# * Adding to the configuration file:
#
# * `IRB.conf[:USE_SINGLELINE] = true` or `IRB.conf[:USE_MULTILINE]=
# false` sets the input method to IRB::ReadlineInputMethod.
# * `IRB.conf[:USE_SINGLELINE] = false` or `IRB.conf[:USE_MULTILINE] =
# true` sets the input method to IRB::RelineInputMethod.
#
#
# * Giving command-line options:
#
# * `--singleline` or `--nomultiline` sets the input method to
# IRB::ReadlineInputMethod.
# * `--nosingleline` or `--multiline` sets the input method to
# IRB::RelineInputMethod.
# * `--nosingleline` together with `--nomultiline` sets the
# input to IRB::StdioInputMethod.
#
#
# Method `conf.use_multiline?` and its synonym `conf.use_reline` return:
#
# * `true` if option `--multiline` was given.
# * `false` if option `--nomultiline` was given.
# * `nil` if neither was given.
#
#
# Method `conf.use_singleline?` and its synonym `conf.use_readline` return:
#
# * `true` if option `--singleline` was given.
# * `false` if option `--nosingleline` was given.
# * `nil` if neither was given.
#
#
# ## Output
#
# This section describes the features that allow you to change the way IRB
# output works; see also [Input and Output](rdoc-ref:IRB@Input+and+Output).
#
# ### Return-Value Printing (Echoing)
#
# By default, IRB prints (echoes) the values returned by all input commands.
#
# You can change the initial behavior and suppress all echoing by:
#
# * Adding to the configuration file: `IRB.conf[:ECHO] = false`. (The default
# value for this entry is `nil`, which means the same as `true`.)
# * Giving command-line option `--noecho`. (The default is `--echo`.)
#
#
# During the session, you can change the current setting with configuration
# method `conf.echo=` (set to `true` or `false`).
#
# As stated above, by default IRB prints the values returned by all input
# commands; but IRB offers special treatment for values returned by assignment
# statements, which may be:
#
# * Printed with truncation (to fit on a single line of output), which is the
# default; an ellipsis (`...` is suffixed, to indicate the truncation):
#
# irb(main):001> x = 'abc' * 100
#
#
# > "abcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabc...
#
# * Printed in full (regardless of the length).
# * Suppressed (not printed at all)
#
#
# You can change the initial behavior by:
#
# * Adding to the configuration file: `IRB.conf[:ECHO_ON_ASSIGNMENT] = false`.
# (The default value for this entry is `niL`, which means the same as
# `:truncate`.)
# * Giving command-line option `--noecho-on-assignment` or
# `--echo-on-assignment`. (The default is `--truncate-echo-on-assignment`.)
#
#
# During the session, you can change the current setting with configuration
# method `conf.echo_on_assignment=` (set to `true`, `false`, or `:truncate`).
#
# By default, IRB formats returned values by calling method `inspect`.
#
# You can change the initial behavior by:
#
# * Adding to the configuration file: `IRB.conf[:INSPECT_MODE] = false`. (The
# default value for this entry is `true`.)
# * Giving command-line option `--noinspect`. (The default is `--inspect`.)
#
#
# During the session, you can change the setting using method
# `conf.inspect_mode=`.
#
# ### Multiline Output
#
# By default, IRB prefixes a newline to a multiline response.
#
# You can change the initial default value by adding to the configuration file:
#
# IRB.conf[:NEWLINE_BEFORE_MULTILINE_OUTPUT] = false
#
# During a session, you can retrieve or set the value using methods
# `conf.newline_before_multiline_output?` and
# `conf.newline_before_multiline_output=`.
#
# Examples:
#
# irb(main):001> conf.inspect_mode = false
# => false
# irb(main):002> "foo\nbar"
# =>
# foo
# bar
# irb(main):003> conf.newline_before_multiline_output = false
# => false
# irb(main):004> "foo\nbar"
# => foo
# bar
#
# ### Evaluation History
#
# By default, IRB saves no history of evaluations (returned values), and the
# related methods `conf.eval_history`, `_`, and `__` are undefined.
#
# You can turn on that history, and set the maximum number of evaluations to be
# stored:
#
# * In the configuration file: add `IRB.conf[:EVAL_HISTORY] = *n*`. (Examples
# below assume that we've added `IRB.conf[:EVAL_HISTORY] = 5`.)
# * In the session (at any time): `conf.eval_history = *n*`.
#
#
# If `n` is zero, all evaluation history is stored.
#
# Doing either of the above:
#
# * Sets the maximum size of the evaluation history; defines method
# `conf.eval_history`, which returns the maximum size `n` of the evaluation
# history:
#
# irb(main):001> conf.eval_history = 5
# => 5
# irb(main):002> conf.eval_history
# => 5
#
# * Defines variable `_`, which contains the most recent evaluation, or `nil`
# if none; same as method `conf.last_value`:
#
# irb(main):003> _
# => 5
# irb(main):004> :foo
# => :foo
# irb(main):005> :bar
# => :bar
# irb(main):006> _
# => :bar
# irb(main):007> _
# => :bar
#
# * Defines variable `__`:
#
# * `__` unadorned: contains all evaluation history:
#
# irb(main):008> :foo
# => :foo
# irb(main):009> :bar
# => :bar
# irb(main):010> :baz
# => :baz
# irb(main):011> :bat
# => :bat
# irb(main):012> :bam
# => :bam
# irb(main):013> __
# =>
# 9 :bar
# 10 :baz
# 11 :bat
# 12 :bam
# irb(main):014> __
# =>
# 10 :baz
# 11 :bat
# 12 :bam
# 13 ...self-history...
#
# Note that when the evaluation is multiline, it is displayed
# differently.
#
# * `__[`*m*`]`:
#
# * Positive *m*: contains the evaluation for the given line number,
# or `nil` if that line number is not in the evaluation history:
#
# irb(main):015> __[12]
# => :bam
# irb(main):016> __[1]
# => nil
#
# * Negative *m*: contains the `mth`-from-end evaluation, or `nil` if
# that evaluation is not in the evaluation history:
#
# irb(main):017> __[-3]
# => :bam
# irb(main):018> __[-13]
# => nil
#
# * Zero *m*: contains `nil`:
#
# irb(main):019> __[0]
# => nil
#
#
#
#
# ### Prompt and Return Formats
#
# By default, IRB uses the prompt and return value formats defined in its
# `:DEFAULT` prompt mode.
#
# #### The Default Prompt and Return Format
#
# The default prompt and return values look like this:
#
# irb(main):001> 1 + 1
# => 2
# irb(main):002> 2 + 2
# => 4
#
# The prompt includes:
#
# * The name of the running program (`irb`); see [IRB
# Name](rdoc-ref:IRB@IRB+Name).
# * The name of the current session (`main`); See [IRB
# Sessions](rdoc-ref:IRB@IRB+Sessions).
# * A 3-digit line number (1-based).
#
#
# The default prompt actually defines three formats:
#
# * One for most situations (as above):
#
# irb(main):003> Dir
# => Dir
#
# * One for when the typed command is a statement continuation (adds trailing
# asterisk):
#
# irb(main):004* Dir.
#
# * One for when the typed command is a string continuation (adds trailing
# single-quote):
#
# irb(main):005' Dir.entries('.
#
#
# You can see the prompt change as you type the characters in the following:
#
# irb(main):001* Dir.entries('.').select do |entry|
# irb(main):002* entry.start_with?('R')
# irb(main):003> end
# => ["README.md", "Rakefile"]
#
# #### Pre-Defined Prompts
#
# IRB has several pre-defined prompts, stored in hash `IRB.conf[:PROMPT]`:
#
# irb(main):001> IRB.conf[:PROMPT].keys
# => [:NULL, :DEFAULT, :CLASSIC, :SIMPLE, :INF_RUBY, :XMP]
#
# To see the full data for these, type `IRB.conf[:PROMPT]`.
#
# Most of these prompt definitions include specifiers that represent values like
# the IRB name, session name, and line number; see [Prompt
# Specifiers](rdoc-ref:IRB@Prompt+Specifiers).
#
# You can change the initial prompt and return format by:
#
# * Adding to the configuration file: `IRB.conf[:PROMPT] = *mode*` where
# *mode* is the symbol name of a prompt mode.
# * Giving a command-line option:
#
# * `--prompt *mode*`: sets the prompt mode to *mode*. where *mode* is the
# symbol name of a prompt mode.
# * `--simple-prompt` or `--sample-book-mode`: sets the prompt mode to
# `:SIMPLE`.
# * `--inf-ruby-mode`: sets the prompt mode to `:INF_RUBY` and suppresses
# both `--multiline` and `--singleline`.
# * `--noprompt`: suppresses prompting; does not affect echoing.
#
#
#
# You can retrieve or set the current prompt mode with methods
#
# `conf.prompt_mode` and `conf.prompt_mode=`.
#
# If you're interested in prompts and return formats other than the defaults,
# you might experiment by trying some of the others.
#
# #### Custom Prompts
#
# You can also define custom prompts and return formats, which may be done
# either in an IRB session or in the configuration file.
#
# A prompt in IRB actually defines three prompts, as seen above. For simple
# custom data, we'll make all three the same:
#
# irb(main):001* IRB.conf[:PROMPT][:MY_PROMPT] = {
# irb(main):002* PROMPT_I: ': ',
# irb(main):003* PROMPT_C: ': ',
# irb(main):004* PROMPT_S: ': ',
# irb(main):005* RETURN: '=> '
# irb(main):006> }
# => {:PROMPT_I=>": ", :PROMPT_C=>": ", :PROMPT_S=>": ", :RETURN=>"=> "}
#
# If you define the custom prompt in the configuration file, you can also make
# it the current prompt by adding:
#
# IRB.conf[:PROMPT_MODE] = :MY_PROMPT
#
# Regardless of where it's defined, you can make it the current prompt in a
# session:
#
# conf.prompt_mode = :MY_PROMPT
#
# You can view or modify the current prompt data with various configuration
# methods:
#
# * `conf.prompt_mode`, `conf.prompt_mode=`.
# * `conf.prompt_c`, `conf.c=`.
# * `conf.prompt_i`, `conf.i=`.
# * `conf.prompt_s`, `conf.s=`.
# * `conf.return_format`, `return_format=`.
#
#
# #### Prompt Specifiers
#
# A prompt's definition can include specifiers for which certain values are
# substituted:
#
# * `%N`: the name of the running program.
# * `%m`: the value of `self.to_s`.
# * `%M`: the value of `self.inspect`.
# * `%l`: an indication of the type of string; one of `"`, `'`, `/`, `]`.
# * `%NNi`: Indentation level. NN is a 2-digit number that specifies the number
# of digits of the indentation level (03 will result in 001).
# * `%NNn`: Line number. NN is a 2-digit number that specifies the number
# of digits of the line number (03 will result in 001).
# * `%%`: Literal `%`.
#
#
# ### Verbosity
#
# By default, IRB verbosity is disabled, which means that output is smaller
# rather than larger.
#
# You can enable verbosity by:
#
# * Adding to the configuration file: `IRB.conf[:VERBOSE] = true` (the default
# is `nil`).
# * Giving command-line options `--verbose` (the default is `--noverbose`).
#
#
# During a session, you can retrieve or set verbosity with methods
# `conf.verbose` and `conf.verbose=`.
#
# ### Help
#
# Command-line option `--version` causes IRB to print its help text and exit.
#
# ### Version
#
# Command-line option `--version` causes IRB to print its version text and exit.
#
# ## Input and Output
#
# ### Color Highlighting
#
# By default, IRB color highlighting is enabled, and is used for both:
#
# * Input: As you type, IRB reads the typed characters and highlights elements
# that it recognizes; it also highlights errors such as mismatched
# parentheses.
# * Output: IRB highlights syntactical elements.
#
#
# You can disable color highlighting by:
#
# * Adding to the configuration file: `IRB.conf[:USE_COLORIZE] = false` (the
# default value is `true`).
# * Giving command-line option `--nocolorize`
#
#
# ## Debugging
#
# Command-line option `-d` sets variables `$VERBOSE` and `$DEBUG` to `true`;
# these have no effect on IRB output.
#
# ### Warnings
#
# Command-line option `-w` suppresses warnings.
#
# Command-line option `-W[*level*]` sets warning level;
#
# * 0=silence
# * 1=medium
# * 2=verbose
#
# ## Other Features
#
# ### Load Modules
#
# You can specify the names of modules that are to be required at startup.
#
# Array `conf.load_modules` determines the modules (if any) that are to be
# required during session startup. The array is used only during session
# startup, so the initial value is the only one that counts.
#
# The default initial value is `[]` (load no modules):
#
# irb(main):001> conf.load_modules
# => []
#
# You can set the default initial value via:
#
# * Command-line option `-r`
#
# $ irb -r csv -r json
# irb(main):001> conf.load_modules
# => ["csv", "json"]
#
# * Hash entry `IRB.conf[:LOAD_MODULES] = *array*`:
#
# IRB.conf[:LOAD_MODULES] = %w[csv, json]
#
#
# Note that the configuration file entry overrides the command-line options.
#
# ### RI Documentation Directories
#
# You can specify the paths to RI documentation directories that are to be
# loaded (in addition to the default directories) at startup; see details about
# RI by typing `ri --help`.
#
# Array `conf.extra_doc_dirs` determines the directories (if any) that are to be
# loaded during session startup. The array is used only during session startup,
# so the initial value is the only one that counts.
#
# The default initial value is `[]` (load no extra documentation):
#
# irb(main):001> conf.extra_doc_dirs
# => []
#
# You can set the default initial value via:
#
# * Command-line option `--extra_doc_dir`
#
# $ irb --extra-doc-dir your_doc_dir --extra-doc-dir my_doc_dir
# irb(main):001> conf.extra_doc_dirs
# => ["your_doc_dir", "my_doc_dir"]
#
# * Hash entry `IRB.conf[:EXTRA_DOC_DIRS] = *array*`:
#
# IRB.conf[:EXTRA_DOC_DIRS] = %w[your_doc_dir my_doc_dir]
#
#
# Note that the configuration file entry overrides the command-line options.
#
# ### IRB Name
#
# You can specify a name for IRB.
#
# The default initial value is `'irb'`:
#
# irb(main):001> conf.irb_name
# => "irb"
#
# You can set the default initial value via hash entry `IRB.conf[:IRB_NAME] =
# *string*`:
#
# IRB.conf[:IRB_NAME] = 'foo'
#
# ### Application Name
#
# You can specify an application name for the IRB session.
#
# The default initial value is `'irb'`:
#
# irb(main):001> conf.ap_name
# => "irb"
#
# You can set the default initial value via hash entry `IRB.conf[:AP_NAME] =
# *string*`:
#
# IRB.conf[:AP_NAME] = 'my_ap_name'
#
# ### Configuration Monitor
#
# You can monitor changes to the configuration by assigning a proc to
# `IRB.conf[:IRB_RC]` in the configuration file:
#
# IRB.conf[:IRB_RC] = proc {|conf| puts conf.class }
#
# Each time the configuration is changed, that proc is called with argument
# `conf`:
#
# ### Encodings
#
# Command-line option `-E *ex*[:*in*]` sets initial external (ex) and internal
# (in) encodings.
#
# Command-line option `-U` sets both to UTF-8.
#
# ### Commands
#
# Please use the `help` command to see the list of available commands.
#
# ### IRB Sessions
#
# IRB has a special feature, that allows you to manage many sessions at once.
#
# You can create new sessions with Irb.irb, and get a list of current sessions
# with the `jobs` command in the prompt.
#
# #### Configuration
#
# The command line options, or IRB.conf, specify the default behavior of
# Irb.irb.
#
# On the other hand, each conf in IRB@Command-Line+Options is used to
# individually configure IRB.irb.
#
# If a proc is set for `IRB.conf[:IRB_RC]`, its will be invoked after execution
# of that proc with the context of the current session as its argument. Each
# session can be configured using this mechanism.
#
# #### Session variables
#
# There are a few variables in every Irb session that can come in handy:
#
# `_`
# : The value command executed, as a local variable
# `__`
# : The history of evaluated commands. Available only if
# `IRB.conf[:EVAL_HISTORY]` is not `nil` (which is the default). See also
# IRB::Context#eval_history= and IRB::History.
# `__[line_no]`
# : Returns the evaluation value at the given line number, `line_no`. If
# `line_no` is a negative, the return value `line_no` many lines before the
# most recent return value.
#
#
# ## Restrictions
#
# Ruby code typed into IRB behaves the same as Ruby code in a file, except that:
#
# * Because IRB evaluates input immediately after it is syntactically
# complete, some results may be slightly different.
# * Forking may not be well behaved.
#
module IRB
# An exception raised by IRB.irb_abort
class Abort < Exception;end
class << self
# The current IRB::Context of the session, see IRB.conf
#
# irb
# irb(main):001:0> IRB.CurrentContext.irb_name = "foo"
# foo(main):002:0> IRB.conf[:MAIN_CONTEXT].irb_name #=> "foo"
def CurrentContext # :nodoc:
conf[:MAIN_CONTEXT]
end
# Initializes IRB and creates a new Irb.irb object at the `TOPLEVEL_BINDING`
def start(ap_path = nil)
STDOUT.sync = true
$0 = File::basename(ap_path, ".rb") if ap_path
setup(ap_path)
if @CONF[:SCRIPT]
irb = Irb.new(nil, @CONF[:SCRIPT])
else
irb = Irb.new
end
irb.run(@CONF)
end
# Quits irb
def irb_exit(*) # :nodoc:
throw :IRB_EXIT, false
end
# Aborts then interrupts irb.
#
# Will raise an Abort exception, or the given `exception`.
def irb_abort(irb, exception = Abort) # :nodoc:
irb.context.thread.raise exception, "abort then interrupt!"
end
end
class Irb
# Note: instance and index assignment expressions could also be written like:
# "foo.bar=(1)" and "foo.[]=(1, bar)", when expressed that way, the former be
# parsed as :assign and echo will be suppressed, but the latter is parsed as a
# :method_add_arg and the output won't be suppressed
PROMPT_MAIN_TRUNCATE_LENGTH = 32
PROMPT_MAIN_TRUNCATE_OMISSION = '...'
CONTROL_CHARACTERS_PATTERN = "\x00-\x1F"
# Returns the current context of this irb session
attr_reader :context
# The lexer used by this irb session
attr_accessor :scanner
attr_reader :from_binding
# Creates a new irb session
def initialize(workspace = nil, input_method = nil, from_binding: false)
@from_binding = from_binding
@context = Context.new(self, workspace, input_method)
@context.workspace.load_helper_methods_to_main
@signal_status = :IN_IRB
@scanner = RubyLex.new
@line_no = 1
end
# A hook point for `debug` command's breakpoint after :IRB_EXIT as well as its
# clean-up
def debug_break
# it means the debug integration has been activated
if defined?(DEBUGGER__) && DEBUGGER__.respond_to?(:capture_frames_without_irb)
# after leaving this initial breakpoint, revert the capture_frames patch
DEBUGGER__.singleton_class.send(:alias_method, :capture_frames, :capture_frames_without_irb)
# and remove the redundant method
DEBUGGER__.singleton_class.send(:undef_method, :capture_frames_without_irb)
end
end
def debug_readline(binding)
workspace = IRB::WorkSpace.new(binding)
context.replace_workspace(workspace)
context.workspace.load_helper_methods_to_main
@line_no += 1
# When users run:
# 1. Debugging commands, like `step 2`
# 2. Any input that's not irb-command, like `foo = 123`
#
#
# Irb#eval_input will simply return the input, and we need to pass it to the
# debugger.
input = nil
forced_exit = catch(:IRB_EXIT) do
if IRB.conf[:SAVE_HISTORY] && context.io.support_history_saving?
# Previous IRB session's history has been saved when `Irb#run` is exited We need
# to make sure the saved history is not saved again by resetting the counter
context.io.reset_history_counter
begin
input = eval_input
ensure
context.io.save_history
end
else
input = eval_input
end
false
end
Kernel.exit if forced_exit
if input&.include?("\n")
@line_no += input.count("\n") - 1
end
input
end
def run(conf = IRB.conf)
in_nested_session = !!conf[:MAIN_CONTEXT]
conf[:IRB_RC].call(context) if conf[:IRB_RC]
prev_context = conf[:MAIN_CONTEXT]
conf[:MAIN_CONTEXT] = context
save_history = !in_nested_session && conf[:SAVE_HISTORY] && context.io.support_history_saving?
if save_history
context.io.load_history
end
prev_trap = trap("SIGINT") do
signal_handle
end
begin
if defined?(RubyVM.keep_script_lines)
keep_script_lines_backup = RubyVM.keep_script_lines
RubyVM.keep_script_lines = true
end
forced_exit = catch(:IRB_EXIT) do
eval_input
end
ensure
# Do not restore to nil. It will cause IRB crash when used with threads.
IRB.conf[:MAIN_CONTEXT] = prev_context if prev_context
RubyVM.keep_script_lines = keep_script_lines_backup if defined?(RubyVM.keep_script_lines)
trap("SIGINT", prev_trap)
conf[:AT_EXIT].each{|hook| hook.call}
context.io.save_history if save_history
Kernel.exit if forced_exit
end
end
# Evaluates input for this session.
def eval_input
configure_io
each_top_level_statement do |statement, line_no|
signal_status(:IN_EVAL) do
begin
# If the integration with debugger is activated, we return certain input if it
# should be dealt with by debugger
if @context.with_debugger && statement.should_be_handled_by_debugger?
return statement.code
end
@context.evaluate(statement, line_no)
if @context.echo? && !statement.suppresses_echo?
if statement.is_assignment?
if @context.echo_on_assignment?
output_value(@context.echo_on_assignment? == :truncate)
end
else
output_value
end
end
rescue SystemExit, SignalException
raise
rescue Interrupt, Exception => exc
handle_exception(exc)
@context.workspace.local_variable_set(:_, exc)
end
end
end
end
def read_input(prompt)
signal_status(:IN_INPUT) do
@context.io.prompt = prompt
if l = @context.io.gets
print l if @context.verbose?
else
if @context.ignore_eof? and @context.io.readable_after_eof?
l = "\n"
if @context.verbose?
printf "Use \"exit\" to leave %s\n", @context.ap_name
end
else
print "\n" if @context.prompting?
end
end
l
end
end
def readmultiline
prompt = generate_prompt([], false, 0)
# multiline
return read_input(prompt) if @context.io.respond_to?(:check_termination)
# nomultiline
code = +''
line_offset = 0
loop do
line = read_input(prompt)
unless line
return code.empty? ? nil : code
end
code << line
return code if command?(code)
tokens, opens, terminated = @scanner.check_code_state(code, local_variables: @context.local_variables)
return code if terminated
line_offset += 1
continue = @scanner.should_continue?(tokens)
prompt = generate_prompt(opens, continue, line_offset)
end
end
def each_top_level_statement
loop do
code = readmultiline
break unless code
yield build_statement(code), @line_no
@line_no += code.count("\n")
rescue RubyLex::TerminateLineInput
end
end
def build_statement(code)
if code.match?(/\A\n*\z/)
return Statement::EmptyInput.new
end
code.force_encoding(@context.io.encoding)
if (command, arg = @context.parse_command(code))
command_class = Command.load_command(command)
Statement::Command.new(code, command_class, arg)
else
is_assignment_expression = @scanner.assignment_expression?(code, local_variables: @context.local_variables)
Statement::Expression.new(code, is_assignment_expression)
end
end
def command?(code)
!!@context.parse_command(code)
end
def configure_io
if @context.io.respond_to?(:check_termination)
@context.io.check_termination do |code|
if Reline::IOGate.in_pasting?
rest = @scanner.check_termination_in_prev_line(code, local_variables: @context.local_variables)
if rest
Reline.delete_text
rest.bytes.reverse_each do |c|
Reline.ungetc(c)
end
true
else
false
end
else
next true if command?(code)
_tokens, _opens, terminated = @scanner.check_code_state(code, local_variables: @context.local_variables)
terminated
end
end
end
if @context.io.respond_to?(:dynamic_prompt)
@context.io.dynamic_prompt do |lines|
tokens = RubyLex.ripper_lex_without_warning(lines.map{ |l| l + "\n" }.join, local_variables: @context.local_variables)
line_results = IRB::NestingParser.parse_by_line(tokens)
tokens_until_line = []
line_results.map.with_index do |(line_tokens, _prev_opens, next_opens, _min_depth), line_num_offset|
line_tokens.each do |token, _s|
# Avoid appending duplicated token. Tokens that include "n" like multiline
# tstring_content can exist in multiple lines.
tokens_until_line << token if token != tokens_until_line.last
end
continue = @scanner.should_continue?(tokens_until_line)
generate_prompt(next_opens, continue, line_num_offset)
end
end
end
if @context.io.respond_to?(:auto_indent) and @context.auto_indent_mode
@context.io.auto_indent do |lines, line_index, byte_pointer, is_newline|
next nil if lines == [nil] # Workaround for exit IRB with CTRL+d
next nil if !is_newline && lines[line_index]&.byteslice(0, byte_pointer)&.match?(/\A\s*\z/)
code = lines[0..line_index].map { |l| "#{l}\n" }.join
tokens = RubyLex.ripper_lex_without_warning(code, local_variables: @context.local_variables)
@scanner.process_indent_level(tokens, lines, line_index, is_newline)
end
end
end
def convert_invalid_byte_sequence(str, enc)
str.force_encoding(enc)
str.scrub { |c|
c.bytes.map{ |b| "\\x#{b.to_s(16).upcase}" }.join
}
end
def encode_with_invalid_byte_sequence(str, enc)
conv = Encoding::Converter.new(str.encoding, enc)
dst = String.new
begin
ret = conv.primitive_convert(str, dst)
case ret
when :invalid_byte_sequence
conv.insert_output(conv.primitive_errinfo[3].dump[1..-2])
redo
when :undefined_conversion
c = conv.primitive_errinfo[3].dup.force_encoding(conv.primitive_errinfo[1])
conv.insert_output(c.dump[1..-2])
redo
when :incomplete_input
conv.insert_output(conv.primitive_errinfo[3].dump[1..-2])
when :finished
end
break
end while nil
dst
end
def handle_exception(exc)
if exc.backtrace[0] =~ /\/irb(2)?(\/.*|-.*|\.rb)?:/ && exc.class.to_s !~ /^IRB/ &&
!(SyntaxError === exc) && !(EncodingError === exc)
# The backtrace of invalid encoding hash (ex. {"\xAE": 1}) raises EncodingError without lineno.
irb_bug = true
else
irb_bug = false
# To support backtrace filtering while utilizing Exception#full_message, we need to clone
# the exception to avoid modifying the original exception's backtrace.
exc = exc.clone
filtered_backtrace = exc.backtrace.map { |l| @context.workspace.filter_backtrace(l) }.compact
backtrace_filter = IRB.conf[:BACKTRACE_FILTER]
if backtrace_filter
if backtrace_filter.respond_to?(:call)
filtered_backtrace = backtrace_filter.call(filtered_backtrace)
else
warn "IRB.conf[:BACKTRACE_FILTER] #{backtrace_filter} should respond to `call` method"
end
end
exc.set_backtrace(filtered_backtrace)
end
highlight = Color.colorable?
order =
if RUBY_VERSION < '3.0.0'
STDOUT.tty? ? :bottom : :top
else # '3.0.0' <= RUBY_VERSION
:top
end
message = exc.full_message(order: order, highlight: highlight)
message = convert_invalid_byte_sequence(message, exc.message.encoding)
message = encode_with_invalid_byte_sequence(message, IRB.conf[:LC_MESSAGES].encoding) unless message.encoding.to_s.casecmp?(IRB.conf[:LC_MESSAGES].encoding.to_s)
message = message.gsub(/((?:^\t.+$\n)+)/) { |m|
case order
when :top
lines = m.split("\n")
when :bottom
lines = m.split("\n").reverse
end
unless irb_bug
if lines.size > @context.back_trace_limit
omit = lines.size - @context.back_trace_limit
lines = lines[0..(@context.back_trace_limit - 1)]
lines << "\t... %d levels..." % omit
end
end
lines = lines.reverse if order == :bottom
lines.map{ |l| l + "\n" }.join
}
# The "<top (required)>" in "(irb)" may be the top level of IRB so imitate the main object.
message = message.gsub(/\(irb\):(?<num>\d+):in (?<open_quote>[`'])<(?<frame>top \(required\))>'/) { "(irb):#{$~[:num]}:in #{$~[:open_quote]}<main>'" }
puts message
puts 'Maybe IRB bug!' if irb_bug
rescue Exception => handler_exc
begin
puts exc.inspect
puts "backtraces are hidden because #{handler_exc} was raised when processing them"
rescue Exception
puts 'Uninspectable exception occurred'
end
end
# Evaluates the given block using the given `path` as the Context#irb_path and
# `name` as the Context#irb_name.
#
# Used by the irb command `source`, see IRB@IRB+Sessions for more information.
def suspend_name(path = nil, name = nil)
@context.irb_path, back_path = path, @context.irb_path if path
@context.irb_name, back_name = name, @context.irb_name if name
begin
yield back_path, back_name
ensure
@context.irb_path = back_path if path
@context.irb_name = back_name if name
end
end
# Evaluates the given block using the given `workspace` as the
# Context#workspace.
#
# Used by the irb command `irb_load`, see IRB@IRB+Sessions for more information.
def suspend_workspace(workspace)
current_workspace = @context.workspace
@context.replace_workspace(workspace)
yield
ensure
@context.replace_workspace current_workspace
end
# Evaluates the given block using the given `input_method` as the Context#io.
#
# Used by the irb commands `source` and `irb_load`, see IRB@IRB+Sessions for
# more information.
def suspend_input_method(input_method)
back_io = @context.io
@context.instance_eval{@io = input_method}
begin
yield back_io
ensure
@context.instance_eval{@io = back_io}
end
end
# Handler for the signal SIGINT, see Kernel#trap for more information.
def signal_handle
unless @context.ignore_sigint?
print "\nabort!\n" if @context.verbose?
exit
end
case @signal_status
when :IN_INPUT
print "^C\n"
raise RubyLex::TerminateLineInput
when :IN_EVAL
IRB.irb_abort(self)
when :IN_LOAD
IRB.irb_abort(self, LoadAbort)
when :IN_IRB
# ignore
else
# ignore other cases as well
end
end
# Evaluates the given block using the given `status`.
def signal_status(status)
return yield if @signal_status == :IN_LOAD
signal_status_back = @signal_status
@signal_status = status
begin
yield
ensure
@signal_status = signal_status_back
end
end
def output_value(omit = false) # :nodoc:
str = @context.inspect_last_value
multiline_p = str.include?("\n")
if omit
winwidth = @context.io.winsize.last
if multiline_p
first_line = str.split("\n").first
result = @context.newline_before_multiline_output? ? (@context.return_format % first_line) : first_line
output_width = Reline::Unicode.calculate_width(result, true)
diff_size = output_width - Reline::Unicode.calculate_width(first_line, true)
if diff_size.positive? and output_width > winwidth
lines, _ = Reline::Unicode.split_by_width(first_line, winwidth - diff_size - 3)
str = "%s..." % lines.first
str += "\e[0m" if Color.colorable?
multiline_p = false
else
str = str.gsub(/(\A.*?\n).*/m, "\\1...")
str += "\e[0m" if Color.colorable?
end
else
output_width = Reline::Unicode.calculate_width(@context.return_format % str, true)
diff_size = output_width - Reline::Unicode.calculate_width(str, true)
if diff_size.positive? and output_width > winwidth
lines, _ = Reline::Unicode.split_by_width(str, winwidth - diff_size - 3)
str = "%s..." % lines.first
str += "\e[0m" if Color.colorable?
end
end
end
if multiline_p && @context.newline_before_multiline_output?
str = "\n" + str
end
Pager.page_content(format(@context.return_format, str), retain_content: true)
end
# Outputs the local variables to this current session, including #signal_status
# and #context, using IRB::Locale.
def inspect
ary = []
for iv in instance_variables
case (iv = iv.to_s)
when "@signal_status"
ary.push format("%s=:%s", iv, @signal_status.id2name)
when "@context"
ary.push format("%s=%s", iv, eval(iv).__to_s__)
else
ary.push format("%s=%s", iv, eval(iv))
end
end
format("#<%s: %s>", self.class, ary.join(", "))
end
private
def generate_prompt(opens, continue, line_offset)
ltype = @scanner.ltype_from_open_tokens(opens)
indent = @scanner.calc_indent_level(opens)
continue = opens.any? || continue
line_no = @line_no + line_offset
if ltype
f = @context.prompt_s
elsif continue
f = @context.prompt_c
else
f = @context.prompt_i
end
f = "" unless f
if @context.prompting?
p = format_prompt(f, ltype, indent, line_no)
else
p = ""
end
if @context.auto_indent_mode and !@context.io.respond_to?(:auto_indent)
unless ltype
prompt_i = @context.prompt_i.nil? ? "" : @context.prompt_i
ind = format_prompt(prompt_i, ltype, indent, line_no)[/.*\z/].size +
indent * 2 - p.size
p += " " * ind if ind > 0
end
end
p
end
def truncate_prompt_main(str) # :nodoc:
str = str.tr(CONTROL_CHARACTERS_PATTERN, ' ')
if str.size <= PROMPT_MAIN_TRUNCATE_LENGTH
str
else
str[0, PROMPT_MAIN_TRUNCATE_LENGTH - PROMPT_MAIN_TRUNCATE_OMISSION.size] + PROMPT_MAIN_TRUNCATE_OMISSION
end
end
def format_prompt(format, ltype, indent, line_no) # :nodoc:
format.gsub(/%([0-9]+)?([a-zA-Z%])/) do
case $2
when "N"
@context.irb_name
when "m"
main_str = @context.main.to_s rescue "!#{$!.class}"
truncate_prompt_main(main_str)
when "M"
main_str = @context.main.inspect rescue "!#{$!.class}"
truncate_prompt_main(main_str)
when "l"
ltype
when "i"
if indent < 0
if $1
"-".rjust($1.to_i)
else
"-"
end
else
if $1
format("%" + $1 + "d", indent)
else
indent.to_s
end
end
when "n"
if $1
format("%" + $1 + "d", line_no)
else
line_no.to_s
end
when "%"
"%" unless $1
end
end
end
end
end
class Binding
# Opens an IRB session where `binding.irb` is called which allows for
# interactive debugging. You can call any methods or variables available in the
# current scope, and mutate state if you need to.
#
# Given a Ruby file called `potato.rb` containing the following code:
#
# class Potato
# def initialize
# @cooked = false
# binding.irb
# puts "Cooked potato: #{@cooked}"
# end
# end
#
# Potato.new
#
# Running `ruby potato.rb` will open an IRB session where `binding.irb` is
# called, and you will see the following:
#
# $ ruby potato.rb
#
# From: potato.rb @ line 4 :
#
# 1: class Potato
# 2: def initialize
# 3: @cooked = false
# => 4: binding.irb
# 5: puts "Cooked potato: #{@cooked}"
# 6: end
# 7: end
# 8:
# 9: Potato.new
#
# irb(#<Potato:0x00007feea1916670>):001:0>
#
# You can type any valid Ruby code and it will be evaluated in the current
# context. This allows you to debug without having to run your code repeatedly:
#
# irb(#<Potato:0x00007feea1916670>):001:0> @cooked
# => false
# irb(#<Potato:0x00007feea1916670>):002:0> self.class
# => Potato
# irb(#<Potato:0x00007feea1916670>):003:0> caller.first
# => ".../2.5.1/lib/ruby/2.5.0/irb/workspace.rb:85:in `eval'"
# irb(#<Potato:0x00007feea1916670>):004:0> @cooked = true
# => true
#
# You can exit the IRB session with the `exit` command. Note that exiting will
# resume execution where `binding.irb` had paused it, as you can see from the
# output printed to standard output in this example:
#
# irb(#<Potato:0x00007feea1916670>):005:0> exit
# Cooked potato: true
#
# See IRB for more information.
def irb(show_code: true)
# Setup IRB with the current file's path and no command line arguments
IRB.setup(source_location[0], argv: []) unless IRB.initialized?
# Create a new workspace using the current binding
workspace = IRB::WorkSpace.new(self)
# Print the code around the binding if show_code is true
STDOUT.print(workspace.code_around_binding) if show_code
# Get the original IRB instance
debugger_irb = IRB.instance_variable_get(:@debugger_irb)
irb_path = File.expand_path(source_location[0])
if debugger_irb
# If we're already in a debugger session, set the workspace and irb_path for the original IRB instance
debugger_irb.context.replace_workspace(workspace)
debugger_irb.context.irb_path = irb_path
# If we've started a debugger session and hit another binding.irb, we don't want
# to start an IRB session instead, we want to resume the irb:rdbg session.
IRB::Debug.setup(debugger_irb)
IRB::Debug.insert_debug_break
debugger_irb.debug_break
else
# If we're not in a debugger session, create a new IRB instance with the current
# workspace
binding_irb = IRB::Irb.new(workspace, from_binding: true)
binding_irb.context.irb_path = irb_path
binding_irb.run(IRB.conf)
binding_irb.debug_break
end
end
end