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ruby/enumerator.c

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/************************************************
enumerator.c - provides Enumerator class
$Author$
Copyright (C) 2001-2003 Akinori MUSHA
$Idaemons: /home/cvs/rb/enumerator/enumerator.c,v 1.1.1.1 2001/07/15 10:12:48 knu Exp $
$RoughId: enumerator.c,v 1.6 2003/07/27 11:03:24 nobu Exp $
$Id$
************************************************/
#include "ruby/ruby.h"
#include "node.h"
#include "internal.h"
/*
* Document-class: Enumerator
*
* A class which allows both internal and external iteration.
*
* An Enumerator can be created by the following methods.
* - Kernel#to_enum
* - Kernel#enum_for
* - Enumerator.new
*
* Most methods have two forms: a block form where the contents
* are evaluated for each item in the enumeration, and a non-block form
* which returns a new Enumerator wrapping the iteration.
*
* enumerator = %w(one two three).each
* puts enumerator.class # => Enumerator
*
* enumerator.each_with_object("foo") do |item, obj|
* puts "#{obj}: #{item}"
* end
*
* # foo: one
* # foo: two
* # foo: three
*
* enum_with_obj = enumerator.each_with_object("foo")
* puts enum_with_obj.class # => Enumerator
*
* enum_with_obj.each do |item, obj|
* puts "#{obj}: #{item}"
* end
*
* # foo: one
* # foo: two
* # foo: three
*
* This allows you to chain Enumerators together. For example, you
* can map a list's elements to strings containing the index
* and the element as a string via:
*
* puts %w[foo bar baz].map.with_index { |w, i| "#{i}:#{w}" }
* # => ["0:foo", "1:bar", "2:baz"]
*
* An Enumerator can also be used as an external iterator.
* For example, Enumerator#next returns the next value of the iterator
* or raises StopIteration if the Enumerator is at the end.
*
* e = [1,2,3].each # returns an enumerator object.
* puts e.next # => 1
* puts e.next # => 2
* puts e.next # => 3
* puts e.next # raises StopIteration
*
* You can use this to implement an internal iterator as follows:
*
* def ext_each(e)
* while true
* begin
* vs = e.next_values
* rescue StopIteration
* return $!.result
* end
* y = yield(*vs)
* e.feed y
* end
* end
*
* o = Object.new
*
* def o.each
* puts yield
* puts yield(1)
* puts yield(1, 2)
* 3
* end
*
* # use o.each as an internal iterator directly.
* puts o.each {|*x| puts x; [:b, *x] }
* # => [], [:b], [1], [:b, 1], [1, 2], [:b, 1, 2], 3
*
* # convert o.each to an external iterator for
* # implementing an internal iterator.
* puts ext_each(o.to_enum) {|*x| puts x; [:b, *x] }
* # => [], [:b], [1], [:b, 1], [1, 2], [:b, 1, 2], 3
*
*/
VALUE rb_cEnumerator;
VALUE rb_cLazy;
static ID id_rewind, id_each, id_new, id_initialize, id_yield, id_call;
static ID id_eqq, id_next, id_result, id_lazy, id_receiver, id_arguments, id_method;
static VALUE sym_each, sym_cycle;
VALUE rb_eStopIteration;
struct enumerator {
VALUE obj;
ID meth;
VALUE args;
VALUE fib;
VALUE dst;
VALUE lookahead;
VALUE feedvalue;
VALUE stop_exc;
};
static VALUE rb_cGenerator, rb_cYielder;
struct generator {
VALUE proc;
};
struct yielder {
VALUE proc;
};
static VALUE generator_allocate(VALUE klass);
static VALUE generator_init(VALUE obj, VALUE proc);
/*
* Enumerator
*/
static void
enumerator_mark(void *p)
{
struct enumerator *ptr = p;
rb_gc_mark(ptr->obj);
rb_gc_mark(ptr->args);
rb_gc_mark(ptr->fib);
rb_gc_mark(ptr->dst);
rb_gc_mark(ptr->lookahead);
rb_gc_mark(ptr->feedvalue);
rb_gc_mark(ptr->stop_exc);
}
#define enumerator_free RUBY_TYPED_DEFAULT_FREE
static size_t
enumerator_memsize(const void *p)
{
return p ? sizeof(struct enumerator) : 0;
}
static const rb_data_type_t enumerator_data_type = {
"enumerator",
{
enumerator_mark,
enumerator_free,
enumerator_memsize,
},
};
static struct enumerator *
enumerator_ptr(VALUE obj)
{
struct enumerator *ptr;
TypedData_Get_Struct(obj, struct enumerator, &enumerator_data_type, ptr);
if (!ptr || ptr->obj == Qundef) {
rb_raise(rb_eArgError, "uninitialized enumerator");
}
return ptr;
}
/*
* call-seq:
* obj.to_enum(method = :each, *args)
* obj.enum_for(method = :each, *args)
*
* Creates a new Enumerator which will enumerate by on calling +method+ on
* +obj+.
*
* +method+:: the method to call on +obj+ to generate the enumeration
* +args+:: arguments that will be passed in +method+ <i>in addition</i>
* to the item itself. Note that the number of args
* must not exceed the number expected by +method+
*
* === Example
*
* str = "xyz"
*
* enum = str.enum_for(:each_byte)
* enum.each { |b| puts b }
* # => 120
* # => 121
* # => 122
*
* # protect an array from being modified by some_method
* a = [1, 2, 3]
* some_method(a.to_enum)
*
*/
static VALUE
obj_to_enum(int argc, VALUE *argv, VALUE obj)
{
VALUE meth = sym_each;
if (argc > 0) {
--argc;
meth = *argv++;
}
return rb_enumeratorize(obj, meth, argc, argv);
}
static VALUE
enumerator_allocate(VALUE klass)
{
struct enumerator *ptr;
VALUE enum_obj;
enum_obj = TypedData_Make_Struct(klass, struct enumerator, &enumerator_data_type, ptr);
ptr->obj = Qundef;
return enum_obj;
}
static VALUE
enumerator_init(VALUE enum_obj, VALUE obj, VALUE meth, int argc, VALUE *argv)
{
struct enumerator *ptr;
TypedData_Get_Struct(enum_obj, struct enumerator, &enumerator_data_type, ptr);
if (!ptr) {
rb_raise(rb_eArgError, "unallocated enumerator");
}
ptr->obj = obj;
ptr->meth = rb_to_id(meth);
if (argc) ptr->args = rb_ary_new4(argc, argv);
ptr->fib = 0;
ptr->dst = Qnil;
ptr->lookahead = Qundef;
ptr->feedvalue = Qundef;
ptr->stop_exc = Qfalse;
return enum_obj;
}
/*
* call-seq:
* Enumerator.new { |yielder| ... }
* Enumerator.new(obj, method = :each, *args)
*
* Creates a new Enumerator object, which can be used as an
* Enumerable.
*
* In the first form, iteration is defined by the given block, in
* which a "yielder" object, given as block parameter, can be used to
* yield a value by calling the +yield+ method (aliased as +<<+):
*
* fib = Enumerator.new do |y|
* a = b = 1
* loop do
* y << a
* a, b = b, a + b
* end
* end
*
* p fib.take(10) # => [1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
*
* The block form can be used to create a lazy enumeration that only processes
* elements as-needed. The generic pattern for this is:
*
* Enumerator.new do |yielder|
* source.each do |source_item|
* # process source_item and append the yielder
* end
* end
*
* This can be used with infinite streams to support multiple chains:
*
* class Fib
* def initialize(a = 1, b = 1)
* @a, @b = a, b
* end
*
* def each
* a, b = @a, @b
* yield a
* while true
* yield b
* a, b = b, a+b
* end
* end
* end
*
* def lazy_select enum
* Enumerator.new do |y|
* enum.each do |e|
* y << e if yield e
* end
* end
* end
*
* def lazy_map enum
* Enumerator.new do |y|
* enum.each do |e|
* y << yield(e)
* end
* end
* end
*
* even_fibs = lazy_select(Fibs.new) { |x| x % 2 == 0 }
* string_fibs = lazy_map(even_fibs) { |x| "<#{x}>" }
* string_fibs.each_with_index do |fib, i|
* puts "#{i}: #{fib}"
* break if i >= 3
* end
*
* This allows output even though the Fib produces an infinite sequence of
* Fibonacci numbers:
*
* 0: <2>
* 1: <8>
* 2: <34>
* 3: <144>
*
* In the second, deprecated, form, a generated Enumerator iterates over the
* given object using the given method with the given arguments passed.
*
* Use of this form is discouraged. Use Kernel#enum_for or Kernel#to_enum
* instead.
*
* e = Enumerator.new(ObjectSpace, :each_object)
* #-> ObjectSpace.enum_for(:each_object)
*
* e.select { |obj| obj.is_a?(Class) } #=> array of all classes
*
*/
static VALUE
enumerator_initialize(int argc, VALUE *argv, VALUE obj)
{
VALUE recv, meth = sym_each;
if (argc == 0) {
if (!rb_block_given_p())
rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);
recv = generator_init(generator_allocate(rb_cGenerator), rb_block_proc());
}
else {
recv = *argv++;
if (--argc) {
meth = *argv++;
--argc;
}
}
return enumerator_init(obj, recv, meth, argc, argv);
}
/* :nodoc: */
static VALUE
enumerator_init_copy(VALUE obj, VALUE orig)
{
struct enumerator *ptr0, *ptr1;
ptr0 = enumerator_ptr(orig);
if (ptr0->fib) {
/* Fibers cannot be copied */
rb_raise(rb_eTypeError, "can't copy execution context");
}
TypedData_Get_Struct(obj, struct enumerator, &enumerator_data_type, ptr1);
if (!ptr1) {
rb_raise(rb_eArgError, "unallocated enumerator");
}
ptr1->obj = ptr0->obj;
ptr1->meth = ptr0->meth;
ptr1->args = ptr0->args;
ptr1->fib = 0;
ptr1->lookahead = Qundef;
ptr1->feedvalue = Qundef;
return obj;
}
VALUE
rb_enumeratorize(VALUE obj, VALUE meth, int argc, VALUE *argv)
{
return enumerator_init(enumerator_allocate(rb_cEnumerator), obj, meth, argc, argv);
}
static VALUE
enumerator_block_call(VALUE obj, rb_block_call_func *func, VALUE arg)
{
int argc = 0;
VALUE *argv = 0;
const struct enumerator *e = enumerator_ptr(obj);
ID meth = e->meth;
if (e->args) {
argc = RARRAY_LENINT(e->args);
argv = RARRAY_PTR(e->args);
}
return rb_block_call(e->obj, meth, argc, argv, func, arg);
}
/*
* call-seq:
* enum.each {...}
*
* Iterates over the block according to how this Enumerable was constructed.
* If no block is given, returns self.
*
*/
static VALUE
enumerator_each(int argc, VALUE *argv, VALUE obj)
{
if (argc > 0) {
struct enumerator *e = enumerator_ptr(obj = rb_obj_dup(obj));
VALUE args = e->args;
if (args) {
args = rb_ary_dup(args);
rb_ary_cat(args, argv, argc);
}
else {
args = rb_ary_new4(argc, argv);
}
e->args = args;
}
if (!rb_block_given_p()) return obj;
return enumerator_block_call(obj, 0, obj);
}
static VALUE
enumerator_with_index_i(VALUE val, VALUE m, int argc, VALUE *argv)
{
VALUE idx;
VALUE *memo = (VALUE *)m;
idx = INT2FIX(*memo);
++*memo;
if (argc <= 1)
return rb_yield_values(2, val, idx);
return rb_yield_values(2, rb_ary_new4(argc, argv), idx);
}
/*
* call-seq:
* e.with_index(offset = 0) {|(*args), idx| ... }
* e.with_index(offset = 0)
*
* Iterates the given block for each element with an index, which
* starts from +offset+. If no block is given, returns a new Enumerator
* that includes the index, starting from +offset+
*
* +offset+:: the starting index to use
*
*/
static VALUE
enumerator_with_index(int argc, VALUE *argv, VALUE obj)
{
VALUE memo;
rb_scan_args(argc, argv, "01", &memo);
RETURN_ENUMERATOR(obj, argc, argv);
memo = NIL_P(memo) ? 0 : (VALUE)NUM2LONG(memo);
return enumerator_block_call(obj, enumerator_with_index_i, (VALUE)&memo);
}
/*
* call-seq:
* e.each_with_index {|(*args), idx| ... }
* e.each_with_index
*
* Same as Enumerator#with_index(0), i.e. there is no starting offset.
*
* If no block is given, a new Enumerator is returned that includes the index.
*
*/
static VALUE
enumerator_each_with_index(VALUE obj)
{
return enumerator_with_index(0, NULL, obj);
}
static VALUE
enumerator_with_object_i(VALUE val, VALUE memo, int argc, VALUE *argv)
{
if (argc <= 1)
return rb_yield_values(2, val, memo);
return rb_yield_values(2, rb_ary_new4(argc, argv), memo);
}
/*
* call-seq:
* e.with_object(obj) {|(*args), obj| ... }
* e.with_object(obj)
*
* Iterates the given block for each element with an arbitrary object, +obj+,
* and returns +obj+
*
* If no block is given, returns a new Enumerator.
*
* === Example
*
* to_three = Enumerator.new do |y|
* 3.times do |x|
* y << x
* end
* end
*
* to_three_with_string = to_three.with_object("foo")
* to_three_with_string.each do |x,string|
* puts "#{string}: #{x}"
* end
*
* # => foo:0
* # => foo:1
* # => foo:2
*/
static VALUE
enumerator_with_object(VALUE obj, VALUE memo)
{
RETURN_ENUMERATOR(obj, 1, &memo);
enumerator_block_call(obj, enumerator_with_object_i, memo);
return memo;
}
static VALUE
next_ii(VALUE i, VALUE obj, int argc, VALUE *argv)
{
struct enumerator *e = enumerator_ptr(obj);
VALUE feedvalue = Qnil;
VALUE args = rb_ary_new4(argc, argv);
rb_fiber_yield(1, &args);
if (e->feedvalue != Qundef) {
feedvalue = e->feedvalue;
e->feedvalue = Qundef;
}
return feedvalue;
}
static VALUE
next_i(VALUE curr, VALUE obj)
{
struct enumerator *e = enumerator_ptr(obj);
VALUE nil = Qnil;
VALUE result;
result = rb_block_call(obj, id_each, 0, 0, next_ii, obj);
e->stop_exc = rb_exc_new2(rb_eStopIteration, "iteration reached an end");
rb_ivar_set(e->stop_exc, id_result, result);
return rb_fiber_yield(1, &nil);
}
static void
next_init(VALUE obj, struct enumerator *e)
{
VALUE curr = rb_fiber_current();
e->dst = curr;
e->fib = rb_fiber_new(next_i, obj);
e->lookahead = Qundef;
}
static VALUE
get_next_values(VALUE obj, struct enumerator *e)
{
VALUE curr, vs;
if (e->stop_exc)
rb_exc_raise(e->stop_exc);
curr = rb_fiber_current();
if (!e->fib || !rb_fiber_alive_p(e->fib)) {
next_init(obj, e);
}
vs = rb_fiber_resume(e->fib, 1, &curr);
if (e->stop_exc) {
e->fib = 0;
e->dst = Qnil;
e->lookahead = Qundef;
e->feedvalue = Qundef;
rb_exc_raise(e->stop_exc);
}
return vs;
}
/*
* call-seq:
* e.next_values -> array
*
* Returns the next object as an array in the enumerator, and move the
* internal position forward. When the position reached at the end,
* StopIteration is raised.
*
* This method can be used to distinguish <code>yield</code> and <code>yield
* nil</code>.
*
* === Example
*
* o = Object.new
* def o.each
* yield
* yield 1
* yield 1, 2
* yield nil
* yield [1, 2]
* end
* e = o.to_enum
* p e.next_values
* p e.next_values
* p e.next_values
* p e.next_values
* p e.next_values
* e = o.to_enum
* p e.next
* p e.next
* p e.next
* p e.next
* p e.next
*
* ## yield args next_values next
* # yield [] nil
* # yield 1 [1] 1
* # yield 1, 2 [1, 2] [1, 2]
* # yield nil [nil] nil
* # yield [1, 2] [[1, 2]] [1, 2]
*
* Note that +next_values+ does not affect other non-external enumeration
* methods unless underlying iteration method itself has side-effect, e.g.
* IO#each_line.
*
*/
static VALUE
enumerator_next_values(VALUE obj)
{
struct enumerator *e = enumerator_ptr(obj);
VALUE vs;
if (e->lookahead != Qundef) {
vs = e->lookahead;
e->lookahead = Qundef;
return vs;
}
return get_next_values(obj, e);
}
static VALUE
ary2sv(VALUE args, int dup)
{
if (!RB_TYPE_P(args, T_ARRAY))
return args;
switch (RARRAY_LEN(args)) {
case 0:
return Qnil;
case 1:
return RARRAY_PTR(args)[0];
default:
if (dup)
return rb_ary_dup(args);
return args;
}
}
/*
* call-seq:
* e.next -> object
*
* Returns the next object in the enumerator, and move the internal position
* forward. When the position reached at the end, StopIteration is raised.
*
* === Example
*
* a = [1,2,3]
* e = a.to_enum
* p e.next #=> 1
* p e.next #=> 2
* p e.next #=> 3
* p e.next #raises StopIteration
*
* Note that enumeration sequence by +next+ does not affect other non-external
* enumeration methods, unless the underlying iteration methods itself has
* side-effect, e.g. IO#each_line.
*
*/
static VALUE
enumerator_next(VALUE obj)
{
VALUE vs = enumerator_next_values(obj);
return ary2sv(vs, 0);
}
static VALUE
enumerator_peek_values(VALUE obj)
{
struct enumerator *e = enumerator_ptr(obj);
if (e->lookahead == Qundef) {
e->lookahead = get_next_values(obj, e);
}
return e->lookahead;
}
/*
* call-seq:
* e.peek_values -> array
*
* Returns the next object as an array, similar to Enumerator#next_values, but
* doesn't move the internal position forward. If the position is already at
* the end, StopIteration is raised.
*
* === Example
*
* o = Object.new
* def o.each
* yield
* yield 1
* yield 1, 2
* end
* e = o.to_enum
* p e.peek_values #=> []
* e.next
* p e.peek_values #=> [1]
* p e.peek_values #=> [1]
* e.next
* p e.peek_values #=> [1, 2]
* e.next
* p e.peek_values # raises StopIteration
*
*/
static VALUE
enumerator_peek_values_m(VALUE obj)
{
return rb_ary_dup(enumerator_peek_values(obj));
}
/*
* call-seq:
* e.peek -> object
*
* Returns the next object in the enumerator, but doesn't move the internal
* position forward. If the position is already at the end, StopIteration
* is raised.
*
* === Example
*
* a = [1,2,3]
* e = a.to_enum
* p e.next #=> 1
* p e.peek #=> 2
* p e.peek #=> 2
* p e.peek #=> 2
* p e.next #=> 2
* p e.next #=> 3
* p e.next #raises StopIteration
*
*/
static VALUE
enumerator_peek(VALUE obj)
{
VALUE vs = enumerator_peek_values(obj);
return ary2sv(vs, 1);
}
/*
* call-seq:
* e.feed obj -> nil
*
* Sets the value to be returned by the next yield inside +e+.
*
* If the value is not set, the yield returns nil.
*
* This value is cleared after being yielded.
*
* o = Object.new
* def o.each
* x = yield # (2) blocks
* p x # (5) => "foo"
* x = yield # (6) blocks
* p x # (8) => nil
* x = yield # (9) blocks
* p x # not reached w/o another e.next
* end
*
* e = o.to_enum
* e.next # (1)
* e.feed "foo" # (3)
* e.next # (4)
* e.next # (7)
* # (10)
*/
static VALUE
enumerator_feed(VALUE obj, VALUE v)
{
struct enumerator *e = enumerator_ptr(obj);
if (e->feedvalue != Qundef) {
rb_raise(rb_eTypeError, "feed value already set");
}
e->feedvalue = v;
return Qnil;
}
/*
* call-seq:
* e.rewind -> e
*
* Rewinds the enumeration sequence to the beginning.
*
* If the enclosed object responds to a "rewind" method, it is called.
*/
static VALUE
enumerator_rewind(VALUE obj)
{
struct enumerator *e = enumerator_ptr(obj);
rb_check_funcall(e->obj, id_rewind, 0, 0);
e->fib = 0;
e->dst = Qnil;
e->lookahead = Qundef;
e->feedvalue = Qundef;
e->stop_exc = Qfalse;
return obj;
}
static VALUE
inspect_enumerator(VALUE obj, VALUE dummy, int recur)
{
struct enumerator *e;
const char *cname;
VALUE eobj, eargs, str, method;
int tainted, untrusted;
TypedData_Get_Struct(obj, struct enumerator, &enumerator_data_type, e);
cname = rb_obj_classname(obj);
if (!e || e->obj == Qundef) {
return rb_sprintf("#<%s: uninitialized>", cname);
}
if (recur) {
str = rb_sprintf("#<%s: ...>", cname);
OBJ_TAINT(str);
return str;
}
eobj = rb_attr_get(obj, id_receiver);
if (NIL_P(eobj)) {
eobj = e->obj;
}
tainted = OBJ_TAINTED(eobj);
untrusted = OBJ_UNTRUSTED(eobj);
/* (1..100).each_cons(2) => "#<Enumerator: 1..100:each_cons(2)>" */
str = rb_sprintf("#<%s: ", cname);
rb_str_concat(str, rb_inspect(eobj));
method = rb_attr_get(obj, id_method);
if (NIL_P(method)) {
rb_str_buf_cat2(str, ":");
rb_str_buf_cat2(str, rb_id2name(e->meth));
}
else if (method != Qfalse) {
Check_Type(method, T_SYMBOL);
rb_str_buf_cat2(str, ":");
rb_str_buf_cat2(str, rb_id2name(SYM2ID(method)));
}
eargs = rb_attr_get(obj, id_arguments);
if (NIL_P(eargs)) {
eargs = e->args;
}
if (eargs != Qfalse) {
long argc = RARRAY_LEN(eargs);
VALUE *argv = RARRAY_PTR(eargs);
if (argc > 0) {
rb_str_buf_cat2(str, "(");
while (argc--) {
VALUE arg = *argv++;
rb_str_concat(str, rb_inspect(arg));
rb_str_buf_cat2(str, argc > 0 ? ", " : ")");
if (OBJ_TAINTED(arg)) tainted = TRUE;
if (OBJ_UNTRUSTED(arg)) untrusted = TRUE;
}
}
}
rb_str_buf_cat2(str, ">");
if (tainted) OBJ_TAINT(str);
if (untrusted) OBJ_UNTRUST(str);
return str;
}
/*
* call-seq:
* e.inspect -> string
*
* Creates a printable version of <i>e</i>.
*/
static VALUE
enumerator_inspect(VALUE obj)
{
return rb_exec_recursive(inspect_enumerator, obj, 0);
}
/*
* Yielder
*/
static void
yielder_mark(void *p)
{
struct yielder *ptr = p;
rb_gc_mark(ptr->proc);
}
#define yielder_free RUBY_TYPED_DEFAULT_FREE
static size_t
yielder_memsize(const void *p)
{
return p ? sizeof(struct yielder) : 0;
}
static const rb_data_type_t yielder_data_type = {
"yielder",
{
yielder_mark,
yielder_free,
yielder_memsize,
},
};
static struct yielder *
yielder_ptr(VALUE obj)
{
struct yielder *ptr;
TypedData_Get_Struct(obj, struct yielder, &yielder_data_type, ptr);
if (!ptr || ptr->proc == Qundef) {
rb_raise(rb_eArgError, "uninitialized yielder");
}
return ptr;
}
/* :nodoc: */
static VALUE
yielder_allocate(VALUE klass)
{
struct yielder *ptr;
VALUE obj;
obj = TypedData_Make_Struct(klass, struct yielder, &yielder_data_type, ptr);
ptr->proc = Qundef;
return obj;
}
static VALUE
yielder_init(VALUE obj, VALUE proc)
{
struct yielder *ptr;
TypedData_Get_Struct(obj, struct yielder, &yielder_data_type, ptr);
if (!ptr) {
rb_raise(rb_eArgError, "unallocated yielder");
}
ptr->proc = proc;
return obj;
}
/* :nodoc: */
static VALUE
yielder_initialize(VALUE obj)
{
rb_need_block();
return yielder_init(obj, rb_block_proc());
}
/* :nodoc: */
static VALUE
yielder_yield(VALUE obj, VALUE args)
{
struct yielder *ptr = yielder_ptr(obj);
return rb_proc_call(ptr->proc, args);
}
/* :nodoc: */
static VALUE yielder_yield_push(VALUE obj, VALUE args)
{
yielder_yield(obj, args);
return obj;
}
static VALUE
yielder_yield_i(VALUE obj, VALUE memo, int argc, VALUE *argv)
{
return rb_yield_values2(argc, argv);
}
static VALUE
yielder_new(void)
{
return yielder_init(yielder_allocate(rb_cYielder), rb_proc_new(yielder_yield_i, 0));
}
/*
* Generator
*/
static void
generator_mark(void *p)
{
struct generator *ptr = p;
rb_gc_mark(ptr->proc);
}
#define generator_free RUBY_TYPED_DEFAULT_FREE
static size_t
generator_memsize(const void *p)
{
return p ? sizeof(struct generator) : 0;
}
static const rb_data_type_t generator_data_type = {
"generator",
{
generator_mark,
generator_free,
generator_memsize,
},
};
static struct generator *
generator_ptr(VALUE obj)
{
struct generator *ptr;
TypedData_Get_Struct(obj, struct generator, &generator_data_type, ptr);
if (!ptr || ptr->proc == Qundef) {
rb_raise(rb_eArgError, "uninitialized generator");
}
return ptr;
}
/* :nodoc: */
static VALUE
generator_allocate(VALUE klass)
{
struct generator *ptr;
VALUE obj;
obj = TypedData_Make_Struct(klass, struct generator, &generator_data_type, ptr);
ptr->proc = Qundef;
return obj;
}
static VALUE
generator_init(VALUE obj, VALUE proc)
{
struct generator *ptr;
TypedData_Get_Struct(obj, struct generator, &generator_data_type, ptr);
if (!ptr) {
rb_raise(rb_eArgError, "unallocated generator");
}
ptr->proc = proc;
return obj;
}
/* :nodoc: */
static VALUE
generator_initialize(int argc, VALUE *argv, VALUE obj)
{
VALUE proc;
if (argc == 0) {
rb_need_block();
proc = rb_block_proc();
}
else {
rb_scan_args(argc, argv, "1", &proc);
if (!rb_obj_is_proc(proc))
rb_raise(rb_eTypeError,
"wrong argument type %s (expected Proc)",
rb_obj_classname(proc));
if (rb_block_given_p()) {
rb_warn("given block not used");
}
}
return generator_init(obj, proc);
}
/* :nodoc: */
static VALUE
generator_init_copy(VALUE obj, VALUE orig)
{
struct generator *ptr0, *ptr1;
ptr0 = generator_ptr(orig);
TypedData_Get_Struct(obj, struct generator, &generator_data_type, ptr1);
if (!ptr1) {
rb_raise(rb_eArgError, "unallocated generator");
}
ptr1->proc = ptr0->proc;
return obj;
}
/* :nodoc: */
static VALUE
generator_each(int argc, VALUE *argv, VALUE obj)
{
struct generator *ptr = generator_ptr(obj);
VALUE args = rb_ary_new2(argc + 1);
rb_ary_push(args, yielder_new());
if (argc > 0) {
rb_ary_cat(args, argv, argc);
}
return rb_proc_call(ptr->proc, args);
}
/* Lazy Enumerator methods */
static VALUE
lazy_init_iterator(VALUE val, VALUE m, int argc, VALUE *argv)
{
VALUE result;
if (argc == 1) {
VALUE args[2];
args[0] = m;
args[1] = val;
result = rb_yield_values2(2, args);
}
else {
VALUE args;
int len = rb_long2int((long)argc + 1);
args = rb_ary_tmp_new(len);
rb_ary_push(args, m);
if (argc > 0) {
rb_ary_cat(args, argv, argc);
}
result = rb_yield_values2(len, RARRAY_PTR(args));
RB_GC_GUARD(args);
}
if (result == Qundef) rb_iter_break();
return Qnil;
}
static VALUE
lazy_init_yielder(VALUE val, VALUE m, int argc, VALUE *argv)
{
VALUE result;
result = rb_funcall2(m, id_yield, argc, argv);
if (result == Qundef) rb_iter_break();
return Qnil;
}
static VALUE
lazy_init_block_i(VALUE val, VALUE m, int argc, VALUE *argv)
{
rb_block_call(m, id_each, argc-1, argv+1, lazy_init_iterator, val);
return Qnil;
}
static VALUE
lazy_init_block(VALUE val, VALUE m, int argc, VALUE *argv)
{
rb_block_call(m, id_each, argc-1, argv+1, lazy_init_yielder, val);
return Qnil;
}
static VALUE
lazy_initialize(int argc, VALUE *argv, VALUE self)
{
VALUE obj, meth;
VALUE generator;
int offset;
if (argc < 1) {
rb_raise(rb_eArgError, "wrong number of arguments (%d for 1..)", argc);
}
else {
obj = argv[0];
if (argc == 1) {
meth = sym_each;
offset = 1;
}
else {
meth = argv[1];
offset = 2;
}
}
generator = generator_allocate(rb_cGenerator);
rb_block_call(generator, id_initialize, 0, 0,
(rb_block_given_p() ? lazy_init_block_i : lazy_init_block),
obj);
enumerator_init(self, generator, meth, argc - offset, argv + offset);
rb_ivar_set(self, id_receiver, obj);
return self;
}
static VALUE
lazy_set_method(VALUE lazy, VALUE args)
{
ID id = rb_frame_this_func();
rb_ivar_set(lazy, id_method, ID2SYM(id));
if (NIL_P(args)) {
/* Qfalse indicates that the arguments are empty */
rb_ivar_set(lazy, id_arguments, Qfalse);
}
else {
rb_ivar_set(lazy, id_arguments, args);
}
return lazy;
}
/*
* call-seq:
* e.lazy -> lazy_enumerator
*
* Returns a lazy enumerator, whose methods map/collect,
* flat_map/collect_concat, select/find_all, reject, grep, zip, take,
* take_while, drop, drop_while, and cycle enumerate values only on an
* as-needed basis. However, if a block is given to zip or cycle, values
* are enumerated immediately.
*
* === Example
*
* The following program finds pythagorean triples:
*
* def pythagorean_triples
* (1..Float::INFINITY).lazy.flat_map {|z|
* (1..z).flat_map {|x|
* (x..z).select {|y|
* x**2 + y**2 == z**2
* }.map {|y|
* [x, y, z]
* }
* }
* }
* end
* # show first ten pythagorean triples
* p pythagorean_triples.take(10).force # take is lazy, so force is needed
* p pythagorean_triples.first(10) # first is eager
* # show pythagorean triples less than 100
* p pythagorean_triples.take_while { |*, z| z < 100 }.force
*/
static VALUE
enumerable_lazy(VALUE obj)
{
VALUE result;
result = rb_class_new_instance(1, &obj, rb_cLazy);
/* Qfalse indicates that the Enumerator::Lazy has no method name */
rb_ivar_set(result, id_method, Qfalse);
return result;
}
static VALUE
lazy_map_func(VALUE val, VALUE m, int argc, VALUE *argv)
{
VALUE result = rb_yield_values2(argc - 1, &argv[1]);
rb_funcall(argv[0], id_yield, 1, result);
return Qnil;
}
static VALUE
lazy_map(VALUE obj)
{
if (!rb_block_given_p()) {
rb_raise(rb_eArgError, "tried to call lazy map without a block");
}
return lazy_set_method(rb_block_call(rb_cLazy, id_new, 1, &obj,
lazy_map_func, 0),
Qnil);
}
static VALUE
lazy_flat_map_i(VALUE i, VALUE yielder, int argc, VALUE *argv)
{
return rb_funcall2(yielder, id_yield, argc, argv);
}
static VALUE
lazy_flat_map_each(VALUE obj)
{
NODE *memo = RNODE(obj);
rb_block_call(memo->u1.value, id_each, 0, 0, lazy_flat_map_i,
memo->u2.value);
return Qnil;
}
static VALUE
lazy_flat_map_to_ary(VALUE obj)
{
NODE *memo = RNODE(obj);
VALUE ary = rb_check_array_type(memo->u1.value);
if (NIL_P(ary)) {
rb_funcall(memo->u2.value, id_yield, 1, memo->u1.value);
}
else {
long i;
for (i = 0; i < RARRAY_LEN(ary); i++) {
rb_funcall(memo->u2.value, id_yield, 1, RARRAY_PTR(ary)[i]);
}
}
return Qnil;
}
static VALUE
lazy_flat_map_func(VALUE val, VALUE m, int argc, VALUE *argv)
{
VALUE result = rb_yield_values2(argc - 1, &argv[1]);
if (TYPE(result) == T_ARRAY) {
long i;
for (i = 0; i < RARRAY_LEN(result); i++) {
rb_funcall(argv[0], id_yield, 1, RARRAY_PTR(result)[i]);
}
}
else {
NODE *memo;
memo = NEW_MEMO(result, argv[0], 0);
rb_rescue2(lazy_flat_map_each, (VALUE) memo,
lazy_flat_map_to_ary, (VALUE) memo,
rb_eNoMethodError, (VALUE)0);
}
return Qnil;
}
static VALUE
lazy_flat_map(VALUE obj)
{
if (!rb_block_given_p()) {
rb_raise(rb_eArgError, "tried to call lazy flat_map without a block");
}
return lazy_set_method(rb_block_call(rb_cLazy, id_new, 1, &obj,
lazy_flat_map_func, 0),
Qnil);
}
static VALUE
lazy_select_func(VALUE val, VALUE m, int argc, VALUE *argv)
{
VALUE element = rb_enum_values_pack(argc - 1, argv + 1);
if (RTEST(rb_yield(element))) {
return rb_funcall(argv[0], id_yield, 1, element);
}
return Qnil;
}
static VALUE
lazy_select(VALUE obj)
{
if (!rb_block_given_p()) {
rb_raise(rb_eArgError, "tried to call lazy select without a block");
}
return lazy_set_method(rb_block_call(rb_cLazy, id_new, 1, &obj,
lazy_select_func, 0),
Qnil);
}
static VALUE
lazy_reject_func(VALUE val, VALUE m, int argc, VALUE *argv)
{
VALUE element = rb_enum_values_pack(argc - 1, argv + 1);
if (!RTEST(rb_yield(element))) {
return rb_funcall(argv[0], id_yield, 1, element);
}
return Qnil;
}
static VALUE
lazy_reject(VALUE obj)
{
if (!rb_block_given_p()) {
rb_raise(rb_eArgError, "tried to call lazy reject without a block");
}
return lazy_set_method(rb_block_call(rb_cLazy, id_new, 1, &obj,
lazy_reject_func, 0),
Qnil);
}
static VALUE
lazy_grep_func(VALUE val, VALUE m, int argc, VALUE *argv)
{
VALUE i = rb_enum_values_pack(argc - 1, argv + 1);
VALUE result = rb_funcall(m, id_eqq, 1, i);
if (RTEST(result)) {
rb_funcall(argv[0], id_yield, 1, i);
}
return Qnil;
}
static VALUE
lazy_grep_iter(VALUE val, VALUE m, int argc, VALUE *argv)
{
VALUE i = rb_enum_values_pack(argc - 1, argv + 1);
VALUE result = rb_funcall(m, id_eqq, 1, i);
if (RTEST(result)) {
rb_funcall(argv[0], id_yield, 1, rb_yield(i));
}
return Qnil;
}
static VALUE
lazy_grep(VALUE obj, VALUE pattern)
{
return lazy_set_method(rb_block_call(rb_cLazy, id_new, 1, &obj,
rb_block_given_p() ?
lazy_grep_iter : lazy_grep_func,
pattern),
rb_ary_new3(1, pattern));
}
static VALUE
call_next(VALUE obj)
{
return rb_funcall(obj, id_next, 0);
}
static VALUE
next_stopped(VALUE obj)
{
return Qnil;
}
static VALUE
lazy_zip_func(VALUE val, VALUE arg, int argc, VALUE *argv)
{
VALUE yielder, ary, v;
long i;
yielder = argv[0];
ary = rb_ary_new2(RARRAY_LEN(arg) + 1);
rb_ary_push(ary, argv[1]);
for (i = 0; i < RARRAY_LEN(arg); i++) {
v = rb_rescue2(call_next, RARRAY_PTR(arg)[i], next_stopped, 0,
rb_eStopIteration, (VALUE)0);
rb_ary_push(ary, v);
}
rb_funcall(yielder, id_yield, 1, ary);
return Qnil;
}
static VALUE
lazy_zip(int argc, VALUE *argv, VALUE obj)
{
VALUE ary;
int i;
if (rb_block_given_p()) {
return rb_call_super(argc, argv);
}
ary = rb_ary_new2(argc);
for (i = 0; i < argc; i++) {
rb_ary_push(ary, rb_funcall(argv[i], id_lazy, 0));
}
return lazy_set_method(rb_block_call(rb_cLazy, id_new, 1, &obj,
lazy_zip_func, ary),
rb_ary_new4(argc, argv));
}
static VALUE
lazy_take_func(VALUE val, VALUE args, int argc, VALUE *argv)
{
NODE *memo = RNODE(args);
rb_funcall2(argv[0], id_yield, argc - 1, argv + 1);
if (--memo->u3.cnt == 0) {
memo->u3.cnt = memo->u2.argc;
return Qundef;
}
else {
return Qnil;
}
}
static VALUE
lazy_take(VALUE obj, VALUE n)
{
NODE *memo;
long len = NUM2LONG(n);
int argc = 1;
VALUE argv[3];
if (len < 0) {
rb_raise(rb_eArgError, "attempt to take negative size");
}
argv[0] = obj;
if (len == 0) {
argv[1] = sym_cycle;
argv[2] = INT2NUM(0);
argc = 3;
}
memo = NEW_MEMO(0, len, len);
return lazy_set_method(rb_block_call(rb_cLazy, id_new, argc, argv,
lazy_take_func, (VALUE) memo),
rb_ary_new3(1, n));
}
static VALUE
lazy_take_while_func(VALUE val, VALUE args, int argc, VALUE *argv)
{
VALUE result = rb_yield_values2(argc - 1, &argv[1]);
if (!RTEST(result)) return Qundef;
rb_funcall2(argv[0], id_yield, argc - 1, argv + 1);
return Qnil;
}
static VALUE
lazy_take_while(VALUE obj)
{
return lazy_set_method(rb_block_call(rb_cLazy, id_new, 1, &obj,
lazy_take_while_func, 0),
Qnil);
}
static VALUE
lazy_drop_func(VALUE val, VALUE args, int argc, VALUE *argv)
{
NODE *memo = RNODE(args);
if (memo->u3.cnt == 0) {
rb_funcall2(argv[0], id_yield, argc - 1, argv + 1);
}
else {
memo->u3.cnt--;
}
return Qnil;
}
static VALUE
lazy_drop(VALUE obj, VALUE n)
{
NODE *memo;
long len = NUM2LONG(n);
if (len < 0) {
rb_raise(rb_eArgError, "attempt to drop negative size");
}
memo = NEW_MEMO(0, 0, len);
return lazy_set_method(rb_block_call(rb_cLazy, id_new, 1, &obj,
lazy_drop_func, (VALUE) memo),
rb_ary_new3(1, n));
}
static VALUE
lazy_drop_while_func(VALUE val, VALUE args, int argc, VALUE *argv)
{
NODE *memo = RNODE(args);
if (!memo->u3.state && !RTEST(rb_yield_values2(argc - 1, &argv[1]))) {
memo->u3.state = TRUE;
}
if (memo->u3.state) {
rb_funcall2(argv[0], id_yield, argc - 1, argv + 1);
}
return Qnil;
}
static VALUE
lazy_drop_while(VALUE obj)
{
NODE *memo;
memo = NEW_MEMO(0, 0, FALSE);
return lazy_set_method(rb_block_call(rb_cLazy, id_new, 1, &obj,
lazy_drop_while_func, (VALUE) memo),
Qnil);
}
static VALUE
lazy_cycle_func(VALUE val, VALUE m, int argc, VALUE *argv)
{
return rb_funcall2(argv[0], id_yield, argc - 1, argv + 1);
}
static VALUE
lazy_cycle(int argc, VALUE *argv, VALUE obj)
{
VALUE args;
int len = rb_long2int((long)argc + 2);
if (rb_block_given_p()) {
return rb_call_super(argc, argv);
}
args = rb_ary_tmp_new(len);
rb_ary_push(args, obj);
rb_ary_push(args, sym_cycle);
if (argc > 0) {
rb_ary_cat(args, argv, argc);
}
return lazy_set_method(rb_block_call(rb_cLazy, id_new, len,
RARRAY_PTR(args), lazy_cycle_func,
args /* prevent from GC */),
rb_ary_new4(argc, argv));
}
static VALUE
lazy_lazy(VALUE obj)
{
return obj;
}
/*
* Document-class: StopIteration
*
* Raised to stop the iteration, in particular by Enumerator#next. It is
* rescued by Kernel#loop.
*
* loop do
* puts "Hello"
* raise StopIteration
* puts "World"
* end
* puts "Done!"
*
* <em>produces:</em>
*
* Hello
* Done!
*/
/*
* call-seq:
* result -> value
*
* Returns the return value of the iterator.
*
* o = Object.new
* def o.each
* yield 1
* yield 2
* yield 3
* 100
* end
*
* e = o.to_enum
*
* puts e.next #=> 1
* puts e.next #=> 2
* puts e.next #=> 3
*
* begin
* e.next
* rescue StopIteration => ex
* puts ex.result #=> 100
* end
*
*/
static VALUE
stop_result(VALUE self)
{
return rb_attr_get(self, id_result);
}
void
InitVM_Enumerator(void)
{
rb_define_method(rb_mKernel, "to_enum", obj_to_enum, -1);
rb_define_method(rb_mKernel, "enum_for", obj_to_enum, -1);
rb_cEnumerator = rb_define_class("Enumerator", rb_cObject);
rb_include_module(rb_cEnumerator, rb_mEnumerable);
rb_define_alloc_func(rb_cEnumerator, enumerator_allocate);
rb_define_method(rb_cEnumerator, "initialize", enumerator_initialize, -1);
rb_define_method(rb_cEnumerator, "initialize_copy", enumerator_init_copy, 1);
rb_define_method(rb_cEnumerator, "each", enumerator_each, -1);
rb_define_method(rb_cEnumerator, "each_with_index", enumerator_each_with_index, 0);
rb_define_method(rb_cEnumerator, "each_with_object", enumerator_with_object, 1);
rb_define_method(rb_cEnumerator, "with_index", enumerator_with_index, -1);
rb_define_method(rb_cEnumerator, "with_object", enumerator_with_object, 1);
rb_define_method(rb_cEnumerator, "next_values", enumerator_next_values, 0);
rb_define_method(rb_cEnumerator, "peek_values", enumerator_peek_values_m, 0);
rb_define_method(rb_cEnumerator, "next", enumerator_next, 0);
rb_define_method(rb_cEnumerator, "peek", enumerator_peek, 0);
rb_define_method(rb_cEnumerator, "feed", enumerator_feed, 1);
rb_define_method(rb_cEnumerator, "rewind", enumerator_rewind, 0);
rb_define_method(rb_cEnumerator, "inspect", enumerator_inspect, 0);
/* Lazy */
rb_cLazy = rb_define_class_under(rb_cEnumerator, "Lazy", rb_cEnumerator);
rb_define_method(rb_mEnumerable, "lazy", enumerable_lazy, 0);
rb_define_method(rb_cLazy, "initialize", lazy_initialize, -1);
rb_define_method(rb_cLazy, "map", lazy_map, 0);
rb_define_method(rb_cLazy, "collect", lazy_map, 0);
rb_define_method(rb_cLazy, "flat_map", lazy_flat_map, 0);
rb_define_method(rb_cLazy, "collect_concat", lazy_flat_map, 0);
rb_define_method(rb_cLazy, "select", lazy_select, 0);
rb_define_method(rb_cLazy, "find_all", lazy_select, 0);
rb_define_method(rb_cLazy, "reject", lazy_reject, 0);
rb_define_method(rb_cLazy, "grep", lazy_grep, 1);
rb_define_method(rb_cLazy, "zip", lazy_zip, -1);
rb_define_method(rb_cLazy, "take", lazy_take, 1);
rb_define_method(rb_cLazy, "take_while", lazy_take_while, 0);
rb_define_method(rb_cLazy, "drop", lazy_drop, 1);
rb_define_method(rb_cLazy, "drop_while", lazy_drop_while, 0);
rb_define_method(rb_cLazy, "cycle", lazy_cycle, -1);
rb_define_method(rb_cLazy, "lazy", lazy_lazy, 0);
rb_define_alias(rb_cLazy, "force", "to_a");
rb_eStopIteration = rb_define_class("StopIteration", rb_eIndexError);
rb_define_method(rb_eStopIteration, "result", stop_result, 0);
/* Generator */
rb_cGenerator = rb_define_class_under(rb_cEnumerator, "Generator", rb_cObject);
rb_include_module(rb_cGenerator, rb_mEnumerable);
rb_define_alloc_func(rb_cGenerator, generator_allocate);
rb_define_method(rb_cGenerator, "initialize", generator_initialize, -1);
rb_define_method(rb_cGenerator, "initialize_copy", generator_init_copy, 1);
rb_define_method(rb_cGenerator, "each", generator_each, -1);
/* Yielder */
rb_cYielder = rb_define_class_under(rb_cEnumerator, "Yielder", rb_cObject);
rb_define_alloc_func(rb_cYielder, yielder_allocate);
rb_define_method(rb_cYielder, "initialize", yielder_initialize, 0);
rb_define_method(rb_cYielder, "yield", yielder_yield, -2);
rb_define_method(rb_cYielder, "<<", yielder_yield_push, -2);
rb_provide("enumerator.so"); /* for backward compatibility */
}
void
Init_Enumerator(void)
{
id_rewind = rb_intern("rewind");
id_each = rb_intern("each");
id_call = rb_intern("call");
id_yield = rb_intern("yield");
id_new = rb_intern("new");
id_initialize = rb_intern("initialize");
id_next = rb_intern("next");
id_result = rb_intern("result");
id_lazy = rb_intern("lazy");
id_eqq = rb_intern("===");
id_receiver = rb_intern("receiver");
id_arguments = rb_intern("arguments");
id_method = rb_intern("method");
sym_each = ID2SYM(id_each);
sym_cycle = ID2SYM(rb_intern("cycle"));
InitVM(Enumerator);
}
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