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Update doc. and warnings.

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git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47864 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
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akr 2014-10-10 09:42:47 +00:00
parent b44c47d102
commit 5a77a4e71b
1 changed files with 29 additions and 28 deletions
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57
enum.c
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@ -2835,12 +2835,6 @@ chunk_i(RB_BLOCK_CALL_FUNC_ARGLIST(yielder, enumerator))
* }
* }
*
* If the block needs to maintain state over multiple elements,
* an +initial_state+ argument can be used.
* If a non-nil value is given,
* a reference to it is passed as the 2nd argument of the block for the
* +chunk+ method, so state-changes to it persist across block calls.
*
*/
static VALUE
enum_chunk(int argc, VALUE *argv, VALUE enumerable)
@ -2853,7 +2847,7 @@ enum_chunk(int argc, VALUE *argv, VALUE enumerable)
rb_raise(rb_eArgError, "no block given");
n = rb_scan_args(argc, argv, "01", &initial_state);
if (n != 0)
rb_warn("initial_state given for chunk. (Use Enumerator.new with lexical scope variables.)");
rb_warn("initial_state given for chunk. (Use local variables.)");
enumerator = rb_obj_alloc(rb_cEnumerator);
rb_ivar_set(enumerator, rb_intern("chunk_enumerable"), enumerable);
@ -2946,7 +2940,6 @@ slicebefore_i(RB_BLOCK_CALL_FUNC_ARGLIST(yielder, enumerator))
*
* enum.slice_before(pattern).each { |ary| ... }
* enum.slice_before { |elt| bool }.each { |ary| ... }
* enum.slice_before(initial_state) { |elt, state| bool }.each { |ary| ... }
*
* Other methods of the Enumerator class and Enumerable module,
* such as map, etc., are also usable.
@ -2992,33 +2985,34 @@ slicebefore_i(RB_BLOCK_CALL_FUNC_ARGLIST(yielder, enumerator))
* }.join(",")
* #=> "0,2-4,6,7,9"
*
* However local variables are not appropriate to maintain state
* if the result enumerator is used twice or more.
* In such a case, the last state of the 1st +each+ is used in the 2nd +each+.
* The _initial_state_ argument can be used to avoid this problem.
* If non-nil value is given as _initial_state_,
* it is duplicated for each +each+ method invocation of the enumerator.
* The duplicated object is passed to 2nd argument of the block for
* +slice_before+ method.
* However local variables should be used carefully
* if the result enumerator is enumerated twice or more.
* The local variables should be initialized for each enumeration.
* Enumerator.new can be used to do it.
*
* # Word wrapping. This assumes all characters have same width.
* def wordwrap(words, maxwidth)
* # if cols is a local variable, 2nd "each" may start with non-zero cols.
* words.slice_before(cols: 0) { |w, h|
* h[:cols] += 1 if h[:cols] != 0
* h[:cols] += w.length
* if maxwidth < h[:cols]
* h[:cols] = w.length
* true
* else
* false
* end
* Enumerator.new {|y|
* # cols is initialized in Enumerator.new.
* cols = 0
* words.slice_before { |w|
* cols += 1 if cols != 0
* cols += w.length
* if maxwidth < cols
* cols = w.length
* true
* else
* false
* end
* }.each {|ws| y.yield ws }
* }
* end
* text = (1..20).to_a.join(" ")
* enum = wordwrap(text.split(/\s+/), 10)
* puts "-"*10
* enum.each { |ws| puts ws.join(" ") }
* enum.each { |ws| puts ws.join(" ") } # first enumeration.
* puts "-"*10
* enum.each { |ws| puts ws.join(" ") } # second enumeration generates same result as the first.
* puts "-"*10
* #=> ----------
* # 1 2 3 4 5
@ -3028,6 +3022,13 @@ slicebefore_i(RB_BLOCK_CALL_FUNC_ARGLIST(yielder, enumerator))
* # 17 18 19
* # 20
* # ----------
* # 1 2 3 4 5
* # 6 7 8 9 10
* # 11 12 13
* # 14 15 16
* # 17 18 19
* # 20
* # ----------
*
* mbox contains series of mails which start with Unix From line.
* So each mail can be extracted by slice before Unix From line.
@ -3072,7 +3073,7 @@ enum_slice_before(int argc, VALUE *argv, VALUE enumerable)
int n;
n = rb_scan_args(argc, argv, "01", &initial_state);
if (n != 0)
rb_warn("initial_state given for slice_before. (Use Enumerator.new with lexical scope variables.)");
rb_warn("initial_state given for slice_before. (Use local variables.)");
enumerator = rb_obj_alloc(rb_cEnumerator);
rb_ivar_set(enumerator, rb_intern("slicebefore_sep_pred"), rb_block_proc());
rb_ivar_set(enumerator, rb_intern("slicebefore_initial_state"), initial_state);