# Nested fiber invocation

**URL:** <https://www.ruby-forum.com/t/nested-fiber-invocation/112383>\
**Category:** Development\
**Created:** [August 18, 2007, 3:19am UTC](https://www.ruby-forum.com/t/nested-fiber-invocation/112383 "2007-08-18T03:19:07Z")\
**Posts on this page:** 8\
**Page:** 1

<div class="post-metadata">

**Author:** ![Yukihiro\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c57346/32.png) [@Yukihiro\_M](https://www.ruby-forum.com/u/Yukihiro_M)\
**Post date:** [August 18, 2007, 3:19am UTC](https://www.ruby-forum.com/t/nested-fiber-invocation/112383/1 "2007-08-18T03:19:07Z")

</div>

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

e$B1sF#$5$s$+$ie(B

[外部イテレータにケチをつける - まめめも](http://d.hatena.ne.jp/ku-ma-me/20070817/p2)

e$B$G;XE&$5$l$F$$$k$N$G$9$,!“e(BEnumerator#nexte$B$NFbB&$G$5$i$Ke(B  
Enumerator#nexte$B$,8F$P$l$k$H!”%(%i!\<$K$J$j$^$9!#%G%P%C%,$GDI$$e(B  
e$B$+$1$k$He(B rb\_fiber\_yield()  
e$B$+$iEO$7$?CM$H0c$&$b$Ne(B(yielde$B$5$l$?e(B  
e$BCM!)e(B)e$B$,5"$C$F$-$F$$$k$h$&$G$9!#e(B

def (o = Object.new).each  
yield 0  
p [1,2,3].to\_enum.next  
end

p o.to\_enum.next # =\> double.rb:6:in `': unhandled exception

current  
fibere$B$re(Byielde$B$7$F$$$k$O$:$J$N$K!"e(BFIXNUMe$B$Ne(B0(yielde$B$7$?e(B  
e$BCM!)e(B)e$B$,EO$5$l$k!#e(B0e$B$Oe(BFibere$B$G$O$J$$$N$Ge(BTypeErrore$BNc30$,H/@8$7$Fe(B  
e$B$$$k!#e(B

e$B;d$Ne(BFibere$B$NCN\<1$G$O$3$3$^$G$,8B3&$G$7$?!#$3$l$O%P%0$G$7$g$&e(B  
e$B$+!“$=$l$H$b@)8B$H$9$Y$-$G$7$g$&$+!#$G$-$l$P!”%M%9%H$G$-$J$$e(B  
e$B$H8@$&@)8B$O$J$$J}$,$&$l$7$$$N$G$9$,!#e(B

```
                            e$B$^$D$b$He(B e$B$f$-$R$me(B /:|)

```

---

<div class="post-metadata">

**Author:** ![Yukihiro\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c57346/32.png) [@Yukihiro\_M](https://www.ruby-forum.com/u/Yukihiro_M)\
**Post date:** [August 19, 2007, 2:17pm UTC](https://www.ruby-forum.com/t/nested-fiber-invocation/112383/2 "2007-08-19T14:17:16Z")

</div>

e$B!!$5$5$@$G$9!#e(B

Yukihiro M. wrote:

> e$B;d$Ne(BFibere$B$NCN\<1$G$O$3$3$^$G$,8B3&$G$7$?!#$3$l$O%P%0$G$7$g$&e(B  
> e$B$+!"$=$l$H$b@)8B$H$9$Y$-$G$7$g$&$+!#$G$-$l$P!"%M%9%H$G$-$J$$e(B  
> e$B$H8@$&@)8B$O$J$$J}$,$&$l$7$$$N$G$9$,!#e(B
> 
> ```
> e$B$^$D$b$He(B e$B$f$-$R$me(B /:|)
> 
> ```

e$B!!$3$s$J46$8$G$I$&$G$7$g$&!#$D$^$j!"%V%m%C%/$N:G8e$be(B  
rb\_fiber\_yield  
e$B$GLa$k$h$&$K$7$^$7$g$&$C$F46$8$G!#e(B

# Index: enumerator.c

— enumerator.c (e$B%j%S%8%g%se(B 13113)  
+++ enumerator.c (e$B:n6H%3%T!\<e(B)  
@@ -13,6 +13,7 @@  
\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*/

#include “ruby/ruby.h”  
+#include “debug.h”

/\*

- Document-class: Enumerable::Enumerator  
@@ -42,6 +43,7 @@  
VALUE fib;  
VALUE next;  
VALUE dst;

- VALUE has\_next;  
};

static void  
@@ -237,6 +239,7 @@  
if (argc) ptr-\>args = rb\_ary\_new4(argc, argv);  
ptr-\>fib = 0;  
ptr-\>next = ptr-\>dst = Qnil;

- ptr-\>has\_next = Qnil;

- e-\>dst = curr;

- e-\>dst = curr;  
rb\_block\_call(obj, rb\_intern(“each”), 0, 0, next\_ii, obj);
- return e-\>next;

- e-\>has\_next = Qfalse;
- rb\_fiber\_yield(e-\>dst, 1, &e-\>next);  
}

## static void next\_init(VALUE obj, struct enumerator \*e) { VALUE curr = rb\_fiber\_current();

```
 e->dst = curr;
 e->fib = rb_block_call(rb_cFiber, rb_intern("new"), 0, 0,

```

next\_i, obj);

- e-\>has\_next = Qtrue;  
rb\_fiber\_yield(e-\>fib, 1, &curr);  
}

@@ -416,16 +420,18 @@  
{  
struct enumerator \*e = enumerator\_ptr(obj);  
VALUE curr, v;

- curr = rb\_fiber\_current();

- curr = rb\_fiber\_current();  
if (!e-\>fib) {  
next\_init(obj, e);  
}
- if (!rb\_fiber\_alive\_p(e-\>fib)) {

- 
- if (!e-\>has\_next) {  
e-\>fib = 0;  
e-\>next = e-\>dst = Qnil;  
rb\_raise(rb\_eStopIteration, “Enumerator#each reached at end”);  
}
- v = rb\_fiber\_yield(e-\>fib, 1, &curr);  
return v;  
}  
@@ -441,11 +447,7 @@  
enumerator\_next\_p(VALUE obj)  
{  
struct enumerator \*e = enumerator\_ptr(obj);

- 
- if (!e-\>fib) {
- next\_init(obj, e);
- }
- return rb\_fiber\_alive\_p(e-\>fib);

- return e-\>has\_next;  
}

/\*

---

<div class="post-metadata">

**Author:** ![Yukihiro\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c57346/32.png) [@Yukihiro\_M](https://www.ruby-forum.com/u/Yukihiro_M)\
**Post date:** [August 20, 2007, 4:15am UTC](https://www.ruby-forum.com/t/nested-fiber-invocation/112383/3 "2007-08-20T04:15:30Z")

</div>

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:31508] Re: nested fiber invocation”  
on Sun, 19 Aug 2007 21:16:13 +0900, SASADA Koichi [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
writes:

|e$B!!$3$s$J46$8$G$I$&$G$7$g$&!#$D$^$j!"%V%m%C%/$N:G8e$be(B rb\_fiber\_yield  
|e$B$GLa$k$h$&$K$7$^$7$g$&$C$F46$8$G!#e(B

e$B$_$_!“$A$c$s$HF0$/!#$G$b!”$I$&$7$F:#$^$G$N$@$H%@%a$G!V%V%m%Ce(B  
e$B%/$N:G8e$be(B rb\_fiber\_yield e$B$GLa$k!W$HBg\>fIW$J$N$+$O$h$/$o$+$ie(B  
e$B$J$$$s$G$9$1$I!#e(B

e$B$“$H!”\<B:]$KFI$\_9~$`A0$Ne(Bnext?e$B$,e(Bnile$B$rJV$9$s$G$9$,!“$3$l$O$”$se(B  
e$B$^$j$&$l$7$/$J$$;EMMJQ99$G$9$M$(!#e(Bnext\_pe$B$N\<BAu$r$A$g$C$H9)IWe(B  
e$B$9$l$P$h$$$N$+$7$i$s!#e(B

---

<div class="post-metadata">

**Author:** ![Yukihiro\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c57346/32.png) [@Yukihiro\_M](https://www.ruby-forum.com/u/Yukihiro_M)\
**Post date:** [August 20, 2007, 4:20am UTC](https://www.ruby-forum.com/t/nested-fiber-invocation/112383/4 "2007-08-20T04:20:30Z")

</div>

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:31513] Re: nested fiber invocation”  
on Mon, 20 Aug 2007 11:14:53 +0900, Yukihiro M.  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes:

|e$B$“$H!”\<B:]$KFI$\_9~$`A0$Ne(Bnext?e$B$,e(Bnile$B$rJV$9$s$G$9$,!“$3$l$O$”$se(B  
|e$B$^$j$&$l$7$/$J$$;EMMJQ99$G$9$M$(!#e(Bnext\_pe$B$N\<BAu$r$A$g$C$H9)IWe(B  
|e$B$9$l$P$h$$$N$+$7$i$s!#e(B

- next\_pe$B$NCf$Ge(Be-\>fibe$B$,e(B0e$B$@$C$?$ie(Bnext\_inite$B$r8F$Ve(B
- nexte$B$NCf$GNc30H/@8A0$Ke(Be-\>has\_nexte$B$re(Bnile$B$Ke(B

e$B$7$F$\_$^$7$?!#$I$&$b4|BTDL$jF0$$$F$$$k$h$&$G$9!#$7$+$7!"\<B$Oe(B  
e$B8e\<T$OITMW$N$h$&$G$9!#e(B

---

<div class="post-metadata">

**Author:** ![Yukihiro\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c57346/32.png) [@Yukihiro\_M](https://www.ruby-forum.com/u/Yukihiro_M)\
**Post date:** [August 20, 2007, 9:22pm UTC](https://www.ruby-forum.com/t/nested-fiber-invocation/112383/5 "2007-08-20T21:22:10Z")

</div>

e$B!!$5$5$@$G$9!#e(B

Yukihiro M. wrote:

> e$B$_$_!"$A$c$s$HF0$/!#$G$b!"$I$&$7$F:#$^$G$N$@$H%@%a$G!V%V%m%Ce(B  
> e$B%/$N:G8e$be(B rb\_fiber\_yield e$B$GLa$k!W$HBg\>fIW$J$N$+$O$h$/$o$+$ie(B  
> e$B$J$$$s$G$9$1$I!#e(B

e$B!!5U$K!"%V%m%C%/$,$=$N$^$^=\*N;$7$?$i$I$&$J$k$G$7$g$&!"$H$$$&OC$G$9!#e(B  
e$B5$IU$/$N$N;~4V$,$+$+$C$?$s$@$1$I!"1sF#$5$s$O:G=i$+$i$=$l$r;XE&$7$F$$e(B  
e$B$k$H$$$&!#e(B

e$B!!$D$^$j!“e(BFiber  
e$B$N%V%m%C%/$,=\*N;$7$?$i$I$&$J$k$+!”$H$$$&OC$J$s$G$9e(B  
e$B$,!#e(BFiber  
e$B$N%V%m%C%/$,=\*N;$7$?$i!“Nc30!”$C$D$&$N$,$$$$$h$&$J5$$,$7$Fe(B  
e$B$$$^$9!#$G$O!“2?$KNc30$rEj$2$k$N$+$C$F$N$,$^$?LLE]$J$s$G$9$,!#$&!\<e(B  
e$B$s!”$I$&$7$h$&!#e(B

---

<div class="post-metadata">

**Author:** ![Yukihiro\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c57346/32.png) [@Yukihiro\_M](https://www.ruby-forum.com/u/Yukihiro_M)\
**Post date:** [August 20, 2007, 9:17am UTC](https://www.ruby-forum.com/t/nested-fiber-invocation/112383/6 "2007-08-20T09:17:52Z")

</div>

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:31508] Re: nested fiber invocation”  
on Sun, 19 Aug 2007 21:16:13 +0900, SASADA Koichi [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
writes:

|e$B!!$3$s$J46$8$G$I$&$G$7$g$&!#$D$^$j!"%V%m%C%/$N:G8e$be(B rb\_fiber\_yield  
|e$B$GLa$k$h$&$K$7$^$7$g$&$C$F46$8$G!#e(B

e$B%3%\_%C%H$7$F$/$@$5$$!#e(B

---

<div class="post-metadata">

**Author:** ![Yukihiro\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c57346/32.png) [@Yukihiro\_M](https://www.ruby-forum.com/u/Yukihiro_M)\
**Post date:** [August 21, 2007, 2:18am UTC](https://www.ruby-forum.com/t/nested-fiber-invocation/112383/7 "2007-08-21T02:18:44Z")

</div>

e$B!!$5$5$@$G$9!#e(B

Yukihiro M. wrote:

> e$B%3%\_%C%H$7$F$/$@$5$$!#e(B

e$B!!$D$$$G$K%F%9%H$b%3%\_%C%H$7$^$7$?!de(Btest/ruby/test\_enumerator.rb

e$B!!;d$OF,$,0-$$$N$G!"$I$&$"$k$Y$-$+$9$0$KK:$l$F$7$^$$$^$9!#2?$+DI2C$7e(B  
e$B$?$i%F%9%H$b$D$$$G$KDI2C$7$H$$$F$b$i$($k$H=u$+$j$^$9!#e(B

e$B!!:G6a!"EDCf$5$s$NCf$G$O%F%9%H%U%!!\<%9%H!Je(BSEGVe$B$9$k%F%9%H$bFM$C9~$s$Ge(B  
e$B$\*$/!K$H$$$&$N$,N.9T$C$F$k$=$&$J$s$G$9$,!"3N$+$K=$@5$9$k$N$rK:$l$Je(B  
e$B$$!“NI$$\<j$@$J$”$H;W$$$^$9!#e(B

e$B!!$?$@!“8D?ME\*$K$O!“e(Bknown bug  
e$B$G$”$k$3$H$,L@3N$K$J$k$h$&$K!”%U%!%$%ke(B  
e$B$rJ,$1$F$/$l$k$H$$$$$H;W$&$s$@$1$I!J2r7h$7$?;~E@$GE,@Z$J%F%9%H%U%!%$e(B  
e$B%k$X0\F0!K!#e(B

---

<div class="post-metadata">

**Author:** ![Yukihiro\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c57346/32.png) [@Yukihiro\_M](https://www.ruby-forum.com/u/Yukihiro_M)\
**Post date:** [August 21, 2007, 5:21am UTC](https://www.ruby-forum.com/t/nested-fiber-invocation/112383/8 "2007-08-21T05:21:02Z")

</div>

e$B!!$5$5$@$G$9!#e(B

e$B!!F,$N@0M}$N$?$a$K!"e(BRubye$B$G=q$$$F$\_$^$7$?!#e(B

class Gen  
def initialize e  
@e = e  
@fib = nil  
end

def next?  
init\_next unless @fib  
@has\_next  
end

def next  
init\_next unless @fib  
raise “mou naiyo” unless @has\_next  
r = @next  
@fib.yield(Fiber.current)  
r  
end

def rewind  
@fib = nil  
self  
end

private  
def init\_next  
@fib = Fiber.new{|fib|  
@has\_next = true  
@e.each{|e|  
@next = e  
fib = fib.yield(e)  
}  
@has\_next = false  
fib.yield(nil)  
}  
@fib.yield(Fiber.current)  
end  
end

gen = Gen.new(3.times)  
p gen.next  
p gen.next  
p gen.next  
gen.rewind  
p gen.next

e$B!!e(BFiber  
e$BCf$GH/@8$7$?Nc30$r$I$3$KEAHB$5$;$k$N$+!"$d$C$Q$j$I$&$K$b$o$+e(B  
e$B$i$J$$$N$G!"e(BSemiCoroutine e$B$H$7$F\<BAu$9$k$Y$-$@$m$&$+!#e(B