# When \*a

**URL:** <https://www.ruby-forum.com/t/when-a/96056>\
**Category:** Development\
**Created:** [June 24, 2006, 7:15am UTC](https://www.ruby-forum.com/t/when-a/96056 "2006-06-24T07:15:16Z")\
**Posts on this page:** 7\
**Page:** 1

<div class="post-metadata">

**Author:** ![Minero\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/13edae/32.png) [@Minero\_A](https://www.ruby-forum.com/u/Minero_A)\
**Post date:** [June 24, 2006, 7:15am UTC](https://www.ruby-forum.com/t/when-a/96056/1 "2006-06-24T07:15:16Z")

</div>

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

e$B\<!$N$h$&$K!"e(Bwhen \*a e$B$,F0:n$7$J$/$J$C$F$$$^$9!#e(B

~/c/refe % cat t  
case “string”  
when \*[/s/]  
puts “OK”  
else  
puts “NG”  
end

~/c/refe % ruby-1.8.4 -v t  
ruby 1.8.4 (2005-12-24) [x86\_64-linux]  
OK  
~/c/refe % ruby -v t  
ruby 1.9.0 (2006-06-23) [x86\_64-linux]  
NG

---

<div class="post-metadata">

**Author:** ![Minero\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/13edae/32.png) [@Minero\_A](https://www.ruby-forum.com/u/Minero_A)\
**Post date:** [June 24, 2006, 3:36pm UTC](https://www.ruby-forum.com/t/when-a/96056/2 "2006-06-24T15:36:26Z")

</div>

e$B$J$+$@$G$9!#e(B

At Sat, 24 Jun 2006 14:14:15 +0900,  
Minero A. wrote in [ruby-dev:28822]:

> e$B\<!$N$h$&$K!"e(Bwhen \*a e$B$,F0:n$7$J$/$J$C$F$$$^$9!#e(B

e$B$3$s$J$H$3$G$7$g$&$+!#e(B

# Index: eval.c

RCS file: /cvs/ruby/src/ruby/eval.c,v  
retrieving revision 1.903  
diff -p -U2 -r1.903 eval.c  
— eval.c 23 Jun 2006 08:28:04 -0000 1.903  
+++ eval.c 24 Jun 2006 13:32:04 -0000  
@@ -2855,6 +2855,6 @@ rb\_eval(VALUE self, NODE \*n)  
ruby\_frame-\>this\_func,  
ruby\_frame-\>this\_class);

- 

```
      if (tag->nd_head && nd_type(tag->nd_head) == NODE_WHEN) {

```

- 

```
  	VALUE v = rb_eval(self, tag->nd_head->nd_head);

```

- 

```
      if (nd_type(tag) == NODE_SPLAT) {

```

- 

```
  	VALUE v = rb_eval(self, tag->nd_head);
  	long i;
```

---

<div class="post-metadata">

**Author:** ![Minero\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/13edae/32.png) [@Minero\_A](https://www.ruby-forum.com/u/Minero_A)\
**Post date:** [June 24, 2006, 4:56pm UTC](https://www.ruby-forum.com/t/when-a/96056/3 "2006-06-24T16:56:24Z")

</div>

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

In message “Re: [ruby-dev:28827] Re: when \*a”  
on Sat, 24 Jun 2006 22:33:25 +0900, removed\_email\_address@domain.invalid writes:

|At Sat, 24 Jun 2006 14:14:15 +0900,  
|Minero A. wrote in [ruby-dev:28822]:  
|\> e$B\<!$N$h$&$K!"e(Bwhen \*a e$B$,F0:n$7$J$/$J$C$F$$$^$9!#e(B  
|  
|e$B$3$s$J$H$3$G$7$g$&$+!#e(B

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

---

<div class="post-metadata">

**Author:** ![Minero\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/13edae/32.png) [@Minero\_A](https://www.ruby-forum.com/u/Minero_A)\
**Post date:** [June 25, 2006, 11:45am UTC](https://www.ruby-forum.com/t/when-a/96056/4 "2006-06-25T11:45:08Z")

</div>

e$B$J$+$@$G$9!#e(B

At Sat, 24 Jun 2006 23:53:27 +0900,  
Yukihiro M. wrote in [ruby-dev:28829]:

> |At Sat, 24 Jun 2006 14:14:15 +0900,  
> |Minero A. wrote in [ruby-dev:28822]:  
> |\> e$B\<!$N$h$&$K!"e(Bwhen \*a e$B$,F0:n$7$J$/$J$C$F$$$^$9!#e(B  
> |  
> |e$B$3$s$J$H$3$G$7$g$&$+!#e(B
> 
> e$B%3%\_%C%H$7$F$/$@$5$$!#e(B

e$B$3$l$@$He(B when /b/, \*[/a/]  
e$B$N$h$&$J\>l9g$KF0:n$7$F$^$;$s$G$7$?!#e(B  
e$B8=\>u$G$Oe(Bargse$B$r$=$N$^$^;H$&$h$&$K$J$C$F$$$^$9$,!"!V$R$H$D$R$H$De(B  
e$BI\>2A$7$F$O%^%C%A$5$;$k!W$H$$$&F0:n$K$OIT8~$-$G$9!#e(Bwhen\_argse$B$rI|e(B  
e$B3h$5$;$?$[$&$,$$$$$h$&$J5$$,$7$^$9!#e(B

# Index: eval.c

RCS file: /cvs/ruby/src/ruby/eval.c,v  
retrieving revision 1.903  
diff -p -U2 -r1.903 eval.c  
— eval.c 23 Jun 2006 08:28:04 -0000 1.903  
+++ eval.c 25 Jun 2006 08:01:46 -0000  
@@ -2855,5 +2868,5 @@ rb\_eval(VALUE self, NODE \*n)  
ruby\_frame-\>this\_func,  
ruby\_frame-\>this\_class);

- 

```
      if (tag->nd_head && nd_type(tag->nd_head) == NODE_WHEN) {

```

- 

```
      if (tag->nd_head && nd_type(tag->nd_head) == NODE_SPLAT) {
  	VALUE v = rb_eval(self, tag->nd_head->nd_head);
  	long i;

```

# Index: parse.y

RCS file: /cvs/ruby/src/ruby/parse.y,v  
retrieving revision 1.443  
diff -p -U2 -r1.443 parse.y  
— parse.y 21 Jun 2006 08:08:34 -0000 1.443  
+++ parse.y 25 Jun 2006 07:56:00 -0000  
@@ -533,5 +536,5 @@ static void ripper\_compile\_error(struct  
%type expr\_value arg\_value primary\_value  
%type if\_tail opt\_else case\_body cases opt\_rescue exc\_list  
exc\_var opt\_ensure  
-%type args call\_args call\_args2 opt\_call\_args  
+%type args when\_args call\_args call\_args2 opt\_call\_args  
%type open\_args paren\_args opt\_paren\_args  
%type command\_args aref\_args opt\_block\_arg block\_arg var\_ref  
var\_lhs  
@@ -3377,5 +3385,5 @@ brace\_block : ‘{’  
;

-case\_body : kWHEN args then  
+case\_body : kWHEN when\_args then  
compstmt  
cases  
@@ -3389,4 +3397,38 @@ case\_body : kWHEN args then  
;

+when\_args : arg\_value

- 

```
      {

```

- 

```
      /*%%%*/

```

- 

```
  	$$ = NEW_LIST($1);

```

- 

```
      /*%

```

- 

```
  	$$ = arg_add(arg_new(), $1);

```

- 

```
      %*/

```

- 

```
      }

```

- 

```
  | tSTAR arg_value

```

- 

```
      {

```

- 

```
      /*%%%*/

```

- 

```
  	$$ = NEW_LIST(NEW_SPLAT($2));

```

- 

```
      /*%

```

- 

```
  	$$ = arg_add_star(arg_new(), $2);

```

- 

```
      %*/

```

- 

```
      }

```

- 

```
  | when_args ',' arg_value

```

- 

```
      {

```

- 

```
      /*%%%*/

```

- 

```
  	$$ = list_append($1, $3);

```

- 

```
      /*%

```

- 

```
  	$$ = arg_add($1, $3);

```

- 

```
      %*/

```

- 

```
      }

```

- 

```
  | when_args ',' tSTAR arg_value

```

- 

```
      {

```

- 

```
      /*%%%*/

```

- 

```
  	$$ = list_append($1, NEW_SPLAT($4));

```

- 

```
      /*%

```

- 

```
  	$$ = arg_add_star($1, $4);

```

- 

```
      %*/

```

- 

```
      }

```

- 

```
  ;

```

- 

cases : opt\_else  
| case\_body

---

<div class="post-metadata">

**Author:** ![Minero\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/13edae/32.png) [@Minero\_A](https://www.ruby-forum.com/u/Minero_A)\
**Post date:** [June 28, 2006, 5:57am UTC](https://www.ruby-forum.com/t/when-a/96056/5 "2006-06-28T05:57:25Z")

</div>

e$B$J$+$@$G$9!#e(B

At Wed, 28 Jun 2006 00:52:05 +0900,  
Yukihiro M. wrote in [ruby-dev:28871]:

> |e$B$3$l$@$He(B when /b/, \*[/a/] e$B$N$h$&$J\>l9g$KF0:n$7$F$^$;$s$G$7$?!#e(B  
> |e$B8=\>u$G$Oe(Bargse$B$r$=$N$^$^;H$&$h$&$K$J$C$F$$$^$9$,!"!V$R$H$D$R$H$De(B  
> |e$BI\>2A$7$F$O%^%C%A$5$;$k!W$H$$$&F0:n$K$OIT8~$-$G$9!#e(Bwhen\_argse$B$rI|e(B  
> |e$B3h$5$;$?$[$&$,$$$$$h$&$J5$$,$7$^$9!#e(B
> 
> when\_argse$B$rI|3h$5$;$F$b$$$$$G$9$1$I!"$=$N\>l9g$K$Oe(Bmulti splat  
> e$B$KBP1~$5$;$kI,MW$,$"$k$H;W$$$^$9!#$=$l$,LLE]$Ge(Bargse$B$r$=$N$^$^e(B  
> e$B;H$C$F$k$o$1$G$9$,!#e(B

[ruby-dev:28844]e$B$OBP1~$7$F$k$O$:$G$9$,!#$H$$$&$N$O$H$b$+$/!"e(B

case “b” when \*[/a/], /b/; end

e$B$,e(Bunknown node typee$B$K$J$j$^$9!#e(B

# Index: eval.c

RCS file: /cvs/ruby/src/ruby/eval.c,v  
retrieving revision 1.909  
diff -p -U2 -r1.909 eval.c  
— eval.c 27 Jun 2006 23:13:19 -0000 1.909  
+++ eval.c 28 Jun 2006 03:55:00 -0000  
@@ -2712,5 +2712,6 @@ when\_check(NODE \*tag, VALUE val, VALUE s  
return when\_check(tag-\>nd\_body, val, self);  
default:

- unknown\_node(tag);

- if (when\_cond(val, rb\_eval(self, tag))) return Qtrue;
- break;  
}  
return Qfalse;

---

<div class="post-metadata">

**Author:** ![Minero\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/13edae/32.png) [@Minero\_A](https://www.ruby-forum.com/u/Minero_A)\
**Post date:** [June 28, 2006, 6:06am UTC](https://www.ruby-forum.com/t/when-a/96056/6 "2006-06-28T06:06:59Z")

</div>

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

In message “Re: [ruby-dev:28879] Re: when \*a”  
on Wed, 28 Jun 2006 12:57:07 +0900, removed\_email\_address@domain.invalid writes:

|[ruby-dev:28844]e$B$OBP1~$7$F$k$O$:$G$9$,!#e(B

e$B$"$l!)e(B

|e$B$H$$$&$N$O$H$b$+$/!"e(B  
|  
| case “b” when \*[/a/], /b/; end  
|  
|e$B$,e(Bunknown node typee$B$K$J$j$^$9!#e(B

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

---

<div class="post-metadata">

**Author:** ![Minero\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/13edae/32.png) [@Minero\_A](https://www.ruby-forum.com/u/Minero_A)\
**Post date:** [June 27, 2006, 5:52pm UTC](https://www.ruby-forum.com/t/when-a/96056/7 "2006-06-27T17:52:51Z")

</div>

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

In message “Re: [ruby-dev:28844] Re: when \*a”  
on Sun, 25 Jun 2006 18:42:58 +0900, removed\_email\_address@domain.invalid writes:

|e$B$3$l$@$He(B when /b/, \*[/a/] e$B$N$h$&$J\>l9g$KF0:n$7$F$^$;$s$G$7$?!#e(B  
|e$B8=\>u$G$Oe(Bargse$B$r$=$N$^$^;H$&$h$&$K$J$C$F$$$^$9$,!"!V$R$H$D$R$H$De(B  
|e$BI\>2A$7$F$O%^%C%A$5$;$k!W$H$$$&F0:n$K$OIT8~$-$G$9!#e(Bwhen\_argse$B$rI|e(B  
|e$B3h$5$;$?$[$&$,$$$$$h$&$J5$$,$7$^$9!#e(B

when\_argse$B$rI|3h$5$;$F$b$$$$$G$9$1$I!"$=$N\>l9g$K$Oe(Bmulti splat  
e$B$KBP1~$5$;$kI,MW$,$"$k$H;W$$$^$9!#$=$l$,LLE]$Ge(Bargse$B$r$=$N$^$^e(B  
e$B;H$C$F$k$o$1$G$9$,!#e(B