# Case/when splat

**URL:** <https://www.ruby-forum.com/t/case-when-splat/74997>\
**Category:** Development\
**Created:** [November 7, 2006, 11:05am UTC](https://www.ruby-forum.com/t/case-when-splat/74997 "2006-11-07T11:05:34Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![SASADA\_Koichi](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/f1d935/32.png) [@SASADA\_Koichi](https://www.ruby-forum.com/u/SASADA_Koichi)\
**Post date:** [November 7, 2006, 11:05am UTC](https://www.ruby-forum.com/t/case-when-splat/74997/1 "2006-11-07T11:05:34Z")

</div>

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

e$B!!\<!$N%W%m%0%i%`$Oe(B :ok e$B$H=PNO$9$k$Y$-$@$H;W$&$N$G$9$,!"e(Bruby  
1.9.0  
(2006-11-03) [x86\_64-linux] e$B$G$Oe(B :ng2 e$B$H=PNO$5$l$^$9!#e(B

```
  ary = [1, 2]
  p case 1
  when :x, *ary
    :ok
  when :z
    :ng1
  else
    :ng2
  end

```

e$B!!\<!$N%W%m%0%i%`$Oe(B :ok  
e$B$HI=\<($5$l$k$N$+$J!\<$H;W$C$F$$$?$s$G$9$,!"e(B:ng e$B$He(B  
e$BI=\<($5$l$^$9!#$=$s$J$b$s$G$7$g$&$+!#e(B

```
  ary = []
  p case
  when false, *ary
    :ng
  else
    :ok
  end
```

---

<div class="post-metadata">

**Author:** ![SASADA\_Koichi](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/f1d935/32.png) [@SASADA\_Koichi](https://www.ruby-forum.com/u/SASADA_Koichi)\
**Post date:** [November 7, 2006, 11:08am UTC](https://www.ruby-forum.com/t/case-when-splat/74997/2 "2006-11-07T11:08:59Z")

</div>

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

In message “Re: [ruby-dev:29882] Re: case/when splat”  
on Tue, 7 Nov 2006 00:12:33 +0900, Nobuyoshi N.  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes:

|\> e$B!!\<!$N%W%m%0%i%`$Oe(B :ok e$B$HI=\<($5$l$k$N$+$J!\<$H;W$C$F$$$?$s$G$9$,!"e(B:ng e$B$He(B  
|\> e$BI=\<($5$l$^$9!#$=$s$J$b$s$G$7$g$&$+!#e(B  
|  
|e$B$=$s$J$b$s$G$b$J$$$G$7$g$&!#e(B

e$B%P%0$G$7$g$&$M!#e(B

|when\_check()e$B$N9=B$$,\>/!9$$$^$$$A$C$]$$$G$9$,!#e(B

e$B$3$l$GD\>$j$^$9$M!#\<h$j9~$\_$^$9!#e(B1.9CVSe$B%U%j!\<%:$,6a$$$N$G!";de(B  
e$B$NJ}$G:n6H$7$^$9!#e(B

---

<div class="post-metadata">

**Author:** ![SASADA\_Koichi](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/f1d935/32.png) [@SASADA\_Koichi](https://www.ruby-forum.com/u/SASADA_Koichi)\
**Post date:** [November 7, 2006, 11:06am UTC](https://www.ruby-forum.com/t/case-when-splat/74997/3 "2006-11-07T11:06:39Z")

</div>

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

At Mon, 6 Nov 2006 14:35:02 +0900,  
SASADA Koichi wrote in [ruby-dev:29860]:

> e$B!!\<!$N%W%m%0%i%`$Oe(B :ok e$B$H=PNO$9$k$Y$-$@$H;W$&$N$G$9$,!"e(Bruby 1.9.0  
> (2006-11-03) [x86\_64-linux] e$B$G$Oe(B :ng2 e$B$H=PNO$5$l$^$9!#e(B

e$B$Y$-$@$H;W$$$^$9!#e(B

> e$B!!\<!$N%W%m%0%i%`$Oe(B :ok e$B$HI=\<($5$l$k$N$+$J!\<$H;W$C$F$$$?$s$G$9$,!"e(B:ng e$B$He(B  
> e$BI=\<($5$l$^$9!#$=$s$J$b$s$G$7$g$&$+!#e(B

e$B$=$s$J$b$s$G$b$J$$$G$7$g$&!#e(B

when\_check()e$B$N9=B$$,\>/!9$$$^$$$A$C$]$$$G$9$,!#e(B

# Index: eval.c

RCS file: /cvs/ruby/src/ruby/eval.c,v  
retrieving revision 1.955  
diff -p -U 2 -r1.955 eval.c  
— eval.c 6 Nov 2006 10:27:58 -0000 1.955  
+++ eval.c 6 Nov 2006 14:34:38 -0000  
@@ -2701,8 +2701,8 @@ unknown\_node(NODE \*volatile node)  
when\_cond(VALUE v1, VALUE v2)  
{

- if (v1 == Qundef) {
- return RTEST(v2);

- if (v1 != Qundef) {
- v2 = rb\_funcall2(v2, eqq, 1, &v1);  
}

- return RTEST(rb\_funcall2(v2, eqq, 1, &v1));

- return RTEST(v2);  
}

@@ -2724,5 +2724,7 @@ when\_check(NODE \*tag, VALUE val, VALUE s  
break;  
case NODE\_SPLAT:

- elm = splat\_value(rb\_eval(self, tag-\>nd\_head));

- tag = tag-\>nd\_head;
- 

```
 splat:

```

- elm = splat\_value(rb\_eval(self, tag));  
for (i=0; i\<RARRAY\_LEN(elm); i++) {  
if (when\_cond(val, RARRAY\_PTR(elm)[i])) {  
@@ -2733,5 +2735,6 @@ when\_check(NODE \*tag, VALUE val, VALUE s  
case NODE\_ARGSCAT:  
if (when\_check(tag-\>nd\_head, val, self)) return Qtrue;

- return when\_check(tag-\>nd\_body, val, self);

- tag = tag-\>nd\_body;
- goto splat;  
case NODE\_ARGSPUSH:  
if (when\_check(tag-\>nd\_head, val, self)) return Qtrue;