From: Yusuke Endoh <redmine@...>
Date: 2010-04-09T23:13:42+09:00
Subject: [ruby-core:29383] [Bug #3116] block call with `do' keyword in `until' condition causes parse error

Bug #3116: block call with `do' keyword in `until' condition causes parse error
http://redmine.ruby-lang.org/issues/show/3116

Author: Yusuke Endoh
Status: Rejected, Priority: Low
Target version: 1.9.2
ruby -v: ruby 1.9.2dev (2010-04-09 trunk 27030) [i686-linux]

(derived from #1240)

I noticed that block call with `do' keyword does not work in
`until' condition:

 until begin 1.times { }    end do end # ok
 until begin 1.times do end end do end # parse error
                     ~~
 until if true then 1.times { }    end do end # ok
 until if true then 1.times do end end do end # parse error
                            ~~
 until until true do 1.times { }    end do end # ok
 until until true do 1.times do end end do end # parse error
                             ~~
 until class Foo; 1.times { }   ; end do end # ok
 until class Foo; 1.times do end; end do end # parse error
                          ~~
 until case; when true; 1.times { }   ; end do end # ok
 until case; when true; 1.times do end; end do end # parse error
                                ~~

This is because the underlined `do's are not considered as block call
but beginning of `until' body.

Although this is confusing a little and can be actually fixed, the fix
needs many COND_PUSH(0)/COND_POP(), which may decrease performance and
code maintenability.  In addition, writing such a long and complex
condition directly is absolutely bad (even insane) style.

So, I think there is no need to fix.

-- 
Yusuke Endoh <mame@tsg.ne.jp>


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