Feature #12995: Conditional expression taking a receiver outside the condition

• Status: Rejected
• Assignee: -
• Target version: -

[sawa (Tsuyoshi Sawada)]

Since a conditional expression has a return value, we can continue a method chain after a conditional expression like this:

if hoge
  foo1.foo2.foo3
else
  bar1.bar2
end
.baz1.baz2.baz3.baz4

case hoge
when hoge1
  foo1.foo2.foo3
when hoge2
  bar1.bar2
end
.baz1.baz2.baz3.baz4

It is convenient if we can have a condition after or in the middle of a chain. I would like to do this:

baz1.baz2.baz3.baz4.
if hoge
  foo1.foo2.foo3
else
  bar1.bar2
end

baz1.baz2.baz3.baz4
if hoge
  .foo1.foo2.foo3
else
  .bar1.bar2
end

baz1.baz2.baz3.baz4.
case hoge
when hoge1
  foo1.foo2.foo3
when hoge2
  bar1.bar2
end

baz1.baz2.baz3.baz4
case hoge
when hoge1
  .foo1.foo2.foo3
when hoge2
  .bar1.bar2
end

[herwinw (Herwin Quarantainenet)]

You can do that with #tap. A very stupid example:

array = [true]
res = array.to_a.tap do |obj|
  if obj[0]
    obj.replace([['true', :val]])
  else
    obj.replace([['false', :val]])
  end
end.to_a.to_h
p res

Results in:

{"true"=>:val}

[matz (Yukihiro Matsumoto)]

• Status changed from Open to Rejected

Interesting proposal but this changes the meaning of if and case too much.

Matz.