[#GROOVY-3976] Improve "with" by ending with implied "return delegate" - jira.codehaus.org

Details

Type: Improvement
Status: Open
Priority: Major
Resolution: Unresolved
Affects Version/s: 1.7.0
Fix Version/s: None
Component/s: syntax
Labels:
None

Testcase included:
yes
Number of attachments :
0

Description

In this code:

class Foo { String bar }
def x = new Foo().with {
bar = "baz"
}

"x" is now a String with the value "baz" thanks to the implied return. To work around this, we have to say:

def x = new Foo().with {
bar = "baz"
return delegate
}

...which is pretty ugly, to say the least.

So can we modify the "with" syntax to have an implied "return delegate"? I doubt anyone was depending on the previous behavior for code correctness.

Test will be this:

class Foo { String bar }
def x = new Foo().with {
bar = "baz"
}
assert x instanceof Foo
assert x.bar == "baz"

Issue Links

This issue is duplicated by:
GROOVY-4442	'with' method should return the object in which it was called

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blackdrag blackdrag added a comment - 06/Jan/10 1:50 PM

you can have "it" as last statement in the closure too, to get what you want. The problem I see here is that the change you propose is a breaking one.

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blackdrag blackdrag added a comment - 06/Jan/10 1:50 PM you can have "it" as last statement in the closure too, to get what you want. The problem I see here is that the change you propose is a breaking one.

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Robert Fischer added a comment - 06/Jan/10 2:39 PM

Do you think there is someone who coded to the previous implementation?

Minimally, can we queue it up for 1.8 or 2.0?

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Robert Fischer added a comment - 06/Jan/10 2:39 PM Do you think there is someone who coded to the previous implementation? Minimally, can we queue it up for 1.8 or 2.0?

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Paul King added a comment - 05/Apr/10 2:44 AM

Do you have a better example?
The one provided doesn't seem satisfying justification to me because of the obvious alternate syntax:

def x = new Foo(bar:'baz')

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Paul King added a comment - 05/Apr/10 2:44 AM Do you have a better example? The one provided doesn't seem satisfying justification to me because of the obvious alternate syntax:

def x = new Foo(bar:'baz')

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Robert Fischer added a comment - 05/Apr/10 8:15 AM

It was simplified to illustrate the request.

Something along these lines is what raised the issue in the first place:

def x = new Foo().with {
  bars = []
  inputFile.withReader { reader ->
     def line
     while(line = reader.readLine() =~ /someCheck/) {
       bars << line
     }
  }
}

The variable "x" is now null (IIRC).

It was also just surprising to try out this code:

def x = new Foo().with {
  bar = "baz"
}

And discover that x is now "baz". Is that behavior supposed to be intuitive?

Show

Robert Fischer added a comment - 05/Apr/10 8:15 AM It was simplified to illustrate the request. Something along these lines is what raised the issue in the first place:

def x = new Foo().with {
  bars = []
  inputFile.withReader { reader ->
     def line
     while(line = reader.readLine() =~ /someCheck/) {
       bars << line
     }
  }
}

The variable "x" is now null (IIRC). It was also just surprising to try out this code:

def x = new Foo().with {
  bar = "baz"
}

And discover that x is now "baz". Is that behavior supposed to be intuitive?

groovy

Improve "with" by ending with implied "return delegate"

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