[nem-bug] [Nemerle 0000758]: shortcut for match syntax

[feedback at nemerle.org]

The following issue has been SUBMITTED.
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<http://nemerle.org/bugs/view.php?id=758> 
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Reported By:                aleksey
Assigned To:                
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Project:                    Nemerle
Issue ID:                   758
Category:                   Language Feature
Reproducibility:            N/A
Severity:                   feature
Priority:                   normal
Status:                     new
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Date Submitted:             09-18-2006 20:10 CEST
Last Modified:              09-18-2006 20:10 CEST
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Summary:                    shortcut for match syntax
Description: 
Recent postings in nemerle.devel-en("?? operator" and "match / default
case") reminded me of my old idea. I'm not sure whether it's crazy or
worthwhile, it's up to you.

What I propose is a ?| operator(I couldn't come up with better "name"). It
can be used a complete replacement for "match", but it also has a special
support for option.None and null.

Some examples:
def test = Some("test");
def value = test ?| None => null;
def value = test ?| None => return; // this is evil of course, but it's
just an example
def value = test ?| Some(value) => value ?| _ => null;
assert(value == "test");
value ?| "test" => WriteLine("value == test") ?| null => WriteLine("value
==
null");
// it also can be used instead of (b ?? c)
// b ?| null => c
WriteLine($"$(value ?| null => \"null\")");

// otherwise from special treatment for null and None
// it has little other differences from match
// unlike in match branch several expressions should be placed in block
lst ?| [x, y] => { WriteLine("hello!"); x+y }
    ?| [x]     => x
    ?| _       => 0

Sometimes it can make code a bit more cryptic, but so do ??, :> and many
other operators.
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Issue History
Date Modified  Username       Field                    Change              
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09-18-06 20:10 aleksey        New Issue                                    
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