Anonymous function syntax

[dsimcha]

I'd much rather see the bugs in the current lambda syntax get fixed (e.g.
http://d.puremagic.com/issues/show_bug.cgi?id=4724) rather than spend more time
bikeshedding.

== Quote from Andrei Alexandrescu (SeeWebsiteForEmail at erdani.org)'s article
> On 9/21/11 5:17 PM, Walter Bright wrote:
> > I've collected a few from various languages for comparison:
> [snip]
> I think we should do the following:
> 1. Introduce a new token "=>"
> 2. Add this rewrite to the grammar:
> symbol => expression
> translates to
> (symbol) { return expression; }
> 3. Add this rewrite to the grammar:
> symbol1 symbol2 => expression
> translates to
> (symbol1 symbol2) { return expression; }
> 4. Add this rewrite to the grammar:
> (comma_separated_parms) => expression
> translates to
> (comma_separated_parms) => expression
> Each item in comma_separated_parms may be 1 or 2 symbols separated by
> whitespace. Example:
> (int a, b) => a + b
> is valid and translates to (int a, b) { return a + b; }
> 5. The expression cannot contain commas at top level; an unparenthesized
> comma is considered to finish expression, just like in a function call's
> argument list. For example:
> fun(int a => a + 1, a + 2)
> is interpreted as
> fun((int a => a + 1), (a + 2))
> To use comma inside expression, add parens around it.
> 5. Remove bugs and limitations. A function literal may specify none,
> all, or some parameter types, and the compiler correctly figures out the
> appropriate template and non-template parameters. The literal
> subsequently converts to function pointer or delegate whenever there's a
> match of parameter and result types.
> Andrei

== Quote from Andrei Alexandrescu (SeeWebsiteForEmail at erdani.org)'s article
> On 9/21/11 5:17 PM, Walter Bright wrote:
> > I've collected a few from various languages for comparison:
> [snip]
> I think we should do the following:
> 1. Introduce a new token "=>"
> 2. Add this rewrite to the grammar:
> symbol => expression
> translates to
> (symbol) { return expression; }
> 3. Add this rewrite to the grammar:
> symbol1 symbol2 => expression
> translates to
> (symbol1 symbol2) { return expression; }
> 4. Add this rewrite to the grammar:
> (comma_separated_parms) => expression
> translates to
> (comma_separated_parms) => expression
> Each item in comma_separated_parms may be 1 or 2 symbols separated by
> whitespace. Example:
> (int a, b) => a + b
> is valid and translates to (int a, b) { return a + b; }
> 5. The expression cannot contain commas at top level; an unparenthesized
> comma is considered to finish expression, just like in a function call's
> argument list. For example:
> fun(int a => a + 1, a + 2)
> is interpreted as
> fun((int a => a + 1), (a + 2))
> To use comma inside expression, add parens around it.
> 5. Remove bugs and limitations. A function literal may specify none,
> all, or some parameter types, and the compiler correctly figures out the
> appropriate template and non-template parameters. The literal
> subsequently converts to function pointer or delegate whenever there's a
> match of parameter and result types.
> Andrei

== Quote from Andrei Alexandrescu (SeeWebsiteForEmail at erdani.org)'s article
> On 9/21/11 5:17 PM, Walter Bright wrote:
> > I've collected a few from various languages for comparison:
> [snip]
> I think we should do the following:
> 1. Introduce a new token "=>"
> 2. Add this rewrite to the grammar:
> symbol => expression
> translates to
> (symbol) { return expression; }
> 3. Add this rewrite to the grammar:
> symbol1 symbol2 => expression
> translates to
> (symbol1 symbol2) { return expression; }
> 4. Add this rewrite to the grammar:
> (comma_separated_parms) => expression
> translates to
> (comma_separated_parms) => expression
> Each item in comma_separated_parms may be 1 or 2 symbols separated by
> whitespace. Example:
> (int a, b) => a + b
> is valid and translates to (int a, b) { return a + b; }
> 5. The expression cannot contain commas at top level; an unparenthesized
> comma is considered to finish expression, just like in a function call's
> argument list. For example:
> fun(int a => a + 1, a + 2)
> is interpreted as
> fun((int a => a + 1), (a + 2))
> To use comma inside expression, add parens around it.
> 5. Remove bugs and limitations. A function literal may specify none,
> all, or some parameter types, and the compiler correctly figures out the
> appropriate template and non-template parameters. The literal
> subsequently converts to function pointer or delegate whenever there's a
> match of parameter and result types.
> Andrei