Summary: Lambda syntax

[Alex Blewitt]

Good work.

There are inconsistencies in 7, 16 and 17. One is missing a "throws",  
one declares that it uses PipedException but then uses commas, and one  
has another error I have forgotten (another missing throws?)

In addition, the example with "new" probably shouldn't be included,  
since it's not valid for all lambdas, regardless of the syntax used  
for representing the lambdas themselves.

Alex

Sent from my (new) iPhone

On 18 Mar 2010, at 23:09, Stefan Schulz <schulz at the-loom.de> wrote:

> So I summed up the proposed lambda syntaxes, hopefully picked all of
> them from the list. The summary is below, and the nicer to read  
> document
> version is as before at the following URL:
>   http://docs.google.com/View?id=ddhp95vd_15gqnv8xqm
>
> In case of mistakes or missed proposals, let me know.
>
> Cheers,
> Stefan
>
>
> 0. Common syntax
> Block:
>     { BlockStatements }
>
> BlockStatements:
>     BlockStatement
>     BlockStatements BlockStatement
>
> BlockStatement:
>     LocalVariableDeclarationStatement
>     ClassDeclaration
>     Statement
>
> ParameterList:
>     Parameter
>     Parameter, ParameterList
>
> Parameter:
>     Type Identifier
>
> 1. Straw-man, latest
> Proposes two lambda definitions: lambda expressions and statements.
> Return type is inferred and throws meant to be transparent.
>
> LambdaExpression:
>     # ( ParameterListopt ) ( Expression )
>     # ( ParameterListopt ) Block
>
> Examples:
> #() ( 7 );
> #(Event e) { handle(e); }
> #(File f) { return f.getName(); };
> #(#R(A)(throws E) l, A a) ( #() ( l.(a) ) );
>
>
> 2. Rémy Forax, 05 Jan 2010
> Proposes to use a keyword lambda instead of #.
>
> LambdaExpression:
>     lambda ( ParameterListopt ) ( Expression )
>     lambda ( ParameterListopt ) Block
>
> Examples:
> lambda() ( 7 );
> lambda(Event e) { handle(e); };
> lambda(File f) { return f.getName(); };
> lambda(#R(A)(throws E) l, A a) ( lambda() ( l.(a) ) );
>
> 3. Peter Levart, 26 Jan 2010
> LambdaExpression:
>     # ( ParametersListopt ResultParameteropt ) Block
>
> ResultParameter:
>     : Parameter
>
> Examples:
> #(: int i) { i = 7 };
> #(Event e) { handle(e); };
> #(File f : String s) { s = f.getName(); };
> #(#(A: R throws E) l, A a : #(: R throws E) c) { c = #(: R r) { r =
> l.(a); }; };
>
> 4. Peter Levart, 1 Feb 2010
> LambdaExpression:
>     # ( ParameterListopt -> ReturnTypeopt ) Block
>
> Examples:
> #(->int) { return 7; };
> #(Event e -> void) { handle(e); };
> #(File f -> String) { return f.getName(); };
> #(#(A -> R throws E) l, A a
>   -> #(-> R throws E)) { return #(->R) { return l.(a); }; };
>
> 5. Neal Gafter, 9 Feb 2010
> LambdaExpression:
>     ( ParameterListopt ) -> Expression
>     ( ParameterListopt ) -> Block
>
> Examples:
> () -> 7;
> (Event e) -> { handle(e); };
> (File f) -> { return f.getName(); };
> ((A) -> R throws E l, A a) -> () -> l.(a);
>
> 6. BGGA
> LambdaExpression:
>     { ParameterListopt => BlockStatementsopt Expressionopt }
>
> Examples:
> { => 7 }
> { Event e => handle(e); };
> { File f => f.getName() };
> { { A => R throws E } l, A a => { => l.(a) } };
>
> 7. Peter Levart, 2 Mar 2010
> LambdaExpression:
>     ( ParameterListopt -> BlockStatementsopt Expression )
>
> Examples:
> ( -> 7 );
> ( Event e -> handle(e); void };
> ( File f -> f.getName() );
> ( (A -> R throws E ) l, A a -> ( -> l.(a) ) );
>
> 8. Howard Lovatt, 11 Mar 2010
> LambdaExpression:
>     new #< Signature > ( BlockStatementsopt Expression )
> Signature:
>     ReturnType ( ParameterListopt ) Throwsopt
>
> Examples:
> new #< int() > (7);
> new #< void(Event e) > (handle(e); null);
> new #< String(File f) > (f.getName());
> #< #< R() throws E >( #< R( A ) throws E > l, A a ) >
>   ( new #< R() throws E >()( l.( a ) );
>
> 9. C++ (via Stephen Colebourne), 14 Mar 2010
> (translated to lambda-use)
>
> LambdaExpression:
>     [ Accessorsopt ] ParameterDeclopt ReturnTypeDeclopt {
> BlockStatementsopt }
>
> ParameterDecl:
>     ( ParameterList )
>
> ReturnTypeDecl:
>     -> ReturnType
>
> Accessors:
>     &
>     =
>     Closings
>
> Closings:
>     Closing
>     Closing, Closings
>
> Closing:
>     & Identifier
>     Identifier
>     this
>
> Examples:
> [] { return 7; };
> [] (Event e) { handle(e); };
> [] (File f) { return file.getName(); };
> [] (R (*l)(A), A a) { return []{ return l.(a); };
>
> 10. Rémi Forax, 14 Mar 2010
> LambdaExpression:
>     ( ParameterListopt ) ( Expression )
>     ( ParameterListopt ) Block
>
> Examples:
> () ( 7 );
> (Event e) { handle(e); }
> (File f) { return f.getName(); };
> (R(A)(throws E) l, A a) ( () ( l.(a) ) );
>
> 11. Peter Levart, 17 Mar 2010
> LambdaExpression:
>     ( ParameterListopt : Expression )
>     { ParameterListopt : BlockStatements }
>
> FunctionInvocationExpression:
>     FunctionTypedExpression [ ExpressionListopt ]
>
> Examples:
> (:7);
> { Event e : handle(e); };
> { File f : return f.getName(); };
> ( [ A : R throws E ] l, A a : (: l[a]) );
>
>
>