• Derix (22/22) Oct 27 2013 So, I wanted to wrap my head a little tighter around those
• Maurice (6/13) Oct 27 2013 You still have to call the lambda just like a function, with ():
• Maurice (9/25) Oct 27 2013 Some clarification:
• David Nadlinger (4/9) Oct 27 2013 Yes, this is correct.

"Derix" <derix dexample.com> writes:

So, I wanted to wrap my head a little tighter around those 
strange animals that are lamdas.

I wrote the simpliest program utilizing a lambda :

import std.stdio;
void main(){
	writeln({return "foobar";});
}

and it yields 43106C, which does not look like "foobar" at all, 
but rather, I suspect, like a pointer or something.
So I tried
        writeln(typeid({return "foobar";}));
which in turn yelds immutable(char)[]()*
that hints further to a pointer.
I get the immutable(char)[] : an immutable array of characters, 
why not. But I really don"t get the set of parens between the 
square brackets and the asterisk. Could that mean that what I get 
is in fact a pointer to a function ? (said function having no 
arguments, or having void as sole argument or ...)

Now, the question (and the very point of a lambda if I get it 
right) would be to get this function to evaluate (and precisely 
return the string "foobar" in this example).

What syntactic subtility am I missing ?

"Maurice" <m-ou.se m-ou.se> writes:

On Sunday, 27 October 2013 at 14:01:31 UTC, Derix wrote:
 So, I wanted to wrap my head a little tighter around those 
 strange animals that are lamdas.

 I wrote the simpliest program utilizing a lambda :

 import std.stdio;
 void main(){
 	writeln({return "foobar";});
 }

You still have to call the lambda just like a function, with ():

import std.stdio;
void main() {
	writeln({return "foobar";}());
}

"Maurice" <m-ou.se m-ou.se> writes:

On Sunday, 27 October 2013 at 14:10:50 UTC, Maurice wrote:
 On Sunday, 27 October 2013 at 14:01:31 UTC, Derix wrote:
 So, I wanted to wrap my head a little tighter around those 
 strange animals that are lamdas.

 I wrote the simpliest program utilizing a lambda :

 import std.stdio;
 void main(){
 	writeln({return "foobar";});
 }

 You still have to call the lambda just like a function, with ():

 import std.stdio;
 void main() {
 	writeln({return "foobar";}());
 }

Some clarification:

import std.stdio;
void main() {
     auto f = {return "foobar";}; // f behaves like a function.
     auto s = f(); // it can be called like any other function, it 
takes no parameters.
     writeln(s);
}

"David Nadlinger" <code klickverbot.at> writes:

On Sunday, 27 October 2013 at 14:01:31 UTC, Derix wrote:
 I get the immutable(char)[] : an immutable array of characters, 
 why not. But I really don"t get the set of parens between the 
 square brackets and the asterisk. Could that mean that what I 
 get is in fact a pointer to a function ? (said function having 
 no arguments, or having void as sole argument or ...)

Yes, this is correct.

You still have to call the lambda: { return 42; }().

David