Re: auto functions not authorized inside main?

[Rory McGuire]

On Mon, 28 Jun 2010 16:01:46 +0200, BCS  wrote:


Hello Rory,


On Sun, 27 Jun 2010 17:17:25 +0200, Philippe Sigaud
 wrote:


void main()
{
auto fun(string s) { return s;} // this does not compile
}


Hope this isn't a stupid question, but how would you access this
function
if it did work?
Would it be fun("asdf")?
Is this just shorthand for:
auto fun = function(string s) {return s;};


I would look almost the same to the user but should in fact be a normal  
local function.




Ye I got it now.

My brain was interpreting it as a delegate that wasn't being assigned to  
anything for some reason.


Now I get that it is just return type inferance doesn't work for inner  
functions.


-Rory

Re: auto functions not authorized inside main?

[Rory McGuire]

On Mon, 28 Jun 2010 16:07:43 +0200, Philippe Sigaud  wrote:On Mon, Jun 28, 2010 at 15:40, Rory McGuire  wrote:

void main()
{
    auto fun(string s) { return s;} // this does not compile
}

Hope this isn't a stupid question, but how would you access this function if it did work?
Would it be fun("asdf")?Yes, that's what I had in mind. Basically, just using it as any other auto inner function. void main(){auto fun(string s) { return s;}auto s = fun("abc");
auto t = fun("def");} 
Is this just shorthand for:
auto fun = function(string s) {return s;};That'd be about the same, yes. Fact is, I don't really _need_ this, I was just astonished to be bitten by this.Why can I do
void main(){    string foo(string s) { return s;}}and notvoid main(){    auto foo(string s) { return s;}} ?***OK, I tested it some more, and it seems you cannot define auto function inside any other function. So auto function cannot be inner functions. I'm quite astonished I never did that when using D, but OK.
I filed a bug report, at least to update the docs. It's bug #4401.Philippe
Right! I get what you're saying, didn't realise because it was formatted more how I would format a anon delegate.You're saying "surely the compiler can infer the return type for a inner function just as much as it can infer the return type of a normal function..Must be a compiler bug.-Rory

Re: auto functions not authorized inside main?

[BCS]

Hello Rory,


On Sun, 27 Jun 2010 17:17:25 +0200, Philippe Sigaud
 wrote:


void main()
{
auto fun(string s) { return s;} // this does not compile
}


Hope this isn't a stupid question, but how would you access this
function
if it did work?
Would it be fun("asdf")?
Is this just shorthand for:
auto fun = function(string s) {return s;};


I would look almost the same to the user but should in fact be a normal local 
function.


--
... <

Re: auto functions not authorized inside main?

[Rory McGuire]

On Sun, 27 Jun 2010 17:17:25 +0200, Philippe Sigaud  
 wrote:


Is it defined somewhere that auto functions are not authorized inside  
main?


void main()
{
auto fun(string s) { return s;} // this does not compile
}

error:

main.d|6|found 's' when expecting ')'|
main.d|6|semicolon expected, not ')'|
main.d|6|found ')' instead of statement|
main.d|7|unrecognized declaration|
||=== Build finished: 4 errors, 0 warnings ===|


So it's not even parsed?

I couldn't find a bugzilla entry for this and I cannot believe no one  
ever

tried to put an auto fun inside main!

Is that part of the spec?

Philippe


Hope this isn't a stupid question, but how would you access this function  
if it did work?

Would it be fun("asdf")?
Is this just shorthand for:
auto fun = function(string s) {return s;};



-Rory

Re: auto functions not authorized inside main?

[bearophile]

Philippe Sigaud:
> I couldn't find a bugzilla entry for this and I cannot believe no one ever
> tried to put an auto fun inside main!

Maybe auto funcs are seen as instantiated templates, and templates can't be 
defined inside functions. Anyway, I think you can file this as enhancement 
request.

Bye,
bearophile