• Marcone (11/11) May 13 2021 import std;
• Adam D. Ruppe (6/9) May 13 2021 First, you really shouldn't use these at all. instead of a
• Marcone (3/12) May 13 2021 This is just a simple example of how it works. I won't use it.
• Marcone (2/11) May 13 2021 Thank you. binaryFun solved the problem.

Marcone <marcone email.com> writes:

import std;

template foo(alias pred = "a*b"){
	void foo(int x, int y){
		writeln(x.unaryFun!pred);
	}
}

void main(){
	foo(5, 4);
}


"a" works, but "b" not work.
I get this error: Error: undefined identifier `b`

Adam D. Ruppe <destructionator gmail.com> writes:

On Thursday, 13 May 2021 at 21:30:43 UTC, Marcone wrote:
 template foo(alias pred = "a*b"){
 	void foo(int x, int y){
 		writeln(x.unaryFun!pred);

First, you really shouldn't use these at all. instead of a 
string, just pass an actual function to the thing as the 
predicate.

but if you must use it, unaryFun has one argument, so just a. if 
you want a and b, two arguments, that's binaryFun.

Marcone <marcone email.com> writes:

On Thursday, 13 May 2021 at 21:38:25 UTC, Adam D. Ruppe wrote:
 On Thursday, 13 May 2021 at 21:30:43 UTC, Marcone wrote:
 template foo(alias pred = "a*b"){
 	void foo(int x, int y){
 		writeln(x.unaryFun!pred);

 First, you really shouldn't use these at all. instead of a 
 string, just pass an actual function to the thing as the 
 predicate.

 but if you must use it, unaryFun has one argument, so just a. 
 if you want a and b, two arguments, that's binaryFun.

This is just a simple example of how it works. I won't use it. 
However, I believe it will be very useful for meta programming.

Marcone <marcone email.com> writes:

On Thursday, 13 May 2021 at 21:38:25 UTC, Adam D. Ruppe wrote:
 On Thursday, 13 May 2021 at 21:30:43 UTC, Marcone wrote:
 template foo(alias pred = "a*b"){
 	void foo(int x, int y){
 		writeln(x.unaryFun!pred);

 First, you really shouldn't use these at all. instead of a 
 string, just pass an actual function to the thing as the 
 predicate.

 but if you must use it, unaryFun has one argument, so just a. 
 if you want a and b, two arguments, that's binaryFun.

Thank you. binaryFun solved the problem.