Re: Constant code

First, I always put an explicit return statement in a subroutine rather than relying upon "return value of last statement" except in sort{} blocks where no return statement is the norm.

When you call a sub() in an expression, the paren's are normally required. There are built in functions and ways to make a user defined function work like a built in function with prototypes.

The simple answer here is to call sub1() and sub2() with no arguments, use sub1(), etc. Don't use a bare word sub name for a normal user defined sub/function.

#!usr/bin/perl
use strict;
use warnings;

sub sub1{return 2}
sub sub2{return 2}

my ($a, $b) = (sub1, sub2);
my ($s, $t) = ((2*sub1()+sub2()), (2*$a+$b));


say STDERR "$a==", sub1;
say STDERR "$b==", sub2;
say STDERR "$s==$t";

__END__
2==2
2==2
6==6
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Re^2: Constant code by Anonymous Monk on Jan 20, 2017 at 21:00 UTC
The simple answer here is to call sub1() and sub2() with no arguments, use sub1(), etc. Don't use a bare word sub name for a normal user defined sub/function. And yet, we encourage this all the time in OO paradigms, where we have a member function `foo` to get the value of 'foo': `$obj->foo` instead of `$obj->foo()`, ostensibly because it is a 'value' and the fact that `foo` is a function is just an implemention detail. Fooey, I say: if you end up creating a stack entry, use parens. That's just my curmudgeonly USD 0.02.	[reply] [d/l] [select]
Re^3: Constant code by Anonymous Monk on Jan 20, 2017 at 22:15 UTC
I have seen parentheses-less method calls outside of getting only a (variable) value, namely in cases where no parameters are being passed. (I don't have any examples handy right now.)	[reply]
Re^3: Constant code by mpersico (Monk) on Jan 20, 2017 at 21:02 UTC
Sorry, that ^ was me.	[reply]
Re^4: Constant code by AnomalousMonk (Archbishop) on Jan 20, 2017 at 23:04 UTC
I admit this is a bit of a syntactic nit, but in the `$object_reference->method` and `ClassName->method` OO cases, doesn't the `->` operator as unambiguously indicate function invocation (both to compiler and to programmer) as the parentheses in the `func()` case? I.e., always writing `$obj->method` without any parentheses is the same as always writing `func()` with its empty parentheses. (Although I certainly agree that `$obj->method()` is perfectly valid.) Give a man a fish: `<%-{-{-{-<`	[reply] [d/l] [select]