The original question isn't phrased very carefully, but it does have an interesting core.

Perl has a "peephole optimizer" which evaluates some constant expressions at compile time. You can see that for example here: 

$ perl -c -wE '1+1; say "OH HAI"'
Useless use of a constant (2) in void context at -e line 1.
-e syntax OK

[download]

Note that the -c switch means that the code is only compiled, not run. And yet the warning mentions 2 instead of 1+1, so you can see that the expression 1+1 has been evaluated at compile time, not at run time.

The original question could thus be phrase "Why is the expresion "literal" x <literal_number> not constant-folded at compile time, as <literal_number> + <literal_number> is?"

And yes, that's a valid and interesting question

I think if you want a constant use a constant

That's not very convincing. For example if I write '=' x 80, I see immediately that it's 80 equal signs. But if I write '===============================================================================', can you see immediately how many equal signs that are?

The difference in readability is even larger when whitspaces are concerned, ' ' x 20 vs. '                    '. Imagine that being printed out on a sheet of paper. Which one do you find easier to decipher?

Perl 6 - second systems done right

In reply to Re^2: Why is const x const not a const? by moritz
in thread Why is const x const not a const? by PerlGrey

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