in reply to Optimizing Output

Doesn't it say somewhere that interpolating is faster than multiple .'s? If I remember correctly, each '.' forces a copy, where as interpolation only does it once. 

$string .= $a . $b . $c . $d;

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does like 5 copies, whereas 

$string = "$string$a$b$c$d";

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only does one.

Because of this, I always do interpolation if I can, but I won't go out of my way to do so.

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Re: Re: Optimizing Output
by sfink (Deacon) on Apr 15, 2002 at 20:35 UTC
    No. 
    perl -Dt -e '"$a$b".$c.$d'   

EXECUTING...

(-e:0)    enter
(-e:0)    nextstate
(-e:1)    gvsv(main::a)
(-e:1)    gvsv(main::b)
(-e:1)    concat
(-e:1)    gvsv(main::c)
(-e:1)    concat
(-e:1)    gvsv(main::d)
(-e:1)    concat
(-e:1)    leave

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    They both call the concat opcode.

    At one time, I remember the tokenizer actually rewrote "x$y" to be "x" . $y and "recursed" on it. But it doesn't seem to anymore. O::Deparse can even tell the difference: 

    perl -MO=Deparse -e '"$a$b".$c.$d'
"$a$b" . $c . $d;

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