After running your version of the code on my machine I notice a couple of differences between your results and mine. When you print out the results of the compiled and deparsed macro, you get... 
MACRO (COMPILED & DEPARSED): while ($var3 < $cons4) {
    $body6;
}
continue {
    ++$var5
}

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while I get... 
MACRO (COMPILED & DEPARSED): $var1 = $cons2;
while ($var3 < $cons4) {
    $body6;
}
continue {
    ++$var5
}

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...I notice that the first line $var1 = $cons2; is missing in your report. And strangely enough there's a line is missing from your compilied and deparsed source code ... 
SOURCE (COMPILED & DEPARSED): my $x;
while ($x < 8) {
    my $f = fact($x);
    print "factorial($x)=$f\n";
}
continue {
    ++$x
}
sub fact {
    $_[0] <= 0 and return 1;
    return $_[0] * fact($_[0] - 1);
}
'???';

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vs. my machine 
SOURCE (COMPILED & DEPARSED): my $x;
$x = 0;
while ($x < 8) {
    my $f = fact($x);
    print "factorial($x)=$f\n";
}
continue {
    ++$x
}
sub fact {
    $_[0] <= 0 and return 1;
    return $_[0] * fact($_[0] - 1);
}

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...the $x = 0; has gone missing. So this causes $reorder to differ... 
REORDER: $var3 = $1;$cons4 = $2;$body6 = $3;$var5 = $4;

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vs. 
REORDER: $var1 = $1;$cons2 = $2;$var3 = $3;$cons4 = $4;$body6 = $5;$va
+r5 = $6;

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and is probably what causes the substitution match failure and thus you get the original code back. I don't know why lines would suddenly dissapear. Is it a buffering problem with the back-tick operator?

update:I'd try just running...

perl -MO=Deparse,-x9 -e'for($i=0;$i<10;$i++){$x++}'

...all by itself and see if it matches... 

$i = 0;
while ($i < 10) {
    ++$x;
}
continue {
    ++$i
}

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That's straight from 3rd edition camel p. 480. Anyone else have any ideas? BTW, I'm running perl 5.6.1 under Slackware Linux

In reply to strange differences... by sleepingsquirrel
in thread Playing with (macro/source-filter) fire by sleepingsquirrel

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