Mapping..... (Was Stonehenge)

[Brent Fulgham]

In fact ... all this talk yesterday of 'maps' was coming back to me this
morning
while I tried to get Damian Conway's Coy.pm module to work.  There were
several
routines like the following:

my $foo = join "|", map { chop; $_; }
(
    	"anathema", "bema", "carcinoma", "charisma", "diploma",
	"dogma", "drama", "edema", "enema", "enigma", "lemma",
	"lymphoma", "magma", "melisma", "miasma", "oedema",
	"sarcoma", "schema", "soma", "stigma", "stoma", "trauma",
	"gumma", "pragma",
);

I must admit, I wasn't exactly sure what this did.  I fired it off in a test
program to see what $foo is filled with:

anathem|bem|carcinom|charism|...etc...

So it basically modifies the unnamed list in place, to yield a list of words
with the last character missing.  The funny 'map' statement is a functional
way of doing the following:

my @list = ("anathema", "bema", ... ,"gumma", "pragma");
my $foo;
foreach $word (@list)
{
    chop $word;
    $foo .= $word
    $foo .= "|"
}

(except better because it doesn't stick an extra "|" at the end).

Anyway, Perl 5.6 apparently changes things a bit so you can't modify an
unnamed
construct list (which is basically a constant) in-place.   So the fix is to
say:

my $bar = join "|", map { my $val = $_; chop $val; $val}
(
        "anathema", "bema", "carcinoma", "charisma", "diploma",
        "dogma", "drama", "edema", "enema", "enigma", "lemma",
        "lymphoma", "magma", "melisma", "miasma", "oedema",
        "sarcoma", "schema", "soma", "stigma", "stoma", "trauma",
        "gumma", "pragma",
);

Which just introduces a new temporary variable.  Is it less efficient?  Who
knows.

I sent a funny e-mail to Damian about the fix:

--------------------------------
Tension mounting.  Stress.
Broken Coy is bad karma!
Where can I find peace?

It seems that Perl five
point six broke your Coy module.
Attached is a patch.

You will, no doubt, need
to make it harmonious
with the rest of Coy.

Water falls on a rock.
A small gift from neophyte
to the great teacher.

---------------------------------

It was a great honor to get an e-mail back from him
later this same day:

When the student can
patch the teacher's broken code,
who is the master?

Many thanks, grasshopper.

Damian