Hmmm. My post, as stated, was simply asking why Ovid chose to use a temporary variable where it wasn't necessary. I'm beginning to hate the sight of that phrase 'cargo-cultish'. Especially when it is wrongly used to mean 'not the way I would do it'.

Using your version, if the 'name' param is completely omitted, then param('name') as you state will return undef. Which means that the attempt to apply the m// to results in

Use of uninitialized value in pattern match (m//) at ....
[download]

Which is exactly why the ||'' is there in the first place.

Your correct that this only delays the need to use defined to test for this, but I think that that delay is beneficial. Vis. Instead of,

my $_name = param('name');
my ($name) = $_name =~ /^([[:alpha:]]+)$/ if defined $_name;
my $_color = param('color');
my ($color) = $_color =~ /^([[:alpha:]]+)$/ if defined $_color;
my $_otherReqParam = param('otherReqParam');
my ($otherReqParam) = $_otherReqParam =~ /^([[:alpha:]]+)$/ if defined
+ $_otherReqParam;
# ... and so on for all the other params, and then
print 'location: http:/www.somesite.com/error.htm', $/, $/
     unless defined $name
     and    defined $color
     and    defined $otherReqParameter;
....
[download]

You get the simpler, cleaner

my ($name) =          (param('name')         ||'') =~ /^([[:alpha:][:p
+unct:][:space:]]+)$/;
my ($color) =         (param('color')        ||'') =~ /^([[:alpha:]]+)
+$/;
my ($otherReqParam) = (param('otherReqParam')||'') =~ /^([[:alpha:]]+)
+$/;

#deal with all other params in a similar fashion.
print 'location: http:/www.somesite.com/error.htm', $/, $/
     unless defined $name
     and    defined $color
     and    defined $otherReqParam;
     
# If we got here we have everything we need, untainted.
...
[download]

This allows all the parameter validation to be done at the top of the script without needing temporary variables or to test at least twice for definedness, nicely grouped and with a consistant style, and allows us to bottle out early if we haven't got everything we need.

Not the only way to do it, maybe not the best way to do it, but it is a valid way and not without its merits. And its far from what I understand the definition of "cargo-cultish" to mean.

---

Cor! Like yer ring! ... HALO dammit! ... 'Ave it yer way! Hal-lo, Mister la-de-da. ... Like yer ring!

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.