Parameter parser

phaedrus at phaedrus at
Tue Nov 26 14:42:58 CST 2002

(Trying again... can't remember what email happyfunball expects me to use)

Theres no one here but us endangered bobtailed lesser plumed plum crested
symbol owls!

My solution, in two lines:

# test data
$_ = qq{param1 param2="value2" param3="value3 \\"foo\\""};

s{(\w+)\s*=?\s*(['"]?)(.*?)(?<!\\)\2}{$hash{$1} = $3;''}ge;
foreach my $i (keys %hash) { $hash{$i} =~s/\\//g }

# output results
foreach my $i (keys %hash) { print $i, ' = ', $hash{$i}, "\n"; }

# end perl

This should handle qouting with ' or ".
I'm sure there is a one line solution as well.

Thats somewhat similar to something I just did (this seems to happen
a lot in Perl-land).

I decided that CGI was entirely too large at 6695 lines, so I
decided to rewrite it, or atleast the parts of it that I actually use:

my $in = $ENV{QUERY_STRING}||''; $in.='&'; read(STDIN, $in, $ENV{CONTENT_LENGTH}||0, length($in));
map { $nam='word';s{^([a-z]+)=}{$nam=$1;''}e; tr/+/ /; s/%(..)/pack('c',hex($1))/ge; $$nam=$_; } split/[&;]/, $in;

This decodes GET and/or POST data.

I personally feel that something that can't be done in one line isn't
feel enough understood, or else it could be paired down to its essential core.

I'm reading in $ENV{QUERY_STRING} or else the empty string (to make warn happy),
concat'ing the '&' seperator, then reading from STDIN for whatever length 
$ENV{CONTENT_LENGTH} specifies starting at the end of what we read from the
query string. This way, GET variables have priority over POST variables.
I split that on ";" or "&", and do a few string operations (all of which
default to $_) on $_. First, replace a varname composed of lowercase letters
with '', stashing that in $nam over top of the default 'word'. Then I
decode what is left, using a symbol table lookup to store in the variable
specified by $nam. 

Oh?? And who makes you code Perl? Would it be, hmm, SATAN!?


> Hey all,
> I just implemented a parser that takes something like this:
> command param1 param2="value2" param3="value3 \"foo\""
> and puts the parameters and values into a hash.  The value for param1 
> would be "1".  I'm not sure I implemented it the best way, though.  I 
> thought I'd get some ideas from you folks to get a different 
> perspective.  I'll post what I did after I get some responses.  I don't 
> want to contaminate your thinking. :)

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