toxic !  Mr. Yuck!

map & grep => transformers "More than meets the eye!"
	@humped = grep { $humped{$_} } @animals;

Complexity of a program is a function of:
	length of program
	reading stack depth (mean and max)
	reader understanding of the problem
	reader familiarity with the language 

And is measured by time to read the program with comprehension

OK. So? 
	shell out - use your OS
		it has lots of swiss army knife programs
	use the preset variables $_, @_
		use as few declarations and assignments as possible
		polluting the namespace of perl isn't the worry
		polluting the reader's namespace is.
		e.g. fibonacci.
	organize data into structures 
		if your code looks like yank-put monkey p00
			you probably need another data structure
			e.g. eval
	minimize consecutive reader stack pushes
		keep related code together
		use scoping to containerize code and variables
			and false scoping too
			e.g. regexp
	give the reader a mental model of how your program works
		this is documentation (Aaaaauugh!)
	stick to your style manual	
		what constructs should the reader be familiar with?
	put the important stuff first ;)
		e.g. and, or, if

Cool things:
	map => handles one-to-one or one-to-many mappings
		# this also minimizes namespace pollution for our reader
		@transactions = map { `grep TRANSACTION $_` } ( @ARGV or `ls $logdir` );
	
	unix => lots of useful programs with man pages 
	
	eval => create code on the fly to separate code from data
		%actions = ( 
			accepted_charges => '$test1 eq "CHARGE" and $test2 eq "OK"',
			rejected_charges => '$test1 eq "CHARGE" and $test2 eq "NOK"',
			accepted_refunds => '$test1 eq "REFUND" and $test2 eq "OK"',
			rejected_refunds => '$test1 eq "REFUND" and $test2 eq "NOK"',
		);	
		... 
		for (keys %actions) {
			eval($actions{$_}) and $count{$_}++;	
		}
	
	false scoping => use indents to hide documentation variables
		# this also reduces reader stack usage
		my $regexp = qr|$id \t $type \t $status \t $amount|x if (
			my $id     = qr|\d+|, 
			my $type   = qr|(CHARGE|REFUND)|,
			my $status = qr|(OK|NOK)|,
			my $amount = qr|(\d+\.\d\d)|,
		);

	and/or => allow you to put the important stuff first on the line
		# 'A and B' is the same logic as if A then B. Why?
		# see 'if' in the above example
		for (@transactions) {
			/$regexp/ and do { summarize($1,$2,$3); next };
			/.*/      and do { print }; 
		}