The Perl Purity Test

Version 1.01, October 30, 1992

Additions are welcome. Please send them to okamoto@ranma.corp.hp.com or ..!hplabs!hpcc01!okamoto.

All questions begin with "Have you ever..." Answer each question with a "yes" or "no". Keep track of how many "yes" answers you give. When finished, subtract that number from the total number of questions, then divide by the number of questions to get a percentage. This percentage is your perl purity. There are 125 questions in this version.

• rewritten a Unix command in perl?
• rewritten a DOS command in perl?
• emulated a kernel feature inside a program in perl?
• written a compressor/decompressor using pack?
• written scripts that generate other scripts?
• used undocumented features?

• used reserved keywords as variable names?
• used $x, @x, and %x in a script?
• used $x, @x, %x, and *x in a script?
• not gotten confused when you used $x, @x, %x, and *x all in that script?
• written a script with no alphabetic characters in it?
• no alphanumeric characters in it?
• used variables with control-characters other than ones already defined?
• created variables at runtime?

• used lists of lists?

• used associative array operators on the main symbol table?

• created functions at runtime?
• written a function that returns different types? (e.g., scalar, list, etc.)
• called a subroutine with the & operator and no arguments so that the child function inherited what remains of the caller's argument stack, @_?
• changed function definitions on the fly?
• used wantarray?
• returned a "0 but true" scalar?

• used do BLOCK inside an EXPR?
• used loop controls (e.g., last, next, etc.) from inside a signal handler?
• created a loop label at runtime?

• used the scalar ".." operator?
• used it with things other than line numbers, array indices, or regexps?
• used syscall?

• used the /e switch?
• used the /ee switch?
• used a /eee or higher number of e's in a switch?

• used arrays of file handles?
• used indirect file handles?
• used doubly indirect file handles?
• used a directory handle as a file handle?
• and gotten away with it?
• used a file handle as a directory handle?
• and gotten away with it?

• used all nine sets of parentheses in a regexp?
• used more than nine sets of parentheses in a regexp?
• used nested parentheses in a regexp?
• wished for an equivalent to LISP's meta-close character "]", which closes all currently open parentheses?

• used grep on non-arrays?
• nested grep within another grep (for a total of two greps)?
• nested up to five greps within one statement?
• nested more thann five greps within one statement?

• written self-modifying evals?
• used eval to test for features your brain-damaged version of Unix doesn't have?
• used eval/die to emulate setjmp/longjmp?
• nested an eval inside another eval (for a total of two nested evals)?
• used up to five nested evals?
• used more than five nested evals?

• used references?
• used lists of references?
• used associative arrays of references?
• lost your referents and didn't care?

• used stream sockets?
• used datagram sockets?
• used RPC?

• used the -D flag?
• used the -D1024 flag?
• figured out what all that debugging info meant?
• used the perl debugger?
• modified the perl debugger?

• written your own package?
• used packages to emulate structures?
• referenced a package's symbol table via %_packagename?

• gotten frustrated with the documentation of how to link in user subroutines?
• written a subroutine to be linked in with uperl.o so that your routine can be called from a perl script?
• replaced your version of perl with a version that has your subroutine(s)?

• abused dynamic scoping by fudging @ARGV?
• abused dynamic scoping and changed the names of functions?

• debugged the result of h2ph?
• hacked on h2ph?

• debugged the result of c2ph?
• hacked on c2ph?
• ported gcc so you can use c2ph?

• used autoloading functions?

• used taintperl?
• tried to subvert the TAINT checks?
• read the source to see what happens if you successfully subvert the TAINT checks?
• changed the source to change what happens if you successfully subvert the TAINT checks?
• tried to read the source?
• found the comment "/* Heavy wizardry */" other than by deliberately searching for it now that you know it exists?

• sent mail to Larry asking for help?
• sent mail to Larry reporting a bug in perl?
• sent mail to Larry requesting a feature?
• gotten a reply from Larry (as opposed to his autoreplier)?
• gotten more than ten autoreplies from Larry?
• sent mail to Randal asking for help?
• sent mail to Randal reporting a bug in perl?
• sent mail to Randal with an idea for a JAPH script?
• sent mail to Tom asking for help?
• sent mail to Tom reporting a bug in perl?
• sent mail to Tom pointing out an error in his slides?
• had a requested feature be included in a subsequent set of patches?
• had up to five requested features included?
• had more than five requested features included?

• written a "Just another Perl hacker" script?
• written five or less JAPH scripts?
• written more than five JAPH scripts?
• written any perl poems?
• run these perl poems?

• used unquoted strings?
• used them unintentionally?
• seeked on __DATA__ to reread your script?
• tried to use a bi-directional pipe?
• realized why this is a waste of time?
• used co-routines in a perl script?
• written a script that used command-line switches?
• used up to five command-line switches?
• more than five command-line switches?
• written a script with its own man page embedded in it?
• counted how many perl functions are overloaded?

• referred to the Perl book?
• bought the Perl book?
• bought multiple copies because you wore out the previous copies?
• owned more than one edition of the Perl book?
• owned more than one copy of every edition of the Perl book?
• wondered why Larry and Randall chose a camel for the cover?
• found out why Larry and Randall chose a camel?
• read comp.lang.perl?
• posted to comp.lang.perl?
• applied a kill file to comp.lang.perl?

The Perl Book, "Programming Perl", is written by Larry Wall and Randal L. Schwartz, published by O'Reilly and Associates, Inc. ISBN 0-937175-64-1