Set-Formula Set::Formula - Formula calculation for sets. SYNOPSIS use Set::Formula; formula_checker (string_containing_formula); # syntax check without debug formula_checker (string_containing_formula, 1); # syntax check with debug formula_calcul (string_containing_formula, \%result, \%HoH_sets); # without formula_calcul (string_containing_formula, \%result, \%HoH_sets, 1); # with equality_checker (\%set1, \%set2); # without debug equality_checker (\%set1, \%set2, 1); # with debug DESCRIPTION formula_checker - checks syntax of formula without its calculation. formula_calcul - calculates formula without its syntax check. equality_checker - checks, if 2 sets are equal. Formula should be written in common arithmetic notation (infix notation) and can contain unrestricted amount of nested parentheses (). Supported set operators are "+" - union, "-" - complement, "^" - intersection. All these operators are binary operators, i.e. they require 2 operands. Formula without parentheses is evaluated from left to right with equal priority for all operators. Parentheses increase priority of partial formula expressions. White characters including new line in formula are accepted and ignored. Thus formula might be placed into both a single line and multiple lines. formula_checker and formula_calcul return nonzero on success, the undefined value otherwise. equality_checker returns 1 if both sets are equal, else 0. TECHNICAL IMPLEMENTATION OF SETS For formula_checker and formula_calcul -------------------------------------- All formula operands must be highest level keys of a hash of hashes, that is named in example below as %HoH_sets. Lowest level keys of this hash of hashes form corresponding sets. Values of lowest level hashes are irrelevant (can be undefined). Name convention for formula operands: begin with a character, optionally following by any amount of characters, digits, underlines. Operand names are case sensitive. For equality_checker -------------------- Operands are sets, written in keys of one dimensional hashes. EXAMPLES use Set::Formula; @A{qw (bisque red blue yellow)} = (); @B{qw (bisque brown white yellow)} = (); @C{qw (magenta pink green )} = (); @D{qw (magenta pink rose )} = (); @E{qw (bisque honeydew )} = (); %HoH_sets = ( A=>\%A, B=>\%B, C=>\%C, D=>\%D, E=>\%E ); # or alternatively %HoH_sets = ( A => { bisque => 0, red => 0, blue => 0, yellow => 0, }, B => { bisque => 0, brown => 0, white => 0, yellow => 0, }, C => { magenta => 0, pink => 0, green => 0, }, D => { grey => 0, pink => 0, rose => 0, }, E => { bisque => 0, honeydew => 0, } ); # A, B, C, D, F are operands. Every of them is a set, written in keys of sublev $formula = "A ^ ( B + (C ^ D) ) - E"; %result = (); # this hash must be declared, but it must not be emptied before # call of formula_calcul() # Usage of formula_checker() before formula_calcul() is recommended, # but is not mandatory formula_checker ($formula) || die "Error in formula\n"; formula_calcul ($formula, \%result, \%HoH_sets) || die "Error in formula\n"; for (keys %result) {print "$_\n"} # prints result of formula calculation @expected_result{qw (magenta yellow)} = (); if (equality_checker (\%result, \%expected_result)) { print "equal\n" } else { print "not equal\n" } EXPORT formula_checker, formula_calcul, equality_checker. SEE ALSO Part "Basic operations" - http://en.wikipedia.org/wiki/Set_(mathematics) Infix notation - http://en.wikipedia.org/wiki/Infix_notation AUTHOR Mart Rivilis, rivilism@cpan.com INSTALLATION To install this module, run the following commands: perl Makefile.PL make make test make install SUPPORT AND DOCUMENTATION After installing, you can find documentation for this module with the perldoc command. perldoc Set::Formula You can also look for information at: RT, CPAN's request tracker (report bugs here) http://rt.cpan.org/NoAuth/Bugs.html?Dist=Set-Formula AnnoCPAN, Annotated CPAN documentation http://annocpan.org/dist/Set-Formula CPAN Ratings http://cpanratings.perl.org/d/Set-Formula Search CPAN http://search.cpan.org/dist/Set-Formula/ LICENSE AND COPYRIGHT Copyright (C) 2013 Mart Rivilis This program is free software; you can redistribute it and/or modify it under the terms of the the Artistic License (2.0). 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