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Acme-AlgebraicToRPN-0.02
River stage zero No dependents
/ Acme::AlgebraicToRPN

NAME

Acme::AlgebraicToRPN - convert algebraic notation to sane RPN

VERSION

Version 0.02

SYNOPSIS

$rpn = Acme::AlgebraicToRPN->new;
@RPN = $rpn->eval($equation);

DESCRIPTION

Given a string with algebraic notation, convert to RPN, which is what any crappy dime store calculator needs to do anyway.

Doesn't really process anything, that's up to you. You will get an array back with all of the variables and operations in RPN format. So that 3+4 will come back as

3
4
add

Possible future extensions will be to allow you to actually process this via hooks that allow specifications of how to handle foreign functions. But for my purposes, the array is good enough, as I am passing this on to a C program to do some serious number crunching.

Additionally, you can specify (via the constructor) the names of your own functions. See below.

ACKNOWLEDGEMENT

The Hewlett Packard Company and the HP 35, my first real calculator, and Steffen Mueller for the Math::Symbolic code.

AUTHOR

X Cramps, <cramps.the at gmail.com>

BUGS

Please report any bugs or feature requests to bug-acme-algebraictorpn at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Acme-AlgebraicToRPN. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

perldoc Acme::AlgebraicToRPN

You can also look for information at:

ACKNOWLEDGEMENTS

COPYRIGHT & LICENSE

Copyright 2009 X Cramps, all rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

new

$al = Acme::AlgebraicToRPN->new(%opts);

%opts (optional) can be:

userFunc - user functions, as array reference

If you had a user function box and fft, you'd need to specify them like this:

$al = Acme::AlgebraicToRPN->new(userFunc =>
  [qw(box fft)]);

rpn

@stack = $al->rpn($expr);

Processes $expr (an algebraic format expression) and return the stack necessary to process it. The stack consists entirely of variables, constants and operations. For operations, be prepared to handle (and others, see Math::Symbolic documentation):

negate
add
subtract
multiply
divide
exponentiate
sin
cos
tan
cot
asin
acos
atan
atan2
acot
sinh
cosh
asinh
acosh

Plus any that you may add in constructor [1].

undef is returned if the parens don't balance. That's all the checking we do.

[1] If you supply a custom function, you can supply arguments
    to it. When you see your function name on the returned stack,
    the next thing on the stack is the I<number> of arguments,
    and then the arguments themselves. For example, let's say
    you registered your function 'foo' (in constructor)
    and you gave B<rpn> this equation: 4*foo(a,3)

    You'd get back this:
    4 a 3 2 foo multiply

rpn_as_string

$stack = $al->rpn($expr);

Same as rpn, but returns as a comma-separated list. Split on commas, and you have your stack to be processed.

check

$ok = $al->check(\@stack, @expected);

Checks result of RPN conversion. @stack is what the rpn function returned, and @expected is what you expected the result to be. This is kind of a diagnostic routine for testing.

Returns 1 if both @stack and @expected were the same, 0 if not.