It's been maybe 25 years since I wrote a prefix(algebraic) to postfix (RPN) routine to parse an algebraic expression. I would have to work on this for awhile to get it working.

Example using stack:  (2+3)*5 results in: push 2, push 3, add, push 5, multiply This requires an op precedence table.

I think you are better off with some form of Perl eval if the actual equation is unknown until runtime.

As another technique, for 8 variables, you can make an array of say 256 entries, use one bit for each variable, precalculate the results for the 8 variables and use a simple lookup table for the result.

This is also possible with a Perl hash table. Just calculate values where the 8 or whatever variables describe a "true" result.

In reply to Re: Evaluate arbitrary boolean expressions by Marshall
in thread Evaluate arbitrary boolean expressions by gauss76

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.