Evaluating user-defined conditions

[Paul "LeoNerd" Evans]

On Mon, 9 Jun 2014 13:10:35 +0100
James Laver <james.laver at gmail.com> wrote:

> In short, if you trust the input, just eval() it, and if you don’t,
> you want a parser.
> 
> You might consider transforming it automatically into postfix
> notation and building a really simple stack machine if you just want
> basic arithmetic and placeholders. Otherwise, I can recommend
> Parse::RecDescent.

Parser::MGC will also let you build quite a simple expression evaluator.

For example, see this one that just does +-*/ on integers:

  https://metacpan.org/source/PEVANS/Parser-MGC-0.12/examples/eval-expr.pl

-- 
Paul "LeoNerd" Evans

leonerd at leonerd.org.uk
http://www.leonerd.org.uk/  |  https://metacpan.org/author/PEVANS
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