Problem is, an individual that generates a syntax error might only be one character different to an individual that prints the required string. Or it might be total rubbish.
in reply to Re: Re: Re: JAPH-ing Genetically
in thread JAPH-ing Genetically
The first should (for this method to work) be fitter than the second, but I don't know a way to quantify that.
Also, p(syntax error) is very high for constructing a valid Perl string randomly. The chances are that all members of a population would generate syntax errors - at which point they'd all have the same fitness.
A better approach would be to create a baby language safe (or safer) from syntax errors and eval that. Like maybe just arithmetic operators and numbers.
Although - it's just occured to me - you'd be on fairly safe ground with a subset of a highly structured language like Logo. And you could evaluate fitness by checking how similar the figure drawn was to your target figure.