On Wednesday 04 November 2015 18:21, Christian Gollwitzer wrote: > What rurpy meant, was that regexes can surface to a computer user > earlier than variables and branches; a user who does not go into the > depth to actually program the machine, might still encounter them in a > text editor or database engine. Even some web forms allow some limited > form, like e.g. the DVD rental here or Google.
What Rurpy meant, only Rurpy can say, but I doubt that is what he is talking about. By that logic, a full-screen high-def 3D first-person shooter game with an advanced AI is "more fundamental" than an assembly language branch operation, because there are people who play computer games without doing assembly programming. In context, Michael suggested that programmers should learn the basic fundamentals of their chosen language, such as variables, for-loops and branching, before regexes -- which Rurpy then disagreed with, claiming that regexes are more fundamental than those basic operations. What *I* think that Rurpy means is that one can construct a mathematical system based on pattern matching which is Turing complete, and therefore in principle any problem you can solve using a program written in (say) Python, C, Lisp, Smalltalk, etc, or execute on a CPU (or simulate in your head!) could be written as a sufficiently complex regular expression. I think he is *technically wrong*, if by "regex" we mean actual regular expressions. Perl, and Python, regexes are strictly more powerful than regular expressions (despite the name). I know that Perl regexes are Turing complete (mainly because they can call out to the Perl interpreter), I'm not sure about Python regexes. But I also think that Rurpy is *not even wrong* if he means Perl or Python regexes. The (entirely theoretical) ability to solve a problem like "What is pi to the power of the first prime number larger than 97531000?" using a regex doesn't make regexes more fundamental than variables, branches and loops. It just makes them an alternative computing paradigm -- one which is *exponentially* more difficult to use than the standard paradigms of functional, procedural, OOP, etc. for anything except the limited subset of pattern matching problems they were created for. -- Steve -- https://mail.python.org/mailman/listinfo/python-list
