Question

I have a string with several unix statements, joined with (, ), ||, &&, |. I want to separate them out into arrays (nested?) in the order they would be evaluated in a unix command line. I preferably want them in a prefix notation, but anything would do.

like

a --foo "b|a||r" && a -b || (a || a) | c | d

should become

["|", ["|", ["||", ["&&", "a --foo \"b|a||r\"", "a -b"], ["||", "a", "a"]], "c"], "d"]

(Really tried to give an example that involves all possibilities.

How should I approach this?

I can understand code in most of the popular high level (OOP) languages (ruby, python, etc), or even a pseudocode would help.

Answer 1

If you think about it, the task is not different from parsing a mathematical expression, e.g. a * (b + c) / d ==> [/, [*, a, [+, b, c]], d] . Thus, you can use the same tools:

You need is an infix parser.

(Infix, because your operators are between the operands: e.g. a && b)

Browse over the Wikipedia article for a bit of theoretical background, then grab an existing parser for the language you would like to use and define the operators as well as their precedence.