You might want to look into Lex/Yacc (or Flex/Bison, whatever you want to call them). Flex is a lexical analyzer, which will parse and identify the semantic components ("tokens") of your language, and Bison will be used to define what happens when each token is parsed. This could be, but is definitely not limited to, printing out C code, for a compiler that would compile to C, or dynamically running the instructions.
This FAQ should help you, and this tutorial looks quite useful.
