Interestingly, you are right in that APL grammar is ambiguous, but not in the way you describe above. Programming in APL has been described as the "classical C

Interestingly, you are right in that APL grammar is ambiguous, but not in the way you describe above. Programming in APL has been described as the "classical Chinese" of programming, and that's a good analogy. APL requires you to know both its primitives and implicit execution model off by heart to be efficient. You must learn to read it like a natural language, both vocabulary and grammar. By comparison, LISP has an explicit execution model in that it's explicitly reflected in the syntax by parentheses. Relations between APL primitives are implicit, and that's actually very nice and useful too!