[Kurtz79]

A parser (assuming you are talking about a programming language parser) has the luxury of having highly structured and deterministic inputs, and to be able to refuse giving an "answer" if they are not.

[jgalt212]

> highly structured and deterministic inputs

not all parsers deal with such inputs, and parsers that don't can and often do produce multiple interpretations of the input data.

[Kurtz79]

Tell me of some parsers that do not deal with deterministic inputs and have 100% accuracy, then.