Error vs sentinel

[jtrakk]

Sometimes people say that exceptions should only be raised for unexpected states in the program, but that a nonmatching parse is often an expected state so it should just return a sentinel value instead of raising an error. What do you think?

[gkappler]

I agree. The parse method throws an error to match behaviour of Base.parse(Int,"abc"). Please refer to tryparse instead, that returns nothing if there is no match.

Yet your question makes me wonder whether instead returning NoMatch() singleton would be clearer as nothing might be a intended parsing result. What do you think?

[jtrakk]

I agree returning NoMatch() would be less ambiguous in cases where nothing is a valid parse result. I suppose theoretically NoMatch() could be an intended parsing result, in which case tryparse could take a sentinel argument.