On: Clojure: All grown up

[tikhonj]

The idea is that Parsec represents a grammar, similar to BNF with <|> giving alternative rules. So something like:

    atom =  many digit
        <|> identifier
        <|> stringLiteral
        <|> between (char '(') (char ')') expression

I can't imagine any way this would look better with a name instead of the <|> operator. You could write it something like:

    atom = many digit
        `or` identifier
        `or` stringLiteral
        `or` between (char '(') (char ')') expression

but that's no clearer and a bit harder to follow. With a much longer identifier than "or", it would be completely unreadable. If you had to make "or" prefix (the `` let you use a normal function in infix position), it would be even less readable. Combine the two (a longer, prefix identifier) and you have an even bigger mess!

The operators let you see the structure of an expression at a glance. You don't have to read the whole thing to figure out what's going on. Moreover, the <|> symbol is pretty intuitive--it's clearly based on | which usually represents some sort of alternation.

[rayiner → tikhonj]

I find the second one much clearer than the first one, because there is no ambiguity to me whether '<|>' means the same thing as '|'. It's also less ugly.