The handling of [ is awkward in general

[davxiao]

On IRC dhs227 notes:

If I press F1 it generate [[A, then press enter. fish complains fish: Tokenizer error: “Unexpected end of string, parenthesis do not match”
the problems are: a) it complain twice.
b) it does not clear the cmd line, which I think it should be.
c) in this case,fish likely "eats" the latest cmd line somehow.

Obfuscate also notes that:
That seems like a bug. The handling of [ is awkward in general as well: [[ errors, [[ errors, [[ is an ordinary token, as is [[.

Above all are reproduced on 20130606 build.

[ghost]

I'm personally in favour of dropping [ as a builtin entirely and just using test because it's more orthogonal, unless there happens to be a difference of which I'm unaware.

[ridiculousfish]

There is a real command [ (that is, there really is a file with path /bin/[), so I think fish needs to treat [ as a command.

The "parenthesis do not match" seems like a tokenizer error. Square brackets should only be treated specially after variables.

[ridiculousfish]

I've changed my mind about square brackets only being treated specially after variables. I don't think that's a good idea any more. This commit should improve the error message and ensure it is only reported once:

46452e7

Thanks for reporting this!