Weird indentation on <

[Narven]

If I do something like:

let pi_less_4 = std::f64::consts::PI < 4.0;
                                       let x = 5;

Pushing the next line to bellow the 4.0

[tromey]

I can reproduce it. Looking at the < with M-x describe-char, it has syntax properties indicating it is an open "paren". So the syntax propertizer is mis-characterizing this. This makes some intuitive sense to me because the propertizing is somewhat heuristic by necessity, and what's to differentiate this case from some::generic<type>. So I'm not totally sure what to do.

[tromey]

Maybe one idea would be to change the heuristic to look at whitespace between an identifier and <. That is, if there is whitespace, guess that it is a less-than.

[tromey]

We could also use a heuristic that checks for camel case, though that wouldn't help in this particular situation, or in code that allows violations of that rule.

[AlbertoGP]

I’ve just encountered this problem when using the bit shift left operator <<, and it ruins the indentation of the whole file below that point, everything including other functions, modules, etc.

Edit to add that I’m using the 0.4.0 release.

[AlbertoGP]

Quick workaround: zap the lines that set < and > as parentheses, at line 94 of "rust-mode.el":

;; Angle brackets.  We suppress this with syntactic propertization
;; when needed
;(modify-syntax-entry ?< "(>" table)
;(modify-syntax-entry ?> ")<" table)

It’s a pity to lose the matching for complex types, but wrecking the indentation is a show-stopper for me.

[misson20000]

Still a big problem comparing with namespaced constants.