Comment handling is broken

[russel]

The font-lock behaviour with comments is wrong. // without a following space is not treated as a comment. // with a following space is.

[jgrzebyta]

also /* is not treated as a comment.

Gentoo mode version: 20170516.1155 Emacs: 25.1.1

Attached screenshot:

[russel]

I think we need @Wilfred to take a look at this if he can.

[Wilfred]

I cannot replicate either of the issues mentioned.

Given the text:

// foo

def x = 1

//bar

def y = 2

/* baz */

def z = 2

I'm seeing:

Please provide some example Groovy code that I can copy and paste into Emacs.

It's also possible that you have some state in your Emacs instance, so if you've just upgraded from the previous version of groovy-mode, I suggest restarting Emacs.

[Wilfred]

p.s. thanks for pinging me, I would have missed this otherwise.

[russel]

Try

// foo
//

def x = 1

//bar

def y = 2

/* baz */

def z = 2

where there is no space after the // following // foo. Then add a space and remove it again. Quite weird.

[Wilfred]

Thanks, I can reproduce. Looks like a bug in groovy-stringify-slashy-string which is treating the second / in // as an opening string delimiter. The comment logic isn't quite right.

[andreas-marschke]

Theres another issue related to that I think when defining inline Patterns in Groovy

Example code:

package com.example.groovy

class ExampleClass {

    private ArrayList<Pattern> _patterns = new ArrayList<Pattern> ([
            ~/.*example-[0-9\.]*\.foo$/
    ])

    public ExampleClass(int num) {

    }
}

@Wilfred / @russel Could you test if this also happens in your revisions? Updated to most recent seems to still be the case.

[vincekd]

Also seeing this, as well as @andreas-marschke's addition.

[vincekd]

Looks like there's a conflict between regular slash-quotes and dollar-sign slash quotes in the problem reported by @andreas-marschke.

I've never dealt with emacs syntax parsing, but I'll look at it tomorrow.

[grdryn]

I'm not sure if this is related or not (it sounds like it could be): it appears that a single-line comment ending with a question mark will lead to the next line being indented an extra level. E.g.:

// Could this be better?
    def x = 1

rather than

// Could this be better?
def x = 1

Using a multi-line quote instead works fine:

/* Could this be better? */
def x = 1

[Wilfred]

@grdryn it's not related: this is highlighting, whereas that's indentation.

However, that's a definite bug, which I've fixed in #72 :)

[grdryn]

@Wilfred that was quick...thanks a lot! :)

[vincekd]

Hi @Wilfred, after your fix a / for division opens a slashy-string.

[Wilfred]

Argh, groovy syntax is tricky. I've opened https://stackoverflow.com/questions/45234712/how-does-groovy-distinguish-division-from-strings but it's just not clear to me when Groovy thinks / is a slashy-string delimiter vs when / is divison.

[vincekd]

Seems tricky. At the very least we know that the slashy string should never go multiple lines (so if there is no termination on that line then it must be division).

EDIT: I just saw that you said the slashy-string should be multi-line in your SO post. I thought that was the purpose of the $/ /$ slashy-string and that the regular slashy string was just single line?

[Wilfred]

Slashy-strings can be multiline: http://groovy-lang.org/syntax.html#_slashy_string

I think the correct thing to do is to look at the previous non-whitespace character. If it's ( or an operator like = or + it's a slashy-string. Otherwise, it's just division.

[vincekd]

I played around a bit and got it working, but I have no idea if it's the correct way to do it.

Commit: https://github.com/vincekd/groovy-emacs-modes/commit/d096d15f6d0f85ad94bd820d03de9e2d0650f6e0

[Wilfred]

I think all the issues raised here have been fixed:

Highlighting:

• // without a trailing space
• shebangs
• slashy-strings containing a dollar, /foo$/
• division foo / bar being confused with slashy-strings

Indentation:

• question marks at the end of comments

Please file separate issues for anything else that crops up.