Add OpenEdge ABL lexer

[ghost]

No description provided.

[viitaset]

Any chance on getting this merged?

[ghost]

@viitaset apparently it's only waiting to be merged by @dblessing, see #1063

[pyrmont]

@raphaelhittich @viitaset Sorry this has taken so long. We're going through the backlog now and getting things merged in. I'll review this as soon as I can!

[pyrmont]

@raphaelhittich Sorry again this has taken a long time to get back to you. I'm looking at the code sample and thinking that some of my comments might be the result of OpenEdge just being pretty different to most of the languages I'm looking at. Please feel free to push back if you think I've misunderstood something fundamentally.

[pyrmont]

@raphaelhittich I've just realised that the structure of your states is based on the C lexer. Without having thought much more about it, it seems to me this approach is wrong but it makes sense why you wrote yours the way that you did.

Let me have a bit more of a think. I'll post again here when I have a clearer idea about how best to proceed.

[pyrmont]

OK, had a bit more of a think about things.

Putting to the side for the moment the question of whether the structure of the C lexer should be emulated, is this even appropriate for OpenEdge ABL? Perhaps the code samples I've found online aren't representative but it doesn't look like you need things like macro support (which should be the purpose of the :preproc state).

I'm hopeful that the scope of the language is less encompassing than it seems and a simplified lexer can be used instead.

The language seems pretty simple; did you use this structure for a particular reason? Are elements like string prefixes necessary? Or have these just been copied across from another lexer? I ask because there's nothing in the visual sample that suggests these features are part of the language.

[ghost]

@pyrmont Sorry, should have mentioned that I used the C lexer as my template, it was the simplest to go from for me.

OpenEdge ABL does have some kind of preprocessor, see this. So that's what the :preproc is for, it is also included in the example code, the first line after the comment &ANALYZE-SUSPEND _VERSION-NUMBER UIB_v8r12

I think most of your comments are just from the fact I used the C lexer as my template, except for the String#casecmp, you are correct, might be better to just use String#upcase in the assignment.

[pyrmont]

@raphaelhittich Did you delete your branch? It says 'Unknown repository' as the source for this PR. I ask because I've written a simplified version of the lexer that I think would make a better starting point but I can't propose it as a PR to your code as it appears your fork has been deleted.

In terms of my proposed lexer, the syntax highlighting could be improved by separating the keywords you've defined into functions, attributes, etc. I'm also not sure whether all of the rules are correct or whether they've just been carried across from the C lexer. Does OpenEdge really have string prefixes for example? Oh, and it wasn't clear to me whether periods at the end of statements can have whitespace after them. Your example does but I could imagine that that was a typo.

Anyway, happy to help more if you have any questions.

[ghost]

@pyrmont Yes, a while ago I cleaned up & deleted all my forks on github. How about we close this PR and you just make a new one with your simplified version?

One might separate the keywords, but in most IDE's I have seen they are all highlighted the same, so I guess that's more of a nice to have rather than a necessity.

No string prefixes that I know of.

Periods at the end of statements may have whitespaces before and after them.

Thanks for your help! :)

[pyrmont]

@raphaelhittich Sure thing. I'm sorry you won't get the credit for the commit :(

This PR is being replaced

[ghost]

@pyrmont No worries, getting the lexer in is all that matters! :)