Upgrade to CodeMirror 6.

[drgrice1]

Some features of this change are improved syntax highlighting and the addition of autocompletion. To see available autocompletions at the current cursor location, you can type Ctrl-Space. In many cases, autocompletions are offered automatically when certain things have been typed.

CodeMirror 6 can not be used via script tags. So a PGProblemEditor package has been created for this. The repository for that is https://github.com/openwebwork/pg-problem-editor. An initial package has been published in npm at
https://www.npmjs.com/package/@openwebwork/pg-codemirror-editor. The real work is done in the codemirror-lang-pg package that adds support for the PG language in CodeMirror 6. The repository for that package is https://github.com/openwebwork/codemirror-lang-pg, and the npm package at https://www.npmjs.com/package/@openwebwork/codemirror-lang-pg.

The pg-problem-editor package is designed so that it can be used by webwork2, the standalone renderer, and possible others that want a PG problem editor. It may need a few tweaks to make it work for webwork3 in the future, but should also work for that.

The codemirror-lang-pg package consists of a base PG parser that is largely derived from the codemirror-lang-perl package (at https://github.com/drgrice1/codemirror-lang-perl and https://www.npmjs.com/package/codemirror-lang-perl) with a modifications specific to the perl available in a PG problem. The main differences are that its escape sequence is ~~, much of what can not be used in the safe compartment has been stripped out, and there are special blocks for PGML, PG text, and LaTeX image code. Then there are two other parsers. Those are the PGML and PG text parsers. Those parsers run on the contents of the PGML and PG text blocks found by the base PG parser. Note that the PGML parser is actually a javascript implementation of the parser in PGML.pl with some modifications to track position and things needed to associate the parsed tree with the original code.

Note that the configuration of theme, keymaps, and such are now part of the pg-codemirror-editor, and are shown in a panel of the editor instead of below as before.

Emacs and Vim keymaps are available, but at this point there is not a Sublime keymap for CodeMirror 6.

The themes that are available include a basic default theme (that is part of the pg-problem-editor package and just adds some syntax highlighting that is missing from the CodeMirror 6 default), the OndDark theme that is the only other theme provided by the CodeMirror 6 developers directly, the themes in the thememirror package, and the themes from https://github.com/craftzdog/cm6-themes which are in several separate npm packages. Note that both thememirror and craftzdog/cm6-themes provide a solarized light theme, and that is why there are two of those. They are slightly different though.

I am sure that there is a lot more work to do on this, and there are other things available with CodeMirror 6 that could probably be implemented. In any case, this is a good start.

[somiaj]

I was looking to add functions from the pg macros to the list of highlighted functions, such as PopUp, DropDown, etc. As I was creating a patch for this, it occurred to me, would it be possible to only highlight key words if the associated macro is loaded? Such as PopUp and DropDown will only be included if parserPopUp.pl keyword is found in the code? This might not be 100% accurate (such as if parserPopUp.pl is in a comment, though I guess we could just ignore comments for this case), or if the macros are loaded inside other macros (which I think is nonstandard for most additional things like parserPopUp.pl).

[drgrice1]

No, you can't really do that in a reliable way. Generally CodeMirror 6 is designed to be non-contextual in its parsing.

[drgrice1]

I should point out that since the elements for selecting the theme, keymap, and such are part of the pg-codemirror-editor package, the strings used for those are not translatable unfortunately. That could be done by adding a translation method for that package, but would require translations for that package.