Completion in comint buffers, and in the editting window

[ThibautVerron]

With comint, since the line is sent as a whole, it seems difficult to trigger magma's completion engine from emacs. On the other hand, with a list of magma keywords, it should be possible to implement completion from within emacs (see for example what happens if you press <tab> in ielm).

That list of keywords could be initialized from the magma documentation index, and then completed with user keywords using filters and sentinels in the comint buffer.

Another option would be to parse the input and source using etags.

[ThibautVerron]

Work in progress in the completion branch.

Working:

• completion based on a dictionary
• extraction of completion candidates from an editting buffer at init
• extraction of completion candidates from an editting buffer on demand
• extraction of completion candidates from an editting buffer when idle

Todo:

• extraction of completion candidates from external files with load
• extraction of completion candidates in the magma process buffer
• a way to cache the results in case of long files, or repeated load instructions

[ThibautVerron]

Replaced the extraction of definitions using imenu with some in-house function magma-scan, which is also aware of changes in the working directory and loaded files.

It passes basic testing, but requires some more test to ensure that it isn't too slow in everyday use. No attempt has been made at caching any result.

This function is called:

• when the mode is loaded
• after 30 seconds of inactivity (can be customized)
• on demand
• after input is sent to the comint buffer (in this case, it only scans this input)

[ThibautVerron]

Reimplemented it with caching of the scan results.

It can probably still be improved:

• factor again the scanning feature, so that we would have one scanning function, in which we could plug the specifications, that is a regexp to find together with a line to write in the results file;
• add the possibility of scanning a string directly in magma-scan (at the moment there is duplicate code between magma-scan.el and magma-completion.el, for the interactive buffer).