Allow helm-dictionary-database to be an alist

[astoff]

This is concerning issue #26.

With this change, helm-source-dictionary becomes a list of helm sources. I wasn't sure whether renaming the variable is desirable.

[tmalsburg]

This addresses the second paragraph in #26 but not the first, right? I wonder what use case you had in mind. Is this PR for situations were you have several dictionaries for one language?

[astoff]

Yes, this only addresses the second paragraph in #26. The use case I have in mind is the following: if you use 2 or 3 bilingual dictionaries (which may or may not involve more than 2 languages), then it is easier to just search all of them at the same time.

As to the first paragraph in #26, yes, one could add an optional argument to helm-dictionary which defaults to helm-source-dictionary, but maybe this is overkill... Copying and modifying the definition of helm-dictionary is pretty easy (and the new function helm-dictionary-build comes handy here).

[tmalsburg]

I'm only using a German-English dictionary that is very comprehensive, so there is no need to use several dictionaries. But I know that dictionaries for other language pairs are often much smaller and there it might make sense to use several dictionaries simultaneously. However, there is one very simple hack to achieve this without making any changes in helm-dictionary: just concatenate the dictionary files. In both cases, duplicates are a problem, so it would be preferable to merge dictionaries in some cleaner way, but that may not be trivial.

Anyhow, I think your PR is useful and some people may even use it to combine dictionaries from different language pairs.

[astoff]

I personally use 3 dictionaries. Wiktionary's en->pt and pt->en (precisely for the reason you mentioned) and Ding's de->en. I don't find the need to have 2 separate commands to look up Portuguese and German words.

[tmalsburg]

I just tested it with this configuration:

(setq helm-dictionary-database '(("Ding" . "/usr/share/trans/de-en")
                                 ("Ding 2" . "/usr/share/trans/de-en")))

I expected to see two sections showing the same dictionary (I have only one dictionary installed) but instead I just see one section. Am I missing something?

[astoff]

That should work, but you need to reload helm-dictionary or perhaps restart emacs — the source list helm-source-dictionary is built when the library is loaded.

[tmalsburg]

I see. When I define helm-dictionary-database before loading helm-dictionary it works ok. But it's not ideal that users have to restart Emacs when they change the dictionary. I'll merge and change it a bit.

[tmalsburg]

See 21de838.

[thierryvolpiatto]

Titus von der Malsburg [email protected] writes:

But it's not ideal that users have to restart Emacs when they change
the dictionary.

I generally use a set function in the defcustom that rebuild source, of
course people using setq have to restart emacs.

Thierry

[tmalsburg]

Thanks, @thierryvolpiatto. I'm now generating the sources on the fly which also works when setq is used.