Filter parameter type for languages

[jelmervdl]

Many filters need to know the languages of the two columns. It could be useful if those can be filled in automatically. The interface knows the language of the two columns (albeit only in the three-letter-code)

How to implement? Know idea. Couple of options:

• Heuristic based on parameter name (e.g. $LANG1, $LANG2 seem pretty obvious, but no idea whether that's 2 or 3 letter code)
• Extra attribute for str type parameters
• Special parameter type lang that behaves like str except it has properties to tell you that you'd like it to default to the language of column 1/2 in 2/3 letter code format.

Current preference is the last one for me. Sounds the cleanest.