Re: Syntax tables for multiple modes [was: bug#22983: syntax-ppss returns wrong result.]

[Vitalie Spinu]

>> On Mon, Mar 21 2016 14:31, Stefan Monnier wrote:

>> Other modes should re-use that generic infrastructure, or even better,
>> do nothing, and leave to someone else to define a new polymode with
>> host chunk being *the* mode. That every mode with basic needs for
>> inner sub-modes tries to re-invent the wheel is a dead end.

> I don't understand: every major mode's indentation code will have to pay
> attention to the STRING-BEFORE/AFTER that it receives from the generic
> code and will have to do something with it (it can ignore it but at the
> cost of sub-optimal results).  And AFAIK this can only be done by the
> major mode's code, not the generic mode's code.
> [ I feel like I must be missing something.  ]

The hope is that most modes will need the default implementation. Maybe
prog-indentation-funciton need not even know about those arguments. Along what
Dmitry proposed, there could be an optional extra piece
prog-indentation-with-virtual-context-function that modes might choose to set.

I think it might be good to try this as part of a multi-mode engine first. I can
try it with polymode. If it's generic enough it could be ported into emacs in a
later stage to be re-used with other multi-mode setups.

  Vitalie