New tree-sitter mode: bison-ts-mode

[BTuin]

Hello,
I'd like to propose a new tree-sitter mode for Emacs, bison-ts-mode.
This is a major mode for GNU Bison grammar files, and it supports the 
embedded languages C, C++ and Java.  Bison also supports D, but this 
language is not yet supported in Emacs so this mode does not support it 
either.

Since Bison is a superset of Yacc, it should work with Yacc without 
modification.
The grammar is available here: <https://gitlab.com/btuin2/tree-sitter-bison>

This mode auto-detects the embedded language in the file if the 
directive "%language" is set.


In addition of the mode, three patches are joined (should I open a bug 
report for those?).


The first one is to add some missing rules in c-ts-mode.  Currently 
there is no rule if an identifier in a declaration is on a new line.
In these two cases, "variable_name" is not indented:

static myttype *
variable_name;

static myttype
variable_name;

The new behavior is the same as c-mode.



The second one fix an edge case with multiple languages indentation. 
Here is a simple example:

// language_A
    {
       // language_B
    }
// language_A


Here, brackets are managed by language_A, but everything inside is 
managed by language_B.  Meaning that if the pointer is at the beginning 
of the third line (with the closing bracket), it will use language_B's 
indent rules.  But if the point is located on the bracket, it will use 
language_A's rules.



The third patch simply extracts java-ts-mode's feature list in a 
variable, to allow to reuse it.


Huge thanks to Yuan Fu for his help and his amazing work with tree-sitter.

I'll need to sign the copyright assignment.

0001-Add-missing-indent-rules-in-c-ts-mode.patch
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0002-Fix-tree-sitter-indentation-conflict-with-multiple-l.patch
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0003-Extract-feature-list-of-java-ts-mode-in-a-variable.patch
Description: Text Data

bison-ts-mode.el
Description: Text Data