Re: New package emacs-parser-generator

[Christian Johansson]

Alright, could you give some more details about when a buffer parse is 
triggered, is it via threads, is it sometimes incremental, does it work on a 
string copy of the buffer or on the buffer contents directly?

Does treesitter expose a (faster) regexp matcher that perhaps can be used by my 
library?

Regards
Christian

> 29 nov. 2021 kl. 20:22 skrev Yuan Fu <casouri@gmail.com>:
> 
> The tree-sitter integration doesn’t provide anything to define a grammar nor 
> generating a parser. It merely uses pre-defined grammar (written by 
> tree-sitter community) to parse buffers and produce an AST.
> 
> To write an tree-sitter grammar definition you need to write the grammar in 
> JavaScript and pass it to tree-sitter’s parser generator. The generator spits 
> out a grammar definition encoded in a C source file (in the form of a C 
> struct). To use this grammar definition, we compile it to a library, load it 
> at runtime, pass the struct to tree-sitter library, and tree-sitter can now 
> parse according to this grammar definition.
> 
> The tree-sitter integration provides 1) Lisp wrappers for tree-sitter’s C 
> API; 2) some convenient functions built on the C API; 3) integration with 
> font-lock and indentation. I didn’t add any “common API”, I simply used 
> existing frameworks in Emacs: for font-lock I used 
> font-lock-fontify-region-function, for indent I used indent-line-function. If 
> in the future a common API for parses is desirable, tree-sitter can easily 
> comply.
> 
> IOW, this is what tree-sitter integration currently does:
> 
> font-lock                                indent
>      |                                     |
> font-lock-fontify-region-function        indent-line-function
>      |                                     |
>      |                                     |
> tree-sitter-font-lock-fontify-region     tree-sitter-indent-function
> 
> This is what could happen if we want a common API:
> 
> font-lock                                indent
>      |                                     |
> font-lock-fontify-region-function        indent-line-function
>      |                                     |
>      |                                     |
>     common  API  --------------------------+
>     /         \
>    /           \
>   /             \
> tree-sitter    other parser
> 
> Yuan