bug#64017: Wrong conversion from Emacs to Tree-sitter S-expression syntax

[Yuan Fu]

> 
> Yes, so it seemed to me but reading the source code (lib/src/query.c) seems 
> to indicate that what I thought were symbols -- *, +, ?, @thing, #thing -- 
> appear to be special postfix and prefix operators. (Ironically, there doesn't 
> seem to be a grammar for this language anywhere, or am I mistaken?)
> 
> Thus a structurally correct Lispish translation of
> 
>  (teet "toot"* (#equal "fie" @fum))
> 
> should arguable be something like
> 
>  (teet (* "toot") ((# equal) "fie" (@ fum)))
> 
> rather than the current
> 
>  (teet "toot" :* (:equal "fie @fum))
> 
> but I'm not demanding that it all be changed at this stage.

IMHO the query syntax is already pretty far away from a “proper sexp” that we 
expect, so changing these little things don’t have much benefit. For example, 
the field names and trailing capture names are not conventional, are we going 
to change them to be more sexpy too? 

In a proper sexp they would have been wrapped too, like

(field-name: node) rather than field-name: node
(@fn node) rather than node @fn

Not to mention using colon and @ to distinguish field-names and capture names 
from nodes—not very conventional either.

Also a more conventional sexp syntax would be much more verbose than the 
current one, and arguable harder to translate to the tree-sitter string syntax, 
which is ultimately what we feed to tree-sitter functions.

Yuan