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emacs-tree-sitter / elisp-tree-sitter

Emacs Lisp bindings for tree-sitter
https://emacs-tree-sitter.github.io
MIT License
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Strict option to signal error for non-existing node types in tree-sitter-node-at-pos #172

Closed rolandwalker closed 2 years ago

rolandwalker commented 2 years ago

https://github.com/emacs-tree-sitter/elisp-tree-sitter/pull/171#issuecomment-912477047

tree-sitter-node-at-pos should be made to signal an error when NODE-TYPE is not in the grammar. I'm still not sure whether there should be a corresponding parameter to toggle that. It could be a separate PR, though.

This may not be the best implementation. Is this really the easiest way to access the list of named node types?

Also, per your comment, you haven't decided whether STRICT should be optional.

In my own contributions to pygn-mode, I am leaning on the non-strict expectation for forward compatibility with node-types which are not yet released in tree-sitter-langs. But that is just one data point, and not a big deal to change.

ubolonton commented 2 years ago

This may not be the best implementation. Is this really the easiest way to access the list of named node types?

There isn't a function that list a language's node types. I think such a function would be useful. In this case though, we can check whether a node type is valid using tsc-node-type-id.

Also, per your comment, you haven't decided whether STRICT should be optional.

In my own contributions to pygn-mode, I am leaning on the non-strict expectation for forward compatibility with node-types which are not yet released in tree-sitter-langs. But that is just one data point, and not a big deal to change.

I think the default should be strict, with an optional parameter IGNORE-INVALID-TYPE to turn it off, which can be used by code that wants to be forward-compatible. (I can't think of anything more concise.)

rolandwalker commented 2 years ago

tsc-lang-node-type-id

Ah, that's much better.

We should define a new error symbol

Done: tree-sitter-invalid-node-type.

Anonymous node types should also be checked

Done.

I think the default should be strict, with an optional parameter IGNORE-INVALID-TYPE

Done. ACCEPT-INVALID-TYPE might also make sense.

There isn't a function that list a language's node types. I think such a function would be useful.

FTR my first attempt at that in Lisp (overwritten by force-push) was:

(defun tree-sitter--list-named-node-types ()
  "List all named node types for the current tree-sitter language."
  (mapcar
   '(lambda (id) (tsc-lang-node-type tree-sitter-language id))
   (delq nil
         (mapcar
          '(lambda (id) (when (tsc-lang-node-type-named-p tree-sitter-language id) id))
          (number-sequence 0 (1- (tsc-lang-count-types tree-sitter-language)))))))