How to do case-insensitive query in tree-sitter - case-insensitive

Question

I'm working on trying to create and use tree-sitter grammar in a language server I am implementing in order to support features like finding all references of a variable. Given the grammar I would be able to write a query to find all of the references to a variable with a specific name (ex. myVar). However, the language I am writing a language server for uses case insensitive variables (ex. myVar can be referenced as MYVAR, MyVaR, myvar, etc.).
How would I be able to write a tree-sitter query to match a pattern where a token must case-insensitively match a particular string?
I could write the query to not filter by the variable name and implement my own filtering of the results, but I was wondering if there was a way to handle this within the query itself rather than implementing custom filtering code.
Example
Here is a simplified example case to show what I mean.
Given the following grammar, I want to query for all of the set_statements that set a new value to the variable myVar.
module.exports = grammar({
name: 'mylang',
rules: {
source_file: $ => repeat($._statement),
_statement: $ => choice(
$.set_statement,
),
set_statement: $ => seq(
'set',
field("variable", $.identifier),
field("value", $._expression),
),
_expression: $ => choice(
$.integer_literal
),
identifier: $ => /[a-zA-Z0-9]+/,
integer_literal: $ => /[0-9]+/,
}
});
Normally I would be able to do this with a query like the following.
(
(set_statement
variable: (identifier) #variable)
(#eq? #variable "myVar")
)
However, as we can see with the following example of running the query, this only picks up on the references to myVar that use the same casing as the query.
$ cat set_testing.txt
set myVar 0
set MYVAR 23
set myVar2 72
set MyVaR 14
$ tree-sitter query find_variable.query set_testing.txt
set_testing.txt
pattern: 0
capture: variable, start: (0, 4), text: "myVar"
I want to create a query that would instead find:
tree-sitter query find_variable.query set_testing.txt
set_testing.txt
pattern: 0
capture: variable, start: (0, 4), text: "myVar"
pattern: 0
capture: variable, start: (1, 4), text: "MYVAR"
pattern: 0
capture: variable, start: (3, 4), text: "MyVaR"

Answer 1

Change your query to match a regular expression matching all possible upper/lower combinations of an identifier, in this case myvar.
If you change find_variable.query to use match with a regular expression for all case combinations:
(
(set_statement
variable: (identifier) #variable)
(#match? #variable "^[mM][yY][vV][aA][rR]$")
)
Now running tree-sitter query find_variable.query set_testing.txt returns:
set_testing.txt
pattern: 0
capture: variable, start: (0, 4), text: "myVar"
pattern: 0
capture: variable, start: (1, 4), text: "MYVAR"
pattern: 0
capture: variable, start: (3, 4), text: "MyVaR"
Tree-sitter does not support case insensitive regular expression searches Issue #261 so the regular expressions are a little longer.