tree-sitter
The grammar returns an error if begin is used in a vector
Hi!
The following code:
v = 1:10
for k in 1:10
v[begin + k - 1]
end
is not parsed correctly by the current grammar:
(assignment) ; [1:1 - 8]
(identifier) ; [1:1 - 1]
(operator) ; [1:3 - 3]
(range_expression) ; [1:5 - 8]
(integer_literal) ; [1:5 - 5]
(integer_literal) ; [1:7 - 8]
(for_statement) ; [2:1 - 4:3]
(for_binding) ; [2:5 - 13]
(identifier) ; [2:5 - 5]
(range_expression) ; [2:10 - 13]
(integer_literal) ; [2:10 - 10]
(integer_literal) ; [2:12 - 13]
(index_expression) ; [3:5 - 20]
(identifier) ; [3:5 - 5]
(vector_expression) ; [3:6 - 20]
(identifier) ; [3:7 - 11]
(ERROR) ; [3:13 - 19]
(binary_expression) ; [3:13 - 19]
(unary_expression) ; [3:13 - 15]
(operator) ; [3:13 - 13]
(identifier) ; [3:15 - 15]
(operator) ; [3:17 - 17]
(integer_literal) ; [3:19 - 19]
It seems that the work around is to change the order:
v = 1:10
for k in 1:10
v[k - 1 + begin]
end
Yeah, the way these words that can be keywords or identifiers are handled is still very hacky.
In this case what happens is that the parser sees begin and then sees +k as if it was a unary expression. Reversing the order means begin is only followed by the closing bracket, so it must be an identifier.
Lezer (tree-sitter for codemirror) actually introduced a very good way of handling these keyword/identifier cases (@extend), and this makes a massive difference between the existing grammar and the rewrite I'm working on. Hopefully a similar improvement can be made here.
