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Add -> operator to Dsp.g4 grammar #126

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Merged
hzhangxyz merged 3 commits into from
Dec 20, 2025
Merged

Add -> operator to Dsp.g4 grammar #126

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Copilot Dec 20, 2025
bece183
Add -> operator to Dsp.g4 grammar
Copilot Dec 20, 2025
bb0fd5d
Fix: Place -> operator on same line as . operator
Copilot Dec 20, 2025
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2 changes: 1 addition & 1 deletion bnf/Dsp.g4
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Expand Up @@ -13,7 +13,7 @@ term
: SYMBOL # symbol
| '(' term ')' # parentheses
| term '::' term # binary
| term '.' term # binary
| term ('.' | '->') term # binary

Copilot AI Dec 20, 2025

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The examples in the PR description suggest that p -> q . y should parse as p -> (q . y) (right-associative), but the grammar implementation makes both . and -> left-associative by default in ANTLR4. This means p -> q . y will actually parse as (p -> q) . y. If right-associativity is intended for these operators, they would need separate grammar rules or explicit associativity directives. Please verify the expected associativity behavior and update the PR description examples if needed.

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| term ('.' | '->') term # binary
| <assoc=right> term ('.' | '->') term # binary

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The new -> operator lacks test coverage. Given that comprehensive tests exist for other operators (binary, unary, subscript, function), tests should be added for the -> operator to verify parsing and unparsing behavior, especially its precedence relationship with . operator. Consider adding tests similar to test_parse_binary_operator and test_unparse_binary_operator that specifically test the -> operator.

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| term '[' term (',' term)* ']' # subscript
| term '(' (term (',' term)*)? ')' # function
| <assoc=right> ('~' | '!' | '-' | '+' | '&' | '*') term # unary
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