C - Differens

C extractor

The C extractor maps tree-sitter C CST nodes to canonical concepts. C has no name fields in its grammar, so every declaration name is recovered through the declarator chain: function_definition → function_declarator → identifier.

Detected concepts

tree-sitter node type	Canonical concept
`function_definition`	Function
`declaration` / `init_declarator`	Variable
`field_declaration`	Variable
`struct_specifier`	Struct
`enum_specifier`	Enum
`parameter_declaration`	Parameter
`preproc_include`	PreprocInclude
`return_statement`	Return
`if_statement`	IfBlock
`number_literal`	number_literal

Example

Renaming a function:

// old.c
int total(int a, int b) { return a + b; }

// new.c
int sum(int a, int b) { return a + b; }

Running differens old.c new.c:

~ renamed function `total` to `sum`

Known limitations

Preprocessor macros are tokens, not structure: a macro that generates code does not expand before diffing.
Function prototypes and definitions are matched structurally; a prototype moving between headers reports as a move, not a signature change.