C - Differens

The C extractor reads function and variable names through the declarator chain, following nested pointer and parenthesized declarators to the identifier. This keeps parameter lists and pointer syntax out of declaration names.

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`
  ~ changed function `sum` (`total` → `sum`)

Example: change the body

Keep the declaration name and change what it does:

int total(int n) { return n + 1; }

int total(int n) { return n + 2; }

differens body-before.c body-after.c

  ~ changed function `total` (`1` → `2`)

The report groups the value edit under its containing declaration. Use --format=json to inspect the underlying action and context, or --format=llm for a compact report with source locations.

Known limitations

Preprocessor macros are tokens, not structure: a macro that generates code does not expand before diffing.
Prototypes and definitions are matched structurally. Cross-file prototype moves depend on a supported grammar, candidate kind, and matching evidence; header extensions do not currently have a linked grammar.

Semantic Extractors

Tier Adapters

C

Detected concepts

Example

Example: change the body

Known limitations