cshape

A dependency-free C AST + printer for Python: build a tree and get C11 source back. No parsing, no dependencies beyond the standard library — just CType* / CValue* / CStmt* nodes and a render() function that turns them into text.

Originally the C backend's printer for the Modest compiler, split out because it doesn't know anything about Modest — it only knows about C.

Install

pip install cshape

Example

from cshape import *

func = CStmtDefFunc(
	id="add",
	type=CTypeFunction(
		params=[CField(id="a", type=CTypeIdentifier("int")),
		        CField(id="b", type=CTypeIdentifier("int"))],
		to=CTypeIdentifier("int"),
	),
	block=CStmtBlock([
		CStmtReturn(CValueAdd(CValueIdentifier("a"), CValueIdentifier("b"))),
	]),
)

print(render(func).strip())

int add(int a, int b) {
	return a + b;
}

(render() returns the node's own leading blank lines too — CStmtDefFunc starts with a blank line by default, so .strip() if you're printing a single node standalone rather than concatenating several.)

Documentation

• docs/api.md - documentation index
• docs/quickstart.md - getting started and first example
• docs/reference.md - current API reference

What it covers

• Types: named types, pointers, arrays, function types, structs/unions, enums
• Values: the full C11 expression grammar with correct operator precedence and parenthesization (including the extra parens GCC/Clang warn about for mixed bitwise/shift expressions)
• Statements: blocks, if/while, return, break/continue, inline asm, raw inserts
• Preprocessor: #define, #undef, #include, #if/#elif/#else/#endif regions
• Two brace styles (legacy — K&R-ish, modern — Allman-ish), configurable via render(node, style=...)
• A .mark field on every node: set it to any string and it shows up as a /*mark*/ comment right before that node in the output — useful for tracing which part of your own compiler/generator produced which bit of C
• A .note field on every value, printed as a /* note */ comment after the value — for saying where a value came from once it no longer shows: 3.125 /* totalVolume / elementVolume */

What it doesn't do

No parsing, no semantic analysis, no type checking. It's a printer, not a compiler frontend — you build the tree, it hands you back text.

License

MIT