1"""Rudimentary parser for C struct definitions."""
2
3import re
4
5PyObject_HEAD = "PyObject_HEAD"
6PyObject_VAR_HEAD = "PyObject_VAR_HEAD"
7
8rx_name = re.compile("} (\w+);")
9
10class Struct:
11    def __init__(self, name, head, members):
12        self.name = name
13        self.head = head
14        self.members = members
15
16def parse(s):
17    """Parse a C struct definition.
18
19    The parser is very restricted in what it will accept.
20    """
21
22    lines = filter(None, s.split("\n")) # get non-empty lines
23    assert lines[0].strip() == "typedef struct {"
24    pyhead = lines[1].strip()
25    assert (pyhead.startswith("PyObject") and
26            pyhead.endswith("HEAD"))
27    members = []
28    for line in lines[2:]:
29        line = line.strip()
30        if line.startswith("}"):
31            break
32
33        assert line.endswith(";")
34        line = line[:-1]
35        words = line.split()
36        name = words[-1]
37        type = " ".join(words[:-1])
38        if name[0] == "*":
39            name = name[1:]
40            type += " *"
41        members.append((name, type))
42    name = None
43    mo = rx_name.search(line)
44    assert mo is not None
45    name = mo.group(1)
46    return Struct(name, pyhead, members)
47