add hg and python

1 files changed, 782 insertions, 0 deletions

diff --git a/sys/src/cmd/python/Parser/asdl_c.py b/sys/src/cmd/python/Parser/asdl_c.py
new file mode 100755
index 000000000..2974d7b15
--- /dev/null
+++ b/sys/src/cmd/python/Parser/asdl_c.py
@@ -0,0 +1,782 @@
+#! /usr/bin/env python
+"""Generate C code from an ASDL description."""
+
+# TO DO
+# handle fields that have a type but no name
+
+import os, sys, traceback
+
+import asdl
+
+TABSIZE = 8
+MAX_COL = 80
+
+def get_c_type(name):
+    """Return a string for the C name of the type.
+
+    This function special cases the default types provided by asdl:
+    identifier, string, int, bool.
+    """
+    # XXX ack!  need to figure out where Id is useful and where string
+    if isinstance(name, asdl.Id):
+        name = name.value
+    if name in asdl.builtin_types:
+        return name
+    else:
+        return "%s_ty" % name
+
+def reflow_lines(s, depth):
+    """Reflow the line s indented depth tabs.
+
+    Return a sequence of lines where no line extends beyond MAX_COL
+    when properly indented.  The first line is properly indented based
+    exclusively on depth * TABSIZE.  All following lines -- these are
+    the reflowed lines generated by this function -- start at the same
+    column as the first character beyond the opening { in the first
+    line.
+    """
+    size = MAX_COL - depth * TABSIZE
+    if len(s) < size:
+        return [s]
+
+    lines = []
+    cur = s
+    padding = ""
+    while len(cur) > size:
+        i = cur.rfind(' ', 0, size)
+        # XXX this should be fixed for real
+        if i == -1 and 'GeneratorExp' in cur:
+            i = size + 3
+        assert i != -1, "Impossible line %d to reflow: %s" % (size, `s`)
+        lines.append(padding + cur[:i])
+        if len(lines) == 1:
+            # find new size based on brace
+            j = cur.find('{', 0, i)
+            if j >= 0:
+                j += 2 # account for the brace and the space after it
+                size -= j
+                padding = " " * j
+            else:
+                j = cur.find('(', 0, i)
+                if j >= 0:
+                    j += 1 # account for the paren (no space after it)
+                    size -= j
+                    padding = " " * j
+        cur = cur[i+1:]
+    else:
+        lines.append(padding + cur)
+    return lines
+
+def is_simple(sum):
+    """Return True if a sum is a simple.
+
+    A sum is simple if its types have no fields, e.g.
+    unaryop = Invert | Not | UAdd | USub
+    """
+
+    for t in sum.types:
+        if t.fields:
+            return False
+    return True
+
+class EmitVisitor(asdl.VisitorBase):
+    """Visit that emits lines"""
+
+    def __init__(self, file):
+        self.file = file
+        super(EmitVisitor, self).__init__()
+
+    def emit(self, s, depth, reflow=1):
+        # XXX reflow long lines?
+        if reflow:
+            lines = reflow_lines(s, depth)
+        else:
+            lines = [s]
+        for line in lines:
+            line = (" " * TABSIZE * depth) + line + "\n"
+            self.file.write(line)
+
+class TypeDefVisitor(EmitVisitor):
+    def visitModule(self, mod):
+        for dfn in mod.dfns:
+            self.visit(dfn)
+
+    def visitType(self, type, depth=0):
+        self.visit(type.value, type.name, depth)
+
+    def visitSum(self, sum, name, depth):
+        if is_simple(sum):
+            self.simple_sum(sum, name, depth)
+        else:
+            self.sum_with_constructors(sum, name, depth)
+
+    def simple_sum(self, sum, name, depth):
+        enum = []
+        for i in range(len(sum.types)):
+            type = sum.types[i]
+            enum.append("%s=%d" % (type.name, i + 1))
+        enums = ", ".join(enum)
+        ctype = get_c_type(name)
+        s = "typedef enum _%s { %s } %s;" % (name, enums, ctype)
+        self.emit(s, depth)
+        self.emit("", depth)
+
+    def sum_with_constructors(self, sum, name, depth):
+        ctype = get_c_type(name)
+        s = "typedef struct _%(name)s *%(ctype)s;" % locals()
+        self.emit(s, depth)
+        self.emit("", depth)
+
+    def visitProduct(self, product, name, depth):
+        ctype = get_c_type(name)
+        s = "typedef struct _%(name)s *%(ctype)s;" % locals()
+        self.emit(s, depth)
+        self.emit("", depth)
+
+class StructVisitor(EmitVisitor):
+    """Visitor to generate typdefs for AST."""
+
+    def visitModule(self, mod):
+        for dfn in mod.dfns:
+            self.visit(dfn)
+
+    def visitType(self, type, depth=0):
+        self.visit(type.value, type.name, depth)
+
+    def visitSum(self, sum, name, depth):
+        if not is_simple(sum):
+            self.sum_with_constructors(sum, name, depth)
+
+    def sum_with_constructors(self, sum, name, depth):
+        def emit(s, depth=depth):
+            self.emit(s % sys._getframe(1).f_locals, depth)
+        enum = []
+        for i in range(len(sum.types)):
+            type = sum.types[i]
+            enum.append("%s_kind=%d" % (type.name, i + 1))
+
+        emit("enum _%(name)s_kind {" + ", ".join(enum) + "};")
+
+        emit("struct _%(name)s {")
+        emit("enum _%(name)s_kind kind;", depth + 1)
+        emit("union {", depth + 1)
+        for t in sum.types:
+            self.visit(t, depth + 2)
+        emit("} v;", depth + 1)
+        for field in sum.attributes:
+            # rudimentary attribute handling
+            type = str(field.type)
+            assert type in asdl.builtin_types, type
+            emit("%s %s;" % (type, field.name), depth + 1);
+        emit("};")
+        emit("")
+
+    def visitConstructor(self, cons, depth):
+        if cons.fields:
+            self.emit("struct {", depth)
+            for f in cons.fields:
+                self.visit(f, depth + 1)
+            self.emit("} %s;" % cons.name, depth)
+            self.emit("", depth)
+        else:
+            # XXX not sure what I want here, nothing is probably fine
+            pass
+
+    def visitField(self, field, depth):
+        # XXX need to lookup field.type, because it might be something
+        # like a builtin...
+        ctype = get_c_type(field.type)
+        name = field.name
+        if field.seq:
+            if field.type.value in ('cmpop',):
+                self.emit("asdl_int_seq *%(name)s;" % locals(), depth)
+            else:
+                self.emit("asdl_seq *%(name)s;" % locals(), depth)
+        else:
+            self.emit("%(ctype)s %(name)s;" % locals(), depth)
+
+    def visitProduct(self, product, name, depth):
+        self.emit("struct _%(name)s {" % locals(), depth)
+        for f in product.fields:
+            self.visit(f, depth + 1)
+        self.emit("};", depth)
+        self.emit("", depth)
+
+class PrototypeVisitor(EmitVisitor):
+    """Generate function prototypes for the .h file"""
+
+    def visitModule(self, mod):
+        for dfn in mod.dfns:
+            self.visit(dfn)
+
+    def visitType(self, type):
+        self.visit(type.value, type.name)
+
+    def visitSum(self, sum, name):
+        if is_simple(sum):
+            pass # XXX
+        else:
+            for t in sum.types:
+                self.visit(t, name, sum.attributes)
+
+    def get_args(self, fields):
+        """Return list of C argument into, one for each field.
+
+        Argument info is 3-tuple of a C type, variable name, and flag
+        that is true if type can be NULL.
+        """
+        args = []
+        unnamed = {}
+        for f in fields:
+            if f.name is None:
+                name = f.type
+                c = unnamed[name] = unnamed.get(name, 0) + 1
+                if c > 1:
+                    name = "name%d" % (c - 1)
+            else:
+                name = f.name
+            # XXX should extend get_c_type() to handle this
+            if f.seq:
+                if f.type.value in ('cmpop',):
+                    ctype = "asdl_int_seq *"
+                else:
+                    ctype = "asdl_seq *"
+            else:
+                ctype = get_c_type(f.type)
+            args.append((ctype, name, f.opt or f.seq))
+        return args
+
+    def visitConstructor(self, cons, type, attrs):
+        args = self.get_args(cons.fields)
+        attrs = self.get_args(attrs)
+        ctype = get_c_type(type)
+        self.emit_function(cons.name, ctype, args, attrs)
+
+    def emit_function(self, name, ctype, args, attrs, union=1):
+        args = args + attrs
+        if args:
+            argstr = ", ".join(["%s %s" % (atype, aname)
+                                for atype, aname, opt in args])
+            argstr += ", PyArena *arena"
+        else:
+            argstr = "PyArena *arena"
+        margs = "a0"
+        for i in range(1, len(args)+1):
+            margs += ", a%d" % i
+        self.emit("#define %s(%s) _Py_%s(%s)" % (name, margs, name, margs), 0,
+                reflow = 0)
+        self.emit("%s _Py_%s(%s);" % (ctype, name, argstr), 0)
+
+    def visitProduct(self, prod, name):
+        self.emit_function(name, get_c_type(name),
+                           self.get_args(prod.fields), [], union=0)
+
+class FunctionVisitor(PrototypeVisitor):
+    """Visitor to generate constructor functions for AST."""
+
+    def emit_function(self, name, ctype, args, attrs, union=1):
+        def emit(s, depth=0, reflow=1):
+            self.emit(s, depth, reflow)
+        argstr = ", ".join(["%s %s" % (atype, aname)
+                            for atype, aname, opt in args + attrs])
+        if argstr:
+            argstr += ", PyArena *arena"
+        else:
+            argstr = "PyArena *arena"
+        self.emit("%s" % ctype, 0)
+        emit("%s(%s)" % (name, argstr))
+        emit("{")
+        emit("%s p;" % ctype, 1)
+        for argtype, argname, opt in args:
+            # XXX hack alert: false is allowed for a bool
+            if not opt and not (argtype == "bool" or argtype == "int"):
+                emit("if (!%s) {" % argname, 1)
+                emit("PyErr_SetString(PyExc_ValueError,", 2)
+                msg = "field %s is required for %s" % (argname, name)
+                emit('                "%s");' % msg,
+                     2, reflow=0)
+                emit('return NULL;', 2)
+                emit('}', 1)
+
+        emit("p = (%s)PyArena_Malloc(arena, sizeof(*p));" % ctype, 1);
+        emit("if (!p) {", 1)
+        emit("PyErr_NoMemory();", 2)
+        emit("return NULL;", 2)
+        emit("}", 1)
+        if union:
+            self.emit_body_union(name, args, attrs)
+        else:
+            self.emit_body_struct(name, args, attrs)
+        emit("return p;", 1)
+        emit("}")
+        emit("")
+
+    def emit_body_union(self, name, args, attrs):
+        def emit(s, depth=0, reflow=1):
+            self.emit(s, depth, reflow)
+        emit("p->kind = %s_kind;" % name, 1)
+        for argtype, argname, opt in args:
+            emit("p->v.%s.%s = %s;" % (name, argname, argname), 1)
+        for argtype, argname, opt in attrs:
+            emit("p->%s = %s;" % (argname, argname), 1)
+
+    def emit_body_struct(self, name, args, attrs):
+        def emit(s, depth=0, reflow=1):
+            self.emit(s, depth, reflow)
+        for argtype, argname, opt in args:
+            emit("p->%s = %s;" % (argname, argname), 1)
+        assert not attrs
+
+class PickleVisitor(EmitVisitor):
+
+    def visitModule(self, mod):
+        for dfn in mod.dfns:
+            self.visit(dfn)
+
+    def visitType(self, type):
+        self.visit(type.value, type.name)
+
+    def visitSum(self, sum, name):
+        pass
+
+    def visitProduct(self, sum, name):
+        pass
+
+    def visitConstructor(self, cons, name):
+        pass
+
+    def visitField(self, sum):
+        pass
+
+class MarshalPrototypeVisitor(PickleVisitor):
+
+    def prototype(self, sum, name):
+        ctype = get_c_type(name)
+        self.emit("static int marshal_write_%s(PyObject **, int *, %s);"
+                  % (name, ctype), 0)
+
+    visitProduct = visitSum = prototype
+
+class PyTypesDeclareVisitor(PickleVisitor):
+
+    def visitProduct(self, prod, name):
+        self.emit("static PyTypeObject *%s_type;" % name, 0)
+        self.emit("static PyObject* ast2obj_%s(void*);" % name, 0)
+        if prod.fields:
+            self.emit("static char *%s_fields[]={" % name,0)
+            for f in prod.fields:
+                self.emit('"%s",' % f.name, 1)
+            self.emit("};", 0)
+
+    def visitSum(self, sum, name):
+        self.emit("static PyTypeObject *%s_type;" % name, 0)
+        if sum.attributes:
+            self.emit("static char *%s_attributes[] = {" % name, 0)
+            for a in sum.attributes:
+                self.emit('"%s",' % a.name, 1)
+            self.emit("};", 0)
+        ptype = "void*"
+        if is_simple(sum):
+            ptype = get_c_type(name)
+            tnames = []
+            for t in sum.types:
+                tnames.append(str(t.name)+"_singleton")
+            tnames = ", *".join(tnames)
+            self.emit("static PyObject *%s;" % tnames, 0)
+        self.emit("static PyObject* ast2obj_%s(%s);" % (name, ptype), 0)
+        for t in sum.types:
+            self.visitConstructor(t, name)
+
+    def visitConstructor(self, cons, name):
+        self.emit("static PyTypeObject *%s_type;" % cons.name, 0)
+        if cons.fields:
+            self.emit("static char *%s_fields[]={" % cons.name, 0)
+            for t in cons.fields:
+                self.emit('"%s",' % t.name, 1)
+            self.emit("};",0)
+
+class PyTypesVisitor(PickleVisitor):
+
+    def visitModule(self, mod):
+        self.emit("""
+static PyTypeObject* make_type(char *type, PyTypeObject* base, char**fields, int num_fields)
+{
+    PyObject *fnames, *result;
+    int i;
+    if (num_fields) {
+        fnames = PyTuple_New(num_fields);
+        if (!fnames) return NULL;
+    } else {
+        fnames = Py_None;
+        Py_INCREF(Py_None);
+    }
+    for(i=0; i < num_fields; i++) {
+        PyObject *field = PyString_FromString(fields[i]);
+        if (!field) {
+            Py_DECREF(fnames);
+            return NULL;
+        }
+        PyTuple_SET_ITEM(fnames, i, field);
+    }
+    result = PyObject_CallFunction((PyObject*)&PyType_Type, "s(O){sOss}",
+                    type, base, "_fields", fnames, "__module__", "_ast");
+    Py_DECREF(fnames);
+    return (PyTypeObject*)result;
+}
+
+static int add_attributes(PyTypeObject* type, char**attrs, int num_fields)
+{
+    int i, result;
+    PyObject *s, *l = PyList_New(num_fields);
+    if (!l) return 0;
+    for(i = 0; i < num_fields; i++) {
+        s = PyString_FromString(attrs[i]);
+        if (!s) {
+            Py_DECREF(l);
+            return 0;
+        }
+        PyList_SET_ITEM(l, i, s);
+    }
+    result = PyObject_SetAttrString((PyObject*)type, "_attributes", l) >= 0;
+    Py_DECREF(l);
+    return result;
+}
+
+static PyObject* ast2obj_list(asdl_seq *seq, PyObject* (*func)(void*))
+{
+    int i, n = asdl_seq_LEN(seq);
+    PyObject *result = PyList_New(n);
+    PyObject *value;
+    if (!result)
+        return NULL;
+    for (i = 0; i < n; i++) {
+        value = func(asdl_seq_GET(seq, i));
+        if (!value) {
+            Py_DECREF(result);
+            return NULL;
+        }
+        PyList_SET_ITEM(result, i, value);
+    }
+    return result;
+}
+
+static PyObject* ast2obj_object(void *o)
+{
+    if (!o)
+        o = Py_None;
+    Py_INCREF((PyObject*)o);
+    return (PyObject*)o;
+}
+#define ast2obj_identifier ast2obj_object
+#define ast2obj_string ast2obj_object
+static PyObject* ast2obj_bool(bool b)
+{
+    return PyBool_FromLong(b);
+}
+
+static PyObject* ast2obj_int(bool b)
+{
+    return PyInt_FromLong(b);
+}
+""", 0, reflow=False)
+
+        self.emit("static int init_types(void)",0)
+        self.emit("{", 0)
+        self.emit("static int initialized;", 1)
+        self.emit("if (initialized) return 1;", 1)
+        self.emit('AST_type = make_type("AST", &PyBaseObject_Type, NULL, 0);', 1)
+        for dfn in mod.dfns:
+            self.visit(dfn)
+        self.emit("initialized = 1;", 1)
+        self.emit("return 1;", 1);
+        self.emit("}", 0)
+
+    def visitProduct(self, prod, name):
+        if prod.fields:
+            fields = name.value+"_fields"
+        else:
+            fields = "NULL"
+        self.emit('%s_type = make_type("%s", AST_type, %s, %d);' %
+                        (name, name, fields, len(prod.fields)), 1)
+        self.emit("if (!%s_type) return 0;" % name, 1)
+
+    def visitSum(self, sum, name):
+        self.emit('%s_type = make_type("%s", AST_type, NULL, 0);' % (name, name), 1)
+        self.emit("if (!%s_type) return 0;" % name, 1)
+        if sum.attributes:
+            self.emit("if (!add_attributes(%s_type, %s_attributes, %d)) return 0;" %
+                            (name, name, len(sum.attributes)), 1)
+        else:
+            self.emit("if (!add_attributes(%s_type, NULL, 0)) return 0;" % name, 1)
+        simple = is_simple(sum)
+        for t in sum.types:
+            self.visitConstructor(t, name, simple)
+
+    def visitConstructor(self, cons, name, simple):
+        if cons.fields:
+            fields = cons.name.value+"_fields"
+        else:
+            fields = "NULL"
+        self.emit('%s_type = make_type("%s", %s_type, %s, %d);' %
+                            (cons.name, cons.name, name, fields, len(cons.fields)), 1)
+        self.emit("if (!%s_type) return 0;" % cons.name, 1)
+        if simple:
+            self.emit("%s_singleton = PyType_GenericNew(%s_type, NULL, NULL);" %
+                             (cons.name, cons.name), 1)
+            self.emit("if (!%s_singleton) return 0;" % cons.name, 1)
+
+class ASTModuleVisitor(PickleVisitor):
+
+    def visitModule(self, mod):
+        self.emit("PyMODINIT_FUNC", 0)
+        self.emit("init_ast(void)", 0)
+        self.emit("{", 0)
+        self.emit("PyObject *m, *d;", 1)
+        self.emit("if (!init_types()) return;", 1)
+        self.emit('m = Py_InitModule3("_ast", NULL, NULL);', 1)
+        self.emit("if (!m) return;", 1)
+        self.emit("d = PyModule_GetDict(m);", 1)
+        self.emit('if (PyDict_SetItemString(d, "AST", (PyObject*)AST_type) < 0) return;', 1)
+        self.emit('if (PyModule_AddIntConstant(m, "PyCF_ONLY_AST", PyCF_ONLY_AST) < 0)', 1)
+        self.emit("return;", 2)
+        # Value of version: "$Revision: 53490 $"
+        self.emit('if (PyModule_AddStringConstant(m, "__version__", "%s") < 0)' % mod.version.value[12:-3], 1)
+        self.emit("return;", 2)
+        for dfn in mod.dfns:
+            self.visit(dfn)
+        self.emit("}", 0)
+
+    def visitProduct(self, prod, name):
+        self.addObj(name)
+
+    def visitSum(self, sum, name):
+        self.addObj(name)
+        for t in sum.types:
+            self.visitConstructor(t, name)
+
+    def visitConstructor(self, cons, name):
+        self.addObj(cons.name)
+
+    def addObj(self, name):
+        self.emit('if (PyDict_SetItemString(d, "%s", (PyObject*)%s_type) < 0) return;' % (name, name), 1)
+
+_SPECIALIZED_SEQUENCES = ('stmt', 'expr')
+
+def find_sequence(fields, doing_specialization):
+    """Return True if any field uses a sequence."""
+    for f in fields:
+        if f.seq:
+            if not doing_specialization:
+                return True
+            if str(f.type) not in _SPECIALIZED_SEQUENCES:
+                return True
+    return False
+
+def has_sequence(types, doing_specialization):
+    for t in types:
+        if find_sequence(t.fields, doing_specialization):
+            return True
+    return False
+
+
+class StaticVisitor(PickleVisitor):
+    CODE = '''Very simple, always emit this static code.  Overide CODE'''
+
+    def visit(self, object):
+        self.emit(self.CODE, 0, reflow=False)
+
+class ObjVisitor(PickleVisitor):
+
+    def func_begin(self, name):
+        ctype = get_c_type(name)
+        self.emit("PyObject*", 0)
+        self.emit("ast2obj_%s(void* _o)" % (name), 0)
+        self.emit("{", 0)
+        self.emit("%s o = (%s)_o;" % (ctype, ctype), 1)
+        self.emit("PyObject *result = NULL, *value = NULL;", 1)
+        self.emit('if (!o) {', 1)
+        self.emit("Py_INCREF(Py_None);", 2)
+        self.emit('return Py_None;', 2)
+        self.emit("}", 1)
+        self.emit('', 0)
+
+    def func_end(self):
+        self.emit("return result;", 1)
+        self.emit("failed:", 0)
+        self.emit("Py_XDECREF(value);", 1)
+        self.emit("Py_XDECREF(result);", 1)
+        self.emit("return NULL;", 1)
+        self.emit("}", 0)
+        self.emit("", 0)
+
+    def visitSum(self, sum, name):
+        if is_simple(sum):
+            self.simpleSum(sum, name)
+            return
+        self.func_begin(name)
+        self.emit("switch (o->kind) {", 1)
+        for i in range(len(sum.types)):
+            t = sum.types[i]
+            self.visitConstructor(t, i + 1, name)
+        self.emit("}", 1)
+        for a in sum.attributes:
+            self.emit("value = ast2obj_%s(o->%s);" % (a.type, a.name), 1)
+            self.emit("if (!value) goto failed;", 1)
+            self.emit('if (PyObject_SetAttrString(result, "%s", value) < 0)' % a.name, 1)
+            self.emit('goto failed;', 2)
+            self.emit('Py_DECREF(value);', 1)
+        self.func_end()
+
+    def simpleSum(self, sum, name):
+        self.emit("PyObject* ast2obj_%s(%s_ty o)" % (name, name), 0)
+        self.emit("{", 0)
+        self.emit("switch(o) {", 1)
+        for t in sum.types:
+            self.emit("case %s:" % t.name, 2)
+            self.emit("Py_INCREF(%s_singleton);" % t.name, 3)
+            self.emit("return %s_singleton;" % t.name, 3)
+        self.emit("}", 1)
+        self.emit("return NULL; /* cannot happen */", 1)
+        self.emit("}", 0)
+
+    def visitProduct(self, prod, name):
+        self.func_begin(name)
+        self.emit("result = PyType_GenericNew(%s_type, NULL, NULL);" % name, 1);
+        self.emit("if (!result) return NULL;", 1)
+        for field in prod.fields:
+            self.visitField(field, name, 1, True)
+        self.func_end()
+
+    def visitConstructor(self, cons, enum, name):
+        self.emit("case %s_kind:" % cons.name, 1)
+        self.emit("result = PyType_GenericNew(%s_type, NULL, NULL);" % cons.name, 2);
+        self.emit("if (!result) goto failed;", 2)
+        for f in cons.fields:
+            self.visitField(f, cons.name, 2, False)
+        self.emit("break;", 2)
+
+    def visitField(self, field, name, depth, product):
+        def emit(s, d):
+            self.emit(s, depth + d)
+        if product:
+            value = "o->%s" % field.name
+        else:
+            value = "o->v.%s.%s" % (name, field.name)
+        self.set(field, value, depth)
+        emit("if (!value) goto failed;", 0)
+        emit('if (PyObject_SetAttrString(result, "%s", value) == -1)' % field.name, 0)
+        emit("goto failed;", 1)
+        emit("Py_DECREF(value);", 0)
+
+    def emitSeq(self, field, value, depth, emit):
+        emit("seq = %s;" % value, 0)
+        emit("n = asdl_seq_LEN(seq);", 0)
+        emit("value = PyList_New(n);", 0)
+        emit("if (!value) goto failed;", 0)
+        emit("for (i = 0; i < n; i++) {", 0)
+        self.set("value", field, "asdl_seq_GET(seq, i)", depth + 1)
+        emit("if (!value1) goto failed;", 1)
+        emit("PyList_SET_ITEM(value, i, value1);", 1)
+        emit("value1 = NULL;", 1)
+        emit("}", 0)
+
+    def set(self, field, value, depth):
+        if field.seq:
+            # XXX should really check for is_simple, but that requires a symbol table
+            if field.type.value == "cmpop":
+                # While the sequence elements are stored as void*,
+                # ast2obj_cmpop expects an enum
+                self.emit("{", depth)
+                self.emit("int i, n = asdl_seq_LEN(%s);" % value, depth+1)
+                self.emit("value = PyList_New(n);", depth+1)
+                self.emit("if (!value) goto failed;", depth+1)
+                self.emit("for(i = 0; i < n; i++)", depth+1)
+                # This cannot fail, so no need for error handling
+                self.emit("PyList_SET_ITEM(value, i, ast2obj_cmpop((cmpop_ty)asdl_seq_GET(%s, i)));" % value,
+                          depth+2, reflow=False)
+                self.emit("}", depth)
+            else:
+                self.emit("value = ast2obj_list(%s, ast2obj_%s);" % (value, field.type), depth)
+        else:
+            ctype = get_c_type(field.type)
+            self.emit("value = ast2obj_%s(%s);" % (field.type, value), depth, reflow=False)
+
+
+class PartingShots(StaticVisitor):
+
+    CODE = """
+PyObject* PyAST_mod2obj(mod_ty t)
+{
+    init_types();
+    return ast2obj_mod(t);
+}
+"""
+
+class ChainOfVisitors:
+    def __init__(self, *visitors):
+        self.visitors = visitors
+
+    def visit(self, object):
+        for v in self.visitors:
+            v.visit(object)
+            v.emit("", 0)
+
+def main(srcfile):
+    argv0 = sys.argv[0]
+    components = argv0.split(os.sep)
+    argv0 = os.sep.join(components[-2:])
+    auto_gen_msg = '/* File automatically generated by %s */\n' % argv0
+    mod = asdl.parse(srcfile)
+    if not asdl.check(mod):
+        sys.exit(1)
+    if INC_DIR:
+        p = "%s/%s-ast.h" % (INC_DIR, mod.name)
+        f = open(p, "wb")
+        print >> f, auto_gen_msg
+        print >> f, '#include "asdl.h"\n'
+        c = ChainOfVisitors(TypeDefVisitor(f),
+                            StructVisitor(f),
+                            PrototypeVisitor(f),
+                            )
+        c.visit(mod)
+        print >>f, "PyObject* PyAST_mod2obj(mod_ty t);"
+        f.close()
+
+    if SRC_DIR:
+        p = os.path.join(SRC_DIR, str(mod.name) + "-ast.c")
+        f = open(p, "wb")
+        print >> f, auto_gen_msg
+        print >> f, '#include "Python.h"'
+        print >> f, '#include "%s-ast.h"' % mod.name
+        print >> f
+        print >>f, "static PyTypeObject* AST_type;"
+        v = ChainOfVisitors(
+            PyTypesDeclareVisitor(f),
+            PyTypesVisitor(f),
+            FunctionVisitor(f),
+            ObjVisitor(f),
+            ASTModuleVisitor(f),
+            PartingShots(f),
+            )
+        v.visit(mod)
+        f.close()
+
+if __name__ == "__main__":
+    import sys
+    import getopt
+
+    INC_DIR = ''
+    SRC_DIR = ''
+    opts, args = getopt.getopt(sys.argv[1:], "h:c:")
+    if len(opts) != 1:
+        print "Must specify exactly one output file"
+        sys.exit(1)
+    for o, v in opts:
+        if o == '-h':
+            INC_DIR = v
+        if o == '-c':
+            SRC_DIR = v
+    if len(args) != 1:
+        print "Must specify single input file"
+        sys.exit(1)
+    main(args[0])