/*

* This file includes functions to transform a concrete syntax tree (CST) to

* an abstract syntax tree (AST). The main function is PyAST_FromNode().

*

*/

#include "Python.h"

#include "Python-ast.h"

#include "grammar.h"

#include "node.h"

#include "ast.h"

#include "token.h"

#include "parsetok.h"

#include "graminit.h"

#include <assert.h>

/* Data structure used internally */

struct compiling {

char *c_encoding; /* source encoding */

PyArena *c_arena; /* arena for allocating memeory */

const char *c_filename; /* filename */

};

static asdl_seq *seq_for_testlist(struct compiling *, const node *);

static expr_ty ast_for_expr(struct compiling *, const node *);

static stmt_ty ast_for_stmt(struct compiling *, const node *);

static asdl_seq *ast_for_suite(struct compiling *, const node *);

static asdl_seq *ast_for_exprlist(struct compiling *, const node *,

expr_context_ty);

static expr_ty ast_for_testlist(struct compiling *, const node *);

static stmt_ty ast_for_classdef(struct compiling *, const node *, asdl_seq *);

/* Note different signature for ast_for_call */

static expr_ty ast_for_call(struct compiling *, const node *, expr_ty);

static PyObject *parsenumber(struct compiling *, const char *);

static PyObject *parsestr(struct compiling *, const node *n, int *bytesmode);

static PyObject *parsestrplus(struct compiling *, const node *n,

int *bytesmode);

#ifndef LINENO

#define LINENO(n) ((n)->n_lineno)

#endif

#define COMP_GENEXP 0

#define COMP_LISTCOMP 1

#define COMP_SETCOMP 2

static identifier

new_identifier(const char* n, PyArena *arena)

{

PyObject* id = PyUnicode_DecodeUTF8(n, strlen(n), NULL);

Py_UNICODE *u;

if (!id)

return NULL;

u = PyUnicode_AS_UNICODE(id);

/* Check whether there are non-ASCII characters in the

identifier; if so, normalize to NFKC. */

for (; *u; u++) {

if (*u >= 128) {

PyObject *m = PyImport_ImportModuleNoBlock("unicodedata");

PyObject *id2;

if (!m)

return NULL;

id2 = PyObject_CallMethod(m, "normalize", "sO", "NFKC", id);

Py_DECREF(m);

if (!id2)

return NULL;

Py_DECREF(id);

id = id2;

break;

}

}

PyUnicode_InternInPlace(&id);

PyArena_AddPyObject(arena, id);

return id;

}

#define NEW_IDENTIFIER(n) new_identifier(STR(n), c->c_arena)

/* This routine provides an invalid object for the syntax error.

The outermost routine must unpack this error and create the

proper object. We do this so that we don't have to pass

the filename to everything function.

XXX Maybe we should just pass the filename...

*/

static int

ast_error(const node *n, const char *errstr)

{

PyObject *u = Py_BuildValue("zii", errstr, LINENO(n), n->n_col_offset);

if (!u)

return 0;

PyErr_SetObject(PyExc_SyntaxError, u);

Py_DECREF(u);

return 0;

}

static void

ast_error_finish(const char *filename)

{

PyObject *type, *value, *tback, *errstr, *offset, *loc, *tmp;

PyObject *filename_obj;

long lineno;

assert(PyErr_Occurred());

if (!PyErr_ExceptionMatches(PyExc_SyntaxError))

return;

PyErr_Fetch(&type, &value, &tback);

errstr = PyTuple_GetItem(value, 0);

if (!errstr)

return;

Py_INCREF(errstr);

lineno = PyLong_AsLong(PyTuple_GetItem(value, 1));

if (lineno == -1) {

Py_DECREF(errstr);

return;

}

offset = PyTuple_GetItem(value, 2);

if (!offset) {

Py_DECREF(errstr);

return;

}

Py_DECREF(value);

loc = PyErr_ProgramText(filename, lineno);

if (!loc) {

Py_INCREF(Py_None);

loc = Py_None;

}

if (filename != NULL)

filename_obj = PyUnicode_DecodeFSDefault(filename);

else {

Py_INCREF(Py_None);

filename_obj = Py_None;

}

if (filename_obj != NULL)

tmp = Py_BuildValue("(NlOO)", filename_obj, lineno, offset, loc);

else

tmp = NULL;

Py_DECREF(loc);

if (!tmp) {

Py_DECREF(errstr);

return;

}

value = PyTuple_Pack(2, errstr, tmp);

Py_DECREF(errstr);

Py_DECREF(tmp);

if (!value)

return;

PyErr_Restore(type, value, tback);

}

/* num_stmts() returns number of contained statements.

Use this routine to determine how big a sequence is needed for

the statements in a parse tree. Its raison d'etre is this bit of

grammar:

stmt: simple_stmt | compound_stmt

simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE

A simple_stmt can contain multiple small_stmt elements joined

by semicolons. If the arg is a simple_stmt, the number of

small_stmt elements is returned.

*/

static int

num_stmts(const node *n)

{

int i, l;

node *ch;

switch (TYPE(n)) {

case single_input:

if (TYPE(CHILD(n, 0)) == NEWLINE)

return 0;

else

return num_stmts(CHILD(n, 0));

case file_input:

l = 0;

for (i = 0; i < NCH(n); i++) {

ch = CHILD(n, i);

if (TYPE(ch) == stmt)

l += num_stmts(ch);

}

return l;

case stmt:

return num_stmts(CHILD(n, 0));

case compound_stmt:

return 1;

case simple_stmt:

return NCH(n) / 2; /* Divide by 2 to remove count of semi-colons */

case suite:

if (NCH(n) == 1)

return num_stmts(CHILD(n, 0));

else {

l = 0;

for (i = 2; i < (NCH(n) - 1); i++)

l += num_stmts(CHILD(n, i));

return l;

}

default: {

char buf[128];

sprintf(buf, "Non-statement found: %d %d",

TYPE(n), NCH(n));

Py_FatalError(buf);

}

}

assert(0);

return 0;

}

/* Transform the CST rooted at node * to the appropriate AST

*/

mod_ty

PyAST_FromNode(const node *n, PyCompilerFlags *flags, const char *filename,

PyArena *arena)

{

int i, j, k, num;

asdl_seq *stmts = NULL;

stmt_ty s;

node *ch;

struct compiling c;

if (flags && flags->cf_flags & PyCF_SOURCE_IS_UTF8) {

c.c_encoding = "utf-8";

if (TYPE(n) == encoding_decl) {

#if 0

ast_error(n, "encoding declaration in Unicode string");

goto error;

#endif

n = CHILD(n, 0);

}

} else if (TYPE(n) == encoding_decl) {

c.c_encoding = STR(n);

n = CHILD(n, 0);

} else {

/* PEP 3120 */

c.c_encoding = "utf-8";

}

c.c_arena = arena;

c.c_filename = filename;

k = 0;

switch (TYPE(n)) {

case file_input:

stmts = asdl_seq_new(num_stmts(n), arena);

if (!stmts)

return NULL;

for (i = 0; i < NCH(n) - 1; i++) {

ch = CHILD(n, i);

if (TYPE(ch) == NEWLINE)

continue;

REQ(ch, stmt);

num = num_stmts(ch);

if (num == 1) {

s = ast_for_stmt(&c, ch);

if (!s)

goto error;

asdl_seq_SET(stmts, k++, s);

}

else {

ch = CHILD(ch, 0);

REQ(ch, simple_stmt);

for (j = 0; j < num; j++) {

s = ast_for_stmt(&c, CHILD(ch, j * 2));

if (!s)

goto error;

asdl_seq_SET(stmts, k++, s);

}

}

}

return Module(stmts, arena);

case eval_input: {

expr_ty testlist_ast;

/* XXX Why not comp_for here? */

testlist_ast = ast_for_testlist(&c, CHILD(n, 0));

if (!testlist_ast)

goto error;

return Expression(testlist_ast, arena);

}

case single_input:

if (TYPE(CHILD(n, 0)) == NEWLINE) {

stmts = asdl_seq_new(1, arena);

if (!stmts)

goto error;

asdl_seq_SET(stmts, 0, Pass(n->n_lineno, n->n_col_offset,

arena));

if (!asdl_seq_GET(stmts, 0))

goto error;

return Interactive(stmts, arena);

}

else {

n = CHILD(n, 0);

num = num_stmts(n);

stmts = asdl_seq_new(num, arena);

if (!stmts)

goto error;

if (num == 1) {

s = ast_for_stmt(&c, n);

if (!s)

goto error;

asdl_seq_SET(stmts, 0, s);

}

else {

/* Only a simple_stmt can contain multiple statements. */

REQ(n, simple_stmt);

for (i = 0; i < NCH(n); i += 2) {

if (TYPE(CHILD(n, i)) == NEWLINE)

break;

s = ast_for_stmt(&c, CHILD(n, i));

if (!s)

goto error;

asdl_seq_SET(stmts, i / 2, s);

}

}

return Interactive(stmts, arena);

}

default:

PyErr_Format(PyExc_SystemError,

"invalid node %d for PyAST_FromNode", TYPE(n));

goto error;

}

error:

ast_error_finish(filename);

return NULL;

}

/* Return the AST repr. of the operator represented as syntax (|, ^, etc.)

*/

static operator_ty

get_operator(const node *n)

{

switch (TYPE(n)) {

case VBAR:

return BitOr;

case CIRCUMFLEX:

return BitXor;

case AMPER:

return BitAnd;

case LEFTSHIFT:

return LShift;

case RIGHTSHIFT:

return RShift;

case PLUS:

return Add;

case MINUS:

return Sub;

case STAR:

return Mult;

case SLASH:

return Div;

case DOUBLESLASH:

return FloorDiv;

case PERCENT:

return Mod;

default:

return (operator_ty)0;

}

}

static const char* FORBIDDEN[] = {

"None",

"True",

"False",

NULL,

};

static int

forbidden_name(identifier name, const node *n, int full_checks)

{

assert(PyUnicode_Check(name));

if (PyUnicode_CompareWithASCIIString(name, "__debug__") == 0) {

ast_error(n, "assignment to keyword");

return 1;

}

if (full_checks) {

const char **p;

for (p = FORBIDDEN; *p; p++) {

if (PyUnicode_CompareWithASCIIString(name, *p) == 0) {

ast_error(n, "assignment to keyword");

return 1;

}

}

}

return 0;

}

/* Set the context ctx for expr_ty e, recursively traversing e.

Only sets context for expr kinds that "can appear in assignment context"

(according to ../Parser/Python.asdl). For other expr kinds, it sets

an appropriate syntax error and returns false.

*/

static int

set_context(struct compiling *c, expr_ty e, expr_context_ty ctx, const node *n)

{

asdl_seq *s = NULL;

/* If a particular expression type can't be used for assign / delete,

set expr_name to its name and an error message will be generated.

*/

const char* expr_name = NULL;

/* The ast defines augmented store and load contexts, but the

implementation here doesn't actually use them. The code may be

a little more complex than necessary as a result. It also means

that expressions in an augmented assignment have a Store context.

Consider restructuring so that augmented assignment uses

set_context(), too.

*/

assert(ctx != AugStore && ctx != AugLoad);

switch (e->kind) {

case Attribute_kind:

e->v.Attribute.ctx = ctx;

if (ctx == Store && forbidden_name(e->v.Attribute.attr, n, 1))

return 0;

break;

case Subscript_kind:

e->v.Subscript.ctx = ctx;

break;

case Starred_kind:

e->v.Starred.ctx = ctx;

if (!set_context(c, e->v.Starred.value, ctx, n))

return 0;

break;

case Name_kind:

if (ctx == Store) {

if (forbidden_name(e->v.Name.id, n, 1))

return 0; /* forbidden_name() calls ast_error() */

}

e->v.Name.ctx = ctx;

break;

case List_kind:

e->v.List.ctx = ctx;

s = e->v.List.elts;

break;

case Tuple_kind:

if (asdl_seq_LEN(e->v.Tuple.elts)) {

e->v.Tuple.ctx = ctx;

s = e->v.Tuple.elts;

}

else {

expr_name = "()";

}

break;

case Lambda_kind:

expr_name = "lambda";

break;

case Call_kind:

expr_name = "function call";

break;

case BoolOp_kind:

case BinOp_kind:

case UnaryOp_kind:

expr_name = "operator";

break;

case GeneratorExp_kind:

expr_name = "generator expression";

break;

case Yield_kind:

expr_name = "yield expression";

break;

case ListComp_kind:

expr_name = "list comprehension";

break;

case SetComp_kind:

expr_name = "set comprehension";

break;

case DictComp_kind:

expr_name = "dict comprehension";

break;

case Dict_kind:

case Set_kind:

case Num_kind:

case Str_kind:

case Bytes_kind:

expr_name = "literal";

break;

case Ellipsis_kind:

expr_name = "Ellipsis";

break;

case Compare_kind:

expr_name = "comparison";

break;

case IfExp_kind:

expr_name = "conditional expression";

break;

default:

PyErr_Format(PyExc_SystemError,

"unexpected expression in assignment %d (line %d)",

e->kind, e->lineno);

return 0;

}

/* Check for error string set by switch */

if (expr_name) {

char buf[300];

PyOS_snprintf(buf, sizeof(buf),

"can't %s %s",

ctx == Store ? "assign to" : "delete",

expr_name);

return ast_error(n, buf);

}

/* If the LHS is a list or tuple, we need to set the assignment

context for all the contained elements.

*/

if (s) {

int i;

for (i = 0; i < asdl_seq_LEN(s); i++) {

if (!set_context(c, (expr_ty)asdl_seq_GET(s, i), ctx, n))

return 0;

}

}

return 1;

}

static operator_ty

ast_for_augassign(struct compiling *c, const node *n)

{

REQ(n, augassign);

n = CHILD(n, 0);

switch (STR(n)[0]) {

case '+':

return Add;

case '-':

return Sub;

case '/':

if (STR(n)[1] == '/')

return FloorDiv;

else

return Div;

case '%':

return Mod;

case '<':

return LShift;

case '>':

return RShift;

case '&':

return BitAnd;

case '^':

return BitXor;

case '|':

return BitOr;

case '*':

if (STR(n)[1] == '*')

return Pow;

else

return Mult;

default:

PyErr_Format(PyExc_SystemError, "invalid augassign: %s", STR(n));

return (operator_ty)0;

}

}

static cmpop_ty

ast_for_comp_op(struct compiling *c, const node *n)

{

/* comp_op: '<'|'>'|'=='|'>='|'<='|'!='|'in'|'not' 'in'|'is'

|'is' 'not'

*/

REQ(n, comp_op);

if (NCH(n) == 1) {

n = CHILD(n, 0);

switch (TYPE(n)) {

case LESS:

return Lt;

case GREATER:

return Gt;

case EQEQUAL: /* == */

return Eq;

case LESSEQUAL:

return LtE;

case GREATEREQUAL:

return GtE;

case NOTEQUAL:

return NotEq;

case NAME:

if (strcmp(STR(n), "in") == 0)

return In;

if (strcmp(STR(n), "is") == 0)

return Is;

default:

PyErr_Format(PyExc_SystemError, "invalid comp_op: %s",

STR(n));

return (cmpop_ty)0;

}

}

else if (NCH(n) == 2) {

/* handle "not in" and "is not" */

switch (TYPE(CHILD(n, 0))) {

case NAME:

if (strcmp(STR(CHILD(n, 1)), "in") == 0)

return NotIn;

if (strcmp(STR(CHILD(n, 0)), "is") == 0)

return IsNot;

default:

PyErr_Format(PyExc_SystemError, "invalid comp_op: %s %s",

STR(CHILD(n, 0)), STR(CHILD(n, 1)));

return (cmpop_ty)0;

}

}

PyErr_Format(PyExc_SystemError, "invalid comp_op: has %d children",

NCH(n));

return (cmpop_ty)0;

}

static asdl_seq *

seq_for_testlist(struct compiling *c, const node *n)

{

/* testlist: test (',' test)* [',']

testlist_star_expr: test|star_expr (',' test|star_expr)* [',']

*/

asdl_seq *seq;

expr_ty expression;

int i;

assert(TYPE(n) == testlist || TYPE(n) == testlist_star_expr || TYPE(n) == testlist_comp);

seq = asdl_seq_new((NCH(n) + 1) / 2, c->c_arena);

if (!seq)

return NULL;

for (i = 0; i < NCH(n); i += 2) {

const node *ch = CHILD(n, i);

assert(TYPE(ch) == test || TYPE(ch) == test_nocond || TYPE(ch) == star_expr);

expression = ast_for_expr(c, ch);

if (!expression)

return NULL;

assert(i / 2 < seq->size);

asdl_seq_SET(seq, i / 2, expression);

}

return seq;

}

static arg_ty

compiler_arg(struct compiling *c, const node *n)

{

identifier name;

expr_ty annotation = NULL;

node *ch;

assert(TYPE(n) == tfpdef || TYPE(n) == vfpdef);

ch = CHILD(n, 0);

name = NEW_IDENTIFIER(ch);

if (!name)

return NULL;

if (forbidden_name(name, ch, 0))

return NULL;

if (NCH(n) == 3 && TYPE(CHILD(n, 1)) == COLON) {

annotation = ast_for_expr(c, CHILD(n, 2));

if (!annotation)

return NULL;

}

return arg(name, annotation, c->c_arena);

#if 0

result = Tuple(args, Store, LINENO(n), n->n_col_offset, c->c_arena);

if (!set_context(c, result, Store, n))

return NULL;

return result;

#endif

}

/* returns -1 if failed to handle keyword only arguments

returns new position to keep processing if successful

(',' tfpdef ['=' test])*

^^^

start pointing here

*/

static int

handle_keywordonly_args(struct compiling *c, const node *n, int start,

asdl_seq *kwonlyargs, asdl_seq *kwdefaults)

{

PyObject *argname;

node *ch;

expr_ty expression, annotation;

arg_ty arg;

int i = start;

int j = 0; /* index for kwdefaults and kwonlyargs */

if (kwonlyargs == NULL) {

ast_error(CHILD(n, start), "named arguments must follow bare *");

return -1;

}

assert(kwdefaults != NULL);

while (i < NCH(n)) {

ch = CHILD(n, i);

switch (TYPE(ch)) {

case vfpdef:

case tfpdef:

if (i + 1 < NCH(n) && TYPE(CHILD(n, i + 1)) == EQUAL) {

expression = ast_for_expr(c, CHILD(n, i + 2));

if (!expression)

goto error;

asdl_seq_SET(kwdefaults, j, expression);

i += 2; /* '=' and test */

}

else { /* setting NULL if no default value exists */

asdl_seq_SET(kwdefaults, j, NULL);

}

if (NCH(ch) == 3) {

/* ch is NAME ':' test */

annotation = ast_for_expr(c, CHILD(ch, 2));

if (!annotation)

goto error;

}

else {

annotation = NULL;

}

ch = CHILD(ch, 0);

argname = NEW_IDENTIFIER(ch);

if (!argname)

goto error;

if (forbidden_name(argname, ch, 0))

goto error;

arg = arg(argname, annotation, c->c_arena);

if (!arg)

goto error;

asdl_seq_SET(kwonlyargs, j++, arg);

i += 2; /* the name and the comma */

break;

case DOUBLESTAR:

return i;

default:

ast_error(ch, "unexpected node");

goto error;

}

}

return i;

error:

return -1;

}

/* Create AST for argument list. */

static arguments_ty

ast_for_arguments(struct compiling *c, const node *n)

{

/* This function handles both typedargslist (function definition)

and varargslist (lambda definition).

parameters: '(' [typedargslist] ')'

typedargslist: ((tfpdef ['=' test] ',')*

('*' [tfpdef] (',' tfpdef ['=' test])* [',' '**' tfpdef]

| '**' tfpdef)

| tfpdef ['=' test] (',' tfpdef ['=' test])* [','])

tfpdef: NAME [':' test]

varargslist: ((vfpdef ['=' test] ',')*

('*' [vfpdef] (',' vfpdef ['=' test])* [',' '**' vfpdef]

| '**' vfpdef)

| vfpdef ['=' test] (',' vfpdef ['=' test])* [','])

vfpdef: NAME

*/

int i, j, k, nposargs = 0, nkwonlyargs = 0;

int nposdefaults = 0, found_default = 0;

asdl_seq *posargs, *posdefaults, *kwonlyargs, *kwdefaults;

identifier vararg = NULL, kwarg = NULL;

arg_ty arg;

expr_ty varargannotation = NULL, kwargannotation = NULL;

node *ch;

if (TYPE(n) == parameters) {

if (NCH(n) == 2) /* () as argument list */

return arguments(NULL, NULL, NULL, NULL, NULL, NULL, NULL,

NULL, c->c_arena);

n = CHILD(n, 1);

}

assert(TYPE(n) == typedargslist || TYPE(n) == varargslist);

/* First count the number of positional args & defaults. The

variable i is the loop index for this for loop and the next.

The next loop picks up where the first leaves off.

*/

for (i = 0; i < NCH(n); i++) {

ch = CHILD(n, i);

if (TYPE(ch) == STAR) {

/* skip star */

i++;

if (i < NCH(n) && /* skip argument following star */

(TYPE(CHILD(n, i)) == tfpdef ||

TYPE(CHILD(n, i)) == vfpdef)) {

i++;

}

break;

}

if (TYPE(ch) == DOUBLESTAR) break;

if (TYPE(ch) == vfpdef || TYPE(ch) == tfpdef) nposargs++;

if (TYPE(ch) == EQUAL) nposdefaults++;

}

/* count the number of keyword only args &

defaults for keyword only args */

for ( ; i < NCH(n); ++i) {

ch = CHILD(n, i);

if (TYPE(ch) == DOUBLESTAR) break;

if (TYPE(ch) == tfpdef || TYPE(ch) == vfpdef) nkwonlyargs++;

}

posargs = (nposargs ? asdl_seq_new(nposargs, c->c_arena) : NULL);

if (!posargs && nposargs)

return NULL;

kwonlyargs = (nkwonlyargs ?

asdl_seq_new(nkwonlyargs, c->c_arena) : NULL);

if (!kwonlyargs && nkwonlyargs)

return NULL;

posdefaults = (nposdefaults ?

asdl_seq_new(nposdefaults, c->c_arena) : NULL);

if (!posdefaults && nposdefaults)

return NULL;

/* The length of kwonlyargs and kwdefaults are same

since we set NULL as default for keyword only argument w/o default

- we have sequence data structure, but no dictionary */

kwdefaults = (nkwonlyargs ?

asdl_seq_new(nkwonlyargs, c->c_arena) : NULL);

if (!kwdefaults && nkwonlyargs)

return NULL;

if (nposargs + nkwonlyargs > 255) {

ast_error(n, "more than 255 arguments");

return NULL;

}

/* tfpdef: NAME [':' test]

vfpdef: NAME

*/

i = 0;

j = 0; /* index for defaults */

k = 0; /* index for args */

while (i < NCH(n)) {

ch = CHILD(n, i);

switch (TYPE(ch)) {

case tfpdef:

case vfpdef:

/* XXX Need to worry about checking if TYPE(CHILD(n, i+1)) is

anything other than EQUAL or a comma? */

/* XXX Should NCH(n) check be made a separate check? */

if (i + 1 < NCH(n) && TYPE(CHILD(n, i + 1)) == EQUAL) {

expr_ty expression = ast_for_expr(c, CHILD(n, i + 2));

if (!expression)

return NULL;

assert(posdefaults != NULL);

asdl_seq_SET(posdefaults, j++, expression);

i += 2;

found_default = 1;

}

else if (found_default) {

ast_error(n,

"non-default argument follows default argument");

return NULL;

}

arg = compiler_arg(c, ch);

if (!arg)

return NULL;

asdl_seq_SET(posargs, k++, arg);

i += 2; /* the name and the comma */

break;

case STAR:

if (i+1 >= NCH(n)) {

ast_error(CHILD(n, i),

"named arguments must follow bare *");

return NULL;

}

ch = CHILD(n, i+1); /* tfpdef or COMMA */

if (TYPE(ch) == COMMA) {

int res = 0;

i += 2; /* now follows keyword only arguments */

res = handle_keywordonly_args(c, n, i,

kwonlyargs, kwdefaults);

if (res == -1) return NULL;

i = res; /* res has new position to process */

}

else {

vararg = NEW_IDENTIFIER(CHILD(ch, 0));

if (!vararg)

return NULL;

if (forbidden_name(vararg, CHILD(ch, 0), 0))

return NULL;

if (NCH(ch) > 1) {

/* there is an annotation on the vararg */

varargannotation = ast_for_expr(c, CHILD(ch, 2));

if (!varargannotation)

return NULL;

}

i += 3;

if (i < NCH(n) && (TYPE(CHILD(n, i)) == tfpdef

|| TYPE(CHILD(n, i)) == vfpdef)) {

int res = 0;

res = handle_keywordonly_args(c, n, i,

kwonlyargs, kwdefaults);

if (res == -1) return NULL;

i = res; /* res has new position to process */

}

}

break;

case DOUBLESTAR:

ch = CHILD(n, i+1); /* tfpdef */

assert(TYPE(ch) == tfpdef || TYPE(ch) == vfpdef);

kwarg = NEW_IDENTIFIER(CHILD(ch, 0));

if (!kwarg)

return NULL;

if (NCH(ch) > 1) {

/* there is an annotation on the kwarg */

kwargannotation = ast_for_expr(c, CHILD(ch, 2));

if (!kwargannotation)

return NULL;

}

if (forbidden_name(kwarg, CHILD(ch, 0), 0))

return NULL;

i += 3;

break;

default:

PyErr_Format(PyExc_SystemError,

"unexpected node in varargslist: %d @ %d",

TYPE(ch), i);

return NULL;

}

}

return arguments(posargs, vararg, varargannotation, kwonlyargs, kwarg,

kwargannotation, posdefaults, kwdefaults, c->c_arena);

}

static expr_ty

ast_for_dotted_name(struct compiling *c, const node *n)

{

expr_ty e;

identifier id;

int lineno, col_offset;

int i;

REQ(n, dotted_name);

lineno = LINENO(n);

col_offset = n->n_col_offset;

id = NEW_IDENTIFIER(CHILD(n, 0));

if (!id)

return NULL;

e = Name(id, Load, lineno, col_offset, c->c_arena);

if (!e)

return NULL;

for (i = 2; i < NCH(n); i+=2) {

id = NEW_IDENTIFIER(CHILD(n, i));

if (!id)

return NULL;

e = Attribute(e, id, Load, lineno, col_offset, c->c_arena);

if (!e)

return NULL;

}

return e;

}

static expr_ty

ast_for_decorator(struct compiling *c, const node *n)

{

/* decorator: '@' dotted_name [ '(' [arglist] ')' ] NEWLINE */

expr_ty d = NULL;

expr_ty name_expr;

REQ(n, decorator);

REQ(CHILD(n, 0), AT);

REQ(RCHILD(n, -1), NEWLINE);

name_expr = ast_for_dotted_name(c, CHILD(n, 1));

if (!name_expr)

return NULL;

if (NCH(n) == 3) { /* No arguments */

d = name_expr;

name_expr = NULL;

}

else if (NCH(n) == 5) { /* Call with no arguments */

d = Call(name_expr, NULL, NULL, NULL, NULL, LINENO(n),

n->n_col_offset, c->c_arena);

if (!d)

return NULL;

name_expr = NULL;

}

else {

d = ast_for_call(c, CHILD(n, 3), name_expr);

if (!d)

return NULL;

name_expr = NULL;

}

return d;

}