cpython/Python/ast_unparse.c
Nick Coghlan 1e7b858575
bpo-43892: Make match patterns explicit in the AST (GH-25585)
Co-authored-by: Brandt Bucher <brandtbucher@gmail.com>
2021-04-28 22:58:44 -07:00

978 lines
26 KiB
C

#include "Python.h"
#include "pycore_ast.h" // expr_ty
#include <float.h> // DBL_MAX_10_EXP
#include <stdbool.h>
/* This limited unparser is used to convert annotations back to strings
* during compilation rather than being a full AST unparser.
* See ast.unparse for a full unparser (written in Python)
*/
static PyObject *_str_open_br;
static PyObject *_str_dbl_open_br;
static PyObject *_str_close_br;
static PyObject *_str_dbl_close_br;
static PyObject *_str_inf;
static PyObject *_str_replace_inf;
/* Forward declarations for recursion via helper functions. */
static PyObject *
expr_as_unicode(expr_ty e, int level);
static int
append_ast_expr(_PyUnicodeWriter *writer, expr_ty e, int level);
static int
append_joinedstr(_PyUnicodeWriter *writer, expr_ty e, bool is_format_spec);
static int
append_formattedvalue(_PyUnicodeWriter *writer, expr_ty e);
static int
append_ast_slice(_PyUnicodeWriter *writer, expr_ty e);
static int
append_charp(_PyUnicodeWriter *writer, const char *charp)
{
return _PyUnicodeWriter_WriteASCIIString(writer, charp, -1);
}
#define APPEND_STR_FINISH(str) do { \
return append_charp(writer, (str)); \
} while (0)
#define APPEND_STR(str) do { \
if (-1 == append_charp(writer, (str))) { \
return -1; \
} \
} while (0)
#define APPEND_STR_IF(cond, str) do { \
if ((cond) && -1 == append_charp(writer, (str))) { \
return -1; \
} \
} while (0)
#define APPEND_STR_IF_NOT_FIRST(str) do { \
APPEND_STR_IF(!first, (str)); \
first = false; \
} while (0)
#define APPEND_EXPR(expr, pr) do { \
if (-1 == append_ast_expr(writer, (expr), (pr))) { \
return -1; \
} \
} while (0)
#define APPEND(type, value) do { \
if (-1 == append_ast_ ## type(writer, (value))) { \
return -1; \
} \
} while (0)
static int
append_repr(_PyUnicodeWriter *writer, PyObject *obj)
{
PyObject *repr = PyObject_Repr(obj);
if (!repr) {
return -1;
}
if ((PyFloat_CheckExact(obj) && Py_IS_INFINITY(PyFloat_AS_DOUBLE(obj))) ||
PyComplex_CheckExact(obj))
{
PyObject *new_repr = PyUnicode_Replace(
repr,
_str_inf,
_str_replace_inf,
-1
);
Py_DECREF(repr);
if (!new_repr) {
return -1;
}
repr = new_repr;
}
int ret = _PyUnicodeWriter_WriteStr(writer, repr);
Py_DECREF(repr);
return ret;
}
/* Priority levels */
enum {
PR_TUPLE,
PR_TEST, /* 'if'-'else', 'lambda' */
PR_OR, /* 'or' */
PR_AND, /* 'and' */
PR_NOT, /* 'not' */
PR_CMP, /* '<', '>', '==', '>=', '<=', '!=',
'in', 'not in', 'is', 'is not' */
PR_EXPR,
PR_BOR = PR_EXPR, /* '|' */
PR_BXOR, /* '^' */
PR_BAND, /* '&' */
PR_SHIFT, /* '<<', '>>' */
PR_ARITH, /* '+', '-' */
PR_TERM, /* '*', '@', '/', '%', '//' */
PR_FACTOR, /* unary '+', '-', '~' */
PR_POWER, /* '**' */
PR_AWAIT, /* 'await' */
PR_ATOM,
};
static int
append_ast_boolop(_PyUnicodeWriter *writer, expr_ty e, int level)
{
Py_ssize_t i, value_count;
asdl_expr_seq *values;
const char *op = (e->v.BoolOp.op == And) ? " and " : " or ";
int pr = (e->v.BoolOp.op == And) ? PR_AND : PR_OR;
APPEND_STR_IF(level > pr, "(");
values = e->v.BoolOp.values;
value_count = asdl_seq_LEN(values);
for (i = 0; i < value_count; ++i) {
APPEND_STR_IF(i > 0, op);
APPEND_EXPR((expr_ty)asdl_seq_GET(values, i), pr + 1);
}
APPEND_STR_IF(level > pr, ")");
return 0;
}
static int
append_ast_binop(_PyUnicodeWriter *writer, expr_ty e, int level)
{
const char *op;
int pr;
bool rassoc = false; /* is right-associative? */
switch (e->v.BinOp.op) {
case Add: op = " + "; pr = PR_ARITH; break;
case Sub: op = " - "; pr = PR_ARITH; break;
case Mult: op = " * "; pr = PR_TERM; break;
case MatMult: op = " @ "; pr = PR_TERM; break;
case Div: op = " / "; pr = PR_TERM; break;
case Mod: op = " % "; pr = PR_TERM; break;
case LShift: op = " << "; pr = PR_SHIFT; break;
case RShift: op = " >> "; pr = PR_SHIFT; break;
case BitOr: op = " | "; pr = PR_BOR; break;
case BitXor: op = " ^ "; pr = PR_BXOR; break;
case BitAnd: op = " & "; pr = PR_BAND; break;
case FloorDiv: op = " // "; pr = PR_TERM; break;
case Pow: op = " ** "; pr = PR_POWER; rassoc = true; break;
default:
PyErr_SetString(PyExc_SystemError,
"unknown binary operator");
return -1;
}
APPEND_STR_IF(level > pr, "(");
APPEND_EXPR(e->v.BinOp.left, pr + rassoc);
APPEND_STR(op);
APPEND_EXPR(e->v.BinOp.right, pr + !rassoc);
APPEND_STR_IF(level > pr, ")");
return 0;
}
static int
append_ast_unaryop(_PyUnicodeWriter *writer, expr_ty e, int level)
{
const char *op;
int pr;
switch (e->v.UnaryOp.op) {
case Invert: op = "~"; pr = PR_FACTOR; break;
case Not: op = "not "; pr = PR_NOT; break;
case UAdd: op = "+"; pr = PR_FACTOR; break;
case USub: op = "-"; pr = PR_FACTOR; break;
default:
PyErr_SetString(PyExc_SystemError,
"unknown unary operator");
return -1;
}
APPEND_STR_IF(level > pr, "(");
APPEND_STR(op);
APPEND_EXPR(e->v.UnaryOp.operand, pr);
APPEND_STR_IF(level > pr, ")");
return 0;
}
static int
append_ast_arg(_PyUnicodeWriter *writer, arg_ty arg)
{
if (-1 == _PyUnicodeWriter_WriteStr(writer, arg->arg)) {
return -1;
}
if (arg->annotation) {
APPEND_STR(": ");
APPEND_EXPR(arg->annotation, PR_TEST);
}
return 0;
}
static int
append_ast_args(_PyUnicodeWriter *writer, arguments_ty args)
{
bool first;
Py_ssize_t i, di, arg_count, posonlyarg_count, default_count;
first = true;
/* positional-only and positional arguments with defaults */
posonlyarg_count = asdl_seq_LEN(args->posonlyargs);
arg_count = asdl_seq_LEN(args->args);
default_count = asdl_seq_LEN(args->defaults);
for (i = 0; i < posonlyarg_count + arg_count; i++) {
APPEND_STR_IF_NOT_FIRST(", ");
if (i < posonlyarg_count){
APPEND(arg, (arg_ty)asdl_seq_GET(args->posonlyargs, i));
} else {
APPEND(arg, (arg_ty)asdl_seq_GET(args->args, i-posonlyarg_count));
}
di = i - posonlyarg_count - arg_count + default_count;
if (di >= 0) {
APPEND_STR("=");
APPEND_EXPR((expr_ty)asdl_seq_GET(args->defaults, di), PR_TEST);
}
if (posonlyarg_count && i + 1 == posonlyarg_count) {
APPEND_STR(", /");
}
}
/* vararg, or bare '*' if no varargs but keyword-only arguments present */
if (args->vararg || asdl_seq_LEN(args->kwonlyargs)) {
APPEND_STR_IF_NOT_FIRST(", ");
APPEND_STR("*");
if (args->vararg) {
APPEND(arg, args->vararg);
}
}
/* keyword-only arguments */
arg_count = asdl_seq_LEN(args->kwonlyargs);
default_count = asdl_seq_LEN(args->kw_defaults);
for (i = 0; i < arg_count; i++) {
APPEND_STR_IF_NOT_FIRST(", ");
APPEND(arg, (arg_ty)asdl_seq_GET(args->kwonlyargs, i));
di = i - arg_count + default_count;
if (di >= 0) {
expr_ty default_ = (expr_ty)asdl_seq_GET(args->kw_defaults, di);
if (default_) {
APPEND_STR("=");
APPEND_EXPR(default_, PR_TEST);
}
}
}
/* **kwargs */
if (args->kwarg) {
APPEND_STR_IF_NOT_FIRST(", ");
APPEND_STR("**");
APPEND(arg, args->kwarg);
}
return 0;
}
static int
append_ast_lambda(_PyUnicodeWriter *writer, expr_ty e, int level)
{
APPEND_STR_IF(level > PR_TEST, "(");
Py_ssize_t n_positional = (asdl_seq_LEN(e->v.Lambda.args->args) +
asdl_seq_LEN(e->v.Lambda.args->posonlyargs));
APPEND_STR(n_positional ? "lambda " : "lambda");
APPEND(args, e->v.Lambda.args);
APPEND_STR(": ");
APPEND_EXPR(e->v.Lambda.body, PR_TEST);
APPEND_STR_IF(level > PR_TEST, ")");
return 0;
}
static int
append_ast_ifexp(_PyUnicodeWriter *writer, expr_ty e, int level)
{
APPEND_STR_IF(level > PR_TEST, "(");
APPEND_EXPR(e->v.IfExp.body, PR_TEST + 1);
APPEND_STR(" if ");
APPEND_EXPR(e->v.IfExp.test, PR_TEST + 1);
APPEND_STR(" else ");
APPEND_EXPR(e->v.IfExp.orelse, PR_TEST);
APPEND_STR_IF(level > PR_TEST, ")");
return 0;
}
static int
append_ast_dict(_PyUnicodeWriter *writer, expr_ty e)
{
Py_ssize_t i, value_count;
expr_ty key_node;
APPEND_STR("{");
value_count = asdl_seq_LEN(e->v.Dict.values);
for (i = 0; i < value_count; i++) {
APPEND_STR_IF(i > 0, ", ");
key_node = (expr_ty)asdl_seq_GET(e->v.Dict.keys, i);
if (key_node != NULL) {
APPEND_EXPR(key_node, PR_TEST);
APPEND_STR(": ");
APPEND_EXPR((expr_ty)asdl_seq_GET(e->v.Dict.values, i), PR_TEST);
}
else {
APPEND_STR("**");
APPEND_EXPR((expr_ty)asdl_seq_GET(e->v.Dict.values, i), PR_EXPR);
}
}
APPEND_STR_FINISH("}");
}
static int
append_ast_set(_PyUnicodeWriter *writer, expr_ty e)
{
Py_ssize_t i, elem_count;
APPEND_STR("{");
elem_count = asdl_seq_LEN(e->v.Set.elts);
for (i = 0; i < elem_count; i++) {
APPEND_STR_IF(i > 0, ", ");
APPEND_EXPR((expr_ty)asdl_seq_GET(e->v.Set.elts, i), PR_TEST);
}
APPEND_STR_FINISH("}");
}
static int
append_ast_list(_PyUnicodeWriter *writer, expr_ty e)
{
Py_ssize_t i, elem_count;
APPEND_STR("[");
elem_count = asdl_seq_LEN(e->v.List.elts);
for (i = 0; i < elem_count; i++) {
APPEND_STR_IF(i > 0, ", ");
APPEND_EXPR((expr_ty)asdl_seq_GET(e->v.List.elts, i), PR_TEST);
}
APPEND_STR_FINISH("]");
}
static int
append_ast_tuple(_PyUnicodeWriter *writer, expr_ty e, int level)
{
Py_ssize_t i, elem_count;
elem_count = asdl_seq_LEN(e->v.Tuple.elts);
if (elem_count == 0) {
APPEND_STR_FINISH("()");
}
APPEND_STR_IF(level > PR_TUPLE, "(");
for (i = 0; i < elem_count; i++) {
APPEND_STR_IF(i > 0, ", ");
APPEND_EXPR((expr_ty)asdl_seq_GET(e->v.Tuple.elts, i), PR_TEST);
}
APPEND_STR_IF(elem_count == 1, ",");
APPEND_STR_IF(level > PR_TUPLE, ")");
return 0;
}
static int
append_ast_comprehension(_PyUnicodeWriter *writer, comprehension_ty gen)
{
Py_ssize_t i, if_count;
APPEND_STR(gen->is_async ? " async for " : " for ");
APPEND_EXPR(gen->target, PR_TUPLE);
APPEND_STR(" in ");
APPEND_EXPR(gen->iter, PR_TEST + 1);
if_count = asdl_seq_LEN(gen->ifs);
for (i = 0; i < if_count; i++) {
APPEND_STR(" if ");
APPEND_EXPR((expr_ty)asdl_seq_GET(gen->ifs, i), PR_TEST + 1);
}
return 0;
}
static int
append_ast_comprehensions(_PyUnicodeWriter *writer, asdl_comprehension_seq *comprehensions)
{
Py_ssize_t i, gen_count;
gen_count = asdl_seq_LEN(comprehensions);
for (i = 0; i < gen_count; i++) {
APPEND(comprehension, (comprehension_ty)asdl_seq_GET(comprehensions, i));
}
return 0;
}
static int
append_ast_genexp(_PyUnicodeWriter *writer, expr_ty e)
{
APPEND_STR("(");
APPEND_EXPR(e->v.GeneratorExp.elt, PR_TEST);
APPEND(comprehensions, e->v.GeneratorExp.generators);
APPEND_STR_FINISH(")");
}
static int
append_ast_listcomp(_PyUnicodeWriter *writer, expr_ty e)
{
APPEND_STR("[");
APPEND_EXPR(e->v.ListComp.elt, PR_TEST);
APPEND(comprehensions, e->v.ListComp.generators);
APPEND_STR_FINISH("]");
}
static int
append_ast_setcomp(_PyUnicodeWriter *writer, expr_ty e)
{
APPEND_STR("{");
APPEND_EXPR(e->v.SetComp.elt, PR_TEST);
APPEND(comprehensions, e->v.SetComp.generators);
APPEND_STR_FINISH("}");
}
static int
append_ast_dictcomp(_PyUnicodeWriter *writer, expr_ty e)
{
APPEND_STR("{");
APPEND_EXPR(e->v.DictComp.key, PR_TEST);
APPEND_STR(": ");
APPEND_EXPR(e->v.DictComp.value, PR_TEST);
APPEND(comprehensions, e->v.DictComp.generators);
APPEND_STR_FINISH("}");
}
static int
append_ast_compare(_PyUnicodeWriter *writer, expr_ty e, int level)
{
const char *op;
Py_ssize_t i, comparator_count;
asdl_expr_seq *comparators;
asdl_int_seq *ops;
APPEND_STR_IF(level > PR_CMP, "(");
comparators = e->v.Compare.comparators;
ops = e->v.Compare.ops;
comparator_count = asdl_seq_LEN(comparators);
assert(comparator_count > 0);
assert(comparator_count == asdl_seq_LEN(ops));
APPEND_EXPR(e->v.Compare.left, PR_CMP + 1);
for (i = 0; i < comparator_count; i++) {
switch ((cmpop_ty)asdl_seq_GET(ops, i)) {
case Eq:
op = " == ";
break;
case NotEq:
op = " != ";
break;
case Lt:
op = " < ";
break;
case LtE:
op = " <= ";
break;
case Gt:
op = " > ";
break;
case GtE:
op = " >= ";
break;
case Is:
op = " is ";
break;
case IsNot:
op = " is not ";
break;
case In:
op = " in ";
break;
case NotIn:
op = " not in ";
break;
default:
PyErr_SetString(PyExc_SystemError,
"unexpected comparison kind");
return -1;
}
APPEND_STR(op);
APPEND_EXPR((expr_ty)asdl_seq_GET(comparators, i), PR_CMP + 1);
}
APPEND_STR_IF(level > PR_CMP, ")");
return 0;
}
static int
append_ast_keyword(_PyUnicodeWriter *writer, keyword_ty kw)
{
if (kw->arg == NULL) {
APPEND_STR("**");
}
else {
if (-1 == _PyUnicodeWriter_WriteStr(writer, kw->arg)) {
return -1;
}
APPEND_STR("=");
}
APPEND_EXPR(kw->value, PR_TEST);
return 0;
}
static int
append_ast_call(_PyUnicodeWriter *writer, expr_ty e)
{
bool first;
Py_ssize_t i, arg_count, kw_count;
expr_ty expr;
APPEND_EXPR(e->v.Call.func, PR_ATOM);
arg_count = asdl_seq_LEN(e->v.Call.args);
kw_count = asdl_seq_LEN(e->v.Call.keywords);
if (arg_count == 1 && kw_count == 0) {
expr = (expr_ty)asdl_seq_GET(e->v.Call.args, 0);
if (expr->kind == GeneratorExp_kind) {
/* Special case: a single generator expression. */
return append_ast_genexp(writer, expr);
}
}
APPEND_STR("(");
first = true;
for (i = 0; i < arg_count; i++) {
APPEND_STR_IF_NOT_FIRST(", ");
APPEND_EXPR((expr_ty)asdl_seq_GET(e->v.Call.args, i), PR_TEST);
}
for (i = 0; i < kw_count; i++) {
APPEND_STR_IF_NOT_FIRST(", ");
APPEND(keyword, (keyword_ty)asdl_seq_GET(e->v.Call.keywords, i));
}
APPEND_STR_FINISH(")");
}
static PyObject *
escape_braces(PyObject *orig)
{
PyObject *temp;
PyObject *result;
temp = PyUnicode_Replace(orig, _str_open_br, _str_dbl_open_br, -1);
if (!temp) {
return NULL;
}
result = PyUnicode_Replace(temp, _str_close_br, _str_dbl_close_br, -1);
Py_DECREF(temp);
return result;
}
static int
append_fstring_unicode(_PyUnicodeWriter *writer, PyObject *unicode)
{
PyObject *escaped;
int result = -1;
escaped = escape_braces(unicode);
if (escaped) {
result = _PyUnicodeWriter_WriteStr(writer, escaped);
Py_DECREF(escaped);
}
return result;
}
static int
append_fstring_element(_PyUnicodeWriter *writer, expr_ty e, bool is_format_spec)
{
switch (e->kind) {
case Constant_kind:
return append_fstring_unicode(writer, e->v.Constant.value);
case JoinedStr_kind:
return append_joinedstr(writer, e, is_format_spec);
case FormattedValue_kind:
return append_formattedvalue(writer, e);
default:
PyErr_SetString(PyExc_SystemError,
"unknown expression kind inside f-string");
return -1;
}
}
/* Build body separately to enable wrapping the entire stream of Strs,
Constants and FormattedValues in one opening and one closing quote. */
static PyObject *
build_fstring_body(asdl_expr_seq *values, bool is_format_spec)
{
Py_ssize_t i, value_count;
_PyUnicodeWriter body_writer;
_PyUnicodeWriter_Init(&body_writer);
body_writer.min_length = 256;
body_writer.overallocate = 1;
value_count = asdl_seq_LEN(values);
for (i = 0; i < value_count; ++i) {
if (-1 == append_fstring_element(&body_writer,
(expr_ty)asdl_seq_GET(values, i),
is_format_spec
)) {
_PyUnicodeWriter_Dealloc(&body_writer);
return NULL;
}
}
return _PyUnicodeWriter_Finish(&body_writer);
}
static int
append_joinedstr(_PyUnicodeWriter *writer, expr_ty e, bool is_format_spec)
{
int result = -1;
PyObject *body = build_fstring_body(e->v.JoinedStr.values, is_format_spec);
if (!body) {
return -1;
}
if (!is_format_spec) {
if (-1 != append_charp(writer, "f") &&
-1 != append_repr(writer, body))
{
result = 0;
}
}
else {
result = _PyUnicodeWriter_WriteStr(writer, body);
}
Py_DECREF(body);
return result;
}
static int
append_formattedvalue(_PyUnicodeWriter *writer, expr_ty e)
{
const char *conversion;
const char *outer_brace = "{";
/* Grammar allows PR_TUPLE, but use >PR_TEST for adding parenthesis
around a lambda with ':' */
PyObject *temp_fv_str = expr_as_unicode(e->v.FormattedValue.value, PR_TEST + 1);
if (!temp_fv_str) {
return -1;
}
if (PyUnicode_Find(temp_fv_str, _str_open_br, 0, 1, 1) == 0) {
/* Expression starts with a brace, split it with a space from the outer
one. */
outer_brace = "{ ";
}
if (-1 == append_charp(writer, outer_brace)) {
Py_DECREF(temp_fv_str);
return -1;
}
if (-1 == _PyUnicodeWriter_WriteStr(writer, temp_fv_str)) {
Py_DECREF(temp_fv_str);
return -1;
}
Py_DECREF(temp_fv_str);
if (e->v.FormattedValue.conversion > 0) {
switch (e->v.FormattedValue.conversion) {
case 'a':
conversion = "!a";
break;
case 'r':
conversion = "!r";
break;
case 's':
conversion = "!s";
break;
default:
PyErr_SetString(PyExc_SystemError,
"unknown f-value conversion kind");
return -1;
}
APPEND_STR(conversion);
}
if (e->v.FormattedValue.format_spec) {
if (-1 == _PyUnicodeWriter_WriteASCIIString(writer, ":", 1) ||
-1 == append_fstring_element(writer,
e->v.FormattedValue.format_spec,
true
))
{
return -1;
}
}
APPEND_STR_FINISH("}");
}
static int
append_ast_constant(_PyUnicodeWriter *writer, PyObject *constant)
{
if (PyTuple_CheckExact(constant)) {
Py_ssize_t i, elem_count;
elem_count = PyTuple_GET_SIZE(constant);
APPEND_STR("(");
for (i = 0; i < elem_count; i++) {
APPEND_STR_IF(i > 0, ", ");
if (append_ast_constant(writer, PyTuple_GET_ITEM(constant, i)) < 0) {
return -1;
}
}
APPEND_STR_IF(elem_count == 1, ",");
APPEND_STR(")");
return 0;
}
return append_repr(writer, constant);
}
static int
append_ast_attribute(_PyUnicodeWriter *writer, expr_ty e)
{
const char *period;
expr_ty v = e->v.Attribute.value;
APPEND_EXPR(v, PR_ATOM);
/* Special case: integers require a space for attribute access to be
unambiguous. */
if (v->kind == Constant_kind && PyLong_CheckExact(v->v.Constant.value)) {
period = " .";
}
else {
period = ".";
}
APPEND_STR(period);
return _PyUnicodeWriter_WriteStr(writer, e->v.Attribute.attr);
}
static int
append_ast_slice(_PyUnicodeWriter *writer, expr_ty e)
{
if (e->v.Slice.lower) {
APPEND_EXPR(e->v.Slice.lower, PR_TEST);
}
APPEND_STR(":");
if (e->v.Slice.upper) {
APPEND_EXPR(e->v.Slice.upper, PR_TEST);
}
if (e->v.Slice.step) {
APPEND_STR(":");
APPEND_EXPR(e->v.Slice.step, PR_TEST);
}
return 0;
}
static int
append_ast_subscript(_PyUnicodeWriter *writer, expr_ty e)
{
APPEND_EXPR(e->v.Subscript.value, PR_ATOM);
int level = PR_TUPLE;
expr_ty slice = e->v.Subscript.slice;
if (slice->kind == Tuple_kind) {
for (Py_ssize_t i = 0; i < asdl_seq_LEN(slice->v.Tuple.elts); i++) {
expr_ty element = asdl_seq_GET(slice->v.Tuple.elts, i);
if (element->kind == Starred_kind) {
++level;
break;
}
}
}
APPEND_STR("[");
APPEND_EXPR(e->v.Subscript.slice, level);
APPEND_STR_FINISH("]");
}
static int
append_ast_starred(_PyUnicodeWriter *writer, expr_ty e)
{
APPEND_STR("*");
APPEND_EXPR(e->v.Starred.value, PR_EXPR);
return 0;
}
static int
append_ast_yield(_PyUnicodeWriter *writer, expr_ty e)
{
if (!e->v.Yield.value) {
APPEND_STR_FINISH("(yield)");
}
APPEND_STR("(yield ");
APPEND_EXPR(e->v.Yield.value, PR_TEST);
APPEND_STR_FINISH(")");
}
static int
append_ast_yield_from(_PyUnicodeWriter *writer, expr_ty e)
{
APPEND_STR("(yield from ");
APPEND_EXPR(e->v.YieldFrom.value, PR_TEST);
APPEND_STR_FINISH(")");
}
static int
append_ast_await(_PyUnicodeWriter *writer, expr_ty e, int level)
{
APPEND_STR_IF(level > PR_AWAIT, "(");
APPEND_STR("await ");
APPEND_EXPR(e->v.Await.value, PR_ATOM);
APPEND_STR_IF(level > PR_AWAIT, ")");
return 0;
}
static int
append_named_expr(_PyUnicodeWriter *writer, expr_ty e, int level)
{
APPEND_STR_IF(level > PR_TUPLE, "(");
APPEND_EXPR(e->v.NamedExpr.target, PR_ATOM);
APPEND_STR(" := ");
APPEND_EXPR(e->v.NamedExpr.value, PR_ATOM);
APPEND_STR_IF(level > PR_TUPLE, ")");
return 0;
}
static int
append_ast_expr(_PyUnicodeWriter *writer, expr_ty e, int level)
{
switch (e->kind) {
case BoolOp_kind:
return append_ast_boolop(writer, e, level);
case BinOp_kind:
return append_ast_binop(writer, e, level);
case UnaryOp_kind:
return append_ast_unaryop(writer, e, level);
case Lambda_kind:
return append_ast_lambda(writer, e, level);
case IfExp_kind:
return append_ast_ifexp(writer, e, level);
case Dict_kind:
return append_ast_dict(writer, e);
case Set_kind:
return append_ast_set(writer, e);
case GeneratorExp_kind:
return append_ast_genexp(writer, e);
case ListComp_kind:
return append_ast_listcomp(writer, e);
case SetComp_kind:
return append_ast_setcomp(writer, e);
case DictComp_kind:
return append_ast_dictcomp(writer, e);
case Yield_kind:
return append_ast_yield(writer, e);
case YieldFrom_kind:
return append_ast_yield_from(writer, e);
case Await_kind:
return append_ast_await(writer, e, level);
case Compare_kind:
return append_ast_compare(writer, e, level);
case Call_kind:
return append_ast_call(writer, e);
case Constant_kind:
if (e->v.Constant.value == Py_Ellipsis) {
APPEND_STR_FINISH("...");
}
if (e->v.Constant.kind != NULL
&& -1 == _PyUnicodeWriter_WriteStr(writer, e->v.Constant.kind)) {
return -1;
}
return append_ast_constant(writer, e->v.Constant.value);
case JoinedStr_kind:
return append_joinedstr(writer, e, false);
case FormattedValue_kind:
return append_formattedvalue(writer, e);
/* The following exprs can be assignment targets. */
case Attribute_kind:
return append_ast_attribute(writer, e);
case Subscript_kind:
return append_ast_subscript(writer, e);
case Starred_kind:
return append_ast_starred(writer, e);
case Slice_kind:
return append_ast_slice(writer, e);
case Name_kind:
return _PyUnicodeWriter_WriteStr(writer, e->v.Name.id);
case List_kind:
return append_ast_list(writer, e);
case Tuple_kind:
return append_ast_tuple(writer, e, level);
case NamedExpr_kind:
return append_named_expr(writer, e, level);
// No default so compiler emits a warning for unhandled cases
}
PyErr_SetString(PyExc_SystemError,
"unknown expression kind");
return -1;
}
static int
maybe_init_static_strings(void)
{
if (!_str_open_br &&
!(_str_open_br = PyUnicode_InternFromString("{"))) {
return -1;
}
if (!_str_dbl_open_br &&
!(_str_dbl_open_br = PyUnicode_InternFromString("{{"))) {
return -1;
}
if (!_str_close_br &&
!(_str_close_br = PyUnicode_InternFromString("}"))) {
return -1;
}
if (!_str_dbl_close_br &&
!(_str_dbl_close_br = PyUnicode_InternFromString("}}"))) {
return -1;
}
if (!_str_inf &&
!(_str_inf = PyUnicode_FromString("inf"))) {
return -1;
}
if (!_str_replace_inf &&
!(_str_replace_inf = PyUnicode_FromFormat("1e%d", 1 + DBL_MAX_10_EXP))) {
return -1;
}
return 0;
}
static PyObject *
expr_as_unicode(expr_ty e, int level)
{
_PyUnicodeWriter writer;
_PyUnicodeWriter_Init(&writer);
writer.min_length = 256;
writer.overallocate = 1;
if (-1 == maybe_init_static_strings() ||
-1 == append_ast_expr(&writer, e, level))
{
_PyUnicodeWriter_Dealloc(&writer);
return NULL;
}
return _PyUnicodeWriter_Finish(&writer);
}
PyObject *
_PyAST_ExprAsUnicode(expr_ty e)
{
return expr_as_unicode(e, PR_TEST);
}