#include "Python.h"

#include "pycore_ast.h" // expr_ty

#include "pycore_runtime.h" // _Py_ID()

#include <float.h> // DBL_MAX_10_EXP

#include <stdbool.h>

_Py_DECLARE_STR(open_br, "{");

_Py_DECLARE_STR(dbl_open_br, "{{");

_Py_DECLARE_STR(close_br, "}");

_Py_DECLARE_STR(dbl_close_br, "}}");

static PyObject *_str_replace_inf;

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,

&_Py_ID(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;

}

enum {

PR_TUPLE,

PR_TEST, /* 'if'-'else', 'lambda' */

PR_OR, /* 'or' */

PR_AND, /* 'and' */

PR_NOT, /* 'not' */

PR_CMP, /* '<', '>', '==', '>=', '<=', '!=',

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, &_Py_STR(open_br), &_Py_STR(dbl_open_br), -1);

if (!temp) {

return NULL;

}

result = PyUnicode_Replace(temp, &_Py_STR(close_br), &_Py_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;

}

}

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

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, &_Py_STR(open_br), 0, 1, 1) == 0) {

/* Expression starts with a brace, split it with a space from the outer

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

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_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);

}