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bpo-43892: Make match patterns explicit in the AST (GH-25585)

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Co-authored-by: Brandt Bucher <brandtbucher@gmail.com>
This commit is contained in:
Nick Coghlan 2021-04-29 15:58:44 +10:00 • committed by GitHub
parent e52ab42ced
commit 1e7b858575
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GPG key ID: 4AEE18F83AFDEB23
20 changed files with 3460 additions and 1377 deletions
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383
Python/compile.c
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@ -280,9 +280,9 @@ static int compiler_async_comprehension_generator(
int depth,
expr_ty elt, expr_ty val, int type);
static int compiler_pattern(struct compiler *, expr_ty, pattern_context *);
static int compiler_pattern(struct compiler *, pattern_ty, pattern_context *);
static int compiler_match(struct compiler *, stmt_ty);
static int compiler_pattern_subpattern(struct compiler *, expr_ty,
static int compiler_pattern_subpattern(struct compiler *, pattern_ty,
pattern_context *);
static PyCodeObject *assemble(struct compiler *, int addNone);
@ -5263,10 +5263,6 @@ compiler_visit_expr1(struct compiler *c, expr_ty e)
return compiler_list(c, e);
case Tuple_kind:
return compiler_tuple(c, e);
case MatchAs_kind:
case MatchOr_kind:
// Can only occur in patterns, which are handled elsewhere.
Py_UNREACHABLE();
}
return 1;
}
@ -5600,16 +5596,22 @@ compiler_slice(struct compiler *c, expr_ty s)
// that it's much easier to smooth out any redundant pushing, popping, and
// jumping in the peephole optimizer than to detect or predict it here.
#define WILDCARD_CHECK(N) \
((N)->kind == Name_kind && \
_PyUnicode_EqualToASCIIString((N)->v.Name.id, "_"))
((N)->kind == MatchAs_kind && !(N)->v.MatchAs.name)
#define WILDCARD_STAR_CHECK(N) \
((N)->kind == MatchStar_kind && !(N)->v.MatchStar.name)
// Limit permitted subexpressions, even if the parser & AST validator let them through
#define MATCH_VALUE_EXPR(N) \
((N)->kind == Constant_kind || (N)->kind == Attribute_kind)
static int
pattern_helper_store_name(struct compiler *c, identifier n, pattern_context *pc)
{
assert(!_PyUnicode_EqualToASCIIString(n, "_"));
if (forbidden_name(c, n, Store)) {
return 0;
}
// Can't assign to the same name twice:
if (pc->stores == NULL) {
RETURN_IF_FALSE(pc->stores = PySet_New(NULL));
@ -5631,16 +5633,43 @@ pattern_helper_store_name(struct compiler *c, identifier n, pattern_context *pc)
static int
pattern_helper_sequence_unpack(struct compiler *c, asdl_expr_seq *values,
pattern_unpack_helper(struct compiler *c, asdl_pattern_seq *elts)
{
Py_ssize_t n = asdl_seq_LEN(elts);
int seen_star = 0;
for (Py_ssize_t i = 0; i < n; i++) {
pattern_ty elt = asdl_seq_GET(elts, i);
if (elt->kind == MatchStar_kind && !seen_star) {
if ((i >= (1 << 8)) ||
(n-i-1 >= (INT_MAX >> 8)))
return compiler_error(c,
"too many expressions in "
"star-unpacking sequence pattern");
ADDOP_I(c, UNPACK_EX, (i + ((n-i-1) << 8)));
seen_star = 1;
}
else if (elt->kind == MatchStar_kind) {
return compiler_error(c,
"multiple starred expressions in sequence pattern");
}
}
if (!seen_star) {
ADDOP_I(c, UNPACK_SEQUENCE, n);
}
return 1;
}
static int
pattern_helper_sequence_unpack(struct compiler *c, asdl_pattern_seq *patterns,
Py_ssize_t star, pattern_context *pc)
{
RETURN_IF_FALSE(unpack_helper(c, values));
RETURN_IF_FALSE(pattern_unpack_helper(c, patterns));
// We've now got a bunch of new subjects on the stack. If any of them fail
// to match, we need to pop everything else off, then finally push False.
// fails is an array of blocks that correspond to the necessary amount of
// popping for each element:
basicblock **fails;
Py_ssize_t size = asdl_seq_LEN(values);
Py_ssize_t size = asdl_seq_LEN(patterns);
fails = (basicblock **)PyObject_Malloc(sizeof(basicblock*) * size);
if (fails == NULL) {
PyErr_NoMemory();
@ -5655,12 +5684,9 @@ pattern_helper_sequence_unpack(struct compiler *c, asdl_expr_seq *values,
}
}
for (Py_ssize_t i = 0; i < size; i++) {
expr_ty value = asdl_seq_GET(values, i);
if (i == star) {
assert(value->kind == Starred_kind);
value = value->v.Starred.value;
}
if (!compiler_pattern_subpattern(c, value, pc) ||
pattern_ty pattern = asdl_seq_GET(patterns, i);
assert((i == star) == (pattern->kind == MatchStar_kind));
if (!compiler_pattern_subpattern(c, pattern, pc) ||
!compiler_addop_j(c, POP_JUMP_IF_FALSE, fails[i]) ||
compiler_next_block(c) == NULL)
{
@ -5703,21 +5729,20 @@ error:
// UNPACK_SEQUENCE / UNPACK_EX. This is more efficient for patterns with a
// starred wildcard like [first, *_] / [first, *_, last] / [*_, last] / etc.
static int
pattern_helper_sequence_subscr(struct compiler *c, asdl_expr_seq *values,
pattern_helper_sequence_subscr(struct compiler *c, asdl_pattern_seq *patterns,
Py_ssize_t star, pattern_context *pc)
{
basicblock *end, *fail_pop_1;
RETURN_IF_FALSE(end = compiler_new_block(c));
RETURN_IF_FALSE(fail_pop_1 = compiler_new_block(c));
Py_ssize_t size = asdl_seq_LEN(values);
Py_ssize_t size = asdl_seq_LEN(patterns);
for (Py_ssize_t i = 0; i < size; i++) {
expr_ty value = asdl_seq_GET(values, i);
if (WILDCARD_CHECK(value)) {
pattern_ty pattern = asdl_seq_GET(patterns, i);
if (WILDCARD_CHECK(pattern)) {
continue;
}
if (i == star) {
assert(value->kind == Starred_kind);
assert(WILDCARD_CHECK(value->v.Starred.value));
assert(WILDCARD_STAR_CHECK(pattern));
continue;
}
ADDOP(c, DUP_TOP);
@ -5732,7 +5757,7 @@ pattern_helper_sequence_subscr(struct compiler *c, asdl_expr_seq *values,
ADDOP(c, BINARY_SUBTRACT);
}
ADDOP(c, BINARY_SUBSCR);
RETURN_IF_FALSE(compiler_pattern_subpattern(c, value, pc));
RETURN_IF_FALSE(compiler_pattern_subpattern(c, pattern, pc));
ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_1);
NEXT_BLOCK(c);
}
@ -5746,10 +5771,9 @@ pattern_helper_sequence_subscr(struct compiler *c, asdl_expr_seq *values,
return 1;
}
// Like compiler_pattern, but turn off checks for irrefutability.
static int
compiler_pattern_subpattern(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern_subpattern(struct compiler *c, pattern_ty p, pattern_context *pc)
{
int allow_irrefutable = pc->allow_irrefutable;
pc->allow_irrefutable = 1;
@ -5758,11 +5782,43 @@ compiler_pattern_subpattern(struct compiler *c, expr_ty p, pattern_context *pc)
return 1;
}
static int
compiler_pattern_capture(struct compiler *c, identifier n, pattern_context *pc)
{
RETURN_IF_FALSE(pattern_helper_store_name(c, n, pc));
ADDOP_LOAD_CONST(c, Py_True);
return 1;
}
static int
compiler_pattern_as(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern_wildcard(struct compiler *c, pattern_ty p, pattern_context *pc)
{
assert(p->kind == MatchAs_kind);
if (!pc->allow_irrefutable) {
// Whoops, can't have a wildcard here!
const char *e = "wildcard makes remaining patterns unreachable";
return compiler_error(c, e);
}
ADDOP(c, POP_TOP);
ADDOP_LOAD_CONST(c, Py_True);
return 1;
}
static int
compiler_pattern_as(struct compiler *c, pattern_ty p, pattern_context *pc)
{
assert(p->kind == MatchAs_kind);
if (p->v.MatchAs.name == NULL) {
return compiler_pattern_wildcard(c, p, pc);
}
if (p->v.MatchAs.pattern == NULL) {
if (!pc->allow_irrefutable) {
// Whoops, can't have a name capture here!
const char *e = "name capture %R makes remaining patterns unreachable";
return compiler_error(c, e, p->v.MatchAs.name);
}
return compiler_pattern_capture(c, p->v.MatchAs.name, pc);
}
basicblock *end, *fail_pop_1;
RETURN_IF_FALSE(end = compiler_new_block(c));
RETURN_IF_FALSE(fail_pop_1 = compiler_new_block(c));
@ -5782,71 +5838,101 @@ compiler_pattern_as(struct compiler *c, expr_ty p, pattern_context *pc)
return 1;
}
static int
compiler_pattern_capture(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern_star(struct compiler *c, pattern_ty p, pattern_context *pc)
{
assert(p->kind == Name_kind);
assert(p->v.Name.ctx == Store);
assert(!WILDCARD_CHECK(p));
assert(p->kind == MatchStar_kind);
if (!pc->allow_irrefutable) {
// Whoops, can't have a name capture here!
const char *e = "name capture %R makes remaining patterns unreachable";
return compiler_error(c, e, p->v.Name.id);
// Whoops, can't have a star capture here!
const char *e = "star captures are only allowed as part of sequence patterns";
return compiler_error(c, e);
}
RETURN_IF_FALSE(pattern_helper_store_name(c, p->v.Name.id, pc));
ADDOP_LOAD_CONST(c, Py_True);
return 1;
return compiler_pattern_capture(c, p->v.MatchStar.name, pc);
}
static int
validate_kwd_attrs(struct compiler *c, asdl_identifier_seq *attrs, asdl_pattern_seq* patterns)
{
// Any errors will point to the pattern rather than the arg name as the
// parser is only supplying identifiers rather than Name or keyword nodes
Py_ssize_t nattrs = asdl_seq_LEN(attrs);
for (Py_ssize_t i = 0; i < nattrs; i++) {
identifier attr = ((identifier)asdl_seq_GET(attrs, i));
c->u->u_col_offset = ((pattern_ty) asdl_seq_GET(patterns, i))->col_offset;
if (forbidden_name(c, attr, Store)) {
return -1;
}
for (Py_ssize_t j = i + 1; j < nattrs; j++) {
identifier other = ((identifier)asdl_seq_GET(attrs, j));
if (!PyUnicode_Compare(attr, other)) {
c->u->u_col_offset = ((pattern_ty) asdl_seq_GET(patterns, j))->col_offset;
compiler_error(c, "attribute name repeated in class pattern: %U", attr);
return -1;
}
}
}
return 0;
}
static int
compiler_pattern_class(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern_class(struct compiler *c, pattern_ty p, pattern_context *pc)
{
asdl_expr_seq *args = p->v.Call.args;
asdl_keyword_seq *kwargs = p->v.Call.keywords;
Py_ssize_t nargs = asdl_seq_LEN(args);
Py_ssize_t nkwargs = asdl_seq_LEN(kwargs);
if (INT_MAX < nargs || INT_MAX < nargs + nkwargs - 1) {
const char *e = "too many sub-patterns in class pattern %R";
return compiler_error(c, e, p->v.Call.func);
assert(p->kind == MatchClass_kind);
asdl_pattern_seq *patterns = p->v.MatchClass.patterns;
asdl_identifier_seq *kwd_attrs = p->v.MatchClass.kwd_attrs;
asdl_pattern_seq *kwd_patterns = p->v.MatchClass.kwd_patterns;
Py_ssize_t nargs = asdl_seq_LEN(patterns);
Py_ssize_t nattrs = asdl_seq_LEN(kwd_attrs);
Py_ssize_t nkwd_patterns = asdl_seq_LEN(kwd_patterns);
if (nattrs != nkwd_patterns) {
// AST validator shouldn't let this happen, but if it does,
// just fail, don't crash out of the interpreter
const char * e = "kwd_attrs (%d) / kwd_patterns (%d) length mismatch in class pattern";
return compiler_error(c, e, nattrs, nkwd_patterns);
}
if (INT_MAX < nargs || INT_MAX < nargs + nattrs - 1) {
const char *e = "too many sub-patterns in class pattern %R";
return compiler_error(c, e, p->v.MatchClass.cls);
}
if (nattrs) {
RETURN_IF_FALSE(!validate_kwd_attrs(c, kwd_attrs, kwd_patterns));
c->u->u_col_offset = p->col_offset; // validate_kwd_attrs moves this
}
RETURN_IF_FALSE(!validate_keywords(c, kwargs));
basicblock *end, *fail_pop_1;
RETURN_IF_FALSE(end = compiler_new_block(c));
RETURN_IF_FALSE(fail_pop_1 = compiler_new_block(c));
VISIT(c, expr, p->v.Call.func);
PyObject *kwnames;
RETURN_IF_FALSE(kwnames = PyTuple_New(nkwargs));
VISIT(c, expr, p->v.MatchClass.cls);
PyObject *attr_names;
RETURN_IF_FALSE(attr_names = PyTuple_New(nattrs));
Py_ssize_t i;
for (i = 0; i < nkwargs; i++) {
PyObject *name = ((keyword_ty) asdl_seq_GET(kwargs, i))->arg;
for (i = 0; i < nattrs; i++) {
PyObject *name = asdl_seq_GET(kwd_attrs, i);
Py_INCREF(name);
PyTuple_SET_ITEM(kwnames, i, name);
PyTuple_SET_ITEM(attr_names, i, name);
}
ADDOP_LOAD_CONST_NEW(c, kwnames);
ADDOP_LOAD_CONST_NEW(c, attr_names);
ADDOP_I(c, MATCH_CLASS, nargs);
ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_1);
NEXT_BLOCK(c);
// TOS is now a tuple of (nargs + nkwargs) attributes.
for (i = 0; i < nargs + nkwargs; i++) {
expr_ty arg;
for (i = 0; i < nargs + nattrs; i++) {
pattern_ty pattern;
if (i < nargs) {
// Positional:
arg = asdl_seq_GET(args, i);
pattern = asdl_seq_GET(patterns, i);
}
else {
// Keyword:
arg = ((keyword_ty) asdl_seq_GET(kwargs, i - nargs))->value;
pattern = asdl_seq_GET(kwd_patterns, i - nargs);
}
if (WILDCARD_CHECK(arg)) {
if (WILDCARD_CHECK(pattern)) {
continue;
}
// Get the i-th attribute, and match it against the i-th pattern:
ADDOP(c, DUP_TOP);
ADDOP_LOAD_CONST_NEW(c, PyLong_FromSsize_t(i));
ADDOP(c, BINARY_SUBSCR);
RETURN_IF_FALSE(compiler_pattern_subpattern(c, arg, pc));
RETURN_IF_FALSE(compiler_pattern_subpattern(c, pattern, pc));
ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_1);
NEXT_BLOCK(c);
}
@ -5861,36 +5947,30 @@ compiler_pattern_class(struct compiler *c, expr_ty p, pattern_context *pc)
return 1;
}
static int
compiler_pattern_literal(struct compiler *c, expr_ty p, pattern_context *pc)
{
assert(p->kind == Constant_kind);
PyObject *v = p->v.Constant.value;
ADDOP_LOAD_CONST(c, v);
// Literal True, False, and None are compared by identity. All others use
// equality:
ADDOP_COMPARE(c, (v == Py_None || PyBool_Check(v)) ? Is : Eq);
return 1;
}
static int
compiler_pattern_mapping(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern_mapping(struct compiler *c, pattern_ty p, pattern_context *pc)
{
assert(p->kind == MatchMapping_kind);
basicblock *end, *fail_pop_1, *fail_pop_3;
RETURN_IF_FALSE(end = compiler_new_block(c));
RETURN_IF_FALSE(fail_pop_1 = compiler_new_block(c));
RETURN_IF_FALSE(fail_pop_3 = compiler_new_block(c));
asdl_expr_seq *keys = p->v.Dict.keys;
asdl_expr_seq *values = p->v.Dict.values;
Py_ssize_t size = asdl_seq_LEN(values);
// A starred pattern will be a keyless value. It is guaranteed to be last:
int star = size ? !asdl_seq_GET(keys, size - 1) : 0;
asdl_expr_seq *keys = p->v.MatchMapping.keys;
asdl_pattern_seq *patterns = p->v.MatchMapping.patterns;
Py_ssize_t size = asdl_seq_LEN(keys);
Py_ssize_t npatterns = asdl_seq_LEN(patterns);
if (size != npatterns) {
// AST validator shouldn't let this happen, but if it does,
// just fail, don't crash out of the interpreter
const char * e = "keys (%d) / patterns (%d) length mismatch in mapping pattern";
return compiler_error(c, e, size, npatterns);
}
// We have a double-star target if "rest" is set
PyObject *star_target = p->v.MatchMapping.rest;
ADDOP(c, MATCH_MAPPING);
ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_1);
NEXT_BLOCK(c);
if (!size) {
if (!size && !star_target) {
// If the pattern is just "{}", we're done!
ADDOP(c, POP_TOP);
ADDOP_LOAD_CONST(c, Py_True);
@ -5901,53 +5981,57 @@ compiler_pattern_mapping(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_use_next_block(c, end);
return 1;
}
if (size - star) {
if (size) {
// If the pattern has any keys in it, perform a length check:
ADDOP(c, GET_LEN);
ADDOP_LOAD_CONST_NEW(c, PyLong_FromSsize_t(size - star));
ADDOP_LOAD_CONST_NEW(c, PyLong_FromSsize_t(size));
ADDOP_COMPARE(c, GtE);
ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_1);
NEXT_BLOCK(c);
}
if (INT_MAX < size - star - 1) {
if (INT_MAX < size - 1) {
return compiler_error(c, "too many sub-patterns in mapping pattern");
}
// Collect all of the keys into a tuple for MATCH_KEYS and
// COPY_DICT_WITHOUT_KEYS. They can either be dotted names or literals:
for (Py_ssize_t i = 0; i < size - star; i++) {
for (Py_ssize_t i = 0; i < size; i++) {
expr_ty key = asdl_seq_GET(keys, i);
if (key == NULL) {
const char *e = "can't use starred name here "
"(consider moving to end)";
const char *e = "can't use NULL keys in MatchMapping "
"(set 'rest' parameter instead)";
c->u->u_col_offset = ((pattern_ty) asdl_seq_GET(patterns, i))->col_offset;
return compiler_error(c, e);
}
if (!MATCH_VALUE_EXPR(key)) {
const char *e = "mapping pattern keys may only match literals and attribute lookups";
return compiler_error(c, e);
}
VISIT(c, expr, key);
}
ADDOP_I(c, BUILD_TUPLE, size - star);
ADDOP_I(c, BUILD_TUPLE, size);
ADDOP(c, MATCH_KEYS);
ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_3);
NEXT_BLOCK(c);
// So far so good. There's now a tuple of values on the stack to match
// sub-patterns against:
for (Py_ssize_t i = 0; i < size - star; i++) {
expr_ty value = asdl_seq_GET(values, i);
if (WILDCARD_CHECK(value)) {
for (Py_ssize_t i = 0; i < size; i++) {
pattern_ty pattern = asdl_seq_GET(patterns, i);
if (WILDCARD_CHECK(pattern)) {
continue;
}
ADDOP(c, DUP_TOP);
ADDOP_LOAD_CONST_NEW(c, PyLong_FromSsize_t(i));
ADDOP(c, BINARY_SUBSCR);
RETURN_IF_FALSE(compiler_pattern_subpattern(c, value, pc));
RETURN_IF_FALSE(compiler_pattern_subpattern(c, pattern, pc));
ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_3);
NEXT_BLOCK(c);
}
// If we get this far, it's a match! We're done with that tuple of values.
ADDOP(c, POP_TOP);
if (star) {
// If we had a starred name, bind a dict of remaining items to it:
if (star_target) {
// If we have a starred name, bind a dict of remaining items to it:
ADDOP(c, COPY_DICT_WITHOUT_KEYS);
PyObject *id = asdl_seq_GET(values, size - 1)->v.Name.id;
RETURN_IF_FALSE(pattern_helper_store_name(c, id, pc));
RETURN_IF_FALSE(pattern_helper_store_name(c, star_target, pc));
}
else {
// Otherwise, we don't care about this tuple of keys anymore:
@ -5970,9 +6054,8 @@ compiler_pattern_mapping(struct compiler *c, expr_ty p, pattern_context *pc)
return 1;
}
static int
compiler_pattern_or(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern_or(struct compiler *c, pattern_ty p, pattern_context *pc)
{
assert(p->kind == MatchOr_kind);
// control is the set of names bound by the first alternative. If all of the
@ -5988,7 +6071,7 @@ compiler_pattern_or(struct compiler *c, expr_ty p, pattern_context *pc)
int allow_irrefutable = pc->allow_irrefutable;
for (Py_ssize_t i = 0; i < size; i++) {
// NOTE: Can't use our nice returning macros in here: they'll leak sets!
expr_ty alt = asdl_seq_GET(p->v.MatchOr.patterns, i);
pattern_ty alt = asdl_seq_GET(p->v.MatchOr.patterns, i);
pc->stores = PySet_New(stores_init);
// An irrefutable sub-pattern must be last, if it is allowed at all:
int is_last = i == size - 1;
@ -6044,28 +6127,28 @@ fail:
static int
compiler_pattern_sequence(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern_sequence(struct compiler *c, pattern_ty p, pattern_context *pc)
{
assert(p->kind == List_kind || p->kind == Tuple_kind);
asdl_expr_seq *values = (p->kind == Tuple_kind) ? p->v.Tuple.elts
: p->v.List.elts;
Py_ssize_t size = asdl_seq_LEN(values);
assert(p->kind == MatchSequence_kind);
asdl_pattern_seq *patterns = p->v.MatchSequence.patterns;
Py_ssize_t size = asdl_seq_LEN(patterns);
Py_ssize_t star = -1;
int only_wildcard = 1;
int star_wildcard = 0;
// Find a starred name, if it exists. There may be at most one:
for (Py_ssize_t i = 0; i < size; i++) {
expr_ty value = asdl_seq_GET(values, i);
if (value->kind == Starred_kind) {
value = value->v.Starred.value;
pattern_ty pattern = asdl_seq_GET(patterns, i);
if (pattern->kind == MatchStar_kind) {
if (star >= 0) {
const char *e = "multiple starred names in sequence pattern";
return compiler_error(c, e);
}
star_wildcard = WILDCARD_CHECK(value);
star_wildcard = WILDCARD_STAR_CHECK(pattern);
only_wildcard &= star_wildcard;
star = i;
continue;
}
only_wildcard &= WILDCARD_CHECK(value);
only_wildcard &= WILDCARD_CHECK(pattern);
}
basicblock *end, *fail_pop_1;
RETURN_IF_FALSE(end = compiler_new_block(c));
@ -6095,10 +6178,10 @@ compiler_pattern_sequence(struct compiler *c, expr_ty p, pattern_context *pc)
ADDOP_LOAD_CONST(c, Py_True);
}
else if (star_wildcard) {
RETURN_IF_FALSE(pattern_helper_sequence_subscr(c, values, star, pc));
RETURN_IF_FALSE(pattern_helper_sequence_subscr(c, patterns, star, pc));
}
else {
RETURN_IF_FALSE(pattern_helper_sequence_unpack(c, values, star, pc));
RETURN_IF_FALSE(pattern_helper_sequence_unpack(c, patterns, star, pc));
}
ADDOP_JUMP(c, JUMP_FORWARD, end);
compiler_use_next_block(c, fail_pop_1);
@ -6108,72 +6191,57 @@ compiler_pattern_sequence(struct compiler *c, expr_ty p, pattern_context *pc)
return 1;
}
static int
compiler_pattern_value(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern_value(struct compiler *c, pattern_ty p, pattern_context *pc)
{
assert(p->kind == Attribute_kind);
assert(p->v.Attribute.ctx == Load);
VISIT(c, expr, p);
assert(p->kind == MatchValue_kind);
expr_ty value = p->v.MatchValue.value;
if (!MATCH_VALUE_EXPR(value)) {
const char *e = "patterns may only match literals and attribute lookups";
return compiler_error(c, e);
}
VISIT(c, expr, value);
ADDOP_COMPARE(c, Eq);
return 1;
}
static int
compiler_pattern_wildcard(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern_constant(struct compiler *c, pattern_ty p, pattern_context *pc)
{
assert(p->kind == Name_kind);
assert(p->v.Name.ctx == Store);
assert(WILDCARD_CHECK(p));
if (!pc->allow_irrefutable) {
// Whoops, can't have a wildcard here!
const char *e = "wildcard makes remaining patterns unreachable";
return compiler_error(c, e);
}
ADDOP(c, POP_TOP);
ADDOP_LOAD_CONST(c, Py_True);
assert(p->kind == MatchSingleton_kind);
ADDOP_LOAD_CONST(c, p->v.MatchSingleton.value);
ADDOP_COMPARE(c, Is);
return 1;
}
static int
compiler_pattern(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern(struct compiler *c, pattern_ty p, pattern_context *pc)
{
SET_LOC(c, p);
switch (p->kind) {
case Attribute_kind:
case MatchValue_kind:
return compiler_pattern_value(c, p, pc);
case BinOp_kind:
// Because we allow "2+2j", things like "2+2" make it this far:
return compiler_error(c, "patterns cannot include operators");
case Call_kind:
return compiler_pattern_class(c, p, pc);
case Constant_kind:
return compiler_pattern_literal(c, p, pc);
case Dict_kind:
return compiler_pattern_mapping(c, p, pc);
case JoinedStr_kind:
// Because we allow strings, f-strings make it this far:
return compiler_error(c, "patterns cannot include f-strings");
case List_kind:
case Tuple_kind:
case MatchSingleton_kind:
return compiler_pattern_constant(c, p, pc);
case MatchSequence_kind:
return compiler_pattern_sequence(c, p, pc);
case MatchMapping_kind:
return compiler_pattern_mapping(c, p, pc);
case MatchClass_kind:
return compiler_pattern_class(c, p, pc);
case MatchStar_kind:
return compiler_pattern_star(c, p, pc);
case MatchAs_kind:
return compiler_pattern_as(c, p, pc);
case MatchOr_kind:
return compiler_pattern_or(c, p, pc);
case Name_kind:
if (WILDCARD_CHECK(p)) {
return compiler_pattern_wildcard(c, p, pc);
}
return compiler_pattern_capture(c, p, pc);
default:
Py_UNREACHABLE();
}
// AST validator shouldn't let this happen, but if it does,
// just fail, don't crash out of the interpreter
const char *e = "invalid match pattern node in AST (kind=%d)";
return compiler_error(c, e, p->kind);
}
static int
compiler_match(struct compiler *c, stmt_ty s)
{
@ -6181,7 +6249,7 @@ compiler_match(struct compiler *c, stmt_ty s)
basicblock *next, *end;
RETURN_IF_FALSE(end = compiler_new_block(c));
Py_ssize_t cases = asdl_seq_LEN(s->v.Match.cases);
assert(cases);
assert(cases > 0);
pattern_context pc;
// We use pc.stores to track:
// - Repeated name assignments in the same pattern.
@ -6235,9 +6303,8 @@ compiler_match(struct compiler *c, stmt_ty s)
return 1;
}
#undef WILDCARD_CHECK
#undef WILDCARD_STAR_CHECK
/* End of the compiler section, beginning of the assembler section */