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SF patch #1355913, PEP 341 - Unification of try/except and try/finally 

Modified since ast-arenas was implemented.
This commit is contained in:
Neal Norwitz 2005-12-17 21:33:47 +00:00
parent adb69fcdff
commit f599f424a2
5 changed files with 265 additions and 59 deletions
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3
Grammar/Grammar
View File

@ -67,8 +67,7 @@ compound_stmt: if_stmt | while_stmt | for_stmt | try_stmt | funcdef | classdef
if_stmt: 'if' test ':' suite ('elif' test ':' suite)* ['else' ':' suite]
while_stmt: 'while' test ':' suite ['else' ':' suite]
for_stmt: 'for' exprlist 'in' testlist ':' suite ['else' ':' suite]
try_stmt: ('try' ':' suite (except_clause ':' suite)+ #diagram:break
['else' ':' suite] | 'try' ':' suite 'finally' ':' suite)
try_stmt: 'try' ':' suite ((except_clause ':' suite)+ ['else' ':' suite] ['finally' ':' suite] | 'finally' ':' suite)
# NB compile.c makes sure that the default except clause is last
except_clause: 'except' [test [',' test]]
suite: simple_stmt | NEWLINE INDENT stmt+ DEDENT

180
Lib/test/test_exception_variations.py Normal file
View File

@ -0,0 +1,180 @@
from test.test_support import run_unittest
import unittest
class ExceptionTestCase(unittest.TestCase):
def test_try_except_else_finally(self):
hit_except = False
hit_else = False
hit_finally = False
try:
raise Exception, 'nyaa!'
except:
hit_except = True
else:
hit_else = True
finally:
hit_finally = True
self.assertTrue(hit_except)
self.assertTrue(hit_finally)
self.assertFalse(hit_else)
def test_try_except_else_finally_no_exception(self):
hit_except = False
hit_else = False
hit_finally = False
try:
pass
except:
hit_except = True
else:
hit_else = True
finally:
hit_finally = True
self.assertFalse(hit_except)
self.assertTrue(hit_finally)
self.assertTrue(hit_else)
def test_try_except_finally(self):
hit_except = False
hit_finally = False
try:
raise Exception, 'yarr!'
except:
hit_except = True
finally:
hit_finally = True
self.assertTrue(hit_except)
self.assertTrue(hit_finally)
def test_try_except_finally_no_exception(self):
hit_except = False
hit_finally = False
try:
pass
except:
hit_except = True
finally:
hit_finally = True
self.assertFalse(hit_except)
self.assertTrue(hit_finally)
def test_try_except(self):
hit_except = False
try:
raise Exception, 'ahoy!'
except:
hit_except = True
self.assertTrue(hit_except)
def test_try_except_no_exception(self):
hit_except = False
try:
pass
except:
hit_except = True
self.assertFalse(hit_except)
def test_try_except_else(self):
hit_except = False
hit_else = False
try:
raise Exception, 'foo!'
except:
hit_except = True
else:
hit_else = True
self.assertFalse(hit_else)
self.assertTrue(hit_except)
def test_try_except_else_no_exception(self):
hit_except = False
hit_else = False
try:
pass
except:
hit_except = True
else:
hit_else = True
self.assertFalse(hit_except)
self.assertTrue(hit_else)
def test_try_finally_no_exception(self):
hit_finally = False
try:
pass
finally:
hit_finally = True
self.assertTrue(hit_finally)
def test_nested(self):
hit_finally = False
hit_inner_except = False
hit_inner_finally = False
try:
try:
raise Exception, 'inner exception'
except:
hit_inner_except = True
finally:
hit_inner_finally = True
finally:
hit_finally = True
self.assertTrue(hit_inner_except)
self.assertTrue(hit_inner_finally)
self.assertTrue(hit_finally)
def test_nested_else(self):
hit_else = False
hit_finally = False
hit_except = False
hit_inner_except = False
hit_inner_else = False
try:
try:
pass
except:
hit_inner_except = True
else:
hit_inner_else = True
raise Exception, 'outer exception'
except:
hit_except = True
else:
hit_else = True
finally:
hit_finally = True
self.assertFalse(hit_inner_except)
self.assertTrue(hit_inner_else)
self.assertFalse(hit_else)
self.assertTrue(hit_finally)
self.assertTrue(hit_except)
def test_main():
run_unittest(ExceptionTestCase)
if __name__ == '__main__':
test_main()

1
Misc/ACKS
View File

@ -357,6 +357,7 @@ Chris Lawrence
Christopher Lee
Inyeol Lee
John J. Lee
Thomas Lee
Luc Lefebvre
Kip Lehman
Joerg Lehmann

116
Python/ast.c
View File

@ -2597,66 +2597,78 @@ ast_for_except_clause(struct compiling *c, const node *exc, node *body)
static stmt_ty
ast_for_try_stmt(struct compiling *c, const node *n)
{
const int nch = NCH(n);
int n_except = (nch - 3)/3;
asdl_seq *body, *orelse = NULL, *finally = NULL;
REQ(n, try_stmt);
if (TYPE(CHILD(n, 3)) == NAME) {/* must be 'finally' */
/* try_stmt: 'try' ':' suite 'finally' ':' suite) */
asdl_seq *s1, *s2;
s1 = ast_for_suite(c, CHILD(n, 2));
if (!s1)
return NULL;
s2 = ast_for_suite(c, CHILD(n, 5));
if (!s2) {
return NULL;
}
return TryFinally(s1, s2, LINENO(n), c->c_arena);
}
else if (TYPE(CHILD(n, 3)) == except_clause) {
/* try_stmt: ('try' ':' suite (except_clause ':' suite)+
['else' ':' suite]
*/
asdl_seq *suite_seq1, *suite_seq2;
asdl_seq *handlers;
int i, has_else = 0, n_except = NCH(n) - 3;
if (TYPE(CHILD(n, NCH(n) - 3)) == NAME) {
has_else = 1;
n_except -= 3;
}
n_except /= 3;
handlers = asdl_seq_new(n_except, c->c_arena);
if (!handlers)
return NULL;
for (i = 0; i < n_except; i++) {
excepthandler_ty e = ast_for_except_clause(c,
CHILD(n, 3 + i * 3),
CHILD(n, 5 + i * 3));
if (!e) {
return NULL;
}
asdl_seq_SET(handlers, i, e);
}
body = ast_for_suite(c, CHILD(n, 2));
if (body == NULL)
return NULL;
suite_seq1 = ast_for_suite(c, CHILD(n, 2));
if (!suite_seq1) {
return NULL;
}
if (has_else) {
suite_seq2 = ast_for_suite(c, CHILD(n, NCH(n) - 1));
if (!suite_seq2) {
return NULL;
}
}
else
suite_seq2 = NULL;
if (TYPE(CHILD(n, nch - 3)) == NAME) {
if (strcmp(STR(CHILD(n, nch - 3)), "finally") == 0) {
if (nch >= 9 && TYPE(CHILD(n, nch - 6)) == NAME) {
/* we can assume it's an "else",
because nch >= 9 for try-else-finally and
it would otherwise have a type of except_clause */
orelse = ast_for_suite(c, CHILD(n, nch - 4));
if (orelse == NULL)
return NULL;
n_except--;
}
return TryExcept(suite_seq1, handlers, suite_seq2, LINENO(n),
c->c_arena);
finally = ast_for_suite(c, CHILD(n, nch - 1));
if (finally == NULL)
return NULL;
n_except--;
}
else {
/* we can assume it's an "else",
otherwise it would have a type of except_clause */
orelse = ast_for_suite(c, CHILD(n, nch - 1));
if (orelse == NULL)
return NULL;
n_except--;
}
}
else {
else if (TYPE(CHILD(n, nch - 3)) != except_clause) {
ast_error(n, "malformed 'try' statement");
return NULL;
}
if (n_except > 0) {
int i;
stmt_ty except_st;
/* process except statements to create a try ... except */
asdl_seq *handlers = asdl_seq_new(n_except, c->c_arena);
if (handlers == NULL)
return NULL;
for (i = 0; i < n_except; i++) {
excepthandler_ty e = ast_for_except_clause(c, CHILD(n, 3 + i * 3),
CHILD(n, 5 + i * 3));
if (!e)
return NULL;
asdl_seq_SET(handlers, i, e);
}
except_st = TryExcept(body, handlers, orelse, LINENO(n), c->c_arena);
if (!finally)
return except_st;
/* if a 'finally' is present too, we nest the TryExcept within a
TryFinally to emulate try ... except ... finally */
body = asdl_seq_new(1, c->c_arena);
if (body == NULL)
return NULL;
asdl_seq_SET(body, 0, except_st);
}
/* must be a try ... finally (except clauses are in body, if any exist) */
assert(finally != NULL);
return TryFinally(body, finally, LINENO(n), c->c_arena);
}
static stmt_ty

24
Python/graminit.c
View File

@ -841,15 +841,26 @@ static arc arcs_39_6[1] = {
static arc arcs_39_7[1] = {
{22, 9},
};
static arc arcs_39_8[3] = {
static arc arcs_39_8[4] = {
{95, 4},
{91, 5},
{91, 10},
{96, 5},
{0, 8},
};
static arc arcs_39_9[1] = {
{0, 9},
};
static state states_39[10] = {
static arc arcs_39_10[1] = {
{21, 11},
};
static arc arcs_39_11[1] = {
{22, 12},
};
static arc arcs_39_12[2] = {
{96, 5},
{0, 12},
};
static state states_39[13] = {
{1, arcs_39_0},
{1, arcs_39_1},
{1, arcs_39_2},
@ -858,8 +869,11 @@ static state states_39[10] = {
{1, arcs_39_5},
{1, arcs_39_6},
{1, arcs_39_7},
{3, arcs_39_8},
{4, arcs_39_8},
{1, arcs_39_9},
{1, arcs_39_10},
{1, arcs_39_11},
{2, arcs_39_12},
};
static arc arcs_40_0[1] = {
{97, 1},
@ -1754,7 +1768,7 @@ static dfa dfas[79] = {
"\000\000\000\000\000\000\000\000\000\000\000\020\000\000\000\000\000\000\000\000\000"},
{294, "for_stmt", 0, 10, states_38,
"\000\000\000\000\000\000\000\000\000\000\000\040\000\000\000\000\000\000\000\000\000"},
{295, "try_stmt", 0, 10, states_39,
{295, "try_stmt", 0, 13, states_39,
"\000\000\000\000\000\000\000\000\000\000\000\100\000\000\000\000\000\000\000\000\000"},
{296, "except_clause", 0, 5, states_40,
"\000\000\000\000\000\000\000\000\000\000\000\000\002\000\000\000\000\000\000\000\000"},