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Merge pull request #383 from pfalcon/yield-from

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Implement "yield from"
This commit is contained in:
Damien George 2014-03-29 12:18:14 +00:00
commit da51a399cf
6 changed files with 232 additions and 1 deletions
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58
py/vm.c
View File

@ -9,6 +9,7 @@
#include "runtime.h"
#include "bc0.h"
#include "bc.h"
#include "objgenerator.h"
// Value stack grows up (this makes it incompatible with native C stack, but
// makes sure that arguments to functions are in natural order arg1..argN
@ -146,7 +147,9 @@ outer_dispatch_loop:
// If we have exception to inject, now that we finish setting up
// execution context, raise it. This works as if RAISE_VARARGS
// bytecode was executed.
if (inject_exc != MP_OBJ_NULL) {
// Injecting exc into yield from generator is a special case,
// handled by MP_BC_YIELD_FROM itself
if (inject_exc != MP_OBJ_NULL && *ip != MP_BC_YIELD_FROM) {
mp_obj_t t = inject_exc;
inject_exc = MP_OBJ_NULL;
nlr_jump(rt_make_raise_obj(t));
@ -634,12 +637,65 @@ unwind_return:
nlr_jump(rt_make_raise_obj(obj1));
case MP_BC_YIELD_VALUE:
yield:
nlr_pop();
*ip_in_out = ip;
*sp_in_out = sp;
*exc_sp_in_out = MP_TAGPTR_MAKE(exc_sp, currently_in_except_block);
return MP_VM_RETURN_YIELD;
case MP_BC_YIELD_FROM:
{
//#define EXC_MATCH(exc, type) MP_OBJ_IS_TYPE(exc, type)
#define EXC_MATCH(exc, type) mp_obj_exception_match(exc, type)
#define GENERATOR_EXIT_IF_NEEDED(t) if (t != MP_OBJ_NULL && EXC_MATCH(t, &mp_type_GeneratorExit)) { nlr_jump(t); }
mp_vm_return_kind_t ret_kind;
obj1 = POP();
mp_obj_t t_exc = MP_OBJ_NULL;
if (inject_exc != MP_OBJ_NULL) {
t_exc = inject_exc;
inject_exc = MP_OBJ_NULL;
ret_kind = mp_obj_gen_resume(TOP(), mp_const_none, t_exc, &obj2);
} else {
ret_kind = mp_obj_gen_resume(TOP(), obj1, MP_OBJ_NULL, &obj2);
}
if (ret_kind == MP_VM_RETURN_YIELD) {
ip--;
PUSH(obj2);
goto yield;
}
if (ret_kind == MP_VM_RETURN_NORMAL) {
// Pop exhausted gen
sp--;
if (obj2 == MP_OBJ_NULL) {
// Optimize StopIteration
// TODO: get StopIteration's value
PUSH(mp_const_none);
} else {
PUSH(obj2);
}
// If we injected GeneratorExit downstream, then even
// if it was swallowed, we re-raise GeneratorExit
GENERATOR_EXIT_IF_NEEDED(t_exc);
break;
}
if (ret_kind == MP_VM_RETURN_EXCEPTION) {
// Pop exhausted gen
sp--;
if (EXC_MATCH(obj2, &mp_type_StopIteration)) {
PUSH(mp_obj_exception_get_value(obj2));
// If we injected GeneratorExit downstream, then even
// if it was swallowed, we re-raise GeneratorExit
GENERATOR_EXIT_IF_NEEDED(t_exc);
break;
} else {
nlr_jump(obj2);
}
}
}
case MP_BC_IMPORT_NAME:
DECODE_QSTR;
obj1 = POP();

87
tests/basics/gen-yield-from-close.py Normal file
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@ -0,0 +1,87 @@
def gen():
yield 1
yield 2
yield 3
yield 4
def gen2():
yield -1
print((yield from gen()))
yield 10
yield 11
g = gen2()
print(next(g))
print(next(g))
g.close()
try:
print(next(g))
except StopIteration:
print("StopIteration")
# Now variation of same test, but with leaf generator
# swallowing GeneratorExit exception - its upstream gen
# generator should still receive one.
def gen3():
yield 1
try:
yield 2
except GeneratorExit:
print("leaf caught GeneratorExit and swallowed it")
return
yield 3
yield 4
def gen4():
yield -1
try:
print((yield from gen3()))
except GeneratorExit:
print("delegating caught GeneratorExit")
raise
yield 10
yield 11
g = gen4()
print(next(g))
print(next(g))
print(next(g))
g.close()
try:
print(next(g))
except StopIteration:
print("StopIteration")
# Yet another variation - leaf generator gets GeneratorExit,
# but raises StopIteration instead. This still should close chain properly.
def gen5():
yield 1
try:
yield 2
except GeneratorExit:
print("leaf caught GeneratorExit and raised StopIteration instead")
raise StopIteration(123)
yield 3
yield 4
def gen6():
yield -1
try:
print((yield from gen5()))
except GeneratorExit:
print("delegating caught GeneratorExit")
raise
yield 10
yield 11
g = gen6()
print(next(g))
print(next(g))
print(next(g))
g.close()
try:
print(next(g))
except StopIteration:
print("StopIteration")

13
tests/basics/gen-yield-from-exc.py Normal file
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@ -0,0 +1,13 @@
def gen():
yield 1
yield 2
raise ValueError
def gen2():
try:
print((yield from gen()))
except ValueError:
print("caught ValueError from downstream")
g = gen2()
print(list(g))

14
tests/basics/gen-yield-from-send.py Normal file
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@ -0,0 +1,14 @@
def gen():
print("sent:", (yield 1))
yield 2
def gen2():
print((yield from gen()))
g = gen2()
next(g)
print("yielded:", g.send("val"))
try:
next(g)
except StopIteration:
print("StopIteration")

19
tests/basics/gen-yield-from-throw.py Normal file
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@ -0,0 +1,19 @@
def gen():
try:
yield 1
except ValueError:
print("got ValueError from upstream!")
yield "str1"
raise TypeError
def gen2():
print((yield from gen()))
g = gen2()
print(next(g))
print(g.throw(ValueError))
try:
print(next(g))
except TypeError:
print("got TypeError from downstream!")

42
tests/basics/gen-yield-from.py Normal file
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@ -0,0 +1,42 @@
# Case of terminating subgen using return with value
def gen():
yield 1
yield 2
return 3
def gen2():
print("here1")
print((yield from gen()))
print("here2")
g = gen2()
print(list(g))
# Like above, but terminate subgen using StopIteration
def gen3():
yield 1
yield 2
raise StopIteration
def gen4():
print("here1")
print((yield from gen3()))
print("here2")
g = gen4()
print(list(g))
# Like above, but terminate subgen using StopIteration with value
def gen5():
yield 1
yield 2
raise StopIteration(123)
def gen6():
print("here1")
print((yield from gen5()))
print("here2")
g = gen6()
print(list(g))