Commit 87fa865d authored by Stefan Behnel's avatar Stefan Behnel

parser support for PEP 3132 (extended iterable unpacking)

parent 141b62e6
......@@ -40,6 +40,7 @@ class ExprNode(Node):
# is_temp boolean Result is in a temporary variable
# is_sequence_constructor
# boolean Is a list or tuple constructor expression
# is_starred boolean Is a starred expression (e.g. '*a')
# saved_subexpr_nodes
# [ExprNode or [ExprNode or None] or None]
# Cached result of subexpr_nodes()
......@@ -168,6 +169,7 @@ class ExprNode(Node):
saved_subexpr_nodes = None
is_temp = 0
is_target = 0
is_starred = 0
constant_result = constant_value_not_set
......
......@@ -16,6 +16,7 @@ cpdef p_not_test(PyrexScanner s)
cpdef p_comparison(PyrexScanner s)
cpdef p_cascaded_cmp(PyrexScanner s)
cpdef p_cmp_op(PyrexScanner s)
cpdef p_starred_expr(PyrexScanner s)
cpdef p_bit_expr(PyrexScanner s)
cpdef p_xor_expr(PyrexScanner s)
cpdef p_and_expr(PyrexScanner s)
......
......@@ -130,21 +130,31 @@ def p_not_test(s):
#comp_op: '<'|'>'|'=='|'>='|'<='|'<>'|'!='|'in'|'not' 'in'|'is'|'is' 'not'
def p_comparison(s):
n1 = p_bit_expr(s)
n1 = p_starred_expr(s)
if s.sy in comparison_ops:
pos = s.position()
op = p_cmp_op(s)
n2 = p_bit_expr(s)
n2 = p_starred_expr(s)
n1 = ExprNodes.PrimaryCmpNode(pos,
operator = op, operand1 = n1, operand2 = n2)
if s.sy in comparison_ops:
n1.cascade = p_cascaded_cmp(s)
return n1
def p_starred_expr(s):
if s.sy == '*':
starred = True
s.next()
else:
starred = False
expr = p_bit_expr(s)
expr.is_starred = starred
return expr
def p_cascaded_cmp(s):
pos = s.position()
op = p_cmp_op(s)
n2 = p_bit_expr(s)
n2 = p_starred_expr(s)
result = ExprNodes.CascadedCmpNode(pos,
operator = op, operand2 = n2)
if s.sy in comparison_ops:
......@@ -813,7 +823,8 @@ def p_backquote_expr(s):
def p_simple_expr_list(s):
exprs = []
while s.sy not in expr_terminators:
exprs.append(p_simple_expr(s))
expr = p_simple_expr(s)
exprs.append(expr)
if s.sy != ',':
break
s.next()
......@@ -925,6 +936,11 @@ def find_parallel_assignment_size(input):
rhs = input[-1]
rhs_size = len(rhs.args)
for lhs in input[:-1]:
starred_args = sum([1 for expr in lhs.args if expr.is_starred])
if starred_args:
if starred_args > 1:
error(lhs.pos, "more than 1 starred expression in assignment")
return -1
lhs_size = len(lhs.args)
if lhs_size != rhs_size:
error(lhs.pos, "Unpacking sequence of wrong size (expected %d, got %d)"
......@@ -1275,12 +1291,12 @@ inequality_relations = ('<', '<=', '>', '>=')
def p_target(s, terminator):
pos = s.position()
expr = p_bit_expr(s)
expr = p_starred_expr(s)
if s.sy == ',':
s.next()
exprs = [expr]
while s.sy != terminator:
exprs.append(p_bit_expr(s))
exprs.append(p_starred_expr(s))
if s.sy != ',':
break
s.next()
......
__doc__ = u"""
>>> unpack([1,2])
(1, 2)
>>> unpack_list([1,2])
(1, 2)
>>> unpack_tuple((1,2))
(1, 2)
>>> unpack('12')
('1', '2')
>>> unpack_into_list('123')
('1', ['2'], '3')
>>> unpack_into_tuple('123')
('1', ['2'], '3')
>>> unpack_in_loop([(1,2), (1,2,3), (1,2,3,4)])
1
([1], 2)
([1, 2], 3)
([1, 2, 3], 4)
2
(1, [2])
(1, [2, 3])
(1, [2, 3, 4])
3
(1, [2])
(1, [2], 3)
(1, [2, 3], 4)
>>> assign()
(1, [2, 3, 4], 5)
>>> unpack_right('')
Traceback (most recent call last):
ValueError: need more than 0 values to unpack
>>> unpack_right_list([])
Traceback (most recent call last):
ValueError: need more than 0 values to unpack
>>> unpack_right_tuple(())
Traceback (most recent call last):
ValueError: need more than 0 values to unpack
>>> unpack_right('1')
('1', [])
>>> unpack_right([1])
(1, [])
>>> unpack_right('12')
('1', ['2'])
>>> unpack_right([1,2])
(1, [2])
>>> unpack_right('123')
('1', ['2', '3'])
>>> unpack_right([1,2,3])
(1, [2, 3])
>>> unpack_right_list([1])
(1, [])
>>> unpack_right_list([1,2])
(1, [2])
>>> unpack_right_list([1,2,3])
(1, [2, 3])
>>> unpack_right_tuple((1,))
(1, [])
>>> unpack_right_tuple((1,2))
(1, [2])
>>> unpack_right_tuple((1,2,3))
(1, [2, 3])
>>> unpack_left('')
Traceback (most recent call last):
ValueError: need more than 0 values to unpack
>>> unpack_left_list([])
Traceback (most recent call last):
ValueError: need more than 0 values to unpack
>>> unpack_left_tuple(())
Traceback (most recent call last):
ValueError: need more than 0 values to unpack
>>> unpack_left('1')
([], '1')
>>> unpack_left([1])
([], 1)
>>> unpack_left('12')
(['1'], '2')
>>> unpack_left([1,2])
([1], 2)
>>> unpack_left('123')
(['1', '2'], '3')
>>> unpack_left([1,2,3])
([1, 2], 3)
>>> unpack_left_list([1])
([], 1)
>>> unpack_left_list([1,2])
([1], 2)
>>> unpack_left_list([1,2])
([1, 2], 3)
>>> unpack_left_tuple((1,))
([], 1)
>>> unpack_left_tuple((1,2))
([1], 2)
>>> unpack_left_tuple((1,2,3))
([1, 2], 3)
>>> unpack_middle('')
Traceback (most recent call last):
ValueError: need more than 0 values to unpack
>>> unpack_middle([])
Traceback (most recent call last):
ValueError: need more than 0 values to unpack
>>> unpack_middle(())
Traceback (most recent call last):
ValueError: need more than 0 values to unpack
>>> unpack_middle_list([])
Traceback (most recent call last):
ValueError: need more than 0 values to unpack
>>> unpack_middle_tuple(())
Traceback (most recent call last):
ValueError: need more than 0 values to unpack
>>> unpack_middle('1')
Traceback (most recent call last):
ValueError: need more than 1 value to unpack
>>> unpack_middle([1])
Traceback (most recent call last):
ValueError: need more than 1 value to unpack
>>> unpack_middle_list([1])
Traceback (most recent call last):
ValueError: need more than 1 value to unpack
>>> unpack_middle_tuple((1,))
Traceback (most recent call last):
ValueError: need more than 1 value to unpack
>>> unpack_middle('12')
('1', [], '2')
>>> unpack_middle([1,2])
(1, [], 2)
>>> unpack_middle('123')
('1', ['2'], '3')
>>> unpack_middle([1,2,3])
(1, [2], 3)
>>> unpack_middle_list([1,2])
(1, [], 2)
>>> unpack_middle_list([1,2,3])
(1, [2], 3)
>>> unpack_middle_tuple((1,2))
(1, [], 2)
>>> unpack_middle_tuple((1,2,3))
(1, [2], 3)
>>> a,b,c = unpack_middle(range(100))
>>> a, len(b), c
0, 98, 99
>>> a,b,c = unpack_middle_list(range(100))
>>> a, len(b), c
0, 98, 99
>>> a,b,c = unpack_middle_tuple(tuple(range(100)))
>>> a, len(b), c
0, 98, 99
"""
def unpack(l):
a, b = l
return a,b
def unpack_list(list l):
a, b = l
return a,b
def unpack_tuple(tuple t):
a, b = t
return a,b
def assign():
*a, b = 1,2,3,4,5
assert a+[b] == (1,2,3,4,5)
a, *b = 1,2,3,4,5
assert [a]+b == (1,2,3,4,5)
[a, *b, c] = 1,2,3,4,5
return a,b,c
def unpack_into_list(l):
[*a, b] = l
assert a+[b] == l
[a, *b] = l
assert [a]+b == l
[a, *b, c] = l
return a,b,c
def unpack_into_tuple(t):
(*a, b) = t
assert a+(b,) == t
(a, *b) = t
assert (a,)+b == t
(a, *b, c) = t
return a,b,c
def unpack_in_loop(list_of_sequences):
print 1
for *a,b in list_of_sequences:
print a,b
print 2
for a,*b in list_of_sequences:
print a,b
print 3
for a,*b, c in list_of_sequences:
print a,b,c
def unpack_right(l):
a, *b = l
return a,b
def unpack_right_list(list l):
a, *b = l
return a,b
def unpack_right_tuple(tuple t):
a, *b = t
return a,b
def unpack_left(l):
*a, b = l
return a,b
def unpack_left_list(list l):
*a, b = l
return a,b
def unpack_left_tuple(tuple t):
*a, b = t
return a,b
def unpack_middle(l):
a, *b, c = l
return a,b,c
def unpack_middle_list(list l):
a, *b, c = l
return a,b,c
def unpack_middle_tuple(tuple t):
a, *b, c = t
return a,b,c
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment