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swap_union_renames

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Salvo 'LtWorf' Tomaselli 2020-06-09 12:38:29 +02:00
parent 454f4161bc
commit 4a56b8eaac
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1 changed files with 10 additions and 33 deletions
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43
relational/optimizations.py
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@ -216,42 +216,19 @@ def selection_inside_projection(n: parser.Node) -> Tuple[parser.Node, int]:
return n, 0
def swap_union_renames(n: parser.Node) -> int:
def swap_union_renames(n: parser.Node) -> Tuple[parser.Node, int]:
'''This function locates things like
ρ a➡b(R) ᑌ ρ a➡b(Q)
ρ a➡b(R) ∪ ρ a➡b(Q)
and replaces them with
ρ a➡b(R ᑌ Q).
ρ a➡b(R ∪ Q).
Does the same with subtraction and intersection'''
changes = 0
if n.name in (DIFFERENCE, UNION, INTERSECTION) and n.left.name == n.right.name and n.left.name == RENAME:
l_vars = {}
for i in n.left.prop.split(','):
q = i.split(ARROW)
l_vars[q[0].strip()] = q[1].strip()
r_vars = {}
for i in n.right.prop.split(','):
q = i.split(ARROW)
r_vars[q[0].strip()] = q[1].strip()
if n.name in (DIFFERENCE, UNION, INTERSECTION) and n.left.name == RENAME and n.right.name == RENAME:
l_vars = n.left.rename_dict()
r_vars = n.right.rename_dict()
if r_vars == l_vars:
changes = 1
# Copying self, but child will be child of renames
q = parser.Node()
q.name = n.name
q.kind = parser.BINARY
q.left = n.left.child
q.right = n.right.child
n.name = RENAME
n.kind = parser.UNARY
n.child = q
n.prop = n.left.prop
n.left = n.right = None
return changes + recoursive_scan(swap_union_renames, n)
child = parser.Binary(n.name, n.left.child, n.right.child)
return parser.Unary(RENAME, n.left.prop, child), 1
return n, 0
def futile_renames(n: parser.Node) -> int:
@ -665,7 +642,7 @@ general_optimizations = [
#subsequent_renames,
#swap_rename_select,
futile_union_intersection_subtraction,
#swap_union_renames,
swap_union_renames,
#swap_rename_projection,
#select_union_intersect_subtract,
#union_and_product,