def _parse_tree(cst, candidate, path):
# get the label of the top-most element of the CST
# this should be either 'pause', 'conj', 'disj', or a relation
assert type(cst) == list
label = cst[0]
assert label != 'state'
# root node in cst is a PAUSE
if label == 'pause':
# obtain the candidate partial program from the "pause" node
candidate = lisp.unparse(helper.get_candidate_from_pause(cst),
collapse_lvar=True)
obj = _parse_tree(cst[2], candidate, path)
choices.append(obj)
return obj
# root node in cst is a CONJ
if label == 'conj':
# obtain all children of conj nodes
leafs = [
_parse_tree(leaf, candidate, path)
for p, leaf in helper.flatten_branches(cst, path)
]
return FlatConj(constraints=leafs,
candidate=candidate,
path=path,
unparsed="(" + " && ".join(l.unparsed
for l in leafs) + ")")
if label == 'disj':
# obtain all children of disj nodes
leafs = [
_parse_tree(leaf, candidate, p)
for p, leaf in helper.flatten_branches(cst, path)
]
return FlatDisj(constraints=leafs,
candidate=candidate,
path=path,
unparsed="(" + " || ".join(l.unparsed
for l in leafs) + ")")
# root node is a RELATION; leaf node
leafstr = lisp.unparse(cst, True)
leaf_tokens = lisp.tokenize(leafstr)
leaf_type = leaf_tokens[1]
tok_seq = get_token_ids(leaf_tokens)
return Constraint(unparsed=leafstr,
candidate=candidate,
type=leaf_type,
seq=tok_seq,
len=len(tok_seq),
path=path[:])
def get_candidate(cst, path, collapse_lvar=False):
"""Retrieve the candidate at a path in the cst, and
convert it into a string.
Arguments:
cst -- a constraint tree, consisting of conj / disj / pause
internal nodes and constraint leafs. the tree
representing the "state" of the PBE problem
and comes from Interaction.state
path -- array of 0's and 1's, indicating whether to go left or right
at a disjunction
collapse_lvar -- whether to rename all logic variables to "_"
"""
if cst[0] == 'conj':
return get_candidate(cst[1], path, collapse_lvar)
if cst[0] == 'disj':
if path[0] == 0:
return get_candidate(cst[1], path[1:], collapse_lvar)
else:
return get_candidate(cst[2], path[1:], collapse_lvar)
assert len(path) == 0 and cst[0] == 'pause'
state = get_candidate_from_pause(cst)
return lisp.unparse(state, collapse_lvar)
def get_candidates(cst, current_path=None, candidate=None):
"""Retrieve all (path, candidate) pairs in a cst. Each path is
encoded as an array of 0 / 1 indicating to go left / right at a
disjunction. Each candidate is stringified.
cst -- a constraint tree, consisting of conj / disj / pause
internal nodes and constraint leafs. the tree
representing the "state" of the PBE problem
and comes from Interaction.state
current_path (optional) -- accumulator variable for recursion
indicating path from the root to the current cst node
candidate (optional) -- accumulator variable for recursion
indicating current candidate
"""
if current_path is None:
current_path = []
if type(cst) == list:
label = cst[0]
if label == 'pause':
candidate = get_candidate_from_pause(cst)
candidate = lisp.unparse(candidate, True)
return get_candidates(cst[2], current_path, candidate)
if label == 'state':
raise ValueError("Should not have state")
if label == 'conj': # only go left
return get_candidates(cst[1], current_path, candidate)
if label == 'disj':
return get_candidates(cst[1], current_path + [0], candidate) + \
get_candidates(cst[2], current_path + [1], candidate)
return [(current_path, candidate)]
def _send(self, datum):
"""Helper frunction to write to the scheme process.
Arguments:
datum -- the content of the message to be relayed, as a parsed
lisp data structure.
"""
self.proc.stdin.write((lisp.unparse(datum) + '\n').encode('utf-8'))
self.proc.stdin.flush()
def parse_tree(cst, acc=None, prev=None, candidate=None, path=None):
"""Recursive function that converts a constraint tree into a parsed form
consisting of subclasses of gnn_nodes.Node
cst -- a constraint tree, consisting of conj / disj / pause
internal nodes and constraint leafs. the tree
representing the "state" of the PBE problem
and comes from Interaction.state
acc -- an accumulator that is passed by value
prev -- a previous instance of parsed_tree() accumulator from the previous
step of the same problem
candidate -- candidate partial program related to this part of the subtree
path -- array of 0's and 1's, indicating whether to go left or right
at a disjunction
"""
# set up initial values that are objects
path = path or []
acc = acc or {"constraints": [], "memo": {}, "lvar": {}}
if "constraints" not in acc:
acc["constraints"] = [] # repository of constraints
if "memo" not in acc:
acc["memo"] = {} # memoized parsed subtree
if "lvar" not in acc:
acc["lvar"] = {} # all logic variables
prev = prev or {}
node_type = get_cst_node_type(cst)
# get the pause & state out of the way
if node_type == 'pause':
candidate = lisp.unparse(helper.get_candidate_from_pause(cst), True)
return parse_tree(cst[2], acc, prev, candidate, path)
if node_type == 'state':
raise ValueError("Should never be here!")
# logical constructs
if node_type == 'conj':
children = []
for subpath, subcst in helper.flatten_branches(cst, path):
# for conj, subpath is ignored!
child, acc = parse_tree(subcst, acc, prev, candidate, path)
children.append(child)
return NAryConj(children, path), acc
#left, acc = parse_tree(cst[1], acc, prev, candidate, path)
#right, acc = parse_tree(cst[2], acc, prev, candidate, path)
#return Conj(left, right, path), acc
if node_type == 'disj':
children = []
for subpath, subcst in helper.flatten_branches(cst, path):
child, acc = parse_tree(subcst, acc, prev, candidate, subpath)
children.append(child)
return NAryDisj(children, path), acc
#left, acc = parse_tree(cst[1], acc, prev, candidate, path+[0])
#right, acc = parse_tree(cst[2], acc, prev, candidate, path+[1])
#return Disj(left, right, path), acc
# if using MEMOIZE, check if this (sub-)tree has already been parsed, and
# its parsed version stored
unparsed = lisp.unparse(cst)
if MEMOIZE and unparsed in acc["memo"]:
return acc["memo"][unparsed], acc
# logic variables: add to repository of logic variables if not exist
if node_type == 'lvar':
if cst not in acc['lvar']:
new_node = prev.get('lvar', {}).get(cst)
new_node = new_node or LVar(cst)
acc['lvar'][cst] = new_node
return acc["lvar"][cst], acc
# relations
if node_type in ('evalo', 'lookupo', '==', 'eval-listo', 'not-falseo',
'not-nullo'):
# a relations can have multiple children in its tree
child_asts = []
for child_cst in cst[1:]:
child_ast, acc = parse_tree(child_cst, acc, prev, candidate, path)
child_asts.append(child_ast)
NodeClass = GNN_NODE_CLASS[node_type]
new_node_args = child_asts + [path, unparsed, candidate]
new_node = NodeClass(*new_node_args)
acc["constraints"].append(new_node)
return new_node, acc
# pairs
if node_type == 'pair':
if len(cst) == 3 and cst[1] == '.':
# first
left, acc = parse_tree(cst[0], acc, prev, candidate, path)
# second
right, acc = parse_tree(cst[2], acc, prev, candidate, path)
else:
# first
left, acc = parse_tree(cst[0], acc, prev, candidate, path)
# rest
right, acc = parse_tree(cst[1:], acc, prev, candidate, path)
new_node = Pair(left, right)
if MEMOIZE and not has_lvar(unparsed):
acc["memo"][unparsed] = new_node
return new_node, acc
# language constructs (inside the relations leafs)
if node_type == 'const':
new_node = Constant(unparsed)
if MEMOIZE and not has_lvar(unparsed):
acc["memo"][unparsed] = new_node
return new_node, acc
raise ValueError("Should not be here?")
