def parse_target_string():
"""
Takes a list of terminal nodes and iteratively reduces that list until
the solution has been found.
:return: The complete parsed solution in the form of a GE individual.
"""
# Sort snippets keys to generate the initial solution list of terminals.
solution = sorted([[get_num_from_str(snippet),
get_NT_from_str(snippet),
snippet] for snippet in trackers.snippets.keys()])
# Perform reduction on the solution list.
reduce(solution)
# Check snippets for solution
ind = check_snippets_for_solution()
return ind
def parse_target_string():
"""
Takes a list of terminal nodes and iteratively reduces that list until
the solution has been found.
:return: The complete parsed solution in the form of a GE individual.
"""
# Sort snippets keys to generate the initial solution list of terminals.
solution = sorted([[get_num_from_str(snippet),
get_NT_from_str(snippet),
snippet] for snippet in trackers.snippets.keys()])
# Perform reduction on the solution list.
reduce(solution)
# Check snippets for solution
ind = check_snippets_for_solution()
return ind
def reduce(solution):
"""
Takes a list of all matching subtrees found in the target string and
iteratively combines and reduces subtrees to generate larger matching
subtrees. This process continues until the list of matching subtrees has
been completely reduced into a target string.
:param solution: A list of all snippets (i.e. matching subtrees found in
the target string.
:return: Nothing.
"""
# Find all non-terminals in the grammar that can be used to concatenate
# subtrees to new/larger subtrees.
reduce_NTs = params['BNF_GRAMMAR'].concat_NTs
# Pre-load the target string.
target = params['REVERSE_MAPPING_TARGET']
for idx, snippet_info in enumerate(solution):
# Get current snippet.
snippet = snippet_info[2]
# Find current snippet info.
NT = snippet_info[1]
# Get indexes of the current snippet
indexes = snippet_info[0]
start, end = indexes[0], indexes[1]
# Find if the snippet root (NT) exists anywhere in the
# reduction NTs.
if NT in reduce_NTs:
for reduce in reduce_NTs[NT]:
# Now we're searching for a specific subset of keys in the
# snippets dictionary.
# Generate list of only the desired Non Terminals.
NTs = reduce[2]
if len(NTs) == 1:
# This choice leads directly to the parent, check if parent
# snippet already exists.
# Child is current snippet.
child = [[snippet, trackers.snippets[snippet]]]
# Get key for new snippet.
key, start, end = generate_key_and_check(
start, end, reduce, child)
# Create a new node for the solution list.
new_entry = [indexes, reduce[1], key]
# Insert the current node into the solution.
if new_entry not in solution:
solution.insert(idx + 1, new_entry)
else:
# Find the index of the snippet root in the current
# reduction production choice.
NT_locs = [i for i, x in enumerate(NTs) if x[0] == NT]
for loc in NT_locs:
# We want to check each possible reduction option.
# Set where the original snippet starts and ends on
# the target string.
if loc == 0:
# The current snippet is at the start of the
# reduction attempt.
pre, aft = None, end
elif start == 0 and loc != 0:
# The current snippet is at the start of the target
# string, but we are trying to reduce_trees it with
# something before it.
break
elif end == len(params['TARGET']) and loc != \
NT_locs[-1]:
# The current snippet is at the end of the target
# string, but we are trying to reduce_trees it with
# something after it.
break
elif loc == len(NTs):
# The current snippet is at the end of the
# reduction attempt.
pre, aft = start, None
else:
# The current snippet is in the middle of the
# reduction attempt.
pre, aft = start, end
alt_cs = list(range(len(NTs)))
# Initialise a list of children to be reduced.
children = [[] for _ in range(len(NTs))]
# Set original snippet into children.
children[loc] = [snippet, trackers.snippets[snippet]]
curr_idx = solution.index(snippet_info)
# Step 1: reduce everything before the current loc.
for item in reversed(alt_cs[:loc]):
if NTs[item][1] == "T":
# This is a terminal, decrement by length of T.
# Check output of target string.
check = target[pre - len(NTs[item][0]):pre]
if check == NTs[item][0]:
# We have a match.
# Generate fake key for snippets dict.
key = str([pre - len(NTs[item][0]), pre])
# Create new tree from this terminal.
T_tree = Tree(check, None)
# Add to children.
children[item] = [key, T_tree]
# Decrement target string index.
pre -= len(NTs[item][0])
else:
# No match.
break
else:
# This is a NT. Check solution list for
# matching node.
available = [
sol for sol in solution[:curr_idx] if
sol[1] == NTs[item][0] and sol[0][1] == pre
]
for check in available:
# We have a match.
# Set the correct child in our
# children.
children[item] = [
check[2], trackers.snippets[check[2]]
]
# Decrement target string index.
child_len = get_num_from_str(check[2])
pre -= child_len[1] - child_len[0]
break
# Step cython_backup: reduce everything after the loc.
for i, item in enumerate(alt_cs[loc + 1:]):
if NTs[item][1] == "T":
# This is a terminal, decrement by length of T.
# Check output of target string.
check = target[aft:aft + len(NTs[item][0])]
if check == NTs[item][0]:
# We have a match.
# Generate fake key for snippets dict.
key = str([aft, aft + len(NTs[item][0])])
# Create new tree from this terminal.
T_tree = Tree(check, None)
# Add to children.
children[item] = [key, T_tree]
# Increment target string index.
aft += len(NTs[item][0])
else:
# No match.
break
else:
# We haven't looked ahead in the string,
# we can't add things we don't know yet.
break
if all([child != [] for child in children]):
# We have expanded all children and can collapse
# a node.
key, pre, aft = generate_key_and_check(
pre, aft, reduce, children)
# Create a new node for the solution list.
new_entry = [[pre, aft], reduce[1], key]
# Add the new reduced entry to the solution.
if new_entry not in solution:
solution.insert(idx + 1, new_entry)
def reduce(solution):
"""
Takes a list of all matching subtrees found in the target string and
iteratively combines and reduces subtrees to generate larger matching
subtrees. This process continues until the list of matching subtrees has
been completely reduced into a target string.
:param solution: A list of all snippets (i.e. matching subtrees found in
the target string.
:return: Nothing.
"""
# Find all non-terminals in the grammar that can be used to concatenate
# subtrees to new/larger subtrees.
reduce_NTs = params['BNF_GRAMMAR'].concat_NTs
# Pre-load the target string.
target = params['REVERSE_MAPPING_TARGET']
for idx, snippet_info in enumerate(solution):
# Get current snippet.
snippet = snippet_info[2]
# Find current snippet info.
NT = snippet_info[1]
# Get indexes of the current snippet
indexes = snippet_info[0]
start, end = indexes[0], indexes[1]
# Find if the snippet root (NT) exists anywhere in the
# reduction NTs.
if NT in reduce_NTs:
for reduce in reduce_NTs[NT]:
# Now we're searching for a specific subset of keys in the
# snippets dictionary.
# Generate list of only the desired Non Terminals.
NTs = reduce[2]
if len(NTs) == 1:
# This choice leads directly to the parent, check if parent
# snippet already exists.
# Child is current snippet.
child = [[snippet, trackers.snippets[snippet]]]
# Get key for new snippet.
key, start, end = generate_key_and_check(start, end,
reduce, child)
# Create a new node for the solution list.
new_entry = [indexes, reduce[1], key]
# Insert the current node into the solution.
if new_entry not in solution:
solution.insert(idx + 1, new_entry)
else:
# Find the index of the snippet root in the current
# reduction production choice.
NT_locs = [i for i, x in enumerate(NTs) if x[0] == NT]
for loc in NT_locs:
# We want to check each possible reduction option.
# Set where the original snippet starts and ends on
# the target string.
if loc == 0:
# The current snippet is at the start of the
# reduction attempt.
pre, aft = None, end
elif start == 0 and loc != 0:
# The current snippet is at the start of the target
# string, but we are trying to reduce_trees it with
# something before it.
break
elif end == len(params['TARGET']) and loc != \
NT_locs[-1]:
# The current snippet is at the end of the target
# string, but we are trying to reduce_trees it with
# something after it.
break
elif loc == len(NTs):
# The current snippet is at the end of the
# reduction attempt.
pre, aft = start, None
else:
# The current snippet is in the middle of the
# reduction attempt.
pre, aft = start, end
alt_cs = list(range(len(NTs)))
# Initialise a list of children to be reduced.
children = [[] for _ in range(len(NTs))]
# Set original snippet into children.
children[loc] = [snippet, trackers.snippets[snippet]]
curr_idx = solution.index(snippet_info)
# Step 1: reduce everything before the current loc.
for item in reversed(alt_cs[:loc]):
if NTs[item][1] == "T":
# This is a terminal, decrement by length of T.
# Check output of target string.
check = target[pre-len(NTs[item][0]):pre]
if check == NTs[item][0]:
# We have a match.
# Generate fake key for snippets dict.
key = str([pre - len(NTs[item][0]), pre])
# Create new tree from this terminal.
T_tree = Tree(check, None)
# Add to children.
children[item] = [key, T_tree]
# Decrement target string index.
pre -= len(NTs[item][0])
else:
# No match.
break
else:
# This is a NT. Check solution list for
# matching node.
available = [sol for sol in solution[:curr_idx]
if sol[1] == NTs[item][0] and
sol[0][1] == pre]
for check in available:
# We have a match.
# Set the correct child in our
# children.
children[item] = [check[2],
trackers.snippets[
check[2]]]
# Decrement target string index.
child_len = get_num_from_str(check[2])
pre -= child_len[1] - child_len[0]
break
# Step 2: reduce everything after the loc.
for i, item in enumerate(alt_cs[loc+1:]):
if NTs[item][1] == "T":
# This is a terminal, decrement by length of T.
# Check output of target string.
check = target[aft: aft + len(NTs[item][0])]
if check == NTs[item][0]:
# We have a match.
# Generate fake key for snippets dict.
key = str([aft, aft + len(NTs[item][0])])
# Create new tree from this terminal.
T_tree = Tree(check, None)
# Add to children.
children[item] = [key, T_tree]
# Increment target string index.
aft += len(NTs[item][0])
else:
# No match.
break
else:
# We haven't looked ahead in the string,
# we can't add things we don't know yet.
break
if all([child != [] for child in children]):
# We have expanded all children and can collapse
# a node.
key, pre, aft = generate_key_and_check(pre, aft,
reduce,
children)
# Create a new node for the solution list.
new_entry = [[pre, aft], reduce[1], key]
# Add the new reduced entry to the solution.
if new_entry not in solution:
solution.insert(idx + 1, new_entry)