def _substitute(self, tree, nodes, node_stack):
'''
Let (parent(tree), parent(parent(tree)), ..., parent(...(parent(tree))...))
the parental hierarchy of tree. It can be denoted as (P1, ..., P(n)) where P(i) is
the node id of the i-th grandparent of tree.
The substitution algorithm seeks for P(i) with repl_id == P(i). If found it
replaces P(i) in P(i+1) with nodes = (N1, ..., N(k)). It is guaranteed that the node
id of N(j) is repl_id.
'''
repl_id = nodes[0][0]
if tree[0] == repl_id:
return (tree, node_stack)
if is_token(repl_id): # replace token
if is_token(tree[0]):
tree[:] = nodes[0]
return (tree, node_stack)
else:
i = len(node_stack)-1
while i>=0:
P = node_stack[i]
i-=1
if repl_id == P[0]:
try:
nd_list = node_stack[i]
i-=1
for j, N in enumerate(nd_list):
if id(N) == id(P):
nd_list[:] = nd_list[:j]+list(nodes)+nd_list[j+1:]
return (nd_list, node_stack[i-1:])
except IndexError: # nothing to pop from node_stack
P[:] = nodes[0]
return (P, node_stack[i-1:])
self._create_translation_error(tree, nodes, node_stack)
def check(r, state, tracer, visited):
R = set()
C = {}
msg = ""
must_trace = False
states = tracer.select(state[0])
selection = list(set(s[0] for s in states if s and s[0]!=FIN))
for i,s in enumerate(selection):
if is_token(s):
S = set([s])
else:
S = nfamodule.reachables[s]
if R&S:
for u in C:
if C[u]&S:
if is_token(s):
msg = "%s : %s -> FirstSet(%s) /\\ {%s} = %s\n"%(r, state, u, s, C[u]&S)
elif is_token(u):
msg = "%s : %s -> {%s} /\\ FirstSet(%s) = %s\n"%(r, state, u, s, C[u]&S)
else:
msg = "%s : %s -> FirstSet(%s) /\\ FirstSet(%s) = %s\n"%(r, state, u, s, C[u]&S)
lineno = sys._getframe(0).f_lineno +1
if print_warning:
warnings.warn_explicit(msg, NeedsMoreExpansionWarning, "nfadatagen.py", lineno)
backtracking.add(r)
break
else:
R.update(S)
C[s] = S
for state in states:
if state[0] is not FIN and state not in visited:
visited.add(state)
subtracer = tracer.clone()
check(r, state, subtracer, visited)
def _substitute(self, tree, nodes, node_stack):
'''
Let (parent(tree), parent(parent(tree)), ..., parent(...(parent(tree))...))
the parental hierarchy of tree. It can be denoted as (P1, ..., P(n)) where P(i) is
the node id of the i-th grandparent of tree.
The substitution algorithm seeks for P(i) with repl_id == P(i). If found it
replaces P(i) in P(i+1) with nodes = (N1, ..., N(k)). It is guaranteed that the node
id of N(j) is repl_id.
'''
repl_id = nodes[0][0]
if tree[0] == repl_id:
return (tree, node_stack)
if is_token(repl_id): # replace token
if is_token(tree[0]):
tree[:] = nodes[0]
return (tree, node_stack)
else:
i = len(node_stack) - 1
while i >= 0:
P = node_stack[i]
i -= 1
if repl_id == P[0]:
try:
nd_list = node_stack[i]
i -= 1
for j, N in enumerate(nd_list):
if id(N) == id(P):
nd_list[:] = nd_list[:j] + list(
nodes) + nd_list[j + 1:]
return (nd_list, node_stack[i - 1:])
except IndexError: # nothing to pop from node_stack
P[:] = nodes[0]
return (P, node_stack[i - 1:])
self._create_translation_error(tree, nodes, node_stack)
def node_cmp(cls, tree, node_id):
'''
Compares first node of cst tree with node_id.
@param tree: CST
@param node_id: integer representing a py_symbol or a py_token
@return:
- 0 if node_id is tree-root.
- -1 if tree is a py_token or node_id cannot be the node_id of any subtree.
- 1 otherwise
'''
tree_id = tree[0] % LANGLET_ID_OFFSET
node_id = node_id % LANGLET_ID_OFFSET
if tree_id == node_id: # do we still want this? it makes nodes of two different langlets
return 0 # comparable.
elif is_token(tree_id): # is token
return -1
if cls.activated:
if is_symbol(node_id):
try:
s0 = hierarchy[tree_id] # global ???
s1 = hierarchy[node_id]
if s0 > s1:
return -1
except KeyError:
return 1
else:
return 1
else:
return 1
def node_cmp(cls, tree, node_id):
'''
Compares first node of cst tree with node_id.
@param tree: CST
@param node_id: integer representing a py_symbol or a py_token
@return:
- 0 if node_id is tree-root.
- -1 if tree is a py_token or node_id cannot be the node_id of any subtree.
- 1 otherwise
'''
tree_id = tree[0] % LANGLET_ID_OFFSET
node_id = node_id % LANGLET_ID_OFFSET
if tree_id == node_id: # do we still want this? it makes nodes of two different langlets
return 0 # comparable.
elif is_token(tree_id): # is token
return -1
if cls.activated:
if is_symbol(node_id):
try:
s0 = hierarchy[tree_id] # global ???
s1 = hierarchy[node_id]
if s0>s1:
return -1
except KeyError:
return 1
else:
return 1
else:
return 1
def check_first_follow_conflict(self):
'''
A FirstFollowConflict warning is raised when a conflict occurs.
Background ::
This method checks for first/follow conflicts. A first/follow conflict is an ambiguity that occur
in grammars like
G: A* A
If a word 'AA' is given one can match it with the first A* ( which leads to an error ) or the first character
by A* and the second by A.
A first/follow conflict shall always be removed and it needs to be removed manually!
'''
last_sets = self.nfadata.compute_last_set()
fin_cycles = self.nfadata.compute_fin_cycles()
warned = set()
def format_stream(T, k):
stream = []
for t in [t for t in T[:k+2]]:
if isinstance(t, int):
stream.append(self.node_name(t))
else:
stream.append("'"+t+"'")
return stream[0]+': '+' '.join(stream[1:])
for r, traces in self._cyclefree_traces().items():
for T in traces:
for i in range(1,len(T)-1):
A = T[i]
B = T[i+1]
if (r,A,B) in warned or A == B:
continue
if is_token(B):
if B in last_sets.get(A, set()):
if B in fin_cycles[A]:
warn_text = "%s -> LastSet(%s) /\\ set([%s]) != {}"%(self.node_name(r),self.node_name(A),self.node_name(B)) #, format_stream(T,i))
warnings.warn_explicit(warn_text, FirstFollowConflict, "nfadatagen.py", sys._getframe(0).f_lineno-1)
warned.add((r,A,B))
break
else:
S = last_sets.get(A, set()) & self.nfadata.reachables.get(B, set())
if S:
C = S & fin_cycles[A]
if C:
warn_text = warn_text = "%s -> LastSet(%s) /\\ FirstSet(%s) != {}"%(self.node_name(r), self.node_name(A),self.node_name(B)) #,format_stream(T,i))
warnings.warn_explicit(warn_text, FirstFollowConflict, "nfadatagen.py", sys._getframe(0).f_lineno-1)
warned.add((r,A,B))
print " /\\", set([self.node_name(c) for c in C])
break
def find_token_gen(tree, depth=MAX_DEPTH):
if is_token(tree[0]):
yield tree
elif depth < 0:
raise StopIteration
for sub in tree[1:]:
if isinstance(sub, list):
for item in find_token_gen(sub, depth=depth - 1):
if item:
yield item
def find_token_gen(tree, depth = MAX_DEPTH):
if is_token(tree[0]):
yield tree
elif depth<0:
raise StopIteration
for sub in tree[1:]:
if isinstance(sub, list):
for item in find_token_gen(sub, depth=depth-1):
if item:
yield item
def find_token_chains_gen(tree, depth = MAX_DEPTH, chain=[]):
if is_token(tree[0]):
yield Chain(chain+[tree])
elif depth<0:
raise StopIteration
for sub in tree[1:]:
if isinstance(sub, list):
for item in find_token_chains_gen(sub, depth=depth-1, chain = chain+[tree]):
if item:
yield item
def find_token_chain(tree, depth = MAX_DEPTH, chain = []):
if is_token(tree[0]):
return Chain(chain+[tree])
if depth<0:
return
for sub in tree[1:-1]:
res = find_token_chain(sub, depth=depth-1, chain = chain+[tree])
if res:
return res
if isinstance(tree[-1], list):
return find_token_chain(tree[-1], depth=depth-1, chain = chain+[tree])
def find_token_chains_gen(tree, depth=MAX_DEPTH, chain=[]):
if is_token(tree[0]):
yield Chain(chain + [tree])
elif depth < 0:
raise StopIteration
for sub in tree[1:]:
if isinstance(sub, list):
for item in find_token_chains_gen(sub,
depth=depth - 1,
chain=chain + [tree]):
if item:
yield item
def create_referrer(symbols):
'''
The referrer is a dictionary
'''
referrer = {}
for r, sym in symbols.items():
for s in sym:
if is_token(s):
continue
R = referrer.get(s, set())
R.add(r)
referrer[s] = R
return referrer
def create_referrer(symbols):
'''
The referrer is a dictionary
'''
referrer = {}
for r, sym in symbols.items():
for s in sym:
if is_token(s):
continue
R = referrer.get(s,set())
R.add(r)
referrer[s] = R
return referrer
def find_token_chain(tree, depth=MAX_DEPTH, chain=[]):
if is_token(tree[0]):
return Chain(chain + [tree])
if depth < 0:
return
for sub in tree[1:-1]:
res = find_token_chain(sub, depth=depth - 1, chain=chain + [tree])
if res:
return res
if isinstance(tree[-1], list):
return find_token_chain(tree[-1],
depth=depth - 1,
chain=chain + [tree])
def _create_translation_error(self, tree, nodes, node_stack):
repl_id = nodes[0][0]
if is_token(repl_id):
raise TranslationError(
"Cannot substitute non-terminal %s by terminal %s" %
((tree[0], self.langlet.get_node_name(tree[0])),
(repl_id, self.langlet.get_node_name(repl_id))))
else:
trace = [(tree[0], self.langlet.get_node_name(tree[0]))]
while node_stack:
P = node_stack.pop()
trace.append((P[0], self.langlet.get_node_name(P[0])))
trace = str(trace)
S = "Failed to substitute node %s by %s.\n Node %s must be one of the nodes or a projection in: \n\n%s" % (
(tree[0], self.langlet.get_node_name(tree[0])),
(repl_id, self.langlet.get_node_name(repl_id)),
(repl_id, self.langlet.get_node_name(repl_id)), trace)
raise TranslationError(S)
def _create_translation_error(self, tree, nodes, node_stack):
repl_id = nodes[0][0]
if is_token(repl_id):
raise TranslationError("Cannot substitute non-terminal %s by terminal %s"%(
(tree[0], self.langlet.get_node_name(tree[0])),
(repl_id, self.langlet.get_node_name(repl_id))
))
else:
trace = [(tree[0], self.langlet.get_node_name(tree[0]))]
while node_stack:
P = node_stack.pop()
trace.append((P[0], self.langlet.get_node_name(P[0])))
trace = str(trace)
S = "Failed to substitute node %s by %s.\n Node %s must be one of the nodes or a projection in: \n\n%s"%(
(tree[0], self.langlet.get_node_name(tree[0])),
(repl_id, self.langlet.get_node_name(repl_id)),
(repl_id, self.langlet.get_node_name(repl_id)),
trace)
raise TranslationError( S )
def find_node(tree, nid, depth = MAX_DEPTH, exclude = ()):
'''
Finds one node of a given node id.
( Non-recursive depth first search implementation. )
'''
if is_token(tree[0]):
if nid == tree[0]:
return tree
else:
return
dq = deque()
for sub in tree[1:]:
dq.append((sub, depth-1))
while dq:
node, depth = dq.popleft()
s = node[0]
if s == nid:
return node
elif is_symbol(s) and s not in exclude and depth>0:
subnodes = zip(node[:0:-1], [depth-1]*(len(node)-1))
dq.extendleft(subnodes)
def find_node(tree, nid, depth=MAX_DEPTH, exclude=()):
'''
Finds one node of a given node id.
( Non-recursive depth first search implementation. )
'''
if is_token(tree[0]):
if nid == tree[0]:
return tree
else:
return
dq = deque()
for sub in tree[1:]:
dq.append((sub, depth - 1))
while dq:
node, depth = dq.popleft()
s = node[0]
if s == nid:
return node
elif is_symbol(s) and s not in exclude and depth > 0:
subnodes = zip(node[:0:-1], [depth - 1] * (len(node) - 1))
dq.extendleft(subnodes)
def expand(self, rule = 0, visited = set()):
'''
Algorithm ::
For each transition
S -> {L1, ..., Ln}
in NFA[rule] with at least two follow states L1, L2 and Li!=None we determine
the corresponding selection
sel = {s1, ..., sk}
From sel we build Ri = s1.reach \/ s2.reach \/ .... si.reach successively.
If Ri intersects with s(i+1) find the first sj, j=1,...,i with
sj.reach /\ s(i+1).reach
Now embedd the smaller of both NFAs into NFA[rule].
Repeat this procedure for each transition T until Rn-1 /\ sn.reach = {}.
'''
if not rule:
rule = self.start_symbol
visited.add(rule)
more = True
must_select = False
while more:
more = False
selections = self._all_selections(rule)
if len(selections)>TRAIL_MAX_ALLOWED_STATES:
raise OverflowError("NFA size > TRAIL_MAX_ALLOWED_STATES. Cannot expand rule `%s : %s`"%(rule, self.node_name(rule)))
if self.warn_cnt>10:
raise OverflowError("More than ten expansion warnings issued. Expansion is terminated!")
for follow in selections:
selectable = sorted(list(set(s[0] for s in follow if s and s[0]!=FIN)))
if len(selectable)<=1:
continue
R = set()
C = {}
for i,s in enumerate(selectable):
tok_s = False
if is_token(s):
tok_s = True
S = set([s])
else:
S = self.nfadata.reachables[s]
if R&S:
for u in selectable[:i]:
tok_u,U = C[u]
if U&S:
if tok_s:
k = u
elif tok_u:
k = s
else:
N_s = self.nfadata.nfas[s][2]
N_u = self.nfadata.nfas[u][2]
k = (s if len(N_s)<=len(N_u) else u)
break
for state in (state for state in follow if state[0] == k):
self.maybe_expand(state[0], visited)
self.embedd_nfa(state, rule)
more = True
break
break
else:
R.update(S)
C[s] = (tok_s, S)
else:
continue
break
else:
break
def maybe_expand(self, r, visited):
if r and r not in visited and not is_token(r):
self.expand(r, visited)
