def intersect(transducers):
"""
Return an intersection of *transducers*.
"""
retval = None
for tr in transducers:
if retval == None:
retval = HfstTransducer(tr)
else:
retval.intersect(tr)
retval.minimize()
return retval
def cross_product(transducers):
"""
Return a cross product of *transducers*.
"""
retval = None
for tr in transducers:
if retval == None:
retval = HfstTransducer(tr)
else:
retval.cross_product(tr)
retval.minimize()
return retval
def compose(transducers):
"""
Return a composition of *transducers*.
"""
retval = None
for tr in transducers:
if retval == None:
retval = HfstTransducer(tr)
else:
retval.compose(tr)
retval.minimize()
return retval
def read_prolog_transducer(f, linecount=[0]):
"""
Create a transducer as defined in prolog format in file *f*. *linecount*
keeps track of the current line in the file.
"""
linecount_ = 0
fsm = HfstBasicTransducer()
line = ""
while(True):
line = f.readline()
linecount_ = linecount_ + 1
if line == "":
raise hfst.exceptions.EndOfStreamException("","",linecount[0] + linecount_)
line = line.rstrip()
if line == "":
pass # allow extra prolog separator(s)
if line[0] == '#':
pass # comment line
else:
break
if not libhfst.parse_prolog_network_line(line, fsm):
raise hfst.exceptions.NotValidPrologFormatException(line,"",linecount[0] + linecount_)
while(True):
line = f.readline()
if (line == ""):
retval = HfstTransducer(fsm, get_default_fst_type())
retval.set_name(fsm.name)
linecount[0] = linecount[0] + linecount_
return retval
line = line.rstrip()
linecount_ = linecount_ + 1
if line == "": # prolog separator
retval = HfstTransducer(fsm, get_default_fst_type())
retval.set_name(fsm.name)
linecount[0] = linecount[0] + linecount_
return retval
if libhfst.parse_prolog_arc_line(line, fsm):
pass
elif libhfst.parse_prolog_final_line(line, fsm):
pass
elif libhfst.parse_prolog_symbol_line(line, fsm):
pass
else:
raise hfst.exceptions.NotValidPrologFormatException(line,"",linecount[0] + linecount_)
def read_att_transducer(f, epsilonstr=EPSILON, linecount=[0]):
"""
Create a transducer as defined in AT&T format in file *f*. *epsilonstr*
defines how epsilons are represented. *linecount* keeps track of the current
line in the file.
"""
linecount_ = 0
fsm = HfstBasicTransducer()
while True:
line = f.readline()
if line == "":
if linecount_ == 0:
raise hfst.exceptions.EndOfStreamException("", "", 0)
else:
linecount_ = linecount_ + 1
break
linecount_ = linecount_ + 1
if line[0] == '-':
break
if not _parse_att_line(line, fsm, epsilonstr):
raise hfst.exceptions.NotValidAttFormatException(
line, "", linecount[0] + linecount_)
linecount[0] = linecount[0] + linecount_
return HfstTransducer(fsm, get_default_fst_type())
def fsa(arg):
"""
Get a transducer (automaton in this case) that recognizes one or more paths.
Parameters
----------
* `arg` :
See example below
Possible inputs:
One unweighted identity path:
'foo' -> [f o o]
Weighted path: a tuple of string and number, e.g.
('foo',1.4)
('bar',-3)
('baz',0)
Several paths: a list or a tuple of paths and/or weighted paths, e.g.
['foo', 'bar']
('foo', ('bar',5.0))
('foo', ('bar',5.0), 'baz', 'Foo', ('Bar',2.4))
[('foo',-1), ('bar',0), ('baz',3.5)]
"""
deftok = HfstTokenizer()
retval = HfstBasicTransducer()
if isinstance(arg, str):
if len(arg) == 0:
retval.set_final_weight(0,
0) # epsilon transducer with zero weight
else:
retval.disjunct(deftok.tokenize(_check_word(arg)), 0)
elif _is_weighted_word(arg):
if len(arg) == 0:
retval.set_final_weight(0,
arg[1]) # epsilon transducer with weight
else:
retval.disjunct(deftok.tokenize(_check_word(arg[0])), arg[1])
elif isinstance(arg, tuple) or isinstance(arg, list):
for word in arg:
if _is_weighted_word(word):
if len(word) == 0:
retval.set_final_weight(
0, word[1]) # epsilon transducer with weight
else:
retval.disjunct(deftok.tokenize(_check_word(word[0])),
word[1])
elif isinstance(word, str):
if len(word) == 0:
retval.set_final_weight(
0, 0) # epsilon transducer with zero weight
else:
retval.disjunct(deftok.tokenize(_check_word(word)), 0)
else:
raise RuntimeError(
'Tuple/list element not a string or tuple of string and weight.'
)
else:
raise RuntimeError('Not a string or tuple/list of strings.')
return HfstTransducer(retval, get_default_fst_type())