def do(cls, Target):
if isinstance(Target, TransitionCode):
return Target
elif isinstance(Target, (str, unicode)) or isinstance(Target, list):
return TransitionCode(Target)
elif isinstance(Target, DoorID):
return TransitionCodeByDoorId(Target)
elif isinstance(Target, TargetByStateKey):
if Target.uniform_door_id is not None:
return TransitionCodeByDoorId(Target.uniform_door_id)
assert Target.scheme_id is not None
variable_name = require_scheme_variable(Target.scheme_id,
Target.iterable_door_id_scheme(),
cls.state,
cls.state_db)
return TransitionCode(Lng.GOTO_BY_VARIABLE("%s[%s]" % (variable_name, cls.state_key_str)))
else:
assert False
def framework(txt, PWState, TheAnalyzer):
"""Implement the Pathwalker's framework. The scheme for a path-walker
is the following:
Pathwalker Head:
Compares the current 'input' character if it is still
on the path or not. If it is on the path we increment
the 'path_iterator' and re-enter the path walker. If
not, then the thread of control enters the transition
map.
Pathwalker Transition Map:
The transition map is the common transition map that all
implemented states had in common. Now, transitions to
states outside the path may happen.
"""
dial_db = PWState.entry.dial_db
# Three Versions of PathWalker Heads:
if PWState.uniform_door_id is not None:
# UNIFORM PATHS: Along the path, always the same (or no) commands are executed.
#
# PathWalker Head Implementation:
#
# if input == *path_iterator:
# path_iterator += 1
# if *path_iterator != TerminationCode: goto CommonPathWalkerDoor
# else: goto TerminalDoor
#
# -- "goto CommonPathWalkerDoor"
goto_next_door = " %s\n" % Lng.GOTO(PWState.uniform_door_id,
dial_db)
# -- "goto TerminalDoor"
if PWState.uniform_terminal_door_id is not None:
# All path have same terminal state and enter it at the same door
goto_terminal_door = " %s\n" % Lng.GOTO(
PWState.uniform_terminal_door_id, dial_db)
else:
# The terminals of the paths are different
#
# The "goto TerminalDoor" is implemented for each path. The single
# goto is split into a sequence:
#
# if path_iterator == path_0_end: goto TerminalDoorOfPath0
# else if path_iterator == path_1_end: goto TerminalDoorOfPath1
# else if path_iterator == path_2_end: goto TerminalDoorOfPath2
# ...
tmp = ""
offset = 0
for path_id, door_id_sequence in enumerate(
PWState.door_id_sequence_list):
offset += len(door_id_sequence) + 1
tmp += " %s" % Lng.IF("path_iterator", "==", "&path_walker_%i_path_base[%s]" % \
(PWState.index, offset - 1), FirstF=(path_id == 0)) \
+ " %s\n" % Lng.GOTO(door_id_sequence[-1], dial_db)
tmp += " %s" % Lng.ELSE_FOLLOWS
tmp += " %s\n" % Lng.UNREACHABLE
tmp += " %s\n" % Lng.END_IF
goto_terminal_door = tmp
path_walker_head = \
[" %s" % Lng.IF_INPUT("==", "*path_iterator"),
" %s\n" % Lng.PATH_ITERATOR_INCREMENT,
" %s" % Lng.IF("*path_iterator", "!=", "QUEX_SETTING_BUFFER_LEXATOM_PATH_TERMINATION"),
goto_next_door,
" %s\n" % Lng.ELSE_FOLLOWS,
goto_terminal_door,
" %s\n" % Lng.END_IF,
" %s\n" % Lng.END_IF]
else:
# NON UNIFORM PATHS
#
# PathWalker Head Implementation:
#
# if input == *path_iterator:
# path_iterator += 1
# goto NextDoor(path_iterator)
#
# Here, the "goto TerminalDoor" results from NextDoor(path_iterator)
# automatically, when the path_iterator stands on the last element.
#
label = "path_walker_%i_state_base[path_iterator - path_walker_%i_reference]" \
% (PWState.index, PWState.index)
goto_next_door = "%s" % (Lng.GOTO_BY_VARIABLE(label))
path_walker_head = [
" %s" % Lng.IF_INPUT("==", "*path_iterator"),
" %s\n" % Lng.PATH_ITERATOR_INCREMENT,
" %s\n" % goto_next_door,
" %s\n" % Lng.END_IF
]
txt.extend(path_walker_head)
return
