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fifth/src/cam_parser.py

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Python

"""
Parsers CAM languages for quick construction of CAMs.
For example, when considering CAMs of life, most follow the same formula; check
the total number of cells in a given neighborhood and if there are a certain
number around an off cell, turn it on, and vice versa. Thus the parser takes
in a generic language regarding this and constructs the necessary functions for
the user.
@date: June 4th, 2015
"""
import re
import ruleset as r
import configuration as c
class InvalidFormat(Exception):
"""
Called when parsing an invalid format.
For example, in MCell and RLE, numbers should be in ascending order.
"""
def __init__(self, value):
self.value = value
def __str__(self):
return repr(self.value)
class CAMParser:
"""
The following builds rulesets based on the passed string.
Following notation is supported:
* MCell Notation (x/y)
* RLE Format (By/Sx)
For reference: http://en.wikipedia.org/wiki/Life-like_cellular_automaton
"""
RLE_FORMAT = r'B\d*/S\d*$'
MCELL_FORMAT = r'\d*/\d*$'
def __init__(self, notation, cam):
"""
Parses the passed notation and saves values into members.
@sfunc: Represents the function that returns the next given state.
@ruleset: A created ruleset that matches always
@offsets: Represents the Moore neighborhood corresponding to the given CAM
"""
self.sfunc = None
self.offsets = c.Configuration.moore(cam.master)
self.ruleset = r.Ruleset(r.Ruleset.Method.ALWAYS_PASS)
if re.match(CAMParser.MCELL_FORMAT, notation):
x, y = notation.split('/')
if all(map(self._numasc, [x, y])):
self.sfunc = self._mcell(x, y)
else:
raise InvalidFormat("Non-ascending values in MCELL format")
elif re.match(CAMParser.RLE_FORMAT, notation):
B, S = map(lambda x: x[1:], notation.split('/'))
if all(map(self._numasc, [B, S])):
self.sfunc = self._mcell(S, B)
else:
raise InvalidFormat("Non-ascending values in RLE format")
else:
raise InvalidFormat("No supported format passed to parser.")
# Add configuration to given CAM
config = c.Configuration(self.sfunc, plane=cam.master, offsets=self.offsets)
self.ruleset.configurations.append(config)
def _numasc(self, value):
"""
Check the given value is a string of ascending numbers.
"""
if all(map(str.isnumeric, value)):
return ''.join(sorted(value)) == value
else:
return False
def _mcell(self, x, y):
"""
MCell Notation
A rule is written as a string x/y where each of x and y is a sequence of distinct digits from 0 to 8, in
numerical order. The presence of a digit d in the x string means that a live cell with d live neighbors
survives into the next generation of the pattern, and the presence of d in the y string means that a dead
cell with d live neighbors becomes alive in the next generation. For instance, in this notation,
Conway's Game of Life is denoted 23/3
"""
x, y = list(map(int, x)), list(map(int, y))
def next_state(plane, neighborhood, *args):
if plane.grid.flat[neighborhood.flat_index][neighborhood.bit_index]:
return int(neighborhood.total in x)
else:
return int(neighborhood.total in y)
return next_state