A parsing engine that allows you to define sets of patterns and callbacks, and process any I/O object in Pyton that has a readline() method.
Python, 164 lines
Download
Copy to clipboard1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 | #!/usr/bin/env python
####################################################################################
# #
# Copyright (c) 2013, Mike 'Fuzzy' Partin <fuzzy@fu-manchu.org> #
# All rights reserved. #
# #
# Redistribution and use in source and binary forms, with or without #
# modification, are permitted provided that the following conditions are met: #
# #
# 1. Redistributions of source code must retain the above copyright notice, this #
# list of conditions and the following disclaimer. #
# 2. Redistributions in binary form must reproduce the above copyright notice, #
# this list of conditions and the following disclaimer in the documentation #
# and/or other materials provided with the distribution. #
# #
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND #
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED #
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE #
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR #
# ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES #
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; #
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND #
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT #
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS #
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. #
# #
# The views and conclusions contained in the software and documentation are those #
# of the authors and should not be interpreted as representing official policies, #
# either expressed or implied, of the FreeBSD Project. #
# #
####################################################################################
############
## __NOTE__
############
#
# This is the processing engine code that provides the core of the DSL
#
import re, types
class InvalidArgument(Exception):
""" Inavlid argument exception """
pass
class Slurp:
def __init__(self, ioObj=None):
""" Instantiate a Slurp object
Example:
obj = Slurp(open('/etc/fstab', 'r'))
# This will work for sockets and FIFO's as well
"""
if ioObj != None:
self.ioObj = ioObj
self.triggers = []
else:
raise InvalidArgument("A valid I/O object (file, socket, fifo) is required.\n")
def register(self, patt=None, cback=None, final=True):
""" Register a callback and associated pattern
Slurp.register(patt=None, cback=None, final=True)
Register a handler, using cback, when matching patt.
If final is True, then Slurp will stop processing for that trigger, once it has
matched it (this is on a per line basis).
Example:
obj = Slurp(open('/etc/fstab', 'r'))
# Print only commented out lines
obj.register('^#.*$', print)
# *or*
obj.register('^#.*$', print, False) # This will allow multiple callbacks to match
"""
# Check argument non-None..ness first and foremost
if patt != None and cback != None:
# Then check types
if type(patt) != types.StringType or type(cback) != types.FunctionType:
raise InvalidArgument
else:
# Check to see that our list of callbacks doesn't have one of these
# instances already in it.
for itm in self.triggers:
if itm[0] == patt:
return False
# Ok, passed that, lets add it in
self.triggers.append([patt, cback, final])
return True
else:
raise InvalidArgument
def process(self):
""" Begin processing a given stream
Example:
obj = Slurp(open('/etc/fstab', 'r'))
obj.register('^#.*$', print)
obj.process()
"""
# CAVEAT: The IO object *MUST* have a .readline() interface. This isn't much
# of a showstopper as it's common, but a simple workaround would be to impliment
# my own readline method (scanning for \n would work reasonably well) here inside
# of Slurp to fall back on. I haven't hit a need for that yet, but this should
# serve to remind me about it, if it ever comes up.
buff = self.ioObj.readline()
while buff:
for pair in self.triggers:
tmp_re = re.compile(pair[0])
if tmp_re.match(buff):
# Call the callback with the line of text as the only argument
pair[1](buff.strip())
# Now lets see if we are a final measure
if pair[2] == False:
break
# And refill the well.
buff = self.ioObj.readline()
############
## __NOTE__
############
#
# This is the main execution logic
#
import sy
s
class Builder:
def __init__(self, ioObj=None):
if hasattr(ioObj, 'readline'):
self.obj = {}
self.Slurp = Slurp(ioObj)
handlers = [
# set the package name and version
# Example: package 'ruby', '2.0.0-p0'
('^package\ +.*$',
self.setPackage),
# set the uri or uri's for the package
# Example: fetch_ur <uri>, <uri>, <uri>
('^fetch_uri\ +.*$',
self.setUris),
#
('^depends\ +.*$',
self.addDepends),
#
('^configure_args\ +.*$',
self.configureArgs),
#
('^make_args\ +.*$',
self.makeArgs),
]
def setPackage(self):
pass
def setUris(self):
pass
|
