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# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements. See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied. See the License for the
# specific language governing permissions and limitations
# under the License.
# Simple utility functions
# Scheme-like lists
def cons(a, b):
return (a,) + b
def car(l):
return l[0]
def cdr(l):
return l[1:]
def cadr(l):
return car(cdr(l))
def cddr(l):
return cdr(cdr(l))
def caddr(l):
return car(cddr(l))
def reverse(l):
r = list(l)
r.reverse()
return tuple(r)
def isNil(l):
return l == ()
def isSymbol(v):
return isinstance(v, basestring) and v[0:1] == "'"
def isList(v):
if getattr(v, '__iter__', False) == False:
return False
if isinstance(v, basestring) or isinstance(v, dict):
return False
return True
def isTaggedList(v, t):
return isList(v) and not isNil(v) and car(v) == t
# Scheme-like associations
def assoc(k, l):
if l == ():
return None
if k == car(car(l)):
return car(l)
return assoc(k, cdr(l))
# Currying / partial function application
def curry(f, *args):
return lambda *a: f(*(args + a))
# Split a path into a list of segments
def tokens(path):
return tuple(filter(lambda s: len(s) != 0, path.split("/")))
# Write a list of strings to a stream
def writeStrings(l, os):
if l == ():
return os
os.write(car(l))
return writeStrings(cdr(l), os)
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