2 # -*- coding: ISO-8859-1 -*-
5 # Copyright (C) 2003-2004 Jörg Lehmann <joergl@users.sourceforge.net>
6 # Copyright (C) 2003-2004 Michael Schindler <m-schindler@users.sourceforge.net>
7 # Copyright (C) 2003-2004 André Wobst <wobsta@users.sourceforge.net>
9 # This file is part of PyX (http://pyx.sourceforge.net/).
11 # PyX is free software; you can redistribute it and/or modify
12 # it under the terms of the GNU General Public License as published by
13 # the Free Software Foundation; either version 2 of the License, or
14 # (at your option) any later version.
16 # PyX is distributed in the hope that it will be useful,
17 # but WITHOUT ANY WARRANTY; without even the implied warranty of
18 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 # GNU General Public License for more details.
21 # You should have received a copy of the GNU General Public License
22 # along with PyX; if not, write to the Free Software
23 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
25 # check for an isinstance which accepts both a class and a sequence of classes
26 # as second argument and emulate this behaviour if necessary
28 isinstance(1, (int, float))
30 # workaround for Python 2.1
31 _isinstance
= isinstance
32 def isinstance(instance
, clsarg
):
33 # we explicitely check for clsarg being a sequence, because
34 # a Leap Before Look pattern, i.e., just trying out
35 # _isinstance(instance, clsarg) within an try/except
36 # block, may mask a TypeError occuring when clsarg is
39 if not helper
.issequence(clsarg
):
40 return _isinstance(instance
, clsarg
)
43 if _isinstance(instance
, cls
):
48 # some helper functions for the attribute handling
51 def mergeattrs(attrs
):
52 """perform merging of the attribute list attrs as defined by the
53 merge methods of the attributes"""
56 # XXX Do we really need this test?
57 if isinstance(a
, attr
):
58 newattrs
= a
.merge(newattrs
)
60 raise TypeError("only instances of class attr.attr are allowed")
64 def getattrs(attrs
, getclasses
):
65 """return all attributes in the attribute list attrs, which are
66 instances of one of the classes in getclasses"""
67 return [attr
for attr
in attrs
if isinstance(attr
, tuple(getclasses
))]
70 def checkattrs(attrs
, allowedclasses
):
71 """check whether only attributes which are instances of classes in
72 allowedclasses are present in the attribute list attrs; if not it
74 if len(attrs
) != len(getattrs(attrs
, allowedclasses
)):
75 for attr1
, attr2
in zip(attrs
, getattrs(attrs
, allowedclasses
)):
76 if attr1
is not attr2
:
77 raise TypeError("instance %r not allowed" % attr1
)
79 raise TypeError("instance %r not allowed" % attrs
[len(getattrs(attrs
, allowedclasses
))])
82 # attr class and simple descendants
87 """ attr is the base class of all attributes, i.e., colors, decorators,
88 styles, text attributes and trafos"""
90 def merge(self
, attrs
):
91 """merge self into list of attrs
93 self may either be appended to attrs or inserted at a proper position
94 immediately before a dependent attribute. Attributes of the same type
95 should be removed, if redundant. Note that it is safe to modify
102 class exclusiveattr(attr
):
104 """an attribute which swallows all but the last of the same type (specified
105 by the exlusiveclass argument to the constructor) in an attribute list"""
107 def __init__(self
, exclusiveclass
):
108 self
.exclusiveclass
= exclusiveclass
110 def merge(self
, attrs
):
111 attrs
= [attr
for attr
in attrs
if not isinstance(attr
, self
.exclusiveclass
)]
116 class sortbeforeattr(attr
):
118 """an attribute which places itself previous to all attributes given
119 in the beforetheclasses argument to the constructor"""
121 def __init__(self
, beforetheclasses
):
122 self
.beforetheclasses
= tuple(beforetheclasses
)
124 def merge(self
, attrs
):
128 if first
and isinstance(attr
, self
.beforetheclasses
):
137 class sortbeforeexclusiveattr(attr
):
139 """an attribute which swallows all but the last of the same type (specified
140 by the exlusiveclass argument to the constructor) in an attribute list and
141 places itself previous to all attributes given in the beforetheclasses
142 argument to the constructor"""
144 def __init__(self
, exclusiveclass
, beforetheclasses
):
145 self
.exclusiveclass
= exclusiveclass
146 self
.beforetheclasses
= tuple(beforetheclasses
)
148 def merge(self
, attrs
):
152 if first
and isinstance(attr
, self
.beforetheclasses
):
155 if not isinstance(attr
, self
.exclusiveclass
):
162 class clearclass(attr
):
164 """a special attribute which allows to remove all predecessing attributes of
165 the same type in an attribute list"""
167 def __init__(self
, clearclass
):
168 self
.clearclass
= clearclass
170 def merge(self
, attrs
):
171 return [attr
for attr
in attrs
if not isinstance(attr
, self
.clearclass
)]
176 """a special attribute which removes all predecessing attributes
177 in an attribute list"""
179 def merge(self
, attrs
):
182 # we define the attribute "clear", an instance of "_clear",
183 # which can be used to remove all predecessing attributes
184 # in an attribute list
192 def selectattrs(attrs
, index
, total
):
193 """performs select calls for all changeable attributes and
194 returns the resulting attribute list
195 - attrs should be a list containing attributes and changeable
197 - index should be an unsigned integer
198 - total should be a positive number
199 - valid sections fullfill 0<=index<total
200 - returns None, when attrs is None
201 - returns None, when a changeable attribute returns None"""
206 if isinstance(a
, changeattr
):
207 select
= a
.select(index
, total
)
210 result
.append(select
)
216 def selectattr(attr
, index
, total
):
217 """as select, but for a single attribute"""
218 if isinstance(attr
, changeattr
):
219 select
= attr
.select(index
, total
)
229 """changeattr is the base class of all changeable attributes"""
231 def select(self
, index
, total
):
232 """returns an attribute for a given index out of a total number
233 if attributes to be provided
234 - index should be an unsigned integer
235 - total should be a positive number
236 - valid selections fullfill 0 <= index < total
237 - the select method may raise a ValueError, when the
238 changeable attribute does not allow for a requested
241 raise RuntimeError("not implemented")
244 class changelist(changeattr
):
246 """a changeable attribute over a list of attribute choises"""
248 def __init__(self
, attrs
, cyclic
=1):
249 """initializes the instance
250 - attrs is a list of attributes to cycle
251 - If cyclic is set, we restart from the beginning after
252 the end of the list has been reached; otherwise
253 selecting beyond the end of the list returns None"""
257 def select(self
, index
, total
):
259 return self
.attrs
[index
% len(self
.attrs
)]
260 elif index
< len(self
.attrs
):
261 return self
.attrs
[index
]