author | Claus Gittinger <cg@exept.de> |
Sat, 04 Sep 1999 20:20:55 +0200 | |
changeset 4682 | 4158042a9c8c |
parent 4654 | 3b3f88c73a86 |
child 5471 | a57eeb01c5ab |
permissions | -rw-r--r-- |
1 | 1 |
" |
5 | 2 |
COPYRIGHT (c) 1988 by Claus Gittinger |
159 | 3 |
All Rights Reserved |
1 | 4 |
|
5 |
This software is furnished under a license and may be used |
|
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only in accordance with the terms of that license and with the |
|
7 |
inclusion of the above copyright notice. This software may not |
|
8 |
be provided or otherwise made available to, or used by, any |
|
9 |
other person. No title to or ownership of the software is |
|
10 |
hereby transferred. |
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" |
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||
13 |
Object subclass:#UndefinedObject |
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instanceVariableNames:'' |
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15 |
classVariableNames:'CreateMinimumProtocolInNewSubclassQuery' |
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poolDictionaries:'' |
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category:'Kernel-Objects' |
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! |
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||
88 | 20 |
!UndefinedObject class methodsFor:'documentation'! |
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||
22 |
copyright |
|
23 |
" |
|
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COPYRIGHT (c) 1988 by Claus Gittinger |
|
159 | 25 |
All Rights Reserved |
1 | 26 |
|
88 | 27 |
This software is furnished under a license and may be used |
28 |
only in accordance with the terms of that license and with the |
|
29 |
inclusion of the above copyright notice. This software may not |
|
30 |
be provided or otherwise made available to, or used by, any |
|
31 |
other person. No title to or ownership of the software is |
|
32 |
hereby transferred. |
|
33 |
" |
|
34 |
! |
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35 |
||
36 |
documentation |
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37 |
" |
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1303 | 38 |
there is only one instance of this class: nil, |
39 |
representing an undefined or otherwise unspecified object. |
|
88 | 40 |
|
41 |
All instance variables, array elements and even method/block local |
|
42 |
variables are initially set to nil. |
|
1303 | 43 |
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44 |
Since in Smalltalk/X (and in other smalltalks), nil is represented by |
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a special pointer value (NULL), there can be only one instance of UndefinedObject, |
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and no subclassing is possible. |
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(to be exact: subclassing UndefinedObject is technically possible, |
48 |
but instances of it would not be recognized as being nil |
|
49 |
- therefore, subclassing is blocked and an error is raised when it is tried) |
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50 |
||
51 |
For advanced users: |
|
52 |
Beside the above role, nil can be subclassed (!!). |
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53 |
This creates a class which inherits no protocol whatsoever - not even |
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54 |
the basic interfaces as defined by the Object class. Subclasses of nil |
|
55 |
are useful if all messages send to instances should trap into the |
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#doesNotUnderstand: method. For example, proxy objects are typically defined |
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this way. |
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1294 | 58 |
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[author:] |
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60 |
Claus Gittinger |
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88 | 61 |
" |
62 |
! ! |
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1 | 63 |
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parents:
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!UndefinedObject class methodsFor:'initialization'! |
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65 |
|
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66 |
initialize |
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CreateMinimumProtocolInNewSubclassQuery isNil ifTrue:[ |
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CreateMinimumProtocolInNewSubclassQuery := QuerySignal new. |
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|
69 |
CreateMinimumProtocolInNewSubclassQuery nameClass:self message:#createMinimumProtocolInNewSubclassQuery. |
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70 |
CreateMinimumProtocolInNewSubclassQuery defaultAnswer:false. |
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71 |
]. |
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|
72 |
|
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73 |
" |
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|
74 |
UndefinedObject initialize |
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75 |
" |
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parents:
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|
76 |
|
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parents:
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|
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"Created: 3.1.1997 / 15:02:40 / cg" |
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parents:
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diff
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|
78 |
"Modified: 3.1.1997 / 15:18:33 / cg" |
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79 |
! ! |
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|
80 |
|
1 | 81 |
!UndefinedObject class methodsFor:'instance creation'! |
82 |
||
83 |
basicNew |
|
84 |
"catch new - there MUST be only one nil in the system" |
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85 |
||
86 |
^ nil |
|
87 |
! |
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88 |
||
89 |
basicNew:size |
|
90 |
"catch new - there MUST be only one nil in the system" |
|
91 |
||
92 |
^ nil |
|
93 |
! ! |
|
94 |
||
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!UndefinedObject class methodsFor:'Signal constants'! |
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parents:
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|
96 |
|
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|
97 |
createMinimumProtocolInNewSubclassQuery |
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|
98 |
"return the signal used to ask if the minimum required protocol |
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|
99 |
should be created for nil subclasses. |
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100 |
By default, this is not done, however, the browser answers true |
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|
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here, to avoid big trouble with nil subclasses which do not define |
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102 |
some methods which the inspector needs." |
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|
103 |
|
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104 |
^ CreateMinimumProtocolInNewSubclassQuery |
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105 |
|
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|
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"Created: 3.1.1997 / 15:05:48 / cg" |
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parents:
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"Modified: 3.1.1997 / 15:06:15 / cg" |
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108 |
! ! |
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|
109 |
|
51 | 110 |
!UndefinedObject class methodsFor:'queries'! |
111 |
||
112 |
canBeSubclassed |
|
113 |
"return true, if its allowed to create subclasses of the receiver. |
|
3914 | 114 |
Return false here - since it is NOT possible for UndefinedObject. |
115 |
(due to the representation of nil as a 0-pointer)" |
|
51 | 116 |
|
117 |
^ false |
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|
119 |
"Modified: / 5.11.1998 / 16:11:43 / cg" |
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! |
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|
121 |
|
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hasImmediateInstances |
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"return true if this class has immediate instances |
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124 |
i.e. if the instances are represented in the pointer itself and |
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125 |
no real object header/storage is used for the object. |
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126 |
Redefined from Behavior" |
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127 |
|
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128 |
^ true |
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|
129 |
|
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130 |
"Created: 3.6.1997 / 12:01:39 / cg" |
4321 | 131 |
! |
132 |
||
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hasSharedInstances |
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"return true if this class has shared instances, that is, instances |
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135 |
with the same value are identical. |
4654 | 136 |
True returned here - there is only one nil." |
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|
137 |
|
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|
138 |
^ true |
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parents:
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diff
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|
139 |
|
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parents:
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|
140 |
|
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141 |
! |
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|
142 |
|
4321 | 143 |
isBuiltInClass |
144 |
"return true, if this class is known by the run-time-system, |
|
145 |
i.e. you cannot add/remove instance variables without recompiling |
|
146 |
the VM. |
|
147 |
Here, true is returned for myself, false for subclasses." |
|
148 |
||
149 |
^ self == UndefinedObject |
|
150 |
||
51 | 151 |
! ! |
152 |
||
2416 | 153 |
!UndefinedObject methodsFor:'converting'! |
154 |
||
155 |
decodeAsLiteralArray |
|
156 |
"given a literalEncoding in the receiver, |
|
157 |
create & return the corresponding object. |
|
158 |
The inverse operation to #literalArrayEncoding." |
|
159 |
||
160 |
^ self |
|
161 |
||
162 |
"Created: 25.2.1997 / 19:18:40 / cg" |
|
163 |
! |
|
164 |
||
165 |
literalArrayEncoding |
|
166 |
"encode myself as an array literal, from which a copy of the receiver |
|
167 |
can be reconstructed with #decodeAsLiteralArray." |
|
168 |
||
169 |
^ self |
|
170 |
||
171 |
"Created: 25.2.1997 / 19:18:47 / cg" |
|
172 |
! ! |
|
173 |
||
695 | 174 |
!UndefinedObject methodsFor:'copying'! |
175 |
||
176 |
copy |
|
177 |
"return a shallow copy of myself |
|
178 |
- since there is only one nil in the system return self" |
|
179 |
||
180 |
^ self |
|
181 |
! |
|
182 |
||
183 |
deepCopy |
|
184 |
"return a deep copy of myself |
|
185 |
- since there is only one nil in the system return self" |
|
186 |
||
187 |
^ self |
|
188 |
! |
|
189 |
||
190 |
deepCopyUsing:aDictionary |
|
191 |
"return a deep copy of myself |
|
192 |
- since there is only one nil in the system return self" |
|
193 |
||
194 |
^ self |
|
195 |
! |
|
196 |
||
197 |
shallowCopy |
|
198 |
"return a shallow copy of myself |
|
199 |
- since there is only one nil in the system return self" |
|
200 |
||
201 |
^ self |
|
202 |
! |
|
203 |
||
204 |
simpleDeepCopy |
|
205 |
"return a deep copy of myself |
|
206 |
- since there is only one nil in the system return self" |
|
207 |
||
208 |
^ self |
|
209 |
! ! |
|
210 |
||
3166 | 211 |
!UndefinedObject methodsFor:'dependents access'! |
212 |
||
213 |
addDependent:someObject |
|
214 |
"raise an error here - nil may not have dependents" |
|
215 |
||
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216 |
self error:'nil may not have dependents' mayProceed:true |
793b116fef3e
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|
217 |
|
3166 | 218 |
! |
219 |
||
3183 | 220 |
dependents |
221 |
"nil has no dependents" |
|
222 |
||
223 |
^#() |
|
224 |
! |
|
225 |
||
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changeset
|
226 |
release |
3166 | 227 |
"ignored here - nil has no dependents" |
3183 | 228 |
! |
3166 | 229 |
|
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Claus Gittinger <cg@exept.de>
parents:
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diff
changeset
|
230 |
removeDependent:someObject |
3183 | 231 |
"ignored here - nil has no dependents" |
3166 | 232 |
! ! |
233 |
||
1 | 234 |
!UndefinedObject methodsFor:'error catching'! |
235 |
||
236 |
basicAt:index |
|
237 |
"catch array access - its illegal |
|
238 |
defined here since basicAt: in Object ommits the nil-check" |
|
239 |
||
240 |
^ self notIndexed |
|
241 |
! |
|
242 |
||
243 |
basicAt:index put:anObject |
|
244 |
"catch array access - its illegal |
|
245 |
defined here since basicAt:put: in Object ommits the nil-check" |
|
246 |
||
247 |
^ self notIndexed |
|
248 |
! ! |
|
249 |
||
250 |
!UndefinedObject methodsFor:'printing & storing'! |
|
251 |
||
63 | 252 |
printOn:aStream |
253 |
"append a printed representation of the receiver to the |
|
254 |
argument, aStream" |
|
255 |
||
256 |
aStream nextPutAll:'nil' |
|
257 |
! |
|
258 |
||
695 | 259 |
printString |
260 |
"return a string for printing myself" |
|
261 |
||
262 |
^ 'nil' |
|
263 |
! |
|
264 |
||
63 | 265 |
storeOn:aStream |
266 |
"append a printed representation of the receiver to the |
|
267 |
argument, aStream, which allows reconstruction of it" |
|
268 |
||
269 |
^ self printOn:aStream |
|
695 | 270 |
! |
271 |
||
272 |
storeString |
|
273 |
"return a string for storing myself" |
|
274 |
||
275 |
^ 'nil' |
|
1 | 276 |
! ! |
2 | 277 |
|
77 | 278 |
!UndefinedObject methodsFor:'subclass creation'! |
279 |
||
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parents:
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diff
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|
280 |
nilSubclass:action |
356 | 281 |
"common helper for subclass creation. |
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diff
changeset
|
282 |
Creates a nil-superclass class. |
8ba8b1002902
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parents:
1958
diff
changeset
|
283 |
If the CreateMinimumProtocolInNewSubclassQuery answers true, |
8ba8b1002902
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diff
changeset
|
284 |
entries for the minimum required protocol (#class, #isBehavior |
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|
285 |
and #doesNotUnderstand:) are also automatically created. |
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|
286 |
(this query is typically answered by the browser) |
356 | 287 |
These are required to avoid getting into deep trouble when |
288 |
inspecting or debugging instances of this new class. |
|
289 |
The methods get a modified source code to remind you that these |
|
290 |
methods were automatically generated." |
|
291 |
||
1461
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Use methodDictionary instead of selector/method arrays.
Stefan Vogel <sv@exept.de>
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diff
changeset
|
292 |
|newClass methodDict method| |
202 | 293 |
|
1461
dd25bb1e9973
Use methodDictionary instead of selector/method arrays.
Stefan Vogel <sv@exept.de>
parents:
1303
diff
changeset
|
294 |
Class withoutUpdatingChangesDo:[ |
2040
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parents:
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diff
changeset
|
295 |
newClass := action value |
77 | 296 |
]. |
297 |
newClass notNil ifTrue:[ |
|
1029
c469a63e88e2
only redefine #class/#isbehavior/#doesNotUnderstand once (if no methods are present yet)
Claus Gittinger <cg@exept.de>
parents:
695
diff
changeset
|
298 |
newClass setSuperclass:nil. |
1803
754f9205b651
meta's superclass should be class - not Object.
Claus Gittinger <cg@exept.de>
parents:
1638
diff
changeset
|
299 |
newClass class setSuperclass:Class. |
356 | 300 |
|
1461
dd25bb1e9973
Use methodDictionary instead of selector/method arrays.
Stefan Vogel <sv@exept.de>
parents:
1303
diff
changeset
|
301 |
newClass methodDictionary size == 0 ifTrue:[ |
2040
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
302 |
Class addChangeRecordForClass:newClass. |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
303 |
|
4060
1048a3abf128
Use #query instead of #raise when invoking QuerySignals
Stefan Vogel <sv@exept.de>
parents:
3914
diff
changeset
|
304 |
CreateMinimumProtocolInNewSubclassQuery query |
2040
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
305 |
ifTrue:[ |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
306 |
" |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
307 |
copy over method objects from Object |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
308 |
and modify the source code |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
309 |
" |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
310 |
methodDict := MethodDictionary new:3. |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
311 |
#(#class #isBehavior #doesNotUnderstand:) do:[:sel| |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
312 |
method := (Object compiledMethodAt:sel) copy. |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
313 |
method source: method source , ' |
356 | 314 |
" |
315 |
*** WARNING |
|
316 |
*** |
|
317 |
*** this method has been automatically created, |
|
318 |
*** since all nil-subclasses should respond to some minimum required |
|
319 |
*** protocol. |
|
320 |
*** |
|
321 |
*** Inspection and/or debugging of instances may not be possible, |
|
322 |
*** if you remove/change this method. |
|
323 |
" |
|
324 |
'. |
|
2040
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
325 |
methodDict at:sel put:method. |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
326 |
"/ newClass addChangeRecordForMethod:method |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
327 |
]. |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
328 |
newClass methodDictionary:methodDict. |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
329 |
] |
1029
c469a63e88e2
only redefine #class/#isbehavior/#doesNotUnderstand once (if no methods are present yet)
Claus Gittinger <cg@exept.de>
parents:
695
diff
changeset
|
330 |
] |
77 | 331 |
]. |
332 |
^ newClass |
|
1029
c469a63e88e2
only redefine #class/#isbehavior/#doesNotUnderstand once (if no methods are present yet)
Claus Gittinger <cg@exept.de>
parents:
695
diff
changeset
|
333 |
|
4060
1048a3abf128
Use #query instead of #raise when invoking QuerySignals
Stefan Vogel <sv@exept.de>
parents:
3914
diff
changeset
|
334 |
"Modified: / 3.1.1997 / 15:53:21 / cg" |
1048a3abf128
Use #query instead of #raise when invoking QuerySignals
Stefan Vogel <sv@exept.de>
parents:
3914
diff
changeset
|
335 |
"Created: / 3.1.1997 / 16:00:34 / cg" |
1048a3abf128
Use #query instead of #raise when invoking QuerySignals
Stefan Vogel <sv@exept.de>
parents:
3914
diff
changeset
|
336 |
"Modified: / 18.3.1999 / 18:29:58 / stefan" |
202 | 337 |
! |
338 |
||
2040
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
339 |
subclass:nameSymbol instanceVariableNames:instVarNameString classVariableNames:classVarString poolDictionaries:pool category:cat |
202 | 340 |
"create a new class which has nil as superclass |
2040
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
341 |
- i.e. traps into #doesNotUnderstand: for all of its messages." |
202 | 342 |
|
2040
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
343 |
^ self |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
344 |
nilSubclass:[ |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
345 |
Object class |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
346 |
name:nameSymbol |
4060
1048a3abf128
Use #query instead of #raise when invoking QuerySignals
Stefan Vogel <sv@exept.de>
parents:
3914
diff
changeset
|
347 |
inEnvironment:(Class nameSpaceQuerySignal query) |
2040
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
348 |
subclassOf:self |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
349 |
instanceVariableNames:instVarNameString |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
350 |
variable:false |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
351 |
words:true |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
352 |
pointers:true |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
353 |
classVariableNames:classVarString |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
354 |
poolDictionaries:pool |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
355 |
category:cat |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
356 |
comment:nil |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
357 |
changed:true |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
358 |
] |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
359 |
|
4060
1048a3abf128
Use #query instead of #raise when invoking QuerySignals
Stefan Vogel <sv@exept.de>
parents:
3914
diff
changeset
|
360 |
"Modified: / 3.1.1997 / 16:00:39 / cg" |
1048a3abf128
Use #query instead of #raise when invoking QuerySignals
Stefan Vogel <sv@exept.de>
parents:
3914
diff
changeset
|
361 |
"Modified: / 18.3.1999 / 18:30:07 / stefan" |
695 | 362 |
! |
363 |
||
2040
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
364 |
variableByteSubclass:nameSymbol instanceVariableNames:instVarNameString classVariableNames:classVarString poolDictionaries:pool category:cat |
695 | 365 |
"create a new class which has nil as superclass |
2040
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
366 |
- i.e. traps into #doesNotUnderstand: for all of its messages." |
695 | 367 |
|
2040
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
368 |
^ self |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
369 |
nilSubclass:[ |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
370 |
Object class |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
371 |
name:nameSymbol |
4060
1048a3abf128
Use #query instead of #raise when invoking QuerySignals
Stefan Vogel <sv@exept.de>
parents:
3914
diff
changeset
|
372 |
inEnvironment:(Class nameSpaceQuerySignal query) |
2040
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
373 |
subclassOf:self |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
374 |
instanceVariableNames:instVarNameString |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
375 |
variable:true |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
376 |
words:false |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
377 |
pointers:false |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
378 |
classVariableNames:classVarString |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
379 |
poolDictionaries:pool |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
380 |
category:cat |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
381 |
comment:nil |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
382 |
changed:true |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
383 |
] |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
384 |
|
4060
1048a3abf128
Use #query instead of #raise when invoking QuerySignals
Stefan Vogel <sv@exept.de>
parents:
3914
diff
changeset
|
385 |
"Modified: / 3.1.1997 / 16:00:42 / cg" |
1048a3abf128
Use #query instead of #raise when invoking QuerySignals
Stefan Vogel <sv@exept.de>
parents:
3914
diff
changeset
|
386 |
"Modified: / 18.3.1999 / 18:30:11 / stefan" |
695 | 387 |
! |
77 | 388 |
|
2040
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
389 |
variableSubclass:nameSymbol instanceVariableNames:instVarNameString classVariableNames:classVarString poolDictionaries:pool category:cat |
159 | 390 |
"create a new class which has nil as superclass |
2040
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
391 |
- i.e. traps into #doesNotUnderstand: for all of its messages." |
77 | 392 |
|
2040
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
393 |
^ self |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
394 |
nilSubclass:[ |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
395 |
Object class |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
396 |
name:nameSymbol |
4060
1048a3abf128
Use #query instead of #raise when invoking QuerySignals
Stefan Vogel <sv@exept.de>
parents:
3914
diff
changeset
|
397 |
inEnvironment:(Class nameSpaceQuerySignal query) |
2040
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
398 |
subclassOf:self |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
399 |
instanceVariableNames:instVarNameString |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
400 |
variable:true |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
401 |
words:false |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
402 |
pointers:true |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
403 |
classVariableNames:classVarString |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
404 |
poolDictionaries:pool |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
405 |
category:cat |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
406 |
comment:nil |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
407 |
changed:true |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
408 |
] |
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
409 |
|
4060
1048a3abf128
Use #query instead of #raise when invoking QuerySignals
Stefan Vogel <sv@exept.de>
parents:
3914
diff
changeset
|
410 |
"Modified: / 3.1.1997 / 16:00:45 / cg" |
1048a3abf128
Use #query instead of #raise when invoking QuerySignals
Stefan Vogel <sv@exept.de>
parents:
3914
diff
changeset
|
411 |
"Modified: / 18.3.1999 / 18:30:16 / stefan" |
695 | 412 |
! ! |
413 |
||
414 |
!UndefinedObject methodsFor:'testing'! |
|
415 |
||
1868 | 416 |
? defaultValue |
3466 | 417 |
"a syntactic shugar-piece: |
418 |
if the receiver is nil, return the defaultValue; |
|
1868 | 419 |
otherwise, return the receiver. |
420 |
This method is redefined from Object; |
|
421 |
the argument is retuned unconditionally here. |
|
422 |
||
1958 | 423 |
Thus, if foo and bar are simple variables or constants, |
424 |
foo ? bar |
|
425 |
is the same as: |
|
426 |
(foo isNil ifTrue:[bar] ifFalse:[foo]) |
|
427 |
||
428 |
if they are message sends, the equivalent code is: |
|
429 |
[ |
|
430 |
|t1 t2| |
|
431 |
||
432 |
t1 := foo. |
|
433 |
t2 := bar. |
|
434 |
t1 isNil ifTrue:[t2] ifFalse:[t1] |
|
435 |
] value |
|
436 |
||
1868 | 437 |
Can be used to provide defaultValues to variables, |
438 |
as in: |
|
1958 | 439 |
foo := arg ? #defaultValue |
1868 | 440 |
" |
441 |
||
442 |
^ defaultValue |
|
443 |
||
444 |
" |
|
445 |
1 ? #default |
|
446 |
nil ? #default |
|
447 |
" |
|
448 |
||
3466 | 449 |
"Created: / 4.11.1996 / 20:37:09 / cg" |
450 |
"Modified: / 19.5.1998 / 17:39:36 / cg" |
|
1868 | 451 |
! |
452 |
||
3464
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
453 |
?? defaultValue |
3466 | 454 |
"a syntactic shugar-piece: |
455 |
much like ?, but sends value to the argument if required. |
|
3464
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
456 |
If the receiver is nil, return the defaultValues value; |
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
457 |
otherwise, return the receiver. |
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
458 |
This method is redefined from Object. |
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
459 |
|
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
460 |
Thus, if foo and bar are simple variables or constants, |
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
461 |
foo ?? bar |
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
462 |
is the same as: |
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
463 |
(foo isNil ifTrue:[bar value] ifFalse:[foo]) |
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
464 |
|
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
465 |
if they are message sends, the equivalent code is: |
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
466 |
[ |
3466 | 467 |
|t| |
3464
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
468 |
|
3466 | 469 |
t := foo. |
470 |
t isNil ifTrue:[bar value] ifFalse:[t] |
|
3464
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
471 |
] value |
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
472 |
|
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
473 |
Can be used to provide defaultValues to variables, |
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
474 |
as in: |
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
475 |
foo := arg ?? [something] |
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
476 |
" |
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
477 |
|
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
478 |
^ defaultValue value |
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
479 |
|
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
480 |
" |
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
481 |
1 ?? #default |
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
482 |
nil ?? #default |
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
483 |
" |
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
484 |
|
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
485 |
"Created: / 4.11.1996 / 20:37:09 / cg" |
3466 | 486 |
"Modified: / 19.5.1998 / 17:42:10 / cg" |
3464
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
487 |
! |
b0009b3ea4f2
added ?? - much like ?, but sends #value to its argument.
Claus Gittinger <cg@exept.de>
parents:
3183
diff
changeset
|
488 |
|
695 | 489 |
basicSize |
490 |
"return the number of indexed instvars |
|
491 |
defined here since size in Object ommits the nil-check" |
|
492 |
||
493 |
^ 0 |
|
494 |
! |
|
495 |
||
496 |
hash |
|
497 |
"return an integer useful as a hash key" |
|
498 |
||
499 |
^ 0 |
|
500 |
! |
|
501 |
||
502 |
identityHash |
|
503 |
"return an integer useful as a hash key" |
|
504 |
||
505 |
^ 0 |
|
506 |
! |
|
507 |
||
4339
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
508 |
ifNil:aBlockOrValue |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
509 |
"return myself, or the result from evaluating the argument, if I am nil. |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
510 |
This is much like #?, but sends #value to the argument in case of a nil |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
511 |
receiver." |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
512 |
|
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
513 |
^ aBlockOrValue value |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
514 |
|
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
515 |
! |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
516 |
|
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
517 |
ifNil:nilBlockOrValue ifNotNil:notNilBlockOrValue |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
518 |
"return the value of the first arg, if I am nil, |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
519 |
the result from evaluating the 2nd argument, if I am not nil" |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
520 |
|
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
521 |
^ nilBlockOrValue value |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
522 |
|
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
523 |
! |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
524 |
|
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
525 |
ifNotNil:aBlockOrValue |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
526 |
"return myself if nil, or the result from evaluating the argument, if I am not nil" |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
527 |
|
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
528 |
^ self |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
529 |
|
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
530 |
! |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
531 |
|
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
532 |
ifNotNil:notNilBlockOrValue ifNil:nilBlockOrValue |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
533 |
"return the value of the 2nd arg, if I am nil, |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
534 |
the result from evaluating the 1st argument, if I am not nil" |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
535 |
|
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
536 |
^ nilBlockOrValue value |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
537 |
|
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
538 |
! |
18c19912a67c
added #ifNil and friends - squeak compatibility.
Claus Gittinger <cg@exept.de>
parents:
4321
diff
changeset
|
539 |
|
695 | 540 |
isLiteral |
4652
8b3118a923d1
added #hasSharedInstances & tracing support
Claus Gittinger <cg@exept.de>
parents:
4530
diff
changeset
|
541 |
"return true, if the receiver can be used as a literal constant in ST syntax |
695 | 542 |
(i.e. can be used in constant arrays)" |
77 | 543 |
|
695 | 544 |
^ true |
545 |
! |
|
546 |
||
547 |
isNil |
|
3044 | 548 |
"return true if I am nil - since I am, return true. |
549 |
Notice: |
|
550 |
This method is open coded (inlined) by the compiler(s) |
|
551 |
- redefining it may not work as expected." |
|
695 | 552 |
|
553 |
^ true |
|
554 |
! |
|
555 |
||
556 |
notNil |
|
3044 | 557 |
"return true if I am not nil - since I am nil, return false. |
558 |
Notice: |
|
559 |
This method is open coded (inlined) by the compiler(s) |
|
560 |
- redefining it may not work as expected." |
|
77 | 561 |
|
695 | 562 |
^ false |
563 |
! |
|
564 |
||
565 |
size |
|
566 |
"return the number of indexed instvars |
|
567 |
defined here since size in Object ommits the nil-check" |
|
568 |
||
569 |
^ 0 |
|
77 | 570 |
! ! |
695 | 571 |
|
4652
8b3118a923d1
added #hasSharedInstances & tracing support
Claus Gittinger <cg@exept.de>
parents:
4530
diff
changeset
|
572 |
!UndefinedObject methodsFor:'tracing'! |
8b3118a923d1
added #hasSharedInstances & tracing support
Claus Gittinger <cg@exept.de>
parents:
4530
diff
changeset
|
573 |
|
4682 | 574 |
traceInto:aRequestor level:level from:referrer |
4652
8b3118a923d1
added #hasSharedInstances & tracing support
Claus Gittinger <cg@exept.de>
parents:
4530
diff
changeset
|
575 |
"double dispatch into tracer, passing my type implicitely in the selector" |
8b3118a923d1
added #hasSharedInstances & tracing support
Claus Gittinger <cg@exept.de>
parents:
4530
diff
changeset
|
576 |
|
4682 | 577 |
^ aRequestor traceUndefinedObject:self level:level from:referrer |
4652
8b3118a923d1
added #hasSharedInstances & tracing support
Claus Gittinger <cg@exept.de>
parents:
4530
diff
changeset
|
578 |
|
8b3118a923d1
added #hasSharedInstances & tracing support
Claus Gittinger <cg@exept.de>
parents:
4530
diff
changeset
|
579 |
|
8b3118a923d1
added #hasSharedInstances & tracing support
Claus Gittinger <cg@exept.de>
parents:
4530
diff
changeset
|
580 |
! ! |
8b3118a923d1
added #hasSharedInstances & tracing support
Claus Gittinger <cg@exept.de>
parents:
4530
diff
changeset
|
581 |
|
695 | 582 |
!UndefinedObject class methodsFor:'documentation'! |
583 |
||
584 |
version |
|
4682 | 585 |
^ '$Header: /cvs/stx/stx/libbasic/UndefinedObject.st,v 1.44 1999-09-04 18:17:40 cg Exp $' |
695 | 586 |
! ! |
2040
8ba8b1002902
avoid intermediate Object subclass creation.
Claus Gittinger <cg@exept.de>
parents:
1958
diff
changeset
|
587 |
UndefinedObject initialize! |