"====================================================================== | | MetaClass Method Definitions | ======================================================================" "====================================================================== | | Copyright (C) 1990, 1991 Free Software Foundation, Inc. | Written by Steve Byrne. | | This file is part of GNU Smalltalk. | | GNU Smalltalk is free software; you can redistribute it and/or modify it | under the terms of the GNU General Public License as published by the Free | Software Foundation; either version 1, or (at your option) any later version. | | GNU Smalltalk is distributed in the hope that it will be useful, but WITHOUT | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS | FOR A PARTICULAR PURPOSE. See the GNU General Public License for more | details. | | You should have received a copy of the GNU General Public License along with | GNU Smalltalk; see the file COPYING. If not, write to the Free Software | Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. | ======================================================================" " | Change Log | ============================================================================ | Author Date Change | sbyrne 16 May 90 Changed the implementation of name: ... to try to | preserve an existing class (if possible). The | original code exists in newMeta: ... | | sbyrne 25 Apr 89 created. | " ClassDescription subclass: #Metaclass instanceVariableNames: 'instanceClass' classVariableNames: '' poolDictionaries: '' category: nil ! Metaclass comment: 'I am the root of the class hierarchy. My instances are metaclasses, one for each real class. My instances have a single instance, which they hold onto, which is the class that they are the metaclass of. I provide methods for creation of actual class objects from metaclass object, and the creation of metaclass objects, which are my instances. If this is confusing to you, it should be...the Smalltalk metaclass system is strange and complex.' ! !Metaclass class methodsFor: 'instance creation'! subclassOf: superMeta | newMeta | newMeta _ self new. newMeta superclass: superMeta. superMeta addSubclass: newMeta. newMeta initMetaclass. ^newMeta !! !Metaclass methodsFor: 'basic'! name: newName environment: aSystemDictionary subclassOf: superclass instanceVariableNames: stringOfInstVarNames variable: variableBoolean words: wordBoolean pointers: pointerBoolean classVariableNames: stringOfClassVarNames poolDictionaries: stringOfPoolNames category: categoryName comment: commentString changed: changed | aClass variableString variableArray sharedPoolNames poolName pool className classVarDict oldClassPool | "Please don't look at this case for an example of how to create good Smalltalk code. It is inelegantly written and probably highly inefficient." className _ newName asSymbol. aClass _ aSystemDictionary at: className ifAbsent: [ ^self newMeta: newName environment: aSystemDictionary subclassOf: superclass instanceVariableNames: stringOfInstVarNames variable: variableBoolean words: wordBoolean pointers: pointerBoolean classVariableNames: stringOfClassVarNames poolDictionaries: stringOfPoolNames category: categoryName comment: commentString changed: changed ]. (aClass isVariable == variableBoolean) & (aClass isWords == wordBoolean ) & (aClass isPointers == pointerBoolean) ifFalse: [ ^self newMeta: newName environment: aSystemDictionary subclassOf: superclass instanceVariableNames: stringOfInstVarNames variable: variableBoolean words: wordBoolean pointers: pointerBoolean classVariableNames: stringOfClassVarNames poolDictionaries: stringOfPoolNames category: categoryName comment: commentString changed: changed ]. "Here we have an existing class, so try hard to leave it alone" instanceClass _ aClass. aClass setSuperclass: superclass. superclass notNil ifTrue: [ "Inherit instance variables from parent" variableString _ superclass instanceVariableString ] ifFalse: [ variableString _ '' ]. variableString _ variableString , stringOfInstVarNames. variableArray _ self parseVariableString: variableString. 1 to: variableArray size do: [ :i | variableArray at: i put: (variableArray at: i) asSymbol ]. variableArray = aClass instVarNames ifFalse: [ 'Recompilation required!' printNl. "### This should be fixed soon" ]. aClass setInstanceVariables: variableArray. aClass setInstanceSpec: variableBoolean words: wordBoolean pointers: pointerBoolean instVars: variableArray size. classVarDict _ (self parseToDict: stringOfClassVarNames). oldClassPool _ aClass classPool. oldClassPool isNil ifTrue: [ aClass setClassVariables: classVarDict ] ifFalse: [ classVarDict associationsDo: [ :assoc | (oldClassPool includesKey: assoc key) ifFalse: [ aClass addClassVarName: assoc key ] ] ]. classVarDict keys ~= aClass classPool keys ifTrue: [ 'Recompilation required: different class variables!' printNl ]. sharedPoolNames _ self parseVariableString: stringOfPoolNames. 1 to: sharedPoolNames size do: [ :i | poolName _ (sharedPoolNames at: i) asSymbol. "### Check that the pool name starts with an uppercase letter here." "??? Should this create the pool if not there?" pool _ aSystemDictionary at: poolName ifAbsent: [ ^self error: 'Pool name ', poolName , ' does not exist' ]. sharedPoolNames at: i put: pool ]. "### probably should check for recompilation required here in case the intersection of the sets of pool dictionaries shrinks" aClass setSharedPools: sharedPoolNames. "### not done" aClass category: categoryName. "### need to remove the old category maybe" "### don't know what to do with changed" ^aClass ! newMeta: newName environment: aSystemDictionary subclassOf: superclass instanceVariableNames: stringOfInstVarNames variable: variableBoolean words: wordBoolean pointers: pointerBoolean classVariableNames: stringOfClassVarNames poolDictionaries: stringOfPoolNames category: categoryName comment: commentString changed: changed | aClass variableString variableArray sharedPoolNames poolName pool | sharedPoolNames _ self parseVariableString: stringOfPoolNames. 1 to: sharedPoolNames size do: [ :i | poolName _ (sharedPoolNames at: i) asSymbol. "### Check that the pool name starts with an uppercase letter here." pool _ aSystemDictionary at: poolName ifAbsent: [ ^self error: 'Pool name ', poolName , ' does not exist' ]. sharedPoolNames at: i put: pool ]. aClass _ self new. instanceClass _ aClass. aSystemDictionary at: (newName asSymbol) put: aClass. aClass superclass: superclass. aClass setName: newName asSymbol. superclass notNil ifTrue: [ superclass addSubclass: aClass. "Inherit instance variables from parent" variableString _ superclass instanceVariableString ] ifFalse: [ variableString _ '' ]. variableString _ variableString , stringOfInstVarNames. variableArray _ self parseVariableString: variableString. 1 to: variableArray size do: [ :i | variableArray at: i put: (variableArray at: i) asSymbol ]. aClass setInstanceVariables: variableArray. aClass setInstanceSpec: variableBoolean words: wordBoolean pointers: pointerBoolean instVars: variableArray size. aClass setClassVariables: (self parseToDict: stringOfClassVarNames). aClass setSharedPools: sharedPoolNames. "### not done" aClass category: categoryName. aClass comment: commentString. "### don't know what to do with changed" ^aClass !! !Metaclass methodsFor: 'accessing'! instanceClass ^instanceClass !! !Metaclass methodsFor: 'printing'! printOn: aStream instanceClass printOn: aStream. ' class' printOn: aStream ! storeOn: aStream self printOn: aStream !! !Metaclass methodsFor: 'private'! initMetaclass instanceVariables _ Class instVarNames. instanceSpec _ Class instanceSpec ! parseVariableString: aString | stream | stream _ TokenStream on: aString. ^stream contents ! parseToDict: aString | tokenArray dict | tokenArray _ self parseVariableString: aString. dict _ Dictionary new. tokenArray do: [ :element | dict at: element asSymbol put: nil ]. ^dict !!