--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Symbol.st	Fri Jul 16 11:39:45 1993 +0200
@@ -0,0 +1,159 @@
+"
+ COPYRIGHT (c) 1988-93 by Claus Gittinger
+              All Rights Reserved
+
+ This software is furnished under a license and may be used
+ only in accordance with the terms of that license and with the
+ inclusion of the above copyright notice.   This software may not
+ be provided or otherwise made available to, or used by, any
+ other person.  No title to or ownership of the software is
+ hereby transferred.
+"
+
+String subclass:#Symbol
+       instanceVariableNames:''
+       classVariableNames:''
+       poolDictionaries:''
+       category:'Collections-Text'
+!
+
+Symbol comment:'
+
+COPYRIGHT (c) 1988-93 by Claus Gittinger
+              All Rights Reserved
+
+Symbols represent unique strings - every symbol with same printString
+exists exactly once in the system; Symbols are used for selectors, global
+variable-keys etc.
+
+%W% %E%
+'!
+
+!Symbol class methodsFor:'instance creation'!
+
+basicNew:size
+    "catch instance creation - symbols are not created with new"
+
+    self error:'symbols may not be created with new:'
+! 
+
+intern:aString
+    "return a unique symbol with printname taken from the String-argument"
+
+%{
+    if (_isString(aString)) {
+        RETURN ( _MKSYMBOL(_stringVal(aString), (OBJ *)0, __context) );
+    }
+%}
+.
+    ^ self mustBeString
+!
+
+internCharacter:aCharacter
+    "return a unique symbol with printname taken from the Character-argument"
+
+    ^ self intern:(aCharacter asString)
+! !
+
+!Symbol class methodsFor:'queries'!
+
+hasInterned:aString ifTrue:trueBlock
+    "for ST-80 compatibility - if the argument, aString is known
+     as Symbol, evaluate the block with the corresponding symbol
+     as argument and return true; otherwise return false"
+
+    aString knownAsSymbol ifTrue:[
+        trueBlock value:(aString asSymbol).
+        ^ true
+    ].
+    ^ false
+! !
+
+!Symbol methodsFor:'accessing'!
+
+basicAt:index put:something
+    "report an error - symbols may not be changed"
+
+    self error:'symbols may not be changed'
+!
+
+at:index put:something
+    "report an error - symbols may not be changed"
+
+    self error:'symbols may not be changed'
+! !
+
+!Symbol methodsFor:'copying'!
+
+deepCopy
+    "return a copy of myself
+     - reimplemented here since symbols are unique"
+
+     ^ self
+! !
+
+!Symbol methodsFor:'converting'!
+
+asString
+    "return a string with printname taken from mine"
+
+    ^ self printString
+!
+
+asSymbol
+    "I am a symbol - just return myself"
+
+    ^ self
+! !
+
+!Symbol methodsFor:'misc'!
+
+species
+    ^ String
+!
+
+nArgsIfSelector
+    "if symbol is used as a selector, how many arguments would it take"
+
+    |binopChars|
+
+    (self size > 2) ifFalse:[
+        binopChars := '|&-+=*/\<>~@,'.
+        (self size == 1) ifTrue:[
+            ((binopChars occurrencesOf:(self at:1)) == 0) ifTrue:[^ 0].
+            ^ 1
+        ].
+        ((binopChars occurrencesOf:(self at:1)) == 0) ifFalse:[
+            ((binopChars occurrencesOf:(self at:2)) == 0) ifFalse:[^ 1]
+        ]
+    ].
+    ^ self occurrencesOf:$:
+! !
+
+!Symbol methodsFor:'printing & storing'!
+
+printString
+%{
+    RETURN ( _MKSTRING(_stringVal(self) COMMA_CON) );
+%}
+!
+
+printOn:aStream
+    "aStream nextPut:$#."
+    aStream nextPutAll:(self printString)
+!
+ 
+displayString
+    ^ self storeString
+!
+
+storeString
+    "return a String for storing myself"
+
+    ^ $# asString , self
+!
+
+storeOn:aStream
+    aStream nextPut:$#.
+    aStream nextPutAll:(self printString)
+! !