# HG changeset patch
# User Claus Gittinger <cg@exept.de>
# Date 1034711579 -7200
# Node ID e34f7e7d28a019ab49374ea24a9faf1e0f407c05
# Parent  5d004fcfd0065eab0c8fb6f057ad273f83209588
preps for character escapes

diff -r 5d004fcfd006 -r e34f7e7d28a0 Scanner.st
--- a/Scanner.st	Mon Oct 14 18:18:35 2002 +0200
+++ b/Scanner.st	Tue Oct 15 21:52:59 2002 +0200
@@ -1351,6 +1351,86 @@
     "Created: / 17.2.1998 / 14:48:49 / cg"
 !
 
+escapeCharacterFor:aCharacter
+    "only if AllowExtendedSTXSyntax is true 
+     For now: do not use, since stc does not support it.
+
+     much like character escapes in C-literals;
+     expands:
+        `n      newLine
+        `r      return
+        `t      tab
+        `b      backspace
+        `f      formfeed
+        `g      bell
+
+        ``      backTick
+        ` ...`  ignored
+        `xNN    hexCharacter
+        `xNN    hexCharacter
+    "
+
+    |ascii nextChar|
+
+    aCharacter == $n ifTrue:[^ Character nl].
+    aCharacter == $r ifTrue:[^ Character return].
+    aCharacter == $t ifTrue:[^ Character tab].
+    aCharacter == $b ifTrue:[^ Character backspace].
+    aCharacter == $f ifTrue:[^ Character ff].
+    aCharacter == $g ifTrue:[^ Character bell].
+    aCharacter == $` ifTrue:[^ aCharacter].
+    aCharacter isSeparator ifTrue:[
+        nextChar := source next.
+        [nextChar notNil and:[nextChar ~~ $`]] whileTrue:[
+            (nextChar == Character cr) ifTrue:[
+                lineNr := lineNr + 1
+            ].
+            nextChar := source next.
+        ].
+        ^ nil
+    ].
+
+    aCharacter == $x ifTrue:[
+        ascii := 0.
+        nextChar := source next.
+        (nextChar notNil and:[nextChar isDigitRadix:16]) ifTrue:[
+            ascii := nextChar digitValue.
+            nextChar := source next.
+            (nextChar notNil and:[nextChar isDigitRadix:16]) ifTrue:[
+                ascii := (ascii bitShift:4) bitOr:nextChar digitValue.
+            ]
+        ].
+        ^ Character value:ascii.
+    ].
+    aCharacter == $0 ifTrue:[
+        ascii := 0.
+        nextChar := source next.
+        (nextChar notNil and:[nextChar isDigitRadix:8]) ifTrue:[
+            ascii := nextChar digitValue.
+            nextChar := source next.
+            (nextChar notNil and:[nextChar isDigitRadix:8]) ifTrue:[
+                ascii := (ascii bitShift:3) bitOr:nextChar digitValue.
+                nextChar := source next.
+                (nextChar notNil and:[nextChar isDigitRadix:8]) ifTrue:[
+                    ascii := (ascii bitShift:3) bitOr:nextChar digitValue.
+                ]
+            ]
+        ].
+        ^ Character value:ascii.
+    ].
+    ^ aCharacter
+
+    "
+     AllowExtendedSTXSyntax := true
+    "
+    "
+     'hello`nworld'          
+     'hello`x08world'   
+     'hello`
+    `world'   
+    "                      
+!
+
 ignoreErrors
     "turn off notification of errors"
 
@@ -2039,7 +2119,7 @@
     |nextChar string pos
      index "{ Class: SmallInteger }"
      len   "{ Class: SmallInteger }"
-     inString|
+     inString peekChar|
 
     string := String basicNew:20.
     len := 20.
@@ -2060,21 +2140,34 @@
         ].
         (nextChar == Character cr) ifTrue:[
             lineNr := lineNr + 1
-        ].
-        (nextChar == Character quote) ifTrue:[
-            (source peekOrNil == Character quote) ifTrue:[
-                source next
+        ] ifFalse:[
+            (nextChar == Character quote) ifTrue:[
+                (source peekOrNil == Character quote) ifTrue:[
+                    source next
+                ] ifFalse:[
+                    inString := false
+                ]
             ] ifFalse:[
-                inString := false
-            ]
+                AllowExtendedSTXSyntax == true ifTrue:[
+                    (nextChar == $`) ifTrue:[
+                        peekChar := source peekOrNil.    
+                        peekChar notNil ifTrue:[
+                            source next.
+                            nextChar := self escapeCharacterFor:peekChar.
+                        ]
+                    ]
+                ]
+            ].
         ].
         inString ifTrue:[
-            string at:index put:nextChar.
-            (index == len) ifTrue:[
-                string := string , (String new:len).
-                len := len * 2
+            nextChar notNil ifTrue:[
+                string at:index put:nextChar.
+                (index == len) ifTrue:[
+                    string := string , (String new:len).
+                    len := len * 2
+                ].
+                index := index + 1.
             ].
-            index := index + 1.
             nextChar := source next
         ]
     ].
@@ -2351,6 +2444,7 @@
 !Scanner class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libcomp/Scanner.st,v 1.152 2002-08-13 16:39:33 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libcomp/Scanner.st,v 1.153 2002-10-15 19:52:59 cg Exp $'
 ! !
+
 Scanner initialize!