added sys.disable_caseswitch() and sys.enable_caseswitch()

compiler/res/prog8lib/atari/syslib.p8

@@ -198,6 +198,14 @@ _longcopy
         }}
     }
 
+    sub disable_caseswitch() {
+        ; no-op
+    }
+
+    sub enable_caseswitch() {
+        ; no-op
+    }
+
     inline asmsub exit(ubyte returnvalue @A) {
         ; -- immediately exit the program with a return code in the A register
         ;    TODO

compiler/res/prog8lib/c128/syslib.p8

@@ -734,6 +734,20 @@ _longcopy
         }}
     }
 
+    inline asmsub disable_caseswitch() {
+        %asm {{
+            lda  #$80
+            sta  247
+        }}
+    }
+
+    inline asmsub enable_caseswitch() {
+        %asm {{
+            lda  #0
+            sta  247
+        }}
+    }
+
     inline asmsub exit(ubyte returnvalue @A) {
         ; -- immediately exit the program with a return code in the A register
         %asm {{

compiler/res/prog8lib/c64/syslib.p8

@@ -737,6 +737,20 @@ _longcopy
         }}
     }
 
+    inline asmsub disable_caseswitch() {
+        %asm {{
+            lda  #$80
+            sta  657
+        }}
+    }
+
+    inline asmsub enable_caseswitch() {
+        %asm {{
+            lda  #0
+            sta  657
+        }}
+    }
+
     inline asmsub exit(ubyte returnvalue @A) {
         ; -- immediately exit the program with a return code in the A register
         %asm {{

compiler/res/prog8lib/cx16/syslib.p8

@@ -873,6 +873,8 @@ asmsub  init_system()  {
         jsr  cbm.CHROUT
         lda  #147       ; clear screen
         jsr  cbm.CHROUT
+        lda  #8         ; disable charset case switch
+        jsr  cbm.CHROUT
         lda  #PROG8_VARSHIGH_RAMBANK
         sta  $00    ; select ram bank
         lda  #0
@@ -1250,6 +1252,20 @@ _longcopy
         }}
     }
 
+    inline asmsub disable_caseswitch() {
+        %asm {{
+            lda  #8
+            jsr  cbm.CHROUT
+        }}
+    }
+
+    inline asmsub enable_caseswitch() {
+        %asm {{
+            lda  #9
+            jsr  cbm.CHROUT
+        }}
+    }
+
     inline asmsub exit(ubyte returnvalue @A) {
         ; -- immediately exit the program with a return code in the A register
         %asm {{

compiler/res/prog8lib/pet32/syslib.p8

@@ -297,6 +297,14 @@ _longcopy
         }}
     }
 
+    sub disable_caseswitch() {
+        ; PET doesn't have a key to swap case, so no-op
+    }
+
+    sub enable_caseswitch() {
+        ; PET doesn't have a key to swap case, so no-op
+    }
+
     inline asmsub exit(ubyte returnvalue @A) {
         ; -- immediately exit the program with a return code in the A register
         %asm {{

compiler/res/prog8lib/virtual/syslib.p8

@@ -79,6 +79,13 @@ sys {
         }}
     }
 
+    sub disable_caseswitch() {
+        ; no-op
+    }
+
+    sub enable_caseswitch() {
+        ; no-op
+    }
 
     sub gfx_enable(ubyte mode) {
         %ir {{

docs/source/libraries.rst

@@ -132,6 +132,9 @@ sys (part of syslib)
 ``set_leds_brightness (ubyte activity, ubyte power)``  (commander x16 only)
     Sets the brightness of the activity and power leds on the computer.
 
+``disable_caseswitch()`` and ``enable_caseswitch()``
+    Disable or enable the ability to switch character set case using a keyboard combination.
+
 
 conv
 ----

docs/source/todo.rst

@@ -1,7 +1,6 @@
 TODO
 ====
 
-- optimize when in case of constant value (only keep choice that matches)
 - revisit the seek example to see if write-seeking now works?
 - remove unused interned strings in the resulting code (for example from removed if/else blocks)
 - [on branch: shortcircuit] investigate McCarthy evaluation again? this may also reduce code size perhaps for things like if a>4 or a<2 ....