patterns: Added Commodore BASIC (#428)

* Commodore BASIC

* Update desc

* I made it

* Implemented suggestion

* Implemented suggestion

* Test file

* Rename file

---------

Co-authored-by: Nik <werwolv98@gmail.com>

README.md

@@ -198,6 +198,7 @@ Everything will immediately show up in ImHex's Content Store and gets bundled wi
 | ZLIB | `application/zlib` | [`patterns/zlib.hexpat`](patterns/zlib.hexpat) | ZLIB compressed data format |
 | ZSTD | `application/zstd` | [`patterns/zstd.hexpat`](patterns/zstd.hexpat) | Zstandard compressed data format |
 | MOD | `3d-model/mod` | [`patterns/DMC3HD-Mod.hexpat`](patterns/dmc3_hd_mod.hexpat) | 3D Model files used in Devil May Cry 3 HD Collection |
+| CBM BASIC | | [`commodore_basic.hexpat`](patterns/commodore_basic.hexpat) | Commodore BASIC |
 
 ### Scripts
 

patterns/commodore_basic.hexpat

@@ -0,0 +1,158 @@
+#pragma description Commodore BASIC
+#pragma author Stephen Hewitt
+
+import std.io;
+import std.mem;
+
+bool in_quotes = false;
+
+le u16 LoadAddress @0 [[color("ff0000")]];
+
+fn formatll(u16 offset) {
+    if (offset&0xff00 == 0)
+        return "No next line";
+    u16 fo = offset-LoadAddress+2;
+    return std::format("Next line: ${:04X} (offset ${:04X})", offset, fo);
+};
+
+enum Token : u8 {
+    END      = 0x80,
+    FOR      = 0x81,
+    NEXT     = 0x82,
+    DATA     = 0x83,
+    INPUT_   = 0x84,
+    INPUT    = 0x85,
+    DIM      = 0x86,
+    READ     = 0x87,
+    LET      = 0x88,
+    GOTO     = 0x89,
+    RUN      = 0x8a,
+    IF       = 0x8b,
+    RESTORE  = 0x8c,
+    GOSUB    = 0x8d,
+    RETURN   = 0x8e,
+    REM      = 0x8f,
+    STOP     = 0x90,
+    ON       = 0x91,
+    WAIT     = 0x92,
+    LOAD     = 0x93,
+    SAVE     = 0x94,
+    VERIFY   = 0x95,
+    DEF      = 0x96,
+    POKE     = 0x97,
+    PRINT_   = 0x98,
+    PRINT    = 0x99,
+    CONT     = 0x9a,
+    LIST     = 0x9b,
+    CLR      = 0x9c,
+    CMD      = 0x9d,
+    SYS      = 0x9e,
+    OPEN     = 0x9f,
+    CLOSE    = 0xa0,
+    GET      = 0xa1,
+    NEW      = 0xa2,
+    TAB_     = 0xa3,
+    TO       = 0xa4,
+    FN       = 0xa5,
+    SPC_     = 0xa6,
+    THEN     = 0xa7,
+    NOT      = 0xa8,
+    STEP     = 0xa9,
+    PLUS_    = 0xaa,
+    MINUS_   = 0xab,
+    TIMES_   = 0xac,
+    DIVIDE_  = 0xad,
+    POW_     = 0xae,
+    AND      = 0xaf,
+    OR       = 0xb0,
+    GT_      = 0xb1,
+    EQ_      = 0xb2,
+    LT_      = 0xb3,
+    SGN      = 0xb4,
+    INT      = 0xb5,
+    ABS      = 0xb6,
+    USR      = 0xb7,
+    FRE      = 0xb7,
+    POS      = 0xb9,
+    SQR      = 0xba,
+    RND      = 0xbb,
+    LOG      = 0xbc,
+    EXP      = 0xbd,
+    COS      = 0xbe,
+    SIN      = 0xbf,
+    TAN      = 0xc0,
+    ATN      = 0xc1,
+    PEEK     = 0xc2,
+    LEN      = 0xc3,
+    STR_     = 0xc4,
+    VAL      = 0xc5,
+    ASC      = 0xc6,
+    CHR_     = 0xc7,
+    LEFT_    = 0xc8,
+    RIGHT_   = 0xc9,
+    MID_     = 0xca,
+    PI_      = 0xff
+} [[format("formate")]];
+
+// Can't seem to put attributes on enum members. Hack around it.
+fn formate(Token t) {
+    match (t) {
+        (Token::INPUT_):  return "INPUT#"; // $84
+        (Token::PRINT_):  return "PRINT#"; // $98
+        (Token::TAB_):    return "TAB(";   // $a3
+        (Token::SPC_):    return "SPC(";   // $a6
+        (Token::PLUS_):   return "+";      // $aa
+        (Token::MINUS_):  return "-";      // $ab
+        (Token::TIMES_):  return "*";      // $ac
+        (Token::DIVIDE_): return "/";      // $ad
+        //(Token::POW_):    return "↑";      // $ae
+        (Token::GT_):     return ">";      // $b1
+        (Token::EQ_):     return "=";      // $b2
+        (Token::LT_):     return "<";      // $b3
+        (Token::STR_):    return "STR$";   // $c4
+        (Token::CHR_):    return "CHR$";   // $c7
+        (Token::LEFT_):   return "LEFT$";  // $c8
+        (Token::RIGHT_):  return "RIGHT$"; // $c9
+        (Token::MID_):    return "MID$";   // $ca
+        //(Token::PI_):     return "π";      // $ff
+    }
+
+    return t;
+};
+
+fn NotZero() {
+    u8 b = std::mem::read_unsigned($, 1);
+    return b!=0;
+};
+
+fn IsToken() {
+     u8 b = std::mem::read_unsigned($, 1);
+     return b&0x80!=0;
+};
+
+fn IsPETSCII() {
+    u8 b = std::mem::read_unsigned($, 1);
+    if (b == '"')
+        in_quotes = !in_quotes;
+    return (b!=0) && (in_quotes || (b&0x80)==0);
+};
+
+struct LineSegment
+{
+    Token tokens[while(IsToken())] [[color("a040a0")]]; 
+    char petscii[while(IsPETSCII())] [[color("a0a0a0")]]; 
+};
+
+struct Line
+{
+    in_quotes = false;
+
+    u16 next [[color("8080ff"), format("formatll")]];
+    if (next&0xff00 == 0)
+        break;
+    le u16 line_number [[color("00FF00")]];
+    LineSegment contents[while(NotZero())];
+    u8 eol [[color("00ffff")]];
+};
+
+Line Lines[while(!std::mem::eof())] @ 2;