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bastok

 _ _ _ | |__ __ _ ___| |_ ___ | | __
| '_ \ / _` / __| __/ _ \| |/ /
| |_) | (_| \__ \ || (_) | < |_.__/ \__,_|___/\__\___/|_|\_\

A Node.js-based utility for converting BASIC source text to tokenized program images (.prg / .bas) for the 6502 homebrew BIOS, and back again. Write your BASIC on a real keyboard, tokenize it here, and drop the result straight onto a CompactFlash card or send it over XMODEM.

Inspired by the petcat utility distributed with the VICE emulator.

📖 Guide:AC6502 Documentation — the user's and programmer's guide for the whole family. See the tool belt and BASIC in a cross-dev workflow.

Installation

From NPM

npm install -g bastok

From Source

  1. Clone the repository:
git clone https://github.com/acwright/bastok.git
cd bastok
  1. Install dependencies:
npm install
  1. Build the project:
npm run build
  1. (Optional) Link globally:
npm link

Usage

bastok [options] <path>

The conversion direction is chosen from the file extension: .txt, .asc and .bs are tokenized; .prg and .bas are detokenized. Anything else is sniffed — a file of printable ASCII is treated as source, otherwise as a program image. Use -t / -d to decide for yourself.

Tokenize

bastok game.txt

Writes game.prg. To pick the name and extension yourself:

bastok -o GAME.BAS game.txt

Detokenize

bastok game.prg

Writes game.txt. To list to the terminal instead:

bastok -o - game.prg

Command Line Options

  • -v, --version — Output the current version
  • -h, --help — Display help information
  • -t, --tokenize — Force text → tokenized binary
  • -d, --detokenize — Force tokenized binary → text
  • -o, --output <path> — Output file, or - for stdout
  • -a, --address <address> — Program load address in hex (default: 0x0800)
  • -H, --header — Read / write a 2-byte load address header
  • -c, --crlf — Emit CRLF line endings when detokenizing
  • -q, --quiet — Suppress warnings and the summary line
  • -T, --tokens — Print the token table and exit

Warnings and the "wrote N bytes" summary go to stderr, so -o - stays pipe-safe.

Getting the program onto the machine

The image bastok produces is byte-for-byte what BASIC's SAVE writes, so it can be used directly:

bastok game.txt -o GAME.BAS # copy GAME.BAS to a CF card, then LOAD "GAME.BAS"
bastok game.txt -o game.prg # send game.prg with XMODEM after a bare LOAD

Load it with BASIC's LOAD, not by writing it straight into RAM. The image is only half the story: BASIC also keeps VARTAB ($035F), the pointer to the end of the program, in its workspace. LOAD walks the line chain and updates it via BasFixChain; a debugger, monitor or emulator that just pokes the bytes into $0800 does not.

If VARTAB is left at its post-NEW value of $0802, the program appears to list and run correctly right up until it assigns its first variable — which is written as a 7-byte record on top of line 10. The failure looks like this:

?UNDEF'D STATEMENT ERROR IN 90 GOTO can no longer find its target
LIST
78 FOR the variable table, listed as if it were a line

78 is the two name bytes of the variable N ($4E $00) read as a line number, and FOR is $81, the exponent byte of its floating-point value. If you must inject the image directly, set VARTAB, ARYTAB ($0361) and STREND ($0363) to the load address plus the file size afterwards.

File Format

A tokenized program is a raw memory image of the program area starting at $0800 (PROGRAM_START). There is no load-address header — SAVE writes $0800 through VARTAB verbatim. Each line is:

[next-lo][next-hi][num-lo][num-hi][tokens...][$00]

and the program ends with a next-pointer of $0000, which is included in the file. Next-pointers are absolute addresses, so they depend on the load address; use -a if you are linking for somewhere other than $0800. LOAD relinks the chain via BasFixChain anyway, so a stale pointer is harmless — bastok warns about mismatches rather than refusing to read the file.

-H prepends (or consumes) a two-byte little-endian load address, the Commodore .prg convention. The BIOS does not use it; it is there for interoperating with other tools. When detokenizing with -H, the address in the header wins over -a.

Tokens

85 keywords, $80–$D4, transcribed from KeywordTbl in BASIC.asm. Run bastok --tokens for the full list.

$80 END$81 FOR$82 NEXT$83 DATA$84 INPUT
$85 DIM$86 READ$87 LET$88 GOTO$89 RUN
$8A IF$8B RESTORE$8C GOSUB$8D RETURN$8E REM
$8F STOP$90 ON$91 WAIT$92 LOAD$93 SAVE
$94 DEF$95 POKE$96 PRINT$97 CONT$98 LIST
$99 CLR$9A NEW$9B TAB$9C TO$9D FN
$9E SPC$9F THEN$A0 NOT$A1 STEP$A2 AND
$A3 OR$A4 ELSE$A5 SYS$A6 DIR$A7 DEL
$A8 CLS$A9 LOCATE$AA COLOR$AB SOUND$AC VOL
$AD TIME$AE DATE$AF SETTIME$B0 SETDATE$B1 NVRAM
$B2 PAUSE$B3 BANK$B4 BRK$B5 MEM$B6 SGN
$B7 INT$B8 ABS$B9 FRE$BA POS$BB SQR
$BC RND$BD LOG$BE EXP$BF COS$C0 SIN
$C1 TAN$C2 ATN$C3 PEEK$C4 LEN$C5 STR$
$C6 VAL$C7 ASC$C8 CHR$$C9 LEFT$$CA RIGHT$
$CB MID$$CC JOY$CD INKEY$CE HEX$CF MIN
$D0 MAX$D1 DISK$D2 BLOAD$D3 BSAVE$D4 FORMAT

Tokenizer Behaviour

bastok is a port of BasCrunch / BasMatchKeyword / BasStoreLine from BASIC.asm, and reproduces what the interpreter does rather than improving on it. Typing your source in by hand gives the same bytes.

  • Case is folded to uppercase outside of quoted strings. Text inside quotes, and everything after REM, is kept exactly as written.
  • Keywords match first, not longest. The interpreter walks the keyword table in token order and takes the first hit, so FORMAT tokenizes as FOR ($81) followed by the letters MAT. Type it into the machine and you get the same.
  • Keywords inside identifiers are tokenized.TOTAL=1 becomes TO ($9C) plus TAL=1, the classic MS BASIC hazard. Avoid variable names that contain keywords.
  • Spaces are preserved as typed — this BASIC does not squeeze them out.
  • Lines are stored in numeric order regardless of their order in the file. A repeated line number replaces the earlier line, and a bare line number with no statement deletes it, exactly as retyping would.
  • Blank lines are skipped. Lines without a line number are an error; a program file cannot hold immediate-mode statements.

Limits and errors

  • Source lines are capped at 200 characters (BAS_LINBUF_MAX) and tokenized payloads at 250 bytes (BAS_TOKBUF_MAX).
  • @ & [ ] { } | \ ` ~ are rejected — BasValidPunct does not accept them.
  • Only printable ASCII $20–$7E may appear in source; tabs are an error, since the machine's line editor cannot accept one.
  • A program that would run past the top of program RAM ($8000) is written, but warned about.

Detokenizing a byte in $80–$FF that is not a valid token emits {$xx} and a warning. Such a file will not tokenize back — { and } are illegal input.

Example

examples/guess.txt round-trips exactly:

bastok examples/guess.txt # -> examples/guess.prg
bastok -o - examples/guess.prg # lists it back, identical to the source

Development

Run in Development Mode

npm run build
node ./dist/index.js examples/guess.txt

Tests

npm test

Release Build

git tag vX.Y.Z
git push origin main --tags
npm publish

Project Structure

bastok/
├── src/
│ ├── index.ts # CLI entry point
│ ├── Bastok/
│ │ ├── Bastok.ts # File-level facade, direction detection
│ │ ├── Tokenizer.ts # Text -> program image (port of BasCrunch)
│ │ ├── Detokenizer.ts # Program image -> text (port of BasCmdList)
│ │ ├── Tokens.ts # Keyword table, transcribed from BASIC.asm
│ │ └── Errors.ts # BastokError
│ └── test/ # Round-trip and behaviour tests
├── examples/ # Sample BASIC programs
├── dist/ # Compiled JavaScript
├── package.json
├── tsconfig.json
└── README.md

Keeping in sync with the BIOS

src/Bastok/Tokens.ts mirrors KeywordTbl and the TOK_xxx equates in 6502-BIOS/BASIC.asm. If keywords are added, removed or reordered there, update the KEYWORDS array here to match — order determines both the token values and the matching behaviour.

Library Use

import{Bastok}from'bastok'constbastok=newBastok()const{ buffer, warnings }=bastok.tokenize('10 PRINT "HELLO"\n')const{ text }=bastok.detokenize(buffer)

Related

License

MIT: https://github.com/acwright/bastok/blob/main/LICENSE

Credits

Inspired by petcat from VICE.

About

A Node.js-based utility for converting BASIC source text to tokenized program images

www.npmjs.com/package/bastok

Resources

Readme
MIT license
Activity

Stars

0 stars

Watchers

0 watching

Forks

0 forks
Report repository

Releases

Contributors

Languages

, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

Skip to content
BranchesTags
Repository files navigation
bastok
 _ _ _ | |__ __ _ ___| |_ ___ | | __
| '_ \ / _` / __| __/ _ \| |/ /
| |_) | (_| \__ \ || (_) | < |_.__/ \__,_|___/\__\___/|_|\_\

A Node.js-based utility for converting BASIC source text to tokenized program
images (.prg / .bas) for the 6502 homebrew BIOS,
and back again. Write your BASIC on a real keyboard, tokenize it here, and drop
the result straight onto a CompactFlash card or send it over XMODEM.
Inspired by the petcat utility distributed with the VICE emulator.
📖 Guide:AC6502 Documentation — the user's and programmer's guide for the whole family.
See the tool belt and BASIC in a cross-dev workflow.
Installation
From NPM
npm install -g bastok

From Source
  1. Clone the repository:
git clone https://github.com/acwright/bastok.git
cd bastok

  1. Install dependencies:
npm install

  1. Build the project:
npm run build

  1. (Optional) Link globally:
npm link

Usage
bastok [options] <path>

The conversion direction is chosen from the file extension: .txt, .asc and
.bs are tokenized; .prg and .bas are detokenized. Anything else is
sniffed — a file of printable ASCII is treated as source, otherwise as a
program image. Use -t / -d to decide for yourself.
Tokenize
bastok game.txt

Writes game.prg. To pick the name and extension yourself:
bastok -o GAME.BAS game.txt

Detokenize
bastok game.prg

Writes game.txt. To list to the terminal instead:
bastok -o - game.prg

Command Line Options
  • -v, --version — Output the current version
  • -h, --help — Display help information
  • -t, --tokenize — Force text → tokenized binary
  • -d, --detokenize — Force tokenized binary → text
  • -o, --output <path> — Output file, or - for stdout
  • -a, --address <address> — Program load address in hex (default: 0x0800)
  • -H, --header — Read / write a 2-byte load address header
  • -c, --crlf — Emit CRLF line endings when detokenizing
  • -q, --quiet — Suppress warnings and the summary line
  • -T, --tokens — Print the token table and exit
Warnings and the "wrote N bytes" summary go to stderr, so -o - stays pipe-safe.
Getting the program onto the machine
The image bastok produces is byte-for-byte what BASIC's SAVE writes, so it
can be used directly:
bastok game.txt -o GAME.BAS # copy GAME.BAS to a CF card, then LOAD "GAME.BAS"
bastok game.txt -o game.prg # send game.prg with XMODEM after a bare LOAD

Load it with BASIC's LOAD, not by writing it straight into RAM. The image
is only half the story: BASIC also keeps VARTAB ($035F), the pointer to the
end of the program, in its workspace. LOAD walks the line chain and updates it
via BasFixChain; a debugger, monitor or emulator that just pokes the bytes
into $0800 does not.
If VARTAB is left at its post-NEW value of $0802, the program appears to
list and run correctly right up until it assigns its first variable — which is
written as a 7-byte record on top of line 10. The failure looks like this:
?UNDEF'D STATEMENT ERROR IN 90 GOTO can no longer find its target
LIST
78 FOR the variable table, listed as if it were a line

78 is the two name bytes of the variable N ($4E $00) read as a line
number, and FOR is $81, the exponent byte of its floating-point value. If
you must inject the image directly, set VARTAB, ARYTAB ($0361) and
STREND ($0363) to the load address plus the file size afterwards.
File Format
A tokenized program is a raw memory image of the program area starting at
$0800 (PROGRAM_START). There is no load-address header — SAVE writes
$0800 through VARTAB verbatim. Each line is:
[next-lo][next-hi][num-lo][num-hi][tokens...][$00]

and the program ends with a next-pointer of $0000, which is included in the
file. Next-pointers are absolute addresses, so they depend on the load address;
use -a if you are linking for somewhere other than $0800. LOAD relinks the
chain via BasFixChain anyway, so a stale pointer is harmless — bastok warns
about mismatches rather than refusing to read the file.
-H prepends (or consumes) a two-byte little-endian load address, the
Commodore .prg convention. The BIOS does not use it; it is there for
interoperating with other tools. When detokenizing with -H, the address in the
header wins over -a.
Tokens
85 keywords, $80–$D4, transcribed from KeywordTbl in BASIC.asm. Run
bastok --tokens for the full list.
$80 END$81 FOR$82 NEXT$83 DATA$84 INPUT
$85 DIM$86 READ$87 LET$88 GOTO$89 RUN
$8A IF$8B RESTORE$8C GOSUB$8D RETURN$8E REM
$8F STOP$90 ON$91 WAIT$92 LOAD$93 SAVE
$94 DEF$95 POKE$96 PRINT$97 CONT$98 LIST
$99 CLR$9A NEW$9B TAB$9C TO$9D FN
$9E SPC$9F THEN$A0 NOT$A1 STEP$A2 AND
$A3 OR$A4 ELSE$A5 SYS$A6 DIR$A7 DEL
$A8 CLS$A9 LOCATE$AA COLOR$AB SOUND$AC VOL
$AD TIME$AE DATE$AF SETTIME$B0 SETDATE$B1 NVRAM
$B2 PAUSE$B3 BANK$B4 BRK$B5 MEM$B6 SGN
$B7 INT$B8 ABS$B9 FRE$BA POS$BB SQR
$BC RND$BD LOG$BE EXP$BF COS$C0 SIN
$C1 TAN$C2 ATN$C3 PEEK$C4 LEN$C5 STR$
$C6 VAL$C7 ASC$C8 CHR$$C9 LEFT$$CA RIGHT$
$CB MID$$CC JOY$CD INKEY$CE HEX$CF MIN
$D0 MAX$D1 DISK$D2 BLOAD$D3 BSAVE$D4 FORMAT
Tokenizer Behaviour
bastok is a port of BasCrunch / BasMatchKeyword / BasStoreLine from
BASIC.asm, and reproduces what the interpreter does rather than improving on
it. Typing your source in by hand gives the same bytes.
  • Case is folded to uppercase outside of quoted strings. Text inside quotes,
and everything after REM, is kept exactly as written.
  • Keywords match first, not longest. The interpreter walks the keyword table
in token order and takes the first hit, so FORMAT tokenizes as FOR ($81)
followed by the letters MAT. Type it into the machine and you get the same.
  • Keywords inside identifiers are tokenized.TOTAL=1 becomes TO ($9C)
plus TAL=1, the classic MS BASIC hazard. Avoid variable names that contain
keywords.
  • Spaces are preserved as typed — this BASIC does not squeeze them out.
  • Lines are stored in numeric order regardless of their order in the file.
A repeated line number replaces the earlier line, and a bare line number with
no statement deletes it, exactly as retyping would.
  • Blank lines are skipped. Lines without a line number are an error; a
program file cannot hold immediate-mode statements.
Limits and errors
  • Source lines are capped at 200 characters (BAS_LINBUF_MAX) and tokenized
payloads at 250 bytes (BAS_TOKBUF_MAX).
  • @ & [ ] { } | \ ` ~ are rejected — BasValidPunct does not accept them.
  • Only printable ASCII $20–$7E may appear in source; tabs are an error,
since the machine's line editor cannot accept one.
  • A program that would run past the top of program RAM ($8000) is written,
but warned about.
Detokenizing a byte in $80–$FF that is not a valid token emits {$xx} and a
warning. Such a file will not tokenize back — { and } are illegal input.
Example
examples/guess.txt round-trips exactly:
bastok examples/guess.txt # -> examples/guess.prg
bastok -o - examples/guess.prg # lists it back, identical to the source

Development
Run in Development Mode
npm run build
node ./dist/index.js examples/guess.txt

Tests
npm test

Release Build
git tag vX.Y.Z
git push origin main --tags
npm publish

Project Structure
bastok/
├── src/
│ ├── index.ts # CLI entry point
│ ├── Bastok/
│ │ ├── Bastok.ts # File-level facade, direction detection
│ │ ├── Tokenizer.ts # Text -> program image (port of BasCrunch)
│ │ ├── Detokenizer.ts # Program image -> text (port of BasCmdList)
│ │ ├── Tokens.ts # Keyword table, transcribed from BASIC.asm
│ │ └── Errors.ts # BastokError
│ └── test/ # Round-trip and behaviour tests
├── examples/ # Sample BASIC programs
├── dist/ # Compiled JavaScript
├── package.json
├── tsconfig.json
└── README.md

Keeping in sync with the BIOS
src/Bastok/Tokens.ts mirrors KeywordTbl and the TOK_xxx equates in
6502-BIOS/BASIC.asm. If keywords are added, removed or reordered there, update
the KEYWORDS array here to match — order determines both the token values and
the matching behaviour.
Library Use
import{Bastok}from'bastok'constbastok=newBastok()const{ buffer, warnings }=bastok.tokenize('10 PRINT "HELLO"\n')const{ text }=bastok.detokenize(buffer)
Related
License
MIT: https://github.com/acwright/bastok/blob/main/LICENSE
Credits
Inspired by petcat from VICE.
About
A Node.js-based utility for converting BASIC source text to tokenized program images
www.npmjs.com/package/bastok
Resources
Readme
MIT license
Activity
Stars
0 stars
Watchers
0 watching
Forks
0 forks
Report repository
Releases
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
bastok
 _ _ _ | |__ __ _ ___| |_ ___ | | __
| '_ \ / _` / __| __/ _ \| |/ /
| |_) | (_| \__ \ || (_) | < |_.__/ \__,_|___/\__\___/|_|\_\

A Node.js-based utility for converting BASIC source text to tokenized program
images (.prg / .bas) for the 6502 homebrew BIOS,
and back again. Write your BASIC on a real keyboard, tokenize it here, and drop
the result straight onto a CompactFlash card or send it over XMODEM.
Inspired by the petcat utility distributed with the VICE emulator.
📖 Guide:AC6502 Documentation — the user's and programmer's guide for the whole family.
See the tool belt and BASIC in a cross-dev workflow.
Installation
From NPM
npm install -g bastok

From Source
  1. Clone the repository:
git clone https://github.com/acwright/bastok.git
cd bastok

  1. Install dependencies:
npm install

  1. Build the project:
npm run build

  1. (Optional) Link globally:
npm link

Usage
bastok [options] <path>

The conversion direction is chosen from the file extension: .txt, .asc and
.bs are tokenized; .prg and .bas are detokenized. Anything else is
sniffed — a file of printable ASCII is treated as source, otherwise as a
program image. Use -t / -d to decide for yourself.
Tokenize
bastok game.txt

Writes game.prg. To pick the name and extension yourself:
bastok -o GAME.BAS game.txt

Detokenize
bastok game.prg

Writes game.txt. To list to the terminal instead:
bastok -o - game.prg

Command Line Options
  • -v, --version — Output the current version
  • -h, --help — Display help information
  • -t, --tokenize — Force text → tokenized binary
  • -d, --detokenize — Force tokenized binary → text
  • -o, --output <path> — Output file, or - for stdout
  • -a, --address <address> — Program load address in hex (default: 0x0800)
  • -H, --header — Read / write a 2-byte load address header
  • -c, --crlf — Emit CRLF line endings when detokenizing
  • -q, --quiet — Suppress warnings and the summary line
  • -T, --tokens — Print the token table and exit
Warnings and the "wrote N bytes" summary go to stderr, so -o - stays pipe-safe.
Getting the program onto the machine
The image bastok produces is byte-for-byte what BASIC's SAVE writes, so it
can be used directly:
bastok game.txt -o GAME.BAS # copy GAME.BAS to a CF card, then LOAD "GAME.BAS"
bastok game.txt -o game.prg # send game.prg with XMODEM after a bare LOAD

Load it with BASIC's LOAD, not by writing it straight into RAM. The image
is only half the story: BASIC also keeps VARTAB ($035F), the pointer to the
end of the program, in its workspace. LOAD walks the line chain and updates it
via BasFixChain; a debugger, monitor or emulator that just pokes the bytes
into $0800 does not.
If VARTAB is left at its post-NEW value of $0802, the program appears to
list and run correctly right up until it assigns its first variable — which is
written as a 7-byte record on top of line 10. The failure looks like this:
?UNDEF'D STATEMENT ERROR IN 90 GOTO can no longer find its target
LIST
78 FOR the variable table, listed as if it were a line

78 is the two name bytes of the variable N ($4E $00) read as a line
number, and FOR is $81, the exponent byte of its floating-point value. If
you must inject the image directly, set VARTAB, ARYTAB ($0361) and
STREND ($0363) to the load address plus the file size afterwards.
File Format
A tokenized program is a raw memory image of the program area starting at
$0800 (PROGRAM_START). There is no load-address header — SAVE writes
$0800 through VARTAB verbatim. Each line is:
[next-lo][next-hi][num-lo][num-hi][tokens...][$00]

and the program ends with a next-pointer of $0000, which is included in the
file. Next-pointers are absolute addresses, so they depend on the load address;
use -a if you are linking for somewhere other than $0800. LOAD relinks the
chain via BasFixChain anyway, so a stale pointer is harmless — bastok warns
about mismatches rather than refusing to read the file.
-H prepends (or consumes) a two-byte little-endian load address, the
Commodore .prg convention. The BIOS does not use it; it is there for
interoperating with other tools. When detokenizing with -H, the address in the
header wins over -a.
Tokens
85 keywords, $80–$D4, transcribed from KeywordTbl in BASIC.asm. Run
bastok --tokens for the full list.
$80 END$81 FOR$82 NEXT$83 DATA$84 INPUT
$85 DIM$86 READ$87 LET$88 GOTO$89 RUN
$8A IF$8B RESTORE$8C GOSUB$8D RETURN$8E REM
$8F STOP$90 ON$91 WAIT$92 LOAD$93 SAVE
$94 DEF$95 POKE$96 PRINT$97 CONT$98 LIST
$99 CLR$9A NEW$9B TAB$9C TO$9D FN
$9E SPC$9F THEN$A0 NOT$A1 STEP$A2 AND
$A3 OR$A4 ELSE$A5 SYS$A6 DIR$A7 DEL
$A8 CLS$A9 LOCATE$AA COLOR$AB SOUND$AC VOL
$AD TIME$AE DATE$AF SETTIME$B0 SETDATE$B1 NVRAM
$B2 PAUSE$B3 BANK$B4 BRK$B5 MEM$B6 SGN
$B7 INT$B8 ABS$B9 FRE$BA POS$BB SQR
$BC RND$BD LOG$BE EXP$BF COS$C0 SIN
$C1 TAN$C2 ATN$C3 PEEK$C4 LEN$C5 STR$
$C6 VAL$C7 ASC$C8 CHR$$C9 LEFT$$CA RIGHT$
$CB MID$$CC JOY$CD INKEY$CE HEX$CF MIN
$D0 MAX$D1 DISK$D2 BLOAD$D3 BSAVE$D4 FORMAT
Tokenizer Behaviour
bastok is a port of BasCrunch / BasMatchKeyword / BasStoreLine from
BASIC.asm, and reproduces what the interpreter does rather than improving on
it. Typing your source in by hand gives the same bytes.
  • Case is folded to uppercase outside of quoted strings. Text inside quotes,
and everything after REM, is kept exactly as written.
  • Keywords match first, not longest. The interpreter walks the keyword table
in token order and takes the first hit, so FORMAT tokenizes as FOR ($81)
followed by the letters MAT. Type it into the machine and you get the same.
  • Keywords inside identifiers are tokenized.TOTAL=1 becomes TO ($9C)
plus TAL=1, the classic MS BASIC hazard. Avoid variable names that contain
keywords.
  • Spaces are preserved as typed — this BASIC does not squeeze them out.
  • Lines are stored in numeric order regardless of their order in the file.
A repeated line number replaces the earlier line, and a bare line number with
no statement deletes it, exactly as retyping would.
  • Blank lines are skipped. Lines without a line number are an error; a
program file cannot hold immediate-mode statements.
Limits and errors
  • Source lines are capped at 200 characters (BAS_LINBUF_MAX) and tokenized
payloads at 250 bytes (BAS_TOKBUF_MAX).
  • @ & [ ] { } | \ ` ~ are rejected — BasValidPunct does not accept them.
  • Only printable ASCII $20–$7E may appear in source; tabs are an error,
since the machine's line editor cannot accept one.
  • A program that would run past the top of program RAM ($8000) is written,
but warned about.
Detokenizing a byte in $80–$FF that is not a valid token emits {$xx} and a
warning. Such a file will not tokenize back — { and } are illegal input.
Example
examples/guess.txt round-trips exactly:
bastok examples/guess.txt # -> examples/guess.prg
bastok -o - examples/guess.prg # lists it back, identical to the source

Development
Run in Development Mode
npm run build
node ./dist/index.js examples/guess.txt

Tests
npm test

Release Build
git tag vX.Y.Z
git push origin main --tags
npm publish

Project Structure
bastok/
├── src/
│ ├── index.ts # CLI entry point
│ ├── Bastok/
│ │ ├── Bastok.ts # File-level facade, direction detection
│ │ ├── Tokenizer.ts # Text -> program image (port of BasCrunch)
│ │ ├── Detokenizer.ts # Program image -> text (port of BasCmdList)
│ │ ├── Tokens.ts # Keyword table, transcribed from BASIC.asm
│ │ └── Errors.ts # BastokError
│ └── test/ # Round-trip and behaviour tests
├── examples/ # Sample BASIC programs
├── dist/ # Compiled JavaScript
├── package.json
├── tsconfig.json
└── README.md

Keeping in sync with the BIOS
src/Bastok/Tokens.ts mirrors KeywordTbl and the TOK_xxx equates in
6502-BIOS/BASIC.asm. If keywords are added, removed or reordered there, update
the KEYWORDS array here to match — order determines both the token values and
the matching behaviour.
Library Use
import{Bastok}from'bastok'constbastok=newBastok()const{ buffer, warnings }=bastok.tokenize('10 PRINT "HELLO"\n')const{ text }=bastok.detokenize(buffer)
Related
License
MIT: https://github.com/acwright/bastok/blob/main/LICENSE
Credits
Inspired by petcat from VICE.
About
A Node.js-based utility for converting BASIC source text to tokenized program images
www.npmjs.com/package/bastok
Resources
Readme
MIT license
Activity
Stars
0 stars
Watchers
0 watching
Forks
0 forks
Report repository
Releases
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
bastok
 _ _ _ | |__ __ _ ___| |_ ___ | | __
| '_ \ / _` / __| __/ _ \| |/ /
| |_) | (_| \__ \ || (_) | < |_.__/ \__,_|___/\__\___/|_|\_\

A Node.js-based utility for converting BASIC source text to tokenized program
images (.prg / .bas) for the 6502 homebrew BIOS,
and back again. Write your BASIC on a real keyboard, tokenize it here, and drop
the result straight onto a CompactFlash card or send it over XMODEM.
Inspired by the petcat utility distributed with the VICE emulator.
📖 Guide:AC6502 Documentation — the user's and programmer's guide for the whole family.
See the tool belt and BASIC in a cross-dev workflow.
Installation
From NPM
npm install -g bastok

From Source
  1. Clone the repository:
git clone https://github.com/acwright/bastok.git
cd bastok

  1. Install dependencies:
npm install

  1. Build the project:
npm run build

  1. (Optional) Link globally:
npm link

Usage
bastok [options] <path>

The conversion direction is chosen from the file extension: .txt, .asc and
.bs are tokenized; .prg and .bas are detokenized. Anything else is
sniffed — a file of printable ASCII is treated as source, otherwise as a
program image. Use -t / -d to decide for yourself.
Tokenize
bastok game.txt

Writes game.prg. To pick the name and extension yourself:
bastok -o GAME.BAS game.txt

Detokenize
bastok game.prg

Writes game.txt. To list to the terminal instead:
bastok -o - game.prg

Command Line Options
  • -v, --version — Output the current version
  • -h, --help — Display help information
  • -t, --tokenize — Force text → tokenized binary
  • -d, --detokenize — Force tokenized binary → text
  • -o, --output <path> — Output file, or - for stdout
  • -a, --address <address> — Program load address in hex (default: 0x0800)
  • -H, --header — Read / write a 2-byte load address header
  • -c, --crlf — Emit CRLF line endings when detokenizing
  • -q, --quiet — Suppress warnings and the summary line
  • -T, --tokens — Print the token table and exit
Warnings and the "wrote N bytes" summary go to stderr, so -o - stays pipe-safe.
Getting the program onto the machine
The image bastok produces is byte-for-byte what BASIC's SAVE writes, so it
can be used directly:
bastok game.txt -o GAME.BAS # copy GAME.BAS to a CF card, then LOAD "GAME.BAS"
bastok game.txt -o game.prg # send game.prg with XMODEM after a bare LOAD

Load it with BASIC's LOAD, not by writing it straight into RAM. The image
is only half the story: BASIC also keeps VARTAB ($035F), the pointer to the
end of the program, in its workspace. LOAD walks the line chain and updates it
via BasFixChain; a debugger, monitor or emulator that just pokes the bytes
into $0800 does not.
If VARTAB is left at its post-NEW value of $0802, the program appears to
list and run correctly right up until it assigns its first variable — which is
written as a 7-byte record on top of line 10. The failure looks like this:
?UNDEF'D STATEMENT ERROR IN 90 GOTO can no longer find its target
LIST
78 FOR the variable table, listed as if it were a line

78 is the two name bytes of the variable N ($4E $00) read as a line
number, and FOR is $81, the exponent byte of its floating-point value. If
you must inject the image directly, set VARTAB, ARYTAB ($0361) and
STREND ($0363) to the load address plus the file size afterwards.
File Format
A tokenized program is a raw memory image of the program area starting at
$0800 (PROGRAM_START). There is no load-address header — SAVE writes
$0800 through VARTAB verbatim. Each line is:
[next-lo][next-hi][num-lo][num-hi][tokens...][$00]

and the program ends with a next-pointer of $0000, which is included in the
file. Next-pointers are absolute addresses, so they depend on the load address;
use -a if you are linking for somewhere other than $0800. LOAD relinks the
chain via BasFixChain anyway, so a stale pointer is harmless — bastok warns
about mismatches rather than refusing to read the file.
-H prepends (or consumes) a two-byte little-endian load address, the
Commodore .prg convention. The BIOS does not use it; it is there for
interoperating with other tools. When detokenizing with -H, the address in the
header wins over -a.
Tokens
85 keywords, $80–$D4, transcribed from KeywordTbl in BASIC.asm. Run
bastok --tokens for the full list.
$80 END$81 FOR$82 NEXT$83 DATA$84 INPUT
$85 DIM$86 READ$87 LET$88 GOTO$89 RUN
$8A IF$8B RESTORE$8C GOSUB$8D RETURN$8E REM
$8F STOP$90 ON$91 WAIT$92 LOAD$93 SAVE
$94 DEF$95 POKE$96 PRINT$97 CONT$98 LIST
$99 CLR$9A NEW$9B TAB$9C TO$9D FN
$9E SPC$9F THEN$A0 NOT$A1 STEP$A2 AND
$A3 OR$A4 ELSE$A5 SYS$A6 DIR$A7 DEL
$A8 CLS$A9 LOCATE$AA COLOR$AB SOUND$AC VOL
$AD TIME$AE DATE$AF SETTIME$B0 SETDATE$B1 NVRAM
$B2 PAUSE$B3 BANK$B4 BRK$B5 MEM$B6 SGN
$B7 INT$B8 ABS$B9 FRE$BA POS$BB SQR
$BC RND$BD LOG$BE EXP$BF COS$C0 SIN
$C1 TAN$C2 ATN$C3 PEEK$C4 LEN$C5 STR$
$C6 VAL$C7 ASC$C8 CHR$$C9 LEFT$$CA RIGHT$
$CB MID$$CC JOY$CD INKEY$CE HEX$CF MIN
$D0 MAX$D1 DISK$D2 BLOAD$D3 BSAVE$D4 FORMAT
Tokenizer Behaviour
bastok is a port of BasCrunch / BasMatchKeyword / BasStoreLine from
BASIC.asm, and reproduces what the interpreter does rather than improving on
it. Typing your source in by hand gives the same bytes.
  • Case is folded to uppercase outside of quoted strings. Text inside quotes,
and everything after REM, is kept exactly as written.
  • Keywords match first, not longest. The interpreter walks the keyword table
in token order and takes the first hit, so FORMAT tokenizes as FOR ($81)
followed by the letters MAT. Type it into the machine and you get the same.
  • Keywords inside identifiers are tokenized.TOTAL=1 becomes TO ($9C)
plus TAL=1, the classic MS BASIC hazard. Avoid variable names that contain
keywords.
  • Spaces are preserved as typed — this BASIC does not squeeze them out.
  • Lines are stored in numeric order regardless of their order in the file.
A repeated line number replaces the earlier line, and a bare line number with
no statement deletes it, exactly as retyping would.
  • Blank lines are skipped. Lines without a line number are an error; a
program file cannot hold immediate-mode statements.
Limits and errors
  • Source lines are capped at 200 characters (BAS_LINBUF_MAX) and tokenized
payloads at 250 bytes (BAS_TOKBUF_MAX).
  • @ & [ ] { } | \ ` ~ are rejected — BasValidPunct does not accept them.
  • Only printable ASCII $20–$7E may appear in source; tabs are an error,
since the machine's line editor cannot accept one.
  • A program that would run past the top of program RAM ($8000) is written,
but warned about.
Detokenizing a byte in $80–$FF that is not a valid token emits {$xx} and a
warning. Such a file will not tokenize back — { and } are illegal input.
Example
examples/guess.txt round-trips exactly:
bastok examples/guess.txt # -> examples/guess.prg
bastok -o - examples/guess.prg # lists it back, identical to the source

Development
Run in Development Mode
npm run build
node ./dist/index.js examples/guess.txt

Tests
npm test

Release Build
git tag vX.Y.Z
git push origin main --tags
npm publish

Project Structure
bastok/
├── src/
│ ├── index.ts # CLI entry point
│ ├── Bastok/
│ │ ├── Bastok.ts # File-level facade, direction detection
│ │ ├── Tokenizer.ts # Text -> program image (port of BasCrunch)
│ │ ├── Detokenizer.ts # Program image -> text (port of BasCmdList)
│ │ ├── Tokens.ts # Keyword table, transcribed from BASIC.asm
│ │ └── Errors.ts # BastokError
│ └── test/ # Round-trip and behaviour tests
├── examples/ # Sample BASIC programs
├── dist/ # Compiled JavaScript
├── package.json
├── tsconfig.json
└── README.md

Keeping in sync with the BIOS
src/Bastok/Tokens.ts mirrors KeywordTbl and the TOK_xxx equates in
6502-BIOS/BASIC.asm. If keywords are added, removed or reordered there, update
the KEYWORDS array here to match — order determines both the token values and
the matching behaviour.
Library Use
import{Bastok}from'bastok'constbastok=newBastok()const{ buffer, warnings }=bastok.tokenize('10 PRINT "HELLO"\n')const{ text }=bastok.detokenize(buffer)
Related
License
MIT: https://github.com/acwright/bastok/blob/main/LICENSE
Credits
Inspired by petcat from VICE.
About
A Node.js-based utility for converting BASIC source text to tokenized program images
www.npmjs.com/package/bastok
Resources
Readme
MIT license
Activity
Stars
0 stars
Watchers
0 watching
Forks
0 forks
Report repository
Releases
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

Skip to content
BranchesTags
Repository files navigation
bastok
 _ _ _ | |__ __ _ ___| |_ ___ | | __
| '_ \ / _` / __| __/ _ \| |/ /
| |_) | (_| \__ \ || (_) | < |_.__/ \__,_|___/\__\___/|_|\_\

A Node.js-based utility for converting BASIC source text to tokenized program
images (.prg / .bas) for the 6502 homebrew BIOS,
and back again. Write your BASIC on a real keyboard, tokenize it here, and drop
the result straight onto a CompactFlash card or send it over XMODEM.
Inspired by the petcat utility distributed with the VICE emulator.
📖 Guide:AC6502 Documentation — the user's and programmer's guide for the whole family.
See the tool belt and BASIC in a cross-dev workflow.
Installation
From NPM
npm install -g bastok

From Source
  1. Clone the repository:
git clone https://github.com/acwright/bastok.git
cd bastok

  1. Install dependencies:
npm install

  1. Build the project:
npm run build

  1. (Optional) Link globally:
npm link

Usage
bastok [options] <path>

The conversion direction is chosen from the file extension: .txt, .asc and
.bs are tokenized; .prg and .bas are detokenized. Anything else is
sniffed — a file of printable ASCII is treated as source, otherwise as a
program image. Use -t / -d to decide for yourself.
Tokenize
bastok game.txt

Writes game.prg. To pick the name and extension yourself:
bastok -o GAME.BAS game.txt

Detokenize
bastok game.prg

Writes game.txt. To list to the terminal instead:
bastok -o - game.prg

Command Line Options
  • -v, --version — Output the current version
  • -h, --help — Display help information
  • -t, --tokenize — Force text → tokenized binary
  • -d, --detokenize — Force tokenized binary → text
  • -o, --output <path> — Output file, or - for stdout
  • -a, --address <address> — Program load address in hex (default: 0x0800)
  • -H, --header — Read / write a 2-byte load address header
  • -c, --crlf — Emit CRLF line endings when detokenizing
  • -q, --quiet — Suppress warnings and the summary line
  • -T, --tokens — Print the token table and exit
Warnings and the "wrote N bytes" summary go to stderr, so -o - stays pipe-safe.
Getting the program onto the machine
The image bastok produces is byte-for-byte what BASIC's SAVE writes, so it
can be used directly:
bastok game.txt -o GAME.BAS # copy GAME.BAS to a CF card, then LOAD "GAME.BAS"
bastok game.txt -o game.prg # send game.prg with XMODEM after a bare LOAD

Load it with BASIC's LOAD, not by writing it straight into RAM. The image
is only half the story: BASIC also keeps VARTAB ($035F), the pointer to the
end of the program, in its workspace. LOAD walks the line chain and updates it
via BasFixChain; a debugger, monitor or emulator that just pokes the bytes
into $0800 does not.
If VARTAB is left at its post-NEW value of $0802, the program appears to
list and run correctly right up until it assigns its first variable — which is
written as a 7-byte record on top of line 10. The failure looks like this:
?UNDEF'D STATEMENT ERROR IN 90 GOTO can no longer find its target
LIST
78 FOR the variable table, listed as if it were a line

78 is the two name bytes of the variable N ($4E $00) read as a line
number, and FOR is $81, the exponent byte of its floating-point value. If
you must inject the image directly, set VARTAB, ARYTAB ($0361) and
STREND ($0363) to the load address plus the file size afterwards.
File Format
A tokenized program is a raw memory image of the program area starting at
$0800 (PROGRAM_START). There is no load-address header — SAVE writes
$0800 through VARTAB verbatim. Each line is:
[next-lo][next-hi][num-lo][num-hi][tokens...][$00]

and the program ends with a next-pointer of $0000, which is included in the
file. Next-pointers are absolute addresses, so they depend on the load address;
use -a if you are linking for somewhere other than $0800. LOAD relinks the
chain via BasFixChain anyway, so a stale pointer is harmless — bastok warns
about mismatches rather than refusing to read the file.
-H prepends (or consumes) a two-byte little-endian load address, the
Commodore .prg convention. The BIOS does not use it; it is there for
interoperating with other tools. When detokenizing with -H, the address in the
header wins over -a.
Tokens
85 keywords, $80–$D4, transcribed from KeywordTbl in BASIC.asm. Run
bastok --tokens for the full list.
$80 END$81 FOR$82 NEXT$83 DATA$84 INPUT
$85 DIM$86 READ$87 LET$88 GOTO$89 RUN
$8A IF$8B RESTORE$8C GOSUB$8D RETURN$8E REM
$8F STOP$90 ON$91 WAIT$92 LOAD$93 SAVE
$94 DEF$95 POKE$96 PRINT$97 CONT$98 LIST
$99 CLR$9A NEW$9B TAB$9C TO$9D FN
$9E SPC$9F THEN$A0 NOT$A1 STEP$A2 AND
$A3 OR$A4 ELSE$A5 SYS$A6 DIR$A7 DEL
$A8 CLS$A9 LOCATE$AA COLOR$AB SOUND$AC VOL
$AD TIME$AE DATE$AF SETTIME$B0 SETDATE$B1 NVRAM
$B2 PAUSE$B3 BANK$B4 BRK$B5 MEM$B6 SGN
$B7 INT$B8 ABS$B9 FRE$BA POS$BB SQR
$BC RND$BD LOG$BE EXP$BF COS$C0 SIN
$C1 TAN$C2 ATN$C3 PEEK$C4 LEN$C5 STR$
$C6 VAL$C7 ASC$C8 CHR$$C9 LEFT$$CA RIGHT$
$CB MID$$CC JOY$CD INKEY$CE HEX$CF MIN
$D0 MAX$D1 DISK$D2 BLOAD$D3 BSAVE$D4 FORMAT
Tokenizer Behaviour
bastok is a port of BasCrunch / BasMatchKeyword / BasStoreLine from
BASIC.asm, and reproduces what the interpreter does rather than improving on
it. Typing your source in by hand gives the same bytes.
  • Case is folded to uppercase outside of quoted strings. Text inside quotes,
and everything after REM, is kept exactly as written.
  • Keywords match first, not longest. The interpreter walks the keyword table
in token order and takes the first hit, so FORMAT tokenizes as FOR ($81)
followed by the letters MAT. Type it into the machine and you get the same.
  • Keywords inside identifiers are tokenized.TOTAL=1 becomes TO ($9C)
plus TAL=1, the classic MS BASIC hazard. Avoid variable names that contain
keywords.
  • Spaces are preserved as typed — this BASIC does not squeeze them out.
  • Lines are stored in numeric order regardless of their order in the file.
A repeated line number replaces the earlier line, and a bare line number with
no statement deletes it, exactly as retyping would.
  • Blank lines are skipped. Lines without a line number are an error; a
program file cannot hold immediate-mode statements.
Limits and errors
  • Source lines are capped at 200 characters (BAS_LINBUF_MAX) and tokenized
payloads at 250 bytes (BAS_TOKBUF_MAX).
  • @ & [ ] { } | \ ` ~ are rejected — BasValidPunct does not accept them.
  • Only printable ASCII $20–$7E may appear in source; tabs are an error,
since the machine's line editor cannot accept one.
  • A program that would run past the top of program RAM ($8000) is written,
but warned about.
Detokenizing a byte in $80–$FF that is not a valid token emits {$xx} and a
warning. Such a file will not tokenize back — { and } are illegal input.
Example
examples/guess.txt round-trips exactly:
bastok examples/guess.txt # -> examples/guess.prg
bastok -o - examples/guess.prg # lists it back, identical to the source

Development
Run in Development Mode
npm run build
node ./dist/index.js examples/guess.txt

Tests
npm test

Release Build
git tag vX.Y.Z
git push origin main --tags
npm publish

Project Structure
bastok/
├── src/
│ ├── index.ts # CLI entry point
│ ├── Bastok/
│ │ ├── Bastok.ts # File-level facade, direction detection
│ │ ├── Tokenizer.ts # Text -> program image (port of BasCrunch)
│ │ ├── Detokenizer.ts # Program image -> text (port of BasCmdList)
│ │ ├── Tokens.ts # Keyword table, transcribed from BASIC.asm
│ │ └── Errors.ts # BastokError
│ └── test/ # Round-trip and behaviour tests
├── examples/ # Sample BASIC programs
├── dist/ # Compiled JavaScript
├── package.json
├── tsconfig.json
└── README.md

Keeping in sync with the BIOS
src/Bastok/Tokens.ts mirrors KeywordTbl and the TOK_xxx equates in
6502-BIOS/BASIC.asm. If keywords are added, removed or reordered there, update
the KEYWORDS array here to match — order determines both the token values and
the matching behaviour.
Library Use
import{Bastok}from'bastok'constbastok=newBastok()const{ buffer, warnings }=bastok.tokenize('10 PRINT "HELLO"\n')const{ text }=bastok.detokenize(buffer)
Related
License
MIT: https://github.com/acwright/bastok/blob/main/LICENSE
Credits
Inspired by petcat from VICE.
About
A Node.js-based utility for converting BASIC source text to tokenized program images
www.npmjs.com/package/bastok
Resources
Readme
MIT license
Activity
Stars
0 stars
Watchers
0 watching
Forks
0 forks
Report repository
Releases
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
bastok
 _ _ _ | |__ __ _ ___| |_ ___ | | __
| '_ \ / _` / __| __/ _ \| |/ /
| |_) | (_| \__ \ || (_) | < |_.__/ \__,_|___/\__\___/|_|\_\

A Node.js-based utility for converting BASIC source text to tokenized program
images (.prg / .bas) for the 6502 homebrew BIOS,
and back again. Write your BASIC on a real keyboard, tokenize it here, and drop
the result straight onto a CompactFlash card or send it over XMODEM.
Inspired by the petcat utility distributed with the VICE emulator.
📖 Guide:AC6502 Documentation — the user's and programmer's guide for the whole family.
See the tool belt and BASIC in a cross-dev workflow.
Installation
From NPM
npm install -g bastok

From Source
  1. Clone the repository:
git clone https://github.com/acwright/bastok.git
cd bastok

  1. Install dependencies:
npm install

  1. Build the project:
npm run build

  1. (Optional) Link globally:
npm link

Usage
bastok [options] <path>

The conversion direction is chosen from the file extension: .txt, .asc and
.bs are tokenized; .prg and .bas are detokenized. Anything else is
sniffed — a file of printable ASCII is treated as source, otherwise as a
program image. Use -t / -d to decide for yourself.
Tokenize
bastok game.txt

Writes game.prg. To pick the name and extension yourself:
bastok -o GAME.BAS game.txt

Detokenize
bastok game.prg

Writes game.txt. To list to the terminal instead:
bastok -o - game.prg

Command Line Options
  • -v, --version — Output the current version
  • -h, --help — Display help information
  • -t, --tokenize — Force text → tokenized binary
  • -d, --detokenize — Force tokenized binary → text
  • -o, --output <path> — Output file, or - for stdout
  • -a, --address <address> — Program load address in hex (default: 0x0800)
  • -H, --header — Read / write a 2-byte load address header
  • -c, --crlf — Emit CRLF line endings when detokenizing
  • -q, --quiet — Suppress warnings and the summary line
  • -T, --tokens — Print the token table and exit
Warnings and the "wrote N bytes" summary go to stderr, so -o - stays pipe-safe.
Getting the program onto the machine
The image bastok produces is byte-for-byte what BASIC's SAVE writes, so it
can be used directly:
bastok game.txt -o GAME.BAS # copy GAME.BAS to a CF card, then LOAD "GAME.BAS"
bastok game.txt -o game.prg # send game.prg with XMODEM after a bare LOAD

Load it with BASIC's LOAD, not by writing it straight into RAM. The image
is only half the story: BASIC also keeps VARTAB ($035F), the pointer to the
end of the program, in its workspace. LOAD walks the line chain and updates it
via BasFixChain; a debugger, monitor or emulator that just pokes the bytes
into $0800 does not.
If VARTAB is left at its post-NEW value of $0802, the program appears to
list and run correctly right up until it assigns its first variable — which is
written as a 7-byte record on top of line 10. The failure looks like this:
?UNDEF'D STATEMENT ERROR IN 90 GOTO can no longer find its target
LIST
78 FOR the variable table, listed as if it were a line

78 is the two name bytes of the variable N ($4E $00) read as a line
number, and FOR is $81, the exponent byte of its floating-point value. If
you must inject the image directly, set VARTAB, ARYTAB ($0361) and
STREND ($0363) to the load address plus the file size afterwards.
File Format
A tokenized program is a raw memory image of the program area starting at
$0800 (PROGRAM_START). There is no load-address header — SAVE writes
$0800 through VARTAB verbatim. Each line is:
[next-lo][next-hi][num-lo][num-hi][tokens...][$00]

and the program ends with a next-pointer of $0000, which is included in the
file. Next-pointers are absolute addresses, so they depend on the load address;
use -a if you are linking for somewhere other than $0800. LOAD relinks the
chain via BasFixChain anyway, so a stale pointer is harmless — bastok warns
about mismatches rather than refusing to read the file.
-H prepends (or consumes) a two-byte little-endian load address, the
Commodore .prg convention. The BIOS does not use it; it is there for
interoperating with other tools. When detokenizing with -H, the address in the
header wins over -a.
Tokens
85 keywords, $80–$D4, transcribed from KeywordTbl in BASIC.asm. Run
bastok --tokens for the full list.
$80 END$81 FOR$82 NEXT$83 DATA$84 INPUT
$85 DIM$86 READ$87 LET$88 GOTO$89 RUN
$8A IF$8B RESTORE$8C GOSUB$8D RETURN$8E REM
$8F STOP$90 ON$91 WAIT$92 LOAD$93 SAVE
$94 DEF$95 POKE$96 PRINT$97 CONT$98 LIST
$99 CLR$9A NEW$9B TAB$9C TO$9D FN
$9E SPC$9F THEN$A0 NOT$A1 STEP$A2 AND
$A3 OR$A4 ELSE$A5 SYS$A6 DIR$A7 DEL
$A8 CLS$A9 LOCATE$AA COLOR$AB SOUND$AC VOL
$AD TIME$AE DATE$AF SETTIME$B0 SETDATE$B1 NVRAM
$B2 PAUSE$B3 BANK$B4 BRK$B5 MEM$B6 SGN
$B7 INT$B8 ABS$B9 FRE$BA POS$BB SQR
$BC RND$BD LOG$BE EXP$BF COS$C0 SIN
$C1 TAN$C2 ATN$C3 PEEK$C4 LEN$C5 STR$
$C6 VAL$C7 ASC$C8 CHR$$C9 LEFT$$CA RIGHT$
$CB MID$$CC JOY$CD INKEY$CE HEX$CF MIN
$D0 MAX$D1 DISK$D2 BLOAD$D3 BSAVE$D4 FORMAT
Tokenizer Behaviour
bastok is a port of BasCrunch / BasMatchKeyword / BasStoreLine from
BASIC.asm, and reproduces what the interpreter does rather than improving on
it. Typing your source in by hand gives the same bytes.
  • Case is folded to uppercase outside of quoted strings. Text inside quotes,
and everything after REM, is kept exactly as written.
  • Keywords match first, not longest. The interpreter walks the keyword table
in token order and takes the first hit, so FORMAT tokenizes as FOR ($81)
followed by the letters MAT. Type it into the machine and you get the same.
  • Keywords inside identifiers are tokenized.TOTAL=1 becomes TO ($9C)
plus TAL=1, the classic MS BASIC hazard. Avoid variable names that contain
keywords.
  • Spaces are preserved as typed — this BASIC does not squeeze them out.
  • Lines are stored in numeric order regardless of their order in the file.
A repeated line number replaces the earlier line, and a bare line number with
no statement deletes it, exactly as retyping would.
  • Blank lines are skipped. Lines without a line number are an error; a
program file cannot hold immediate-mode statements.
Limits and errors
  • Source lines are capped at 200 characters (BAS_LINBUF_MAX) and tokenized
payloads at 250 bytes (BAS_TOKBUF_MAX).
  • @ & [ ] { } | \ ` ~ are rejected — BasValidPunct does not accept them.
  • Only printable ASCII $20–$7E may appear in source; tabs are an error,
since the machine's line editor cannot accept one.
  • A program that would run past the top of program RAM ($8000) is written,
but warned about.
Detokenizing a byte in $80–$FF that is not a valid token emits {$xx} and a
warning. Such a file will not tokenize back — { and } are illegal input.
Example
examples/guess.txt round-trips exactly:
bastok examples/guess.txt # -> examples/guess.prg
bastok -o - examples/guess.prg # lists it back, identical to the source

Development
Run in Development Mode
npm run build
node ./dist/index.js examples/guess.txt

Tests
npm test

Release Build
git tag vX.Y.Z
git push origin main --tags
npm publish

Project Structure
bastok/
├── src/
│ ├── index.ts # CLI entry point
│ ├── Bastok/
│ │ ├── Bastok.ts # File-level facade, direction detection
│ │ ├── Tokenizer.ts # Text -> program image (port of BasCrunch)
│ │ ├── Detokenizer.ts # Program image -> text (port of BasCmdList)
│ │ ├── Tokens.ts # Keyword table, transcribed from BASIC.asm
│ │ └── Errors.ts # BastokError
│ └── test/ # Round-trip and behaviour tests
├── examples/ # Sample BASIC programs
├── dist/ # Compiled JavaScript
├── package.json
├── tsconfig.json
└── README.md

Keeping in sync with the BIOS
src/Bastok/Tokens.ts mirrors KeywordTbl and the TOK_xxx equates in
6502-BIOS/BASIC.asm. If keywords are added, removed or reordered there, update
the KEYWORDS array here to match — order determines both the token values and
the matching behaviour.
Library Use
import{Bastok}from'bastok'constbastok=newBastok()const{ buffer, warnings }=bastok.tokenize('10 PRINT "HELLO"\n')const{ text }=bastok.detokenize(buffer)
Related
License
MIT: https://github.com/acwright/bastok/blob/main/LICENSE
Credits
Inspired by petcat from VICE.
About
A Node.js-based utility for converting BASIC source text to tokenized program images
www.npmjs.com/package/bastok
Resources
Readme
MIT license
Activity
Stars
0 stars
Watchers
0 watching
Forks
0 forks
Report repository
Releases
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
bastok
 _ _ _ | |__ __ _ ___| |_ ___ | | __
| '_ \ / _` / __| __/ _ \| |/ /
| |_) | (_| \__ \ || (_) | < |_.__/ \__,_|___/\__\___/|_|\_\

A Node.js-based utility for converting BASIC source text to tokenized program
images (.prg / .bas) for the 6502 homebrew BIOS,
and back again. Write your BASIC on a real keyboard, tokenize it here, and drop
the result straight onto a CompactFlash card or send it over XMODEM.
Inspired by the petcat utility distributed with the VICE emulator.
📖 Guide:AC6502 Documentation — the user's and programmer's guide for the whole family.
See the tool belt and BASIC in a cross-dev workflow.
Installation
From NPM
npm install -g bastok

From Source
  1. Clone the repository:
git clone https://github.com/acwright/bastok.git
cd bastok

  1. Install dependencies:
npm install

  1. Build the project:
npm run build

  1. (Optional) Link globally:
npm link

Usage
bastok [options] <path>

The conversion direction is chosen from the file extension: .txt, .asc and
.bs are tokenized; .prg and .bas are detokenized. Anything else is
sniffed — a file of printable ASCII is treated as source, otherwise as a
program image. Use -t / -d to decide for yourself.
Tokenize
bastok game.txt

Writes game.prg. To pick the name and extension yourself:
bastok -o GAME.BAS game.txt

Detokenize
bastok game.prg

Writes game.txt. To list to the terminal instead:
bastok -o - game.prg

Command Line Options
  • -v, --version — Output the current version
  • -h, --help — Display help information
  • -t, --tokenize — Force text → tokenized binary
  • -d, --detokenize — Force tokenized binary → text
  • -o, --output <path> — Output file, or - for stdout
  • -a, --address <address> — Program load address in hex (default: 0x0800)
  • -H, --header — Read / write a 2-byte load address header
  • -c, --crlf — Emit CRLF line endings when detokenizing
  • -q, --quiet — Suppress warnings and the summary line
  • -T, --tokens — Print the token table and exit
Warnings and the "wrote N bytes" summary go to stderr, so -o - stays pipe-safe.
Getting the program onto the machine
The image bastok produces is byte-for-byte what BASIC's SAVE writes, so it
can be used directly:
bastok game.txt -o GAME.BAS # copy GAME.BAS to a CF card, then LOAD "GAME.BAS"
bastok game.txt -o game.prg # send game.prg with XMODEM after a bare LOAD

Load it with BASIC's LOAD, not by writing it straight into RAM. The image
is only half the story: BASIC also keeps VARTAB ($035F), the pointer to the
end of the program, in its workspace. LOAD walks the line chain and updates it
via BasFixChain; a debugger, monitor or emulator that just pokes the bytes
into $0800 does not.
If VARTAB is left at its post-NEW value of $0802, the program appears to
list and run correctly right up until it assigns its first variable — which is
written as a 7-byte record on top of line 10. The failure looks like this:
?UNDEF'D STATEMENT ERROR IN 90 GOTO can no longer find its target
LIST
78 FOR the variable table, listed as if it were a line

78 is the two name bytes of the variable N ($4E $00) read as a line
number, and FOR is $81, the exponent byte of its floating-point value. If
you must inject the image directly, set VARTAB, ARYTAB ($0361) and
STREND ($0363) to the load address plus the file size afterwards.
File Format
A tokenized program is a raw memory image of the program area starting at
$0800 (PROGRAM_START). There is no load-address header — SAVE writes
$0800 through VARTAB verbatim. Each line is:
[next-lo][next-hi][num-lo][num-hi][tokens...][$00]

and the program ends with a next-pointer of $0000, which is included in the
file. Next-pointers are absolute addresses, so they depend on the load address;
use -a if you are linking for somewhere other than $0800. LOAD relinks the
chain via BasFixChain anyway, so a stale pointer is harmless — bastok warns
about mismatches rather than refusing to read the file.
-H prepends (or consumes) a two-byte little-endian load address, the
Commodore .prg convention. The BIOS does not use it; it is there for
interoperating with other tools. When detokenizing with -H, the address in the
header wins over -a.
Tokens
85 keywords, $80–$D4, transcribed from KeywordTbl in BASIC.asm. Run
bastok --tokens for the full list.
$80 END$81 FOR$82 NEXT$83 DATA$84 INPUT
$85 DIM$86 READ$87 LET$88 GOTO$89 RUN
$8A IF$8B RESTORE$8C GOSUB$8D RETURN$8E REM
$8F STOP$90 ON$91 WAIT$92 LOAD$93 SAVE
$94 DEF$95 POKE$96 PRINT$97 CONT$98 LIST
$99 CLR$9A NEW$9B TAB$9C TO$9D FN
$9E SPC$9F THEN$A0 NOT$A1 STEP$A2 AND
$A3 OR$A4 ELSE$A5 SYS$A6 DIR$A7 DEL
$A8 CLS$A9 LOCATE$AA COLOR$AB SOUND$AC VOL
$AD TIME$AE DATE$AF SETTIME$B0 SETDATE$B1 NVRAM
$B2 PAUSE$B3 BANK$B4 BRK$B5 MEM$B6 SGN
$B7 INT$B8 ABS$B9 FRE$BA POS$BB SQR
$BC RND$BD LOG$BE EXP$BF COS$C0 SIN
$C1 TAN$C2 ATN$C3 PEEK$C4 LEN$C5 STR$
$C6 VAL$C7 ASC$C8 CHR$$C9 LEFT$$CA RIGHT$
$CB MID$$CC JOY$CD INKEY$CE HEX$CF MIN
$D0 MAX$D1 DISK$D2 BLOAD$D3 BSAVE$D4 FORMAT
Tokenizer Behaviour
bastok is a port of BasCrunch / BasMatchKeyword / BasStoreLine from
BASIC.asm, and reproduces what the interpreter does rather than improving on
it. Typing your source in by hand gives the same bytes.
  • Case is folded to uppercase outside of quoted strings. Text inside quotes,
and everything after REM, is kept exactly as written.
  • Keywords match first, not longest. The interpreter walks the keyword table
in token order and takes the first hit, so FORMAT tokenizes as FOR ($81)
followed by the letters MAT. Type it into the machine and you get the same.
  • Keywords inside identifiers are tokenized.TOTAL=1 becomes TO ($9C)
plus TAL=1, the classic MS BASIC hazard. Avoid variable names that contain
keywords.
  • Spaces are preserved as typed — this BASIC does not squeeze them out.
  • Lines are stored in numeric order regardless of their order in the file.
A repeated line number replaces the earlier line, and a bare line number with
no statement deletes it, exactly as retyping would.
  • Blank lines are skipped. Lines without a line number are an error; a
program file cannot hold immediate-mode statements.
Limits and errors
  • Source lines are capped at 200 characters (BAS_LINBUF_MAX) and tokenized
payloads at 250 bytes (BAS_TOKBUF_MAX).
  • @ & [ ] { } | \ ` ~ are rejected — BasValidPunct does not accept them.
  • Only printable ASCII $20–$7E may appear in source; tabs are an error,
since the machine's line editor cannot accept one.
  • A program that would run past the top of program RAM ($8000) is written,
but warned about.
Detokenizing a byte in $80–$FF that is not a valid token emits {$xx} and a
warning. Such a file will not tokenize back — { and } are illegal input.
Example
examples/guess.txt round-trips exactly:
bastok examples/guess.txt # -> examples/guess.prg
bastok -o - examples/guess.prg # lists it back, identical to the source

Development
Run in Development Mode
npm run build
node ./dist/index.js examples/guess.txt

Tests
npm test

Release Build
git tag vX.Y.Z
git push origin main --tags
npm publish

Project Structure
bastok/
├── src/
│ ├── index.ts # CLI entry point
│ ├── Bastok/
│ │ ├── Bastok.ts # File-level facade, direction detection
│ │ ├── Tokenizer.ts # Text -> program image (port of BasCrunch)
│ │ ├── Detokenizer.ts # Program image -> text (port of BasCmdList)
│ │ ├── Tokens.ts # Keyword table, transcribed from BASIC.asm
│ │ └── Errors.ts # BastokError
│ └── test/ # Round-trip and behaviour tests
├── examples/ # Sample BASIC programs
├── dist/ # Compiled JavaScript
├── package.json
├── tsconfig.json
└── README.md

Keeping in sync with the BIOS
src/Bastok/Tokens.ts mirrors KeywordTbl and the TOK_xxx equates in
6502-BIOS/BASIC.asm. If keywords are added, removed or reordered there, update
the KEYWORDS array here to match — order determines both the token values and
the matching behaviour.
Library Use
import{Bastok}from'bastok'constbastok=newBastok()const{ buffer, warnings }=bastok.tokenize('10 PRINT "HELLO"\n')const{ text }=bastok.detokenize(buffer)
Related
License
MIT: https://github.com/acwright/bastok/blob/main/LICENSE
Credits
Inspired by petcat from VICE.
About
A Node.js-based utility for converting BASIC source text to tokenized program images
www.npmjs.com/package/bastok
Resources
Readme
MIT license
Activity
Stars
0 stars
Watchers
0 watching
Forks
0 forks
Report repository
Releases
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

Skip to content
BranchesTags
Repository files navigation
bastok
 _ _ _ | |__ __ _ ___| |_ ___ | | __
| '_ \ / _` / __| __/ _ \| |/ /
| |_) | (_| \__ \ || (_) | < |_.__/ \__,_|___/\__\___/|_|\_\

A Node.js-based utility for converting BASIC source text to tokenized program
images (.prg / .bas) for the 6502 homebrew BIOS,
and back again. Write your BASIC on a real keyboard, tokenize it here, and drop
the result straight onto a CompactFlash card or send it over XMODEM.
Inspired by the petcat utility distributed with the VICE emulator.
📖 Guide:AC6502 Documentation — the user's and programmer's guide for the whole family.
See the tool belt and BASIC in a cross-dev workflow.
Installation
From NPM
npm install -g bastok

From Source
  1. Clone the repository:
git clone https://github.com/acwright/bastok.git
cd bastok

  1. Install dependencies:
npm install

  1. Build the project:
npm run build

  1. (Optional) Link globally:
npm link

Usage
bastok [options] <path>

The conversion direction is chosen from the file extension: .txt, .asc and
.bs are tokenized; .prg and .bas are detokenized. Anything else is
sniffed — a file of printable ASCII is treated as source, otherwise as a
program image. Use -t / -d to decide for yourself.
Tokenize
bastok game.txt

Writes game.prg. To pick the name and extension yourself:
bastok -o GAME.BAS game.txt

Detokenize
bastok game.prg

Writes game.txt. To list to the terminal instead:
bastok -o - game.prg

Command Line Options
  • -v, --version — Output the current version
  • -h, --help — Display help information
  • -t, --tokenize — Force text → tokenized binary
  • -d, --detokenize — Force tokenized binary → text
  • -o, --output <path> — Output file, or - for stdout
  • -a, --address <address> — Program load address in hex (default: 0x0800)
  • -H, --header — Read / write a 2-byte load address header
  • -c, --crlf — Emit CRLF line endings when detokenizing
  • -q, --quiet — Suppress warnings and the summary line
  • -T, --tokens — Print the token table and exit
Warnings and the "wrote N bytes" summary go to stderr, so -o - stays pipe-safe.
Getting the program onto the machine
The image bastok produces is byte-for-byte what BASIC's SAVE writes, so it
can be used directly:
bastok game.txt -o GAME.BAS # copy GAME.BAS to a CF card, then LOAD "GAME.BAS"
bastok game.txt -o game.prg # send game.prg with XMODEM after a bare LOAD

Load it with BASIC's LOAD, not by writing it straight into RAM. The image
is only half the story: BASIC also keeps VARTAB ($035F), the pointer to the
end of the program, in its workspace. LOAD walks the line chain and updates it
via BasFixChain; a debugger, monitor or emulator that just pokes the bytes
into $0800 does not.
If VARTAB is left at its post-NEW value of $0802, the program appears to
list and run correctly right up until it assigns its first variable — which is
written as a 7-byte record on top of line 10. The failure looks like this:
?UNDEF'D STATEMENT ERROR IN 90 GOTO can no longer find its target
LIST
78 FOR the variable table, listed as if it were a line

78 is the two name bytes of the variable N ($4E $00) read as a line
number, and FOR is $81, the exponent byte of its floating-point value. If
you must inject the image directly, set VARTAB, ARYTAB ($0361) and
STREND ($0363) to the load address plus the file size afterwards.
File Format
A tokenized program is a raw memory image of the program area starting at
$0800 (PROGRAM_START). There is no load-address header — SAVE writes
$0800 through VARTAB verbatim. Each line is:
[next-lo][next-hi][num-lo][num-hi][tokens...][$00]

and the program ends with a next-pointer of $0000, which is included in the
file. Next-pointers are absolute addresses, so they depend on the load address;
use -a if you are linking for somewhere other than $0800. LOAD relinks the
chain via BasFixChain anyway, so a stale pointer is harmless — bastok warns
about mismatches rather than refusing to read the file.
-H prepends (or consumes) a two-byte little-endian load address, the
Commodore .prg convention. The BIOS does not use it; it is there for
interoperating with other tools. When detokenizing with -H, the address in the
header wins over -a.
Tokens
85 keywords, $80–$D4, transcribed from KeywordTbl in BASIC.asm. Run
bastok --tokens for the full list.
$80 END$81 FOR$82 NEXT$83 DATA$84 INPUT
$85 DIM$86 READ$87 LET$88 GOTO$89 RUN
$8A IF$8B RESTORE$8C GOSUB$8D RETURN$8E REM
$8F STOP$90 ON$91 WAIT$92 LOAD$93 SAVE
$94 DEF$95 POKE$96 PRINT$97 CONT$98 LIST
$99 CLR$9A NEW$9B TAB$9C TO$9D FN
$9E SPC$9F THEN$A0 NOT$A1 STEP$A2 AND
$A3 OR$A4 ELSE$A5 SYS$A6 DIR$A7 DEL
$A8 CLS$A9 LOCATE$AA COLOR$AB SOUND$AC VOL
$AD TIME$AE DATE$AF SETTIME$B0 SETDATE$B1 NVRAM
$B2 PAUSE$B3 BANK$B4 BRK$B5 MEM$B6 SGN
$B7 INT$B8 ABS$B9 FRE$BA POS$BB SQR
$BC RND$BD LOG$BE EXP$BF COS$C0 SIN
$C1 TAN$C2 ATN$C3 PEEK$C4 LEN$C5 STR$
$C6 VAL$C7 ASC$C8 CHR$$C9 LEFT$$CA RIGHT$
$CB MID$$CC JOY$CD INKEY$CE HEX$CF MIN
$D0 MAX$D1 DISK$D2 BLOAD$D3 BSAVE$D4 FORMAT
Tokenizer Behaviour
bastok is a port of BasCrunch / BasMatchKeyword / BasStoreLine from
BASIC.asm, and reproduces what the interpreter does rather than improving on
it. Typing your source in by hand gives the same bytes.
  • Case is folded to uppercase outside of quoted strings. Text inside quotes,
and everything after REM, is kept exactly as written.
  • Keywords match first, not longest. The interpreter walks the keyword table
in token order and takes the first hit, so FORMAT tokenizes as FOR ($81)
followed by the letters MAT. Type it into the machine and you get the same.
  • Keywords inside identifiers are tokenized.TOTAL=1 becomes TO ($9C)
plus TAL=1, the classic MS BASIC hazard. Avoid variable names that contain
keywords.
  • Spaces are preserved as typed — this BASIC does not squeeze them out.
  • Lines are stored in numeric order regardless of their order in the file.
A repeated line number replaces the earlier line, and a bare line number with
no statement deletes it, exactly as retyping would.
  • Blank lines are skipped. Lines without a line number are an error; a
program file cannot hold immediate-mode statements.
Limits and errors
  • Source lines are capped at 200 characters (BAS_LINBUF_MAX) and tokenized
payloads at 250 bytes (BAS_TOKBUF_MAX).
  • @ & [ ] { } | \ ` ~ are rejected — BasValidPunct does not accept them.
  • Only printable ASCII $20–$7E may appear in source; tabs are an error,
since the machine's line editor cannot accept one.
  • A program that would run past the top of program RAM ($8000) is written,
but warned about.
Detokenizing a byte in $80–$FF that is not a valid token emits {$xx} and a
warning. Such a file will not tokenize back — { and } are illegal input.
Example
examples/guess.txt round-trips exactly:
bastok examples/guess.txt # -> examples/guess.prg
bastok -o - examples/guess.prg # lists it back, identical to the source

Development
Run in Development Mode
npm run build
node ./dist/index.js examples/guess.txt

Tests
npm test

Release Build
git tag vX.Y.Z
git push origin main --tags
npm publish

Project Structure
bastok/
├── src/
│ ├── index.ts # CLI entry point
│ ├── Bastok/
│ │ ├── Bastok.ts # File-level facade, direction detection
│ │ ├── Tokenizer.ts # Text -> program image (port of BasCrunch)
│ │ ├── Detokenizer.ts # Program image -> text (port of BasCmdList)
│ │ ├── Tokens.ts # Keyword table, transcribed from BASIC.asm
│ │ └── Errors.ts # BastokError
│ └── test/ # Round-trip and behaviour tests
├── examples/ # Sample BASIC programs
├── dist/ # Compiled JavaScript
├── package.json
├── tsconfig.json
└── README.md

Keeping in sync with the BIOS
src/Bastok/Tokens.ts mirrors KeywordTbl and the TOK_xxx equates in
6502-BIOS/BASIC.asm. If keywords are added, removed or reordered there, update
the KEYWORDS array here to match — order determines both the token values and
the matching behaviour.
Library Use
import{Bastok}from'bastok'constbastok=newBastok()const{ buffer, warnings }=bastok.tokenize('10 PRINT "HELLO"\n')const{ text }=bastok.detokenize(buffer)
Related
License
MIT: https://github.com/acwright/bastok/blob/main/LICENSE
Credits
Inspired by petcat from VICE.
About
A Node.js-based utility for converting BASIC source text to tokenized program images
www.npmjs.com/package/bastok
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