Apple-2-SW
/
jsbasic
mirror of https://github.com/inexorabletash/jsbasic.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
Applesoft BASIC in JavaScript
64 Commits 1 Branch 0 Tags 1.1 MiB
JavaScript 61.4%
CSS 23.3%
HTML 15.3%
Go to file
Joshua Bell 0a509a7360 Squish the font bitmaps 2013-08-18 15:30:55 -07:00
cm Simplify tokenizers; remove jslint cruft 2013-08-16 19:53:09 -07:00
samples Tweak demo 2013-08-17 22:04:19 -07:00
tools Squish the font bitmaps 2013-08-18 15:30:55 -07:00
vfs Snapshot 2012-02-08 22:13:44 -05:00
.gitignore Remove old ignore entry 2013-05-08 00:00:56 -04:00
CHANGELOG Added CHANGELOG of pre-git changes 2013-05-06 23:23:50 -04:00
LICENSE.md Create LICENSE.md 2013-05-07 21:31:47 -07:00
README.md Move cscript/rhino console support to separate file 2013-08-16 21:00:47 -07:00
basic.js Parse error cleanup. Don't tokenize digraphs. 2013-08-17 16:00:23 -07:00
bell.js Inline audio snippets via data: URLs 2013-08-17 22:40:29 -07:00
bell.wav Snapshot 2012-02-08 22:13:44 -05:00
cbasic.js Move cscript/rhino console support to separate file 2013-08-16 21:00:47 -07:00
display.css Squish the font bitmaps 2013-08-18 15:30:55 -07:00
dos.js Drop underscores in named function expressions 2013-08-17 15:30:46 -07:00
font-40col.png Squish the font bitmaps 2013-08-18 15:30:55 -07:00
font-80col.png Squish the font bitmaps 2013-08-18 15:30:55 -07:00
font.png Squish the font bitmaps 2013-08-18 15:30:55 -07:00
hires.js Make sure all display styles are prefixed with jsb- 2013-08-17 15:28:40 -07:00
index.htm Style separation 2013-08-17 15:15:54 -07:00
index.js Style separation 2013-08-17 15:15:54 -07:00
lores.js Make sure all display styles are prefixed with jsb- 2013-08-17 15:28:40 -07:00
lpt.jpg Revamp printer mechanism 2013-08-16 01:37:54 -07:00
printer.js Revamp printer mechanism 2013-08-16 01:37:54 -07:00
reference.htm Formatting 2013-08-16 20:00:21 -07:00
script.js Report compile/runtime errors to TTY in script usage 2013-08-17 21:56:51 -07:00
script.md Ditch the name basicscript 2013-08-17 21:39:36 -07:00
styles.css Style separation 2013-08-17 15:15:54 -07:00
tty.js Drop underscores in named function expressions 2013-08-17 15:30:46 -07:00

README.md

jsbasic - Applesoft BASIC in JavaScript

This is hosted for playing with at http://calormen.com/applesoft/

For older browsers, the code depends on various polyfills. For syntax highlighting, the editor optionally uses CodeMirror and custom BASIC parser/styles. Clone these into sibling directories, so you end up with a structure like:

jsbasic/
polyfill/
CodeMirror/

Notes & Known Issues

  • The BASIC program is compiled to JavaScript before execution. Syntax errors are therefore detected at compile-time rather than at run-time as on a traditional interpreter. For example, the following program would run without errors on an Apple since the erroneous second statement is never reached. 10 END : CHR$(PRINT)
  • Handling of BASIC code that does not match the canonical LIST output format may not behave as on an Apple:
  • Keyword parsing differs from Applesoft command line. For example FOR I = S TO P doesn't collapse into FOR I = STOP.
  • The interpreter doesn't actually care about line numbers for statement ordering (just for GOTO/GOSUB targets and IF statements). So 20 PRINT "A", 10 PRINT "B" will just print A, then B
  • To improve readability, lines may start with : and continue the previously numbered line.
  • Floating point overflow is only detected on variable assignment.
  • The DOS operating system implements only a subset of DOS 3.3 and ProDOS useful for basic file I/O.
  • Except for a small number of compatibility shims for common operations (e.g. keyboard strobe), commands that refer to assembly routines (PEEK, POKE, CALL, USR etc.), shape tables, or tape I/O are not implemented.
  • Commands that operate on the program itself (LIST, RUN, DEL, etc.) are not implemented.

You can run your basic programs from the command line (with only basic text input and output, and no graphics or DOS commands):

  • Clone the repository locally
  • On Windows, run from a command prompt via: cscript.exe cbasic.js your_program.txt
  • On Mac/Linux, install Mozilla Rhino, run from the command prompt via: java -jar PATH_TO/js.jar cbasic.js your_program.txt

To Do

  • Snapshot and/or link sensibly to the polyfills
  • Implement DOS functionality for consoles

Links