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1.6 KiB
1.6 KiB
jsbasic - Applesoft BASIC in JavaScript
This is hosted for playing with at http://inexorabletash.github.io/jsbasic/
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$(PRINT) - Handling of BASIC code that does not match the canonical
LISToutput format may not behave as on an Apple:- Keyword parsing differs from Applesoft command line. For example
FOR I = S TO Pdoesn't collapse intoFOR I = STOP.
- Keyword parsing differs from Applesoft command line. For example
- Limitations:
- Floating point overflow is only detected on variable assignment.
- Only a subset of DOS 3.3 and ProDOS useful for basic file I/O are implemented.
- Only a small number of common
PEEK,POKEandCALLlocations are supported. - Commands that refer to assembly routines (
&,USR()etc.), shape tables, and tape I/O are not implemented.
- Commands that operate on the program itself (
LIST,RUN,DEL, etc.) are not implemented. - A handful of extensions are made beyond Applesoft BASIC:
- To improve readability, lines may start with
:and continue the previously numbered line. DEF FNcan define string functions==can be used as=CHR$()values > 255 do interesting thingsHSCRN(x, y)allows probing the hi-res screen- hexadecimal literals e.g.
$C010can be used as numbers
- To improve readability, lines may start with