Interpreter for Genshi BASIC; A simple dialect of BASIC created to learn the basics of making a programming language.
Even though writing an interpreter for a custom BASIC dialect is pretty useless, the same lexing, parsing, and interpreting fundamentals I learned can be applied to other languages.
I originally wrote this in 2019, but decided that this year (2021) I would rewrite it to practice concepts I had learned since the original implementation.
I did get kind of lazy and skipped out on implementing a REPL, so for right now it justs interprets an array of strings or a source file.
Genshi BASIC has 41 keywords. As stated above, the grammar is based on BASIC version 2.
Genshi (原始) means "simple" in romaji. I chose this name because I stripped out a lot of functionality to make a simpler BASIC. Arguably this makes it pretty useless, but this is a learning project rather than a useful one.
Its worth noting that this is not fully tested. I more or less got a couple programs working correctly and called it a day. As I said before, this is a rewrite and I'm honestly very bored of it now.
Genshi BASIC is meant to be a simpler version of BASIC version 2. I stripped out a bunch of stuff and didn't really add anything special.
I used this page on Commodore 64 commands as reference for BASIC version 2.
Removed:
- function declarations -
DEF,FN - memory operations -
FRE,PEEK,POKE,WAIT,NEW - system operations -
GET,STATUS,SYS,USR,TIME - file operations -
OPEN,LOAD,CLOSE,VERIFY,SAVE - "interactive" operations -
RUN,STOP,LIST
Changed:
- string variables are no longer required to end with '$'
- removed '$' characters from
CHR$,LEFT$,MID$,RIGHT$operations
Added:
- new keywords -
XOR - I lost motivation to add anything else cool
# Usage of genshi BASIC interpreter
from genshibasic.interpreter import Interpeter
pgm = [
'10 REM Example 1',
'20 LET A=3+4 * 6/2',
'30 PRINT "A="; A',
'40 A=8',
'50 PRINT "NOW A="; A',
'100 END'
]
genshi_int = Interpeter()
genshi_int.interpret(pgm)
# A=15.0
# NOW A=8- Install deps -
pip3 install -r requirements.txt - Run tests -
python3 -m unittest discover