The L-BASIC compiler

[luke]

For some time now I have been working on a BASIC compiler which I've called L-BASIC. In many ways it's still rather primitive and in early stages, but it's reached the point where it can compile simple programs to executable format so I thought I'd make a thread for it.

Although all the source is available here on github and it's mostly written in QB64, it's rather complicated to build. If you'd like to try it, there's a prebuilt download-and-run version for 64 bit windows here: https://github.com/flukiluke/L-BASIC/rel...-x86_64.7z

You'll need to run it from a command prompt: "lbasic.exe test.bas" to compile test.bas, then run "test.exe" assuming you got no errors.

Some notes and warnings:
- Very poor support for most commands. All programs are console programs, you have a primitive PRINT but no input.
- DO, WHILE, IF, ELSE, FOR should work. ELSEIF, SELECT and EXIT don't.
- No GOTO or GOSUB, but SUB and FUNCTION can create subs/functions, and you can call them. Recursion works.
- Data types are INTEGER, LONG, INTEGER64 (no underscore), SINGLE, DOUBLE, QUAD, STRING. No _UNSIGNED. The usual suffixes %, & etc. are available.
- Basic string support: concatenation (a$ + b$), LEFT$, RIGHT$, MID$, CHR$
- All numeric operators are available and should work with proper precedence. This includes bitwise (AND, OR, XOR, NOT, IMP, EQV), relational (<, >, <=, >=, =, <>), arithmetic (+, -, *, /, \, MOD, ^).

Some programs that work:

Code: (Select All)

'Recursive factorial

'Functions can come before the main program
function fact(n)
  if n = 1 then fact = 1 else fact = n * fact(n-1)
end function

for i = 1 to 10 step 2
  print "fact("; i; ") = "; fact(i)
next i

Code: (Select All)

text$ = "hello" + " " + "world"
for i = 1 to len(text) 'Notice you can leave off the $ on text
  print left(text, i) 'And the $ is optional on left too
next i