Compiler for the B programming language

Tribute to the legend 👑 Ken Thompson 👑 - creator of B, Unix, UTF-8 and more

Features

• ELF32/64 + Win32/64 support
• Lexer + parser
• Abstract syntax tree (AST) creation
• Intermediate language (IL) emission
• Several compiler flags (read flags section)
• Recursive directory search for easy multi-file compilations

Requirements

• Make (for building)
• GCC (for assembling)
• NASM (for linking)

Extensions

While the point of the language is to be extremely minimal, it does get a bit overkill due to the advancements of languages the past 56+ years. Hence, it was decided to extend the language to make it slightly more practical.

• Inline assembly blocks
• Strings are byte arrays instead of word arrays, for the sake of interop with C functions
• Compound assignments
• Else-clause for if-statements

Compiler flags

Name	Description	Arguments	Default	Required
-h / --help	Display help information	None	0	False
-x / --architecture	Target architecture	86 / 64	NULL	True
-os / --platform	Target platform	windows / linux	NULL	True
-v / --verbose	Print detailed information during compilation	None	False	False
-sw / --suppress	Suppress warnings	None	False	False
-wc / --warnings	Maximum warning count before forcibly exiting	A number, -1 for no cap	-1	False
-ec / --errors	Maximum error count before forcibly exiting	A number, -1 for no cap	-1	False
-na / --noasm	Skip assembling stage	None	False	False
-nl / --nolink	Skip linking stage	None	False	False

Examples

N 10;

main() {
    extrn N;
    extrn fib;
    extrn printf;
    
    auto result;
    result = fib(N);
    printf("Fibonacci of 10 = %d", result);
}

fib(x) {
    auto a, b, i, sum;
    a = 0;
    b = 1;
    i = 1;
    sum = 0;

    while(i++ < x) {
        sum = a + b;
        a = b;
        b = sum;
    }

    return sum;
}

Caveats / known issues

• Compiler will blindly process syntactically invalid code (such as unary ++/-- operations) without giving a parsing error
• There is no standard library (yet?), instead C interop is upheld by violating some of B's rules (strings are byte arrays and not word arrays)
• Very lightly tested in Windows, not at all tested on Linux
• Errors may break any further compilation, this can be handled by setting the max error flag to 1