ableos-framebuffer/hblang/README.md

HERE SHALL THE DOCUMENTATION RESIDE

Enforced Political Views

• worse is better
• less is more
• embrace unsafe {}
• adhere macro_rules!
• pessimization == death (put in std::pin::Pin and left with hungry crabs)
• importing external dependencies == death (fn(dependencies) -> ExecutionStrategy)
• above sell not be disputed, discussed, or questioned

What hblang is

Holey-Bytes-Language (hblang for short) (*.hb) is the only true language targeting hbvm byte code. hblang is low level, manually managed, and procedural. Its rumored to be better then writing hbasm and you should probably use it for complex applications.

What hblang isnt't

hblang knows what it isn't, because it knows what it is, hblang computes this by sub...

Examples

Examples are also used in tests. To add an example that runs during testing add:

#### <name>
```hb
<example>
```

and also:

<name> => README;

to the run_tests macro at the bottom of the src/codegen.rs.

Tour Examples

Following examples incrementally introduce language features and syntax.

main_fn

main := fn(): int {
	return 1;
}

arithmetic

main := fn(): int {
	return 10 - 20 / 2 + 4 * (2 + 2) - 4 * 4 + 1;
}

functions

main := fn(): int {
	return add_one(10) + add_two(20);
}

add_two := fn(x: int): int {
	return x + 2;
}

add_one := fn(x: int): int {
	return x + 1;
}

comments

// commant is an item
main := fn(): int {
	// comment is a statement
	foo(/* comment is an exprression /* if you are crazy */ */);
	return 0;
}

foo := fn(comment: void): void
	return /* comment evaluates to void */;

// comments might be formatted in the future

if_statements

main := fn(): int {
	return fib(10);
}

fib := fn(x: int): int {
	if x <= 2 {
		return 1;
	} else {
		return fib(x - 1) + fib(x - 2);
	}
}

variables

main := fn(): int {
	ඞ := 1;
	b := 2;
	ඞ = ඞ + 1;
	return ඞ - b;
}

loops

main := fn(): int {
	return fib(10);
}

fib := fn(n: int): int {
	a := 0;
	b := 1;
	loop {
		if n == 0 break;
		c := a + b;
		a = b;
		b = c;
		n -= 1;

		stack_reclamation_edge_case := 0;

		continue;
	}
	return a;
}

pointers

main := fn(): int {
	a := 1;
	b := &a;
	modify(b);
	drop(a);
	stack_reclamation_edge_case := 0;
	return *b - 2;
}

modify := fn(a: ^int): void {
	*a = 2;
	return;
}

drop := fn(a: int): void {
	return;
}

structs

Ty := struct {
	a: int,
	b: int,
}

Ty2 := struct {
	ty: Ty,
	c: int,
}

main := fn(): int {
	finst := Ty2.{ ty: Ty.{ a: 4, b: 1 }, c: 3 };
	inst := odher_pass(finst);
	if inst.c == 3 {
		return pass(&inst.ty);
	}
	return 0;
}

pass := fn(t: ^Ty): int {
	return t.a - t.b;
}

odher_pass := fn(t: Ty2): Ty2 {
	return t;
}

struct_operators

Point := struct {
	x: int,
	y: int,
}

Rect := struct {
	a: Point,
	b: Point,
}

main := fn(): int {
	a := Point.(1, 2);
	b := Point.(3, 4);

	d := Rect.(a + b, b - a);
	d2 := Rect.(Point.(0, 0) - b, a);
	d2 = d2 + d;

	c := d2.a + d2.b;
	return c.x + c.y;
}

global_variables

global_var := 10;

complex_global_var := fib(global_var) - 5;

fib := fn(n: int): int {
	if 2 > n {
		return n;
	}
	return fib(n - 1) + fib(n - 2);
}

main := fn(): int {
	return complex_global_var;
}

note: values of global variables are evaluated at compile time

directives

Type := struct {
	brah: int,
	blah: int,
}

main := fn(): int {
	byte := @as(u8, 10);
	same_type_as_byte := @as(@TypeOf(byte), 30);
	wide_uint := @as(u32, 40);
	truncated_uint := @as(u8, @intcast(wide_uint));
	size_of_Type_in_bytes := @sizeof(Type);
	align_of_Type_in_bytes := @alignof(Type);
	hardcoded_pointer := @as(^u8, @bitcast(10));
	ecall_that_returns_int := @eca(int, 1, Type.(10, 20), 5, 6);
	return 0;
}

• @TypeOf(<expr>): results into literal type of whatever the type of <expr> is, <expr> is not included in final binary
• @as(<ty>, <expr>): hint to the compiler that @TypeOf(<expr>) == <ty>
• @intcast(<expr>): needs to be used when conversion of @TypeOf(<expr>) would loose precision (widening of integers is implicit)
• @sizeof(<ty>), @alignof(<ty>): I think explaining this would insult your intelligence
• @bitcast(<expr>): tell compiler to assume @TypeOf(<expr>) is whatever is inferred, so long as size and alignment did not change
• @eca(<ty>, <expr>...): invoke eca instruction, where <ty> is the type this will return and <expr>... are arguments passed to the call

c_strings

str_len := fn(str: ^u8): int {
	len := 0;
	loop if *str == 0 break else {
		len += 1;
		str += 1;
	}
	return len;
}

main := fn(): int {
	// when string ends with '\0' its a C string and thus type is '^u8'
	some_str := "abඞ\n\r\t\{ff}\{fff0f0ff}\0";
	len := str_len(some_str);
	some_other_str := "fff\0";
	lep := str_len(some_other_str);
	return lep + len;
}

Incomplete Examples

generic_types

MALLOC_SYS_CALL := 69
FREE_SYS_CALL := 96

malloc := fn(size: uint, align: uint): ^void
	return @eca(^void, MALLOC_SYS_CALL, size, align);

free := fn(ptr: ^void, size: uint, align: uint): void
	return @eca(void, FREE_SYS_CALL, ptr, size, align);

Vec := fn($Elem: type): type {
	return struct {
		data: ^Elem,
		len: uint,
		cap: uint,
	};
}

new := fn($Elem: type): Vec(Elem) return Vec(Elem).{ data: @bitcast(0), len: 0, cap: 0 };

deinit := fn($Elem: type, vec: ^Vec(Elem)): void {
	free(@bitcast(vec.data), vec.cap * @sizeof(Elem), @alignof(Elem));
	*vec = new(Elem);
	return;
}

push := fn($Elem: type, vec: ^Vec(Elem), value: Elem): ^Elem {
	if vec.len == vec.cap {
		if vec.cap == 0 {
			vec.cap = 1;
		} else {
			vec.cap *= 2;
		}

		new_alloc := @as(^Elem, @bitcast(malloc(vec.cap * @sizeof(Elem), @alignof(Elem))));
		if new_alloc == 0 return 0;

		src_cursor := vec.data;
		dst_cursor := new_alloc;
		end := vec.data + vec.len;
		
		loop if src_cursor == end break else {
			*dst_cursor = *src_cursor;
			src_cursor += 1;
			dst_cursor += 1;
		}

		if vec.len != 0 {
			free(@bitcast(vec.data), vec.len * @sizeof(Elem), @alignof(Elem));
		}
		vec.data = new_alloc;
	}

	slot := vec.data + vec.len;
	*slot = value;
	vec.len += 1;
	return slot;
}

main := fn(): int {
	vec := new(int);
	push(int, &vec, 69);
	res := *vec.data;
	deinit(int, &vec);
	return res;
}

generic_functions

add := fn($T: type, a: T, b: T): T return a + b;

main := fn(): int {
	return add(u32, 2, 2) - add(int, 1, 3);
}

fb_driver

arm_fb_ptr := fn(): int return 100;
x86_fb_ptr := fn(): int return 100;


check_platform := fn(): int {
    return x86_fb_ptr();
}

set_pixel := fn(x: int, y: int, width: int): int {
    pix_offset := y * width + x;

    return 0;
}

main := fn(): int {
    fb_ptr := check_platform();
    width := 100;
    height := 30;
    x:= 0;
    y:= 0;

    loop {
        if x <= height + 1 {
            set_pixel(x,y,width);
            x = x + 1;
        } else {
            set_pixel(x,y,width);
            x = 0;
            y = y + 1;
        }
        if y == width {
            break;
        }
    }
    return 0;
}

Purely Testing Examples

different_types

Color := struct {
	r: u8,
	g: u8,
	b: u8,
	a: u8,
}

Point := struct {
	x: u32,
	y: u32,
}

Pixel := struct {
	color: Color,
	point: Point,
}

main := fn(): int {
	pixel := Pixel.{
		color: Color.{
			r: 255,
			g: 0,
			b: 0,
			a: 255,
		},
		point: Point.{
			x: 0,
			y: 2,
		},
	};
	
	soupan := 1;
	if *(&pixel.point.x + soupan) != 2 {
		return 0;
	}

	if *(&pixel.point.y - 1) != 0 {
		return 64;
	}

	return pixel.point.x + pixel.point.y + pixel.color.r
		+ pixel.color.g + pixel.color.b + pixel.color.a;
}