Odin/examples/demo.odin

// Demo 001
#load "basic.odin"
#load "game.odin"

main :: proc() {
	Entity :: type union {
		Frog: struct {
			jump_height: f32
		}
		Helicopter: struct {
			weight:     f32
			blade_code: int
		}
	}

	using Entity
	f: Entity = Frog{137}
	h: Entity = Helicopter{123, 4}

	match type ^f -> e {
	case Frog:
		print_string("Frog!\n")
		print_f32(e.jump_height); nl()
		e.jump_height = 69
		print_f32(e.jump_height); nl()
	case Helicopter:
		print_string("Helicopter!\n")
		e.weight = 1337
	default:
		print_string("Unknown!\n")
	}
}

nl :: proc() { print_nl() }

/*
// Demo 001
#load "basic.odin"
#load "game.odin"

main :: proc() {
	// _ = hellope()
	// procedures()
	// variables()
	// constants()
	// types()
	// data_control()
	// using_fields()

	run_game()
}


hellope :: proc() -> int {
	print_string("Hellope, 世界\n")
	return 1
}


// Line comment
/*
	Block Comment
*/
/*
	Nested /*
		Block /*
			Comment
		*/
	*/
*/

apple, banana, carrot: bool
box, carboard: bool = true, false
// hellope_value: int = hellope() // The procedure is ran just before `main`

variables :: proc() {
	i: int // initialized with zero value
	j: int = 1
	x, y: int = 1, 2

	// Type inference
	apple, banana, 世界 := true, 123, "world"


	// Basic Types of the Language
	//
	// bool
	//
	// i8 i16 i32 i64 i128
	// u8 u16 u32 u64 u128
	//
	// f32 f64
	//
	// int uint (size_of(int) == size_of(uint) == size_of(rawptr))
	//
	// rawptr (equivalent to void * in C/C++)
	//
	// string
	//
	// byte - alias for u8
	// rune - alias for i32 // Unicode Codepoint
	//
	// "untyped" types can implicitly convert to any of the "typed" types
	//                      Default Type
	// untyped bool      -  bool
	// untyped integer   -  int
	// untyped float     -  f64
	// untyped pointer   -  rawptr
	// untyped string    -  string
	// untyped rune      -  rune/i32


	// Zero values
	zero_numeric := 0
	zero_boolean := false
	zero_pointer := null
	zero_string1 := "" // Escaped string
	zero_string2 := `` // Raw string
	// Compound types have a different kind of zero value

	// Unary operators
	// +a
	// -a
	// ~a
	// !a

	// Binary operators
	// a + b    add
	// a - b    sub
	// a ~ b    xor
	// a | b     or

	// a * b    mul
	// a / b    quo
	// a % b    mod
	// a & b    and
	// a &~ b   bitclear == a & (~b)
	// a << b   shl
	// a >> b   shr

	// a as Type         // Type cast
	// a transmute Type  // Bit  cast

	// a == b   eq
	// a != b   ne
	// a < b    lt
	// a > b    gt
	// a <= b   le
	// a >= b   ge

}

procedures :: proc() {
	add :: proc(x: int, y: int) -> int {
		return x + y
	}
	print_int(add(3, 4)) // 7
	print_nl()

	add_v2 :: proc(x, y: int) -> int {
		return x + y
	}

	fibonacci :: proc(n: int) -> int {
		if n < 2 {
			return n
		}
		return fibonacci(n-1) + fibonacci(n-2)
	}
	print_int(fibonacci(12)); nl()


	swap_strings :: proc(x, y: string) -> (string, string) {
		return y, x
	}
	a, b := swap_strings("Hellope\n", "World\n")
	print_string(a)
	print_string(b)

	a, b = b, a // Quirk of grammar the of multiple assignments
	             // Swap variables
	print_string(a)
	print_string(b)

	// Not a hint like C/C++, it's mandatory (unless it cannot do it but it will warn)
	proc1 :: proc(a, b: int) #inline {
		print_int(a + b)
	}
	proc2 :: proc(a, b: int) #no_inline {
		print_int(a + b)
	}

	print_int(3 ''add 4)     // Infix style
	print_nl()
	print_int(12 'fibonacci) // Postfix style
	print_nl()
}


TAU :: 6.28318530718

constants :: proc() {
	TAU :: 6.28318530718 // untyped float
	WORLD_JAPANESE :: "世界" // untyped string

	TAU_32 : f32 : 6.28318530718
	TAU_AS_32 :: 6.28318530718 as f32

	PI :: TAU / 2

	CLOSE_TO_PI :: 3

	DIFF :: (PI - CLOSE_TO_PI) / PI // Evaluated at compile time

	a := TAU         // the constant's value becomes typed as f32
	b := CLOSE_TO_PI // the constant's value becomes typed as int
	c := DIFF
}

nl :: proc() { print_nl() }

types :: proc() {

	x: int = 123
	y := x // y: int = x
	// z: f32 = x // invalid
	z: f32 = x as f32


	ptr_z := ^z  // Pascal notation
	ptr_z^ = 123 // Derefence Notation
	w: f32 = ptr_z^  // 123
	print_f32(z); nl()

	// ^z - pointer to z
	// z^ - z from pointer

	// Implicit conversion to and from rawptr
	r_ptr: rawptr = ptr_z
	ptr_z = r_ptr




	f32_array: [12]f32 // Array of 12 f32
	f32_array[0] = 2
	f32_array[1] = 3
	// f32_array[-1] = 2 // Error - compile time check
	// f32_array[13]  = 2 // Error - compile time check
	f32_array_len := len(f32_array) // builtin procedure
	f32_array_cap := cap(f32_array) // == len(f32_array)


	mda: [2][3][4]int // Column-major
	// mda[x][y][z]



	api: [2]^f32
	papi: ^[2]^f32




	f32_slice: []f32 // Slice / Array reference
	f32_slice = f32_array[0:5]
	f32_slice = f32_array[:5]
	f32_slice = f32_array[:] // f32_array[0:len(f32_array)-1]

	f32_slice = f32_array[1:5:7] // low:1, high:5, max:7
	                              // len: 5-1 == 4
	                              // cap: 7-1 == 6



	append_success := append(^f32_slice, 1)
	_ = append(^f32_slice, 2)

	_ = copy(f32_array[0:2], f32_array[2:4]) // You can use memcpy/memmove if you want






	s := "Hellope World"
	sub_string: string = s[5:10]





	v0: {4}f32 // Vector of 4 f32
	v0[0] = 1
	v0[1] = 3
	v0[2] = 6
	v0[3] = 10

	v1 := v0 + v0 // Simd Arithmetic
	v1 = v1 - v0
	v1 *= v0 // i.e. hadamard product
	v1 /= v0

	// builtin procedure
	v2 := swizzle(v0, 3, 2, 1, 0) // {10, 6, 3, 1}

	v3: {4}bool = v0 == v2
	// LLVM rant?







	Vec4 :: type {4}f32
	Array3Int :: type [3]int

	Vec3 :: type struct {
		x, y, z: f32
	}

	BinaryNode :: type struct {
		left, right: ^BinaryNode // same format as procedure argument
		data: rawptr
	}

	AddProc :: type proc(a, b: int) -> int

	Packed :: type struct #packed {
		a: u8
		b: u16
		c: u32
	}
	assert(size_of(Packed) == 7) // builtin procedure
	{
		a, b: ^BinaryNode
		a = alloc(size_of(BinaryNode)) as ^BinaryNode
		b = alloc(size_of(BinaryNode)) as ^BinaryNode

		c := BinaryNode{a, b, null}
		c.left^.data = null
		c.left.data = null // No need to deference

		dealloc(a)
		dealloc(b)
	}

	{
		MyInt :: type int
		x: int = 1
		y: MyInt = 2
		// z := x + y // Failure - types cannot implicit convert*
		z := x as MyInt + y // Type cast using `as`
	}


	{
		// From: Quake III Arena
		Q_rsqrt :: proc(number: f32) -> f32 {
			i: i32
			x2, y: f32
			THREE_HALFS :: 1.5

			x2 = number * 0.5
			y = number
			i = (^y as ^i32)^                      // evil floating point bit level hacking
			i = 0x5f3759df - i>>1                  // what the fuck?
			y = (^i as ^f32)^
			y = y * (THREE_HALFS - (x2 * y *y))    // 1st iteration
		//	y = y * (THREE_HALFS - (x2 * y *y))    // 2nd iteration, this can be removed
			return y
		}

		Q_rsqrt_v2 :: proc(number: f32) -> f32 {
			THREE_HALFS :: 1.5

			x2 := number * 0.5
			y := number
			i := y transmute i32                   // evil floating point bit level hacking
			i = 0x5f3759df - i>>1                  // what the fuck?
			y = i transmute f32
			y = y * (THREE_HALFS - (x2 * y *y))    // 1st iteration
		//	y = y * (THREE_HALFS - (x2 * y *y))    // 2nd iteration, this can be removed
			return y
		}

		// NOTE(bill): transmute only works if the size of the types are equal

		/*
			// in C
			union {
				i32 i
				f32 y
			}
		 */
	}

	{ // Enumeration
		Thing :: type enum {
			APPLE,
			FROG,
			TREE,
			TOMB,
		}
		a := Thing.APPLE

		Sized :: type enum u64 {
			APPLE,
			FROG,
			TREE,
			TOMB,
		}
		assert(size_of(Sized) == size_of(u64))

		Certain :: type enum {
			APPLE = 3,
			FROG,
			TREE = 7,
			TOMB,
		}
		assert(Certain.TOMB == 8)
	}

	{ // Untagged union
		BitHack :: type raw_union {
			i: i32
			f: f32
		}
		b: BitHack
		b.f = 123
		print_int(b.i as int); print_nl()



		// Manually tagged union

		EntityKind :: type enum {
			Invalid,
			Constant,
			Variable,
			TypeName,
			Procedure,
			Builtin,
			Count,
		}

		Entity :: type struct {
			kind: EntityKind
			guid: u64

			// Other data

			/*using*/
			data: union {
				constant: struct{}
				variable: struct{
					visited, is_field, used, anonymous: bool
				}
				procedure: struct { used: bool }
				buitlin: struct { id: i32 }
			}
		}


		// NOTE(bill): Tagged unions are not added yet but are planned
	}



	{ // Compound Literals
		a := [3]int{1, 2, 3}
		b := [3]int{}
		c := [..]int{1, 2, 3}

		d := []int{1, 2, 3} // slice

		e := {4}f32{1, 2, 3, 4}
		f := {4}f32{1} // broadcasts to all
		// g := {4}f32{1, 2} // require either 1 or 4 elements

		Vec2 :: type {2}f32

		h := Vec2{1, 2}

		i := Vec2{5} * h // For strong type safety
		// FORENOTE: 5 * h was originally allowed but it was an edge case in the
		// compiler I didn't think it was enough to justify have it it.

		print_f32(i[0]); print_rune(#rune ",")
		print_f32(i[1]); print_nl()
	}



	{ // First class procedures

		do_thing :: proc(p: proc(a, b: int) -> int) {
			print_int(p(3, 4)); nl()
		}

		add :: proc(a, b: int) -> int {
			return a + b
		}


		add_lambda := proc(a, b: int) -> int {
			return a - b
		} // note semicolon

		do_thing(add)
		do_thing(add_lambda)
		do_thing(proc(a, b: int) -> int { // Anonymous
			return a * b
		})
	}



	{ // strings and runes
		escaped := "Hellope World\n"
		raw     := `Hellope World\n`
		print_string(escaped)
		print_string(raw); nl()

		// Crap shader example
		shader_string :=
`#version 410

layout (location = 0) in vec3 a_position
layout (location = 1) in vec3 a_normal;
layout (location = 2) in vec2 a_tex_coord;

out vec3 v_position;
out vec3 v_normal;
out vec2 v_tex_coord;

uniform mat4 u_model_view;
uniform mat3 u_normal;
uniform mat4 u_proj;
uniform mat4 u_mvp;

void main() {
    v_tex_coord = a_tex_coord;
    v_normal = normalize(u_normal * a_normal);
    v_position = vec3(u_model_view * vec4(a_position, 1.0));

    gl_Position = u_mvp * vec4(a_position, 1.0);
}`;


		hearts1 := #rune "💕";
		hearts2 := #rune "\U0001f495"; // 32 bit
		hearts3 := #rune "\xf0\x9f\x92\x95";

		㐒 := #rune "㐒";
		㐒16 := #rune "\u4db5"; // 16 bit but will be `rune`
		// String ideas "nicked" from Go, so far. I think I might change how some of it works later.
	}


	{ // size, align, offset
		Thing :: type struct {
			a: u8;
			b: u16;
			c, d, e: u32;
		}

		s := size_of(Thing);
		a := align_of(Thing);
		o := offset_of(Thing, b);

		t: Thing;

		sv := size_of_val(t);
		av := align_of_val(t);
		ov := offset_of_val(t.b);
	}
}

data_control :: proc() {
	sum := 0
	for i := 0; i < 12; i++ {
		sum += 1
	}
	print_string("sum = "); print_int(sum); nl()

	sum = 1
	for ; sum < 1000000; {
		sum += sum
	}
	print_string("sum = "); print_int(sum); nl()

	sum = 1
	for sum < 1000000 {
		sum += sum
	}
	print_string("sum = "); print_int(sum); nl()

	// loop
	// for { } == for true {}

	// Question: Should I separate all these concepts and rename it?
	//
	// range - iterable
	// for   - c style
	// while
	// loop  - while true

	// Notes:
	// conditions _must_ a boolean expression
	// i++ and i-- are statements, not expressions


	x := 2
	if x < 3 {
		print_string("x < 2\n")
	}

	// Unified initializer syntax - same as for statements
	if x := 2; x < 3 {
		print_string("x < 2\n")
	}

	if x := 4; x < 3 {
		print_string("Never called\n")
	} else {
		print_string("This is called\n")
	}

	{ // String comparison
		a := "Hellope"
		b := "World"
		if a < b {
			print_string("a < b\n")
		}
		if a != b {
			print_string("a != b\n")
		}

	}




	{ // Defer statement
		defer print_string("日本語\n")
		print_string("Japanese\n")
	}

	{
		defer print_string("1\n")
		defer print_string("2\n")
		defer print_string("3\n")
	}

	{
		prev_allocator := context.allocator
		context.allocator = __default_allocator()
		defer context.allocator = prev_allocator

		File :: type struct { filename: string }
		FileError :: type int;
		open_file  :: proc(filename: string) -> (File, FileError) {
			return File{}, 0
		}
		close_file :: proc(f: ^File) {}
		f, err := open_file("Test")
		if err != 0 {
			// handle error
		}
		defer close_file(^f)
	}

	for i := 0; i < 100; i++ {
		blah := new_slice(int, 100)
		defer {
			defer print_string("!")
			defer print_string("dealloc")
			delete(blah)
		}

		if i == 3 {
			// defers called
			continue
		}

		if i == 5 {
			// defers called
			return // End of procedure
		}

		if i == 8 {
			// defers called
			break // never happens
		}
	}

	defer print_string("It'll never happen, mate 1")
	print_string("It'll never happen, mate 2")
	print_string("It'll never happen, mate 3")
}


using_fields :: proc() {
	{ // Everyday stuff
		Vec3 :: type struct { x, y, z: f32; }

		Entity :: type struct {
			name: string;
			using pos: Vec3;
			vel: Vec3;
		}
		t: Entity;
		t.y = 456;
		print_f32(t.y);     print_nl();
		print_f32(t.pos.y); print_nl();
		print_f32(t.vel.y); print_nl();


		Frog :: type struct { // Subtype (kind of)
			using entity: Entity;
			colour: u32;
			jump_height: f32;
		}

		f: Frog;
		f.y = 1337;
		print_f32(f.y);     print_nl();
		print_f32(f.pos.y); print_nl();
		print_f32(f.vel.y); print_nl();


		Buffalo :: type struct {
			using entity: Entity;
			speed: f32;
			noise_level: f32;
		}
	}


	{ // Crazy Shit
		Vec2 :: type raw_union {
			using _xy: struct {x, y: f32};
			e: [2]f32;
			v: {2}f32;
		}

		Entity :: type struct {
			using pos: ^Vec2;
			name: string;
		}
		t: Entity;
		t.pos = alloc(size_of(Vec2)) as ^Vec2; // TODO(bill): make an alloc type? i.e. new(Type)?
		t.x = 123;
		print_f32(t._xy.x);     print_nl();
		print_f32(t.pos.x);     print_nl();
		print_f32(t.pos._xy.x); print_nl();
	}
}
*/