138 lines
3.0 KiB
Zig
138 lines
3.0 KiB
Zig
const assert = @import("std").debug.assert;
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test "simple generic fn" {
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assert(max(i32, 3, -1) == 3);
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assert(max(f32, 0.123, 0.456) == 0.456);
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assert(add(2, 3) == 5);
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}
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fn max(comptime T: type, a: T, b: T) -> T {
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return if (a > b) a else b;
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}
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fn add(comptime a: i32, b: i32) -> i32 {
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return (comptime a) + b;
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}
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const the_max = max(u32, 1234, 5678);
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test "compile time generic eval" {
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assert(the_max == 5678);
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}
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fn gimmeTheBigOne(a: u32, b: u32) -> u32 {
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return max(u32, a, b);
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}
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fn shouldCallSameInstance(a: u32, b: u32) -> u32 {
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return max(u32, a, b);
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}
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fn sameButWithFloats(a: f64, b: f64) -> f64 {
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return max(f64, a, b);
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}
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test "fn with comptime args" {
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assert(gimmeTheBigOne(1234, 5678) == 5678);
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assert(shouldCallSameInstance(34, 12) == 34);
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assert(sameButWithFloats(0.43, 0.49) == 0.49);
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}
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test "var params" {
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assert(max_i32(12, 34) == 34);
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assert(max_f64(1.2, 3.4) == 3.4);
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}
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comptime {
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assert(max_i32(12, 34) == 34);
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assert(max_f64(1.2, 3.4) == 3.4);
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}
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fn max_var(a: var, b: var) -> @typeOf(a + b) {
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return if (a > b) a else b;
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}
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fn max_i32(a: i32, b: i32) -> i32 {
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return max_var(a, b);
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}
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fn max_f64(a: f64, b: f64) -> f64 {
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return max_var(a, b);
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}
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pub fn List(comptime T: type) -> type {
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return SmallList(T, 8);
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}
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pub fn SmallList(comptime T: type, comptime STATIC_SIZE: usize) -> type {
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return struct {
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items: []T,
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length: usize,
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prealloc_items: [STATIC_SIZE]T,
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};
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}
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test "function with return type type" {
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var list: List(i32) = undefined;
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var list2: List(i32) = undefined;
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list.length = 10;
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list2.length = 10;
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assert(list.prealloc_items.len == 8);
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assert(list2.prealloc_items.len == 8);
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}
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test "generic struct" {
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var a1 = GenNode(i32) {.value = 13, .next = null,};
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var b1 = GenNode(bool) {.value = true, .next = null,};
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assert(a1.value == 13);
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assert(a1.value == a1.getVal());
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assert(b1.getVal());
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}
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fn GenNode(comptime T: type) -> type {
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return struct {
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value: T,
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next: ?&GenNode(T),
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fn getVal(n: &const GenNode(T)) -> T { return n.value; }
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};
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}
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test "const decls in struct" {
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assert(GenericDataThing(3).count_plus_one == 4);
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}
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fn GenericDataThing(comptime count: isize) -> type {
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return struct {
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const count_plus_one = count + 1;
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};
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}
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test "use generic param in generic param" {
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assert(aGenericFn(i32, 3, 4) == 7);
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}
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fn aGenericFn(comptime T: type, comptime a: T, b: T) -> T {
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return a + b;
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}
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test "generic fn with implicit cast" {
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assert(getFirstByte(u8, []u8 {13}) == 13);
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assert(getFirstByte(u16, []u16 {0, 13}) == 0);
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}
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fn getByte(ptr: ?&const u8) -> u8 {return *??ptr;}
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fn getFirstByte(comptime T: type, mem: []const T) -> u8 {
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return getByte(@ptrCast(&const u8, &mem[0]));
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}
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const foos = []fn(var) -> bool { foo1, foo2 };
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fn foo1(arg: var) -> bool { return arg; }
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fn foo2(arg: var) -> bool { return !arg; }
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test "array of generic fns" {
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assert(foos[0](true));
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assert(!foos[1](true));
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}
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