sx/examples/0131-types-init-blocks.sx

#import "modules/std.sx";
#import "modules/math";
#import "modules/build.sx";
#import "modules/std/test.sx";
pkg :: #import "tests/fixtures/testpkg";

Point :: struct { x, y: s32; }

add :: (a: s32, b: s32) -> s32 { a + b }

Counter :: protocol {
    inc :: ();
    get :: () -> s32;
}

Summable :: protocol {
    sum :: () -> s32;
}

SimpleCounter :: struct { val: s32; }

impl Counter for SimpleCounter {
    inc :: (self: *SimpleCounter) { self.val += 1; }
    get :: (self: *SimpleCounter) -> s32 { self.val }
}

impl Summable for Point {
    sum :: (self: *Point) -> s32 { self.x + self.y }
}

// Phase 2: #inline protocol for dynamic dispatch

// Phase 7: Generic struct impls
Pair :: struct ($T: Type) {
    a: T;
    b: T;
}

impl Summable for Pair($T) {
    sum :: (self: *Pair(T)) -> s32 {
        xx self.a + xx self.b
    }
}

// P6.5: Struct type param constraints

// Init block test struct
Builder :: struct {
    total: s32;
    count: s32;

    add :: (self: *Builder, val: s32) {
        self.total += val;
        self.count += 1;
    }
}

// Global variable for address-of test

main :: () {

    // --- Init Blocks (IB) ---
    print("=== Init Blocks ===\n");

    // IB1: basic init block with struct methods
    {
        b := Builder.{ total = 0, count = 0 } {
            self.add(10);
            self.add(20);
            self.add(30);
        };
        print("IB1: {} {}\n", b.total, b.count);
    }

    // IB2: nested init blocks (self shadows correctly)
    {
        b1 := Builder.{ total = 0, count = 0 } {
            self.add(100);
            b2 := Builder.{ total = 0, count = 0 } {
                self.add(42);
            };
            self.add(b2.total);
        };
        print("IB2: {} {}\n", b1.total, b1.count);
    }

    // IB3: empty init block
    {
        b := Builder.{ total = 5, count = 1 } {};
        print("IB3: {} {}\n", b.total, b.count);
    }

    // IB4: conditional inside init block
    {
        add_extra := true;
        b := Builder.{ total = 0, count = 0 } {
            self.add(10);
            if add_extra {
                self.add(90);
            }
        };
        print("IB4: {}\n", b.total);
    }

    // IB5: init block + auto type erasure combined
    {
        use_counter :: (c: Counter) -> s32 { c.inc(); c.inc(); c.get() }
        result := use_counter(SimpleCounter.{ val = 0 } {
            self.val = 50;
        });
        print("IB5: {}\n", result);
    }

    // ============================================================
    // SECTION: Struct static method shorthand (.method(args) syntax)
    // ============================================================
    print("--- struct static method shorthand ---\n");

    // SM1: Basic shorthand — .create(args) resolves to Dims.create(args)
    {
        Dims :: struct {
            w: f32;
            h: f32;

            create :: (w: f32, h: f32) -> Dims {
                Dims.{ w = w, h = h }
            }

            square :: (size: f32) -> Dims {
                Dims.{ w = size, h = size }
            }
        }
        use_dims :: (d: Dims) { print("SM1: {} {}\n", d.w, d.h); }
        use_dims(.create(16.0, 8.0));
        use_dims(.square(5.0));
    }

    // SM2: Shorthand in variable declaration with explicit type
    {
        Pair :: struct {
            a: s64;
            b: s64;

            make :: (a: s64, b: s64) -> Pair {
                Pair.{ a = a, b = b }
            }
        }
        p : Pair = .make(10, 20);
        print("SM2: {} {}\n", p.a, p.b);
    }

    // ============================================================
    // OPTIONAL IF-ELSE COERCION
    // ============================================================
    {
        print("--- optional if-else coercion ---\n");
        OptF :: struct { width: ?f32; }
        x :f32: 10.0;

        // null in then branch
        f1 := OptF.{ width = if true then null else x };
        print("opt-if1: {}\n", f1.width ?? 99.0);

        // value in then branch, null in else
        f2 := OptF.{ width = if true then x else null };
        print("opt-if2: {}\n", f2.width ?? 99.0);

        // both branches are values
        f3 := OptF.{ width = if false then 5.0 else x };
        print("opt-if3: {}\n", f3.width ?? 99.0);

        // standalone optional variable
        val: ?f32 = if true then null else 42.0;
        print("opt-if4: {}\n", val ?? 0.0);

        val2: ?f32 = if false then null else 42.0;
        print("opt-if5: {}\n", val2 ?? 0.0);
    }

    // --- usize / isize ---
    {
        a : usize = 42;
        b : isize = 0 - 7;
        print("usize: {}\n", a);
        print("isize: {}\n", b);

        // arithmetic
        c : usize = a + 8;
        print("usize+8: {}\n", c);

        // coercion from s32
        x : s32 = 10;
        y : usize = xx x;
        print("s32->usize: {}\n", y);

        // coercion to s64
        z : s64 = xx a;
        print("usize->s64: {}\n", z);
    }
}