stage2 提供词法分析器通过与stage1的差异测试 stage1提供数组到切片的隐式转换

stage2/utils/value.spl

@@ -0,0 +1,100 @@
+// Expect retcode = 0
+
+// 显式装箱值：运行期格式化用的最小 ADT。调用方显式构造（如 Value.int(x)），
+// 库内用 match 分派。不做隐式装箱、不带运行期类型系统。
+// Str 借用 ByteView，不拥有存储；Ptr 是类型擦除指针。
+
+type .{ .ByteView } = @import("byte_view.spl");
+
+type Value = enum {
+    Int: i64,
+    Uint: u64,
+    Bool: bool,
+    Char: u8,
+    Str: ByteView,
+    Ptr: *any,
+}
+
+fn int(value: i64): Value {
+    ret .Int(value);
+}
+
+fn uint(value: u64): Value {
+    ret .Uint(value);
+}
+
+fn boolean(value: bool): Value {
+    ret .Bool(value);
+}
+
+fn char(value: u8): Value {
+    ret .Char(value);
+}
+
+fn str(bytes: []u8): Value {
+    ret .Str(ByteView.from_slice(bytes));
+}
+
+fn str_view(view: ByteView): Value {
+    ret .Str(view);
+}
+
+fn addr(value: *any): Value {
+    ret .Ptr(value);
+}
+
+// ---- 测试 ----
+
+fn test_int_and_uint() {
+    match int(-5) {
+        .Int(v) => { @assert(v == -5, "int payload"); },
+        _ => { @assert(false, "expected int"); },
+    }
+    match uint(5) {
+        .Uint(v) => { @assert(v == 5, "uint payload"); },
+        _ => { @assert(false, "expected uint"); },
+    }
+}
+
+fn test_scalars() {
+    match boolean(true) {
+        .Bool(v) => { @assert(v, "bool payload"); },
+        _ => { @assert(false, "expected bool"); },
+    }
+    match char('A') {
+        .Char(v) => { @assert(v == 'A', "char payload"); },
+        _ => { @assert(false, "expected char"); },
+    }
+}
+
+fn test_borrowed_str() {
+    var text: [3]u8 = .[104, 105, 0];
+    var s = str(text[0..2]);
+    match s {
+        .Str(view) => {
+            @assert(view.len == 2 && view.ptr[0] == 104 && view.ptr[1] == 105,
+                    "str payload borrows");
+        },
+        _ => { @assert(false, "expected str"); },
+    }
+    @assert(text[0] == 104, "source untouched");
+}
+
+fn test_ptr() {
+    var x: i32 = 7;
+    match addr(&x as *any) {
+        .Ptr(p) => { @assert((p as *i32).* == 7, "ptr payload"); },
+        _ => { @assert(false, "expected ptr"); },
+    }
+    match addr(null) {
+        .Ptr(p) => { @assert(p == null, "null ptr payload"); },
+        _ => { @assert(false, "expected ptr"); },
+    }
+}
+
+fn main() {
+    test_int_and_uint();
+    test_scalars();
+    test_borrowed_str();
+    test_ptr();
+}