quick sort

specs.md

@@ -135,7 +135,7 @@ v1.x = 3.0; // assign to field x of struct v1
 #### Struct Interpolation
 Struct values in string interpolation print as `TypeName{field:value, ...}`:
 ```sx
-print("{v1}");  // Vec4{x:1.0, y:2.0, z:3.0, w:0.0}
+print("{}", v1);  // Vec4{x:1.0, y:2.0, z:3.0, w:0.0}
 ```
 
 ### Union Types (Tagged Unions)
@@ -174,7 +174,7 @@ if s == {
 #### Union Interpolation
 Union values in string interpolation print as `<TypeName tag=N>`:
 ```sx
-print("{s}");  // <Shape tag=0>
+print("{}", s);  // <Shape tag=0>
 ```
 
 ### Array Types
@@ -184,6 +184,22 @@ buffer : [5]f32 = .[0, 2, 3.5, 4, 0];
 val := buffer[2];  // 3.5
 ```
 
+### Slice Types
+A slice `[]T` is a fat pointer `{ptr, i32}` referencing a contiguous sequence of `T` elements. Same runtime layout as `string`.
+```sx
+// Arrays implicitly coerce to slices at call sites
+arr : [5]s32 = .[3, 1, 4, 1, 5];
+sortSlice(arr);   // [5]s32 → []s32 coercion
+
+// Slice operations
+items[i]           // read element at index
+items[i] = val;    // write element at index
+items.len          // length (s32)
+items.ptr          // raw pointer
+```
+
+Slices support generic type parameters: `[]$T` introduces type parameter `T` inferred from the element type of the argument (array or slice).
+
 ### Vector Types (SIMD)
 LLVM SIMD vectors, parameterized by length and element type.
 ```sx
@@ -575,16 +591,6 @@ Used for module access (`std.print`) and struct member access.
 ```
 The enum type is inferred from context (expected type from declaration or parameter).
 
-### String Interpolation
-Curly braces inside string literals interpolate expressions:
-```sx
-"z: {z}"
-```
-The expression inside `{}` is evaluated and formatted according to its type:
-- `s32` — decimal integer
-- `f64` — decimal float
-- `string` — as-is
-
 ---
 
 ## 5. Statements