diff --git a/core/fmt.odin b/core/fmt.odin
index f3244a748..690365327 100644
--- a/core/fmt.odin
+++ b/core/fmt.odin
@@ -65,12 +65,12 @@ write_rune :: proc(buf: ^String_Buffer, r: rune) {
 	write_bytes(buf, b[..n]);
 }
 
-write_int :: proc(buf: ^String_Buffer, i: i128, base: int) {
+write_i128 :: proc(buf: ^String_Buffer, i: i128, base: int) {
 	b: [129]byte;
 	s := strconv.append_bits(b[..], u128(i), base, true, 128, strconv.digits, 0);
 	write_string(buf, s);
 }
-write_int :: proc(buf: ^String_Buffer, i: i64, base: int) {
+write_i64 :: proc(buf: ^String_Buffer, i: i64, base: int) {
 	b: [129]byte;
 	s := strconv.append_bits(b[..], u128(i), base, true, 64, strconv.digits, 0);
 	write_string(buf, s);
@@ -171,7 +171,7 @@ write_type :: proc(buf: ^String_Buffer, ti: ^Type_Info) {
 		case:
 			if info.signed do write_byte(buf, 'i');
 			else           do write_byte(buf, 'u');
-			write_int(buf, i64(8*ti.size), 10);
+			write_i64(buf, i64(8*ti.size), 10);
 		}
 	case Type_Info_Rune:
 		write_string(buf, "rune");
@@ -235,7 +235,7 @@ write_type :: proc(buf: ^String_Buffer, ti: ^Type_Info) {
 	case Type_Info_Array:
 		write_string(buf, "[");
 		fi := Fmt_Info{buf = buf};
-		write_int(buf, i64(info.count), 10);
+		write_i64(buf, i64(info.count), 10);
 		write_string(buf, "]");
 		write_type(buf, info.elem);
 	case Type_Info_Dynamic_Array:
@@ -258,7 +258,7 @@ write_type :: proc(buf: ^String_Buffer, ti: ^Type_Info) {
 		if info.is_raw_union do write_string(buf, "#raw_union ");
 		if info.custom_align {
 			write_string(buf, "#align ");
-			write_int(buf, i64(ti.align), 10);
+			write_i64(buf, i64(ti.align), 10);
 			write_byte(buf, ' ');
 		}
 		write_byte(buf, '{');
@@ -292,7 +292,7 @@ write_type :: proc(buf: ^String_Buffer, ti: ^Type_Info) {
 		write_string(buf, "bit_field ");
 		if ti.align != 1 {
 			write_string(buf, "#align ");
-			write_int(buf, i64(ti.align), 10);
+			write_i64(buf, i64(ti.align), 10);
 			write_rune(buf, ' ');
 		}
 		write_string(buf, " {");
@@ -300,7 +300,7 @@ write_type :: proc(buf: ^String_Buffer, ti: ^Type_Info) {
 			if i > 0 do write_string(buf, ", ");
 			write_string(buf, name);
 			write_string(buf, ": ");
-			write_int(buf, i64(info.bits[i]), 10);
+			write_i64(buf, i64(info.bits[i]), 10);
 		}
 		write_string(buf, "}");
 	}
diff --git a/core/utf16.odin b/core/utf16.odin
index 762079c1e..2268fd049 100644
--- a/core/utf16.odin
+++ b/core/utf16.odin
@@ -38,11 +38,11 @@ encode :: proc(d: []u16, s: []rune) -> int {
 
 	for r in s {
 		switch r {
-		case 0.._surr1, _surr3.._surr_self:
+		case 0.._surr1, _surr3 .. _surr_self:
 			d[n] = u16(r);
 			n += 1;
 
-		case _surr_self..MAX_RUNE:
+		case _surr_self .. MAX_RUNE:
 			r1, r2 := encode_surrogate_pair(r);
 			d[n]    = u16(r1);
 			d[n+1]  = u16(r2);
@@ -66,11 +66,11 @@ encode :: proc(d: []u16, s: string) -> int {
 
 	for r in s {
 		switch r {
-		case 0.._surr1, _surr3.._surr_self:
+		case 0.._surr1, _surr3 .. _surr_self:
 			d[n] = u16(r);
 			n += 1;
 
-		case _surr_self..MAX_RUNE:
+		case _surr_self .. MAX_RUNE:
 			r1, r2 := encode_surrogate_pair(r);
 			d[n]    = u16(r1);
 			d[n+1]  = u16(r2);
diff --git a/examples/demo.odin b/examples/demo.odin
index 4992df87f..e218bd7c2 100644
--- a/examples/demo.odin
+++ b/examples/demo.odin
@@ -120,10 +120,10 @@ default_struct_values :: proc() {
 		heap_one      := new(Vector3);         defer free(heap_one);
 		heap_two      := new_clone(Vector3{}); defer free(heap_two);
 
-		fmt.println("stack_default - ", stack_default);
-		fmt.println("stack_literal - ", stack_literal);
-		fmt.println("heap_one      - ", heap_one^);
-		fmt.println("heap_two      - ", heap_two^);
+		fmt.println("stack_default  - ", stack_default);
+		fmt.println("stack_literal  - ", stack_literal);
+		fmt.println("heap_one       - ", heap_one^);
+		fmt.println("heap_two       - ", heap_two^);
 
 
 		N :: 4;
@@ -291,15 +291,15 @@ union_type :: proc() {
 		/*
 			Entity :: struct {
 				...
-				derived: union{^Frog, ^Monster};
+				derived: union{^Frog, ^Monster},
 			}
 
 			Frog :: struct {
-				using entity: Entity;
+				using entity: Entity,
 				...
 			}
 			Monster :: struct {
-				using entity: Entity;
+				using entity: Entity,
 				...
 
 			}
@@ -402,7 +402,7 @@ parametric_polymorphism :: proc() {
 			context <- c {
 				old_slots := table.slots;
 
-				cap := max(2*cap(table.slots), TABLE_SIZE_MIN);
+				cap := max(2*len(table.slots), TABLE_SIZE_MIN);
 				allocate(table, cap);
 
 				for s in old_slots do if s.occupied {
@@ -419,16 +419,16 @@ parametric_polymorphism :: proc() {
 			hash := get_hash(key); // Ad-hoc method which would fail in a different scope
 			index := find_index(table, key, hash);
 			if index < 0 {
-				if f64(table.count) >= 0.75*f64(cap(table.slots)) {
+				if f64(table.count) >= 0.75*f64(len(table.slots)) {
 					expand(table);
 				}
-				assert(table.count <= cap(table.slots));
+				assert(table.count <= len(table.slots));
 
 				hash := get_hash(key);
-				index = int(hash % u32(cap(table.slots)));
+				index = int(hash % u32(len(table.slots)));
 
 				for table.slots[index].occupied {
-					if index += 1; index >= cap(table.slots) {
+					if index += 1; index >= len(table.slots) {
 						index = 0;
 					}
 				}
@@ -455,9 +455,9 @@ parametric_polymorphism :: proc() {
 		}
 
 		find_index :: proc(table: ^Table($Key, $Value), key: Key, hash: u32) -> int {
-			if cap(table.slots) <= 0 do return -1;
+			if len(table.slots) <= 0 do return -1;
 
-			index := int(hash % u32(cap(table.slots)));
+			index := int(hash % u32(len(table.slots)));
 			for table.slots[index].occupied {
 				if table.slots[index].hash == hash {
 					if table.slots[index].key == key {
@@ -465,7 +465,7 @@ parametric_polymorphism :: proc() {
 					}
 				}
 
-				if index += 1; index >= cap(table.slots) {
+				if index += 1; index >= len(table.slots) {
 					index = 0;
 				}
 			}
@@ -565,13 +565,60 @@ threading_example :: proc() {
 	}
 }
 
+array_programming :: proc() {
+	fmt.println("# array_programming");
+	{
+		a := [3]f32{1, 2, 3};
+		b := [3]f32{5, 6, 7};
+		c := a * b;
+		d := a + b;
+		e := 1 +  (c - d) / 2;
+		fmt.printf("%.1f\n", e); // [0.5, 3.0, 6.5]
+	}
+
+	{
+		a := [3]f32{1, 2, 3};
+		b := swizzle(a, 2, 1, 0);
+		assert(b == [3]f32{3, 2, 1});
+
+		c := swizzle(a, 0, 0);
+		assert(c == [2]f32{1, 1});
+		assert(c == 1);
+	}
+
+	{
+		Vector3 :: [3]f32;
+		a := Vector3{1, 2, 3};
+		b := Vector3{5, 6, 7};
+		c := (a * b)/2 + 1;
+		d := c.x + c.y + c.z;
+		fmt.printf("%.1f\n", d); // 22.0
+
+		cross :: proc(a, b: Vector3) -> Vector3 {
+			i := swizzle(a, 1, 2, 0) * swizzle(b, 2, 0, 1);
+			j := swizzle(a, 2, 0, 1) * swizzle(b, 1, 2, 0);
+			return Vector3(i - j);
+		}
+
+		blah :: proc(a: Vector3) -> f32 {
+			return a.x + a.y + a.z;
+		}
+
+		x := cross(a, b);
+		fmt.println(x);
+		fmt.println(blah(x));
+	}
+}
+
+
 main :: proc() {
-	when true {
+	when false {
 		general_stuff();
 		default_struct_values();
 		union_type();
 		parametric_polymorphism();
 		threading_example();
+		array_programming();
 	}
 }
 
diff --git a/src/check_decl.cpp b/src/check_decl.cpp
index 72c8dcd0d..b7bd91183 100644
--- a/src/check_decl.cpp
+++ b/src/check_decl.cpp
@@ -786,6 +786,7 @@ void check_proc_body(Checker *c, Token token, DeclInfo *decl, Type *type, AstNod
 				continue;
 			}
 			bool is_immutable = e->Variable.is_immutable;
+			bool is_value     = (e->flags & EntityFlag_Value) != 0;
 			String name = e->token.string;
 			Type *t = base_type(type_deref(e->type));
 			if (t->kind == Type_Struct) {
@@ -799,6 +800,8 @@ void check_proc_body(Checker *c, Token token, DeclInfo *decl, Type *type, AstNod
 					if (f->kind == Entity_Variable) {
 						Entity *uvar = make_entity_using_variable(c->allocator, e, f->token, f->type);
 						uvar->Variable.is_immutable = is_immutable;
+						if (is_value) uvar->flags |= EntityFlag_Value;
+
 						Entity *prev = scope_insert_entity(c->context.scope, uvar);
 						if (prev != nullptr) {
 							error(e->token, "Namespace collision while 'using' '%.*s' of: %.*s", LIT(name), LIT(prev->token.string));
diff --git a/src/check_expr.cpp b/src/check_expr.cpp
index cf1005055..eaa54306c 100644
--- a/src/check_expr.cpp
+++ b/src/check_expr.cpp
@@ -56,7 +56,7 @@ void     check_expr_or_type             (Checker *c, Operand *operand, AstNode *
 ExprKind check_expr_base                (Checker *c, Operand *operand, AstNode *expression, Type *type_hint);
 void     check_expr_with_type_hint      (Checker *c, Operand *o, AstNode *e, Type *t);
 Type *   check_type                     (Checker *c, AstNode *expression, Type *named_type = nullptr);
-Type *   make_optional_ok_type(gbAllocator a, Type *value);
+Type *   make_optional_ok_type          (gbAllocator a, Type *value);
 void     check_type_decl                (Checker *c, Entity *e, AstNode *type_expr, Type *def, bool alias);
 Entity * check_selector                 (Checker *c, Operand *operand, AstNode *node, Type *type_hint);
 Entity * check_ident                    (Checker *c, Operand *o, AstNode *n, Type *named_type, Type *type_hint, bool allow_import_name);
@@ -2862,7 +2862,7 @@ bool check_builtin_procedure(Checker *c, Operand *operand, AstNode *call, i32 id
 			mode = Addressing_Constant;
 			value = exact_value_i64(at->Array.count);
 			type = t_untyped_integer;
-		} else if (is_type_slice(op_type)) {
+		} else if (is_type_slice(op_type) && id == BuiltinProc_len) {
 			mode = Addressing_Value;
 		} else if (is_type_dynamic_array(op_type)) {
 			mode = Addressing_Value;
diff --git a/src/entity.cpp b/src/entity.cpp
index 00993d407..940288957 100644
--- a/src/entity.cpp
+++ b/src/entity.cpp
@@ -200,11 +200,13 @@ Entity *make_entity_type_name(gbAllocator a, Scope *scope, Token token, Type *ty
 	return entity;
 }
 
-Entity *make_entity_param(gbAllocator a, Scope *scope, Token token, Type *type, bool is_using, bool is_immutable) {
+Entity *make_entity_param(gbAllocator a, Scope *scope, Token token, Type *type, bool is_using, bool is_value) {
+	bool is_immutable = false;
 	Entity *entity = make_entity_variable(a, scope, token, type, is_immutable);
 	entity->flags |= EntityFlag_Used;
-	if (is_using) entity->flags |= EntityFlag_Using;
 	entity->flags |= EntityFlag_Param;
+	if (is_using) entity->flags |= EntityFlag_Using;
+	if (is_value) entity->flags |= EntityFlag_Value;
 	return entity;
 }