From fb4a2317036de68debe9be8bb2cda105a1d91bcd Mon Sep 17 00:00:00 2001
From: Christoffer Lerno <christoffer@aegik.com>
Date: Tue, 20 Aug 2024 14:24:12 +0200
Subject: [PATCH] Add `$member.get(value)` to replace
 `value.$eval($member.nameof)`

---
 releasenotes.md                               |   1 +
 src/compiler/compiler_internal.h              |   4 +-
 src/compiler/copying.c                        |   3 +
 src/compiler/enums.h                          |   2 +
 src/compiler/expr.c                           |   3 +
 src/compiler/llvm_codegen_expr.c              |   1 +
 src/compiler/sema_expr.c                      | 101 +++++++++++++++---
 src/compiler/sema_liveness.c                  |   1 +
 src/compiler/sema_stmts.c                     |   1 +
 src/compiler/symtab.c                         |   1 +
 test/test_suite/assert/assert_with_void.c3    |   2 +-
 .../generic/generic_lambda_complex.c3t        |   2 +-
 test/unit/regression/methodsof.c3             |   2 +
 13 files changed, 106 insertions(+), 18 deletions(-)

diff --git a/releasenotes.md b/releasenotes.md
index 93c2bd576..4e7d5250a 100644
--- a/releasenotes.md
+++ b/releasenotes.md
@@ -35,6 +35,7 @@
 - `$exec` may now provide a stdin parameter.
 - Introduce `$vaarg[...]` syntax and deprecate the old `$vaarg(...)`.
 - Similar change to `$vasplat`: `$vasplat` and `$vasplat[1..]`.
+- Add `$member.get(value)` to replace `value.$eval($member.nameof)`
 
 ### Fixes
 
diff --git a/src/compiler/compiler_internal.h b/src/compiler/compiler_internal.h
index 7296e11f3..74c1c001a 100644
--- a/src/compiler/compiler_internal.h
+++ b/src/compiler/compiler_internal.h
@@ -1090,7 +1090,8 @@ struct Expr_
 		Expr *inner_expr;                           // 8
 		Decl *lambda_expr;                          // 8
 		ExprMacroBlock macro_block;                 // 24
-		ExprMacroBody macro_body_expr;              // 16;
+		ExprMacroBody macro_body_expr;              // 16
+		Decl *member_get_expr;                      // 8
 		OperatorOverload overload_expr;             // 4
 		ExprPointerOffset pointer_offset_expr;
 		ExprGuard rethrow_expr;                     // 16
@@ -3265,6 +3266,7 @@ INLINE void expr_set_span(Expr *expr, SourceSpan loc)
 		case EXPR_MACRO_BODY:
 		case EXPR_DEFAULT_ARG:
 		case EXPR_TAGOF:
+		case EXPR_MEMBER_GET:
 			break;
 	}
 }
diff --git a/src/compiler/copying.c b/src/compiler/copying.c
index c3071bc6c..43f3dd604 100644
--- a/src/compiler/copying.c
+++ b/src/compiler/copying.c
@@ -317,6 +317,9 @@ Expr *copy_expr(CopyStruct *c, Expr *source_expr)
 				MACRO_COPY_DECL(expr->lambda_expr);
 			}
 			return expr;
+		case EXPR_MEMBER_GET:
+			fixup_decl(c, &source_expr->member_get_expr);
+			break;
 		case EXPR_SWIZZLE:
 			MACRO_COPY_EXPRID(expr->swizzle_expr.parent);
 			return expr;
diff --git a/src/compiler/enums.h b/src/compiler/enums.h
index efa8aa35d..8628c7051 100644
--- a/src/compiler/enums.h
+++ b/src/compiler/enums.h
@@ -788,6 +788,7 @@ typedef enum
 	EXPR_MACRO_BLOCK,
 	EXPR_MACRO_BODY,
 	EXPR_MACRO_BODY_EXPANSION,
+	EXPR_MEMBER_GET,
 	EXPR_NOP,
 	EXPR_OPERATOR_CHARS,
 	EXPR_OPTIONAL,
@@ -1363,6 +1364,7 @@ typedef enum
 	TYPE_PROPERTY_ASSOCIATED,
 	TYPE_PROPERTY_ELEMENTS,
 	TYPE_PROPERTY_EXTNAMEOF,
+	TYPE_PROPERTY_GET,
 	TYPE_PROPERTY_INF,
 	TYPE_PROPERTY_IS_EQ,
 	TYPE_PROPERTY_IS_ORDERED,
diff --git a/src/compiler/expr.c b/src/compiler/expr.c
index 4a6ddced3..08a08ab11 100644
--- a/src/compiler/expr.c
+++ b/src/compiler/expr.c
@@ -79,6 +79,7 @@ bool expr_may_addr(Expr *expr)
 			return expr_may_addr(expr->access_expr.parent);
 		case EXPR_SUBSCRIPT:
 		case EXPR_SLICE:
+		case EXPR_MEMBER_GET:
 			return true;
 		case EXPR_BENCHMARK_HOOK:
 		case EXPR_TEST_HOOK:
@@ -226,6 +227,7 @@ bool expr_is_constant_eval(Expr *expr, ConstantEvalKind eval_kind)
 		case EXPR_SLICE_COPY:
 		case EXPR_MACRO_BLOCK:
 		case EXPR_RETHROW:
+		case EXPR_MEMBER_GET:
 			return false;
 		case EXPR_IDENTIFIER:
 		{
@@ -704,6 +706,7 @@ bool expr_is_pure(Expr *expr)
 		case EXPR_TYPEID:
 		case EXPR_TYPEINFO:
 		case EXPR_LAST_FAULT:
+		case EXPR_MEMBER_GET:
 			return true;
 		case EXPR_VASPLAT:
 			return true;
diff --git a/src/compiler/llvm_codegen_expr.c b/src/compiler/llvm_codegen_expr.c
index 5629849e0..ba15b62e9 100644
--- a/src/compiler/llvm_codegen_expr.c
+++ b/src/compiler/llvm_codegen_expr.c
@@ -7064,6 +7064,7 @@ void llvm_emit_expr(GenContext *c, BEValue *value, Expr *expr)
 		case EXPR_MACRO_BODY:
 		case EXPR_OTHER_CONTEXT:
 		case EXPR_DESIGNATOR:
+		case EXPR_MEMBER_GET:
 			UNREACHABLE
 		case EXPR_DEFAULT_ARG:
 			llvm_emit_default_arg(c, value, expr);
diff --git a/src/compiler/sema_expr.c b/src/compiler/sema_expr.c
index c9305fa59..a7830a6ed 100644
--- a/src/compiler/sema_expr.c
+++ b/src/compiler/sema_expr.c
@@ -593,6 +593,7 @@ static bool sema_binary_is_expr_lvalue(SemaContext *context, Expr *top_expr, Exp
 		case EXPR_GENERIC_IDENT:
 		case EXPR_MACRO_BODY:
 		case EXPR_LAST_FAULT:
+		case EXPR_MEMBER_GET:
 			goto ERR;
 	}
 	UNREACHABLE
@@ -618,6 +619,7 @@ static bool expr_may_ref(Expr *expr)
 		case EXPR_EMBED:
 		case EXPR_DEFAULT_ARG:
 		case EXPR_TAGOF:
+		case EXPR_MEMBER_GET:
 			return false;
 		case EXPR_OTHER_CONTEXT:
 			return expr_may_ref(expr->expr_other_context.inner);
@@ -2519,6 +2521,57 @@ NOT_FOUND:
 	RETURN_SEMA_ERROR(expr, "The tag '%s' is not defined, always check with '.has_tagof'.", tagname);
 }
 
+INLINE bool sema_call_may_not_have_attributes(SemaContext *context, Expr *expr)
+{
+	if (expr->call_expr.attr_force_inline)
+	{
+		RETURN_SEMA_ERROR(expr, "'@inline' is not allowed here.");
+	}
+	if (expr->call_expr.attr_force_inline)
+	{
+		RETURN_SEMA_ERROR(expr, "'@noinline' is not allowed here.");
+	}
+	if (expr->call_expr.attr_force_inline)
+	{
+		RETURN_SEMA_ERROR(expr, "'@pure' is not allowed here.");
+	}
+	return true;
+}
+static inline bool sema_call_analyse_member_get(SemaContext *context, Expr *expr)
+{
+	if (vec_size(expr->call_expr.arguments) != 1)
+	{
+		RETURN_SEMA_ERROR(expr, "Expected a single argument to '.get'.");
+	}
+	if (!sema_call_may_not_have_attributes(context, expr)) return false;
+	Expr *get = exprptr(expr->call_expr.function);
+	Expr *inner = expr->call_expr.arguments[0];
+	if (!sema_analyse_expr(context, inner)) return false;
+	Decl *decl = get->member_get_expr;
+	Type *type = type_flatten(inner->type);
+	if (type->type_kind != TYPE_STRUCT && type->type_kind != TYPE_UNION)
+	{
+		RETURN_SEMA_ERROR(inner, "This value does not match the member.");
+	}
+	Decl **members = type->decl->strukt.members;
+	ArrayIndex index = -1;
+	FOREACH_IDX(i, Decl *, member, members)
+	{
+		if (member == decl)
+		{
+			index = i;
+			break;
+		}
+	}
+	if (index == -1)
+	{
+		RETURN_SEMA_ERROR(inner, "This value does not match the member.");
+	}
+	expr->expr_kind = EXPR_ACCESS;
+	expr->access_expr = (ExprAccess) { .parent = inner, .ref = decl };
+	expr->type = decl->type;
+	return true;
+}
 static inline bool sema_expr_analyse_call(SemaContext *context, Expr *expr, bool *no_match_ref)
 {
 	if (no_match_ref) *no_match_ref = true;
@@ -2528,6 +2581,10 @@ static inline bool sema_expr_analyse_call(SemaContext *context, Expr *expr, bool
 	{
 		return sema_call_analyse_body_expansion(context, expr);
 	}
+	if (func_expr->expr_kind == EXPR_MEMBER_GET)
+	{
+		return sema_call_analyse_member_get(context, expr);
+	}
 	bool optional = func_expr->type && IS_OPTIONAL(func_expr);
 	Decl *decl;
 	Expr *struct_var = NULL;
@@ -3442,6 +3499,11 @@ static inline bool sema_expr_analyse_member_access(SemaContext *context, Expr *e
 			expr->expr_kind = EXPR_TAGOF;
 			expr->tag_of_expr = (ExprTagOf) { .type = decl, .property = type_property };
 			return true;
+		case TYPE_PROPERTY_GET:
+			expr->expr_kind = EXPR_MEMBER_GET;
+			expr->member_get_expr = decl;
+			expr->type = type_void;
+			return true;
 		case TYPE_PROPERTY_NONE:
 			break;
 		case TYPE_PROPERTY_QNAMEOF:
@@ -3910,25 +3972,26 @@ static bool sema_expr_rewrite_to_typeid_property(SemaContext *context, Expr *exp
 		case TYPE_PROPERTY_NAMES:
 			return sema_expr_rewrite_typeid_call(expr, typeid, TYPEID_INFO_NAMES, type_get_slice(type_string));
 		case TYPE_PROPERTY_ALIGNOF:
-		case TYPE_PROPERTY_INF:
-		case TYPE_PROPERTY_MIN:
-		case TYPE_PROPERTY_MAX:
-		case TYPE_PROPERTY_NAN:
-		case TYPE_PROPERTY_ELEMENTS:
-		case TYPE_PROPERTY_VALUES:
-		case TYPE_PROPERTY_RETURNS:
-		case TYPE_PROPERTY_PARAMS:
-		case TYPE_PROPERTY_MEMBERSOF:
-		case TYPE_PROPERTY_METHODSOF:
-		case TYPE_PROPERTY_EXTNAMEOF:
-		case TYPE_PROPERTY_TAGOF:
-		case TYPE_PROPERTY_HAS_TAGOF:
-		case TYPE_PROPERTY_NAMEOF:
-		case TYPE_PROPERTY_QNAMEOF:
 		case TYPE_PROPERTY_ASSOCIATED:
+		case TYPE_PROPERTY_ELEMENTS:
+		case TYPE_PROPERTY_EXTNAMEOF:
+		case TYPE_PROPERTY_GET:
+		case TYPE_PROPERTY_HAS_TAGOF:
+		case TYPE_PROPERTY_INF:
 		case TYPE_PROPERTY_IS_EQ:
 		case TYPE_PROPERTY_IS_ORDERED:
 		case TYPE_PROPERTY_IS_SUBSTRUCT:
+		case TYPE_PROPERTY_MAX:
+		case TYPE_PROPERTY_MEMBERSOF:
+		case TYPE_PROPERTY_METHODSOF:
+		case TYPE_PROPERTY_MIN:
+		case TYPE_PROPERTY_NAMEOF:
+		case TYPE_PROPERTY_NAN:
+		case TYPE_PROPERTY_PARAMS:
+		case TYPE_PROPERTY_QNAMEOF:
+		case TYPE_PROPERTY_RETURNS:
+		case TYPE_PROPERTY_TAGOF:
+		case TYPE_PROPERTY_VALUES:
 			// Not supported by dynamic typeid
 		case TYPE_PROPERTY_NONE:
 			return false;
@@ -4096,6 +4159,8 @@ static bool sema_type_property_is_valid_for_type(Type *original_type, TypeProper
 	{
 		case TYPE_PROPERTY_NONE:
 			return false;
+		case TYPE_PROPERTY_GET:
+			return type == type_member;
 		case TYPE_PROPERTY_INF:
 		case TYPE_PROPERTY_NAN:
 			return type_is_float(type);
@@ -4237,6 +4302,8 @@ static bool sema_expr_rewrite_to_type_property(SemaContext *context, Expr *expr,
 			expr->type = type;
 			expr->resolve_status = RESOLVE_DONE;
 			return true;
+		case TYPE_PROPERTY_GET:
+			UNREACHABLE
 		case TYPE_PROPERTY_MEMBERSOF:
 		{
 			AlignSize align;
@@ -8943,6 +9010,7 @@ static inline bool sema_expr_analyse_ct_defined(SemaContext *context, Expr *expr
 			case EXPR_TYPEID:
 			case EXPR_TYPEID_INFO:
 			case EXPR_TAGOF:
+			case EXPR_MEMBER_GET:
 				if (!sema_analyse_expr(active_context, main_expr)) return false;
 				break;
 		}
@@ -9599,6 +9667,7 @@ static inline bool sema_analyse_expr_dispatch(SemaContext *context, Expr *expr)
 		case EXPR_SWIZZLE:
 		case EXPR_MACRO_BODY:
 		case EXPR_DEFAULT_ARG:
+		case EXPR_MEMBER_GET:
 			UNREACHABLE
 		case EXPR_TAGOF:
 			RETURN_SEMA_ERROR(expr, "Expected '()' after this.");
@@ -9900,6 +9969,8 @@ static inline bool sema_cast_rvalue(SemaContext *context, Expr *expr)
 	if (!expr_ok(expr)) return false;
 	switch (expr->expr_kind)
 	{
+		case EXPR_MEMBER_GET:
+			RETURN_SEMA_ERROR(expr, "Expected a parameter to 'get', e.g. '$member.get(value)'.");
 		case EXPR_MACRO_BODY_EXPANSION:
 			if (!expr->body_expansion_expr.first_stmt)
 			{
diff --git a/src/compiler/sema_liveness.c b/src/compiler/sema_liveness.c
index e92bdb391..630840aa5 100644
--- a/src/compiler/sema_liveness.c
+++ b/src/compiler/sema_liveness.c
@@ -261,6 +261,7 @@ RETRY:
 		case EXPR_EMBED:
 		case EXPR_MACRO_BODY:
 		case EXPR_OTHER_CONTEXT:
+		case EXPR_MEMBER_GET:
 			UNREACHABLE
 		case EXPR_DESIGNATOR:
 			sema_trace_expr_liveness(expr->designator_expr.value);
diff --git a/src/compiler/sema_stmts.c b/src/compiler/sema_stmts.c
index cc08742e9..064b98558 100644
--- a/src/compiler/sema_stmts.c
+++ b/src/compiler/sema_stmts.c
@@ -632,6 +632,7 @@ static inline bool sema_expr_valid_try_expression(Expr *expr)
 		case EXPR_TERNARY:
 		case EXPR_LAST_FAULT:
 		case EXPR_TAGOF:
+		case EXPR_MEMBER_GET:
 			return false;
 		case EXPR_BITACCESS:
 		case EXPR_BUILTIN:
diff --git a/src/compiler/symtab.c b/src/compiler/symtab.c
index 4bedc2ef9..6fc693bd1 100644
--- a/src/compiler/symtab.c
+++ b/src/compiler/symtab.c
@@ -160,6 +160,7 @@ void symtab_init(uint32_t capacity)
 	type_property_list[TYPE_PROPERTY_ASSOCIATED] = KW_DEF("associated");
 	type_property_list[TYPE_PROPERTY_ELEMENTS] = KW_DEF("elements");
 	type_property_list[TYPE_PROPERTY_EXTNAMEOF] = KW_DEF("extnameof");
+	type_property_list[TYPE_PROPERTY_GET] = KW_DEF("get");
 	type_property_list[TYPE_PROPERTY_INF] = KW_DEF("inf");
 	type_property_list[TYPE_PROPERTY_INNER] = KW_DEF("inner");
 	type_property_list[TYPE_PROPERTY_IS_EQ] = KW_DEF("is_eq");
diff --git a/test/test_suite/assert/assert_with_void.c3 b/test/test_suite/assert/assert_with_void.c3
index 905ffe81d..671803880 100644
--- a/test/test_suite/assert/assert_with_void.c3
+++ b/test/test_suite/assert/assert_with_void.c3
@@ -25,7 +25,7 @@ macro deep_print(a)
             io::print("{");
             $foreach ($i, $m : $typeof(a).membersof)
                 if ($i > 0) io::print(", ");
-                deep_print(a.$eval($m.nameof));
+                deep_print($m.get(a));
             $endforeach
             io::print("}");
         $default:
diff --git a/test/test_suite/generic/generic_lambda_complex.c3t b/test/test_suite/generic/generic_lambda_complex.c3t
index feade9ee1..0493b91f6 100644
--- a/test/test_suite/generic/generic_lambda_complex.c3t
+++ b/test/test_suite/generic/generic_lambda_complex.c3t
@@ -74,7 +74,7 @@ fn void! TextTemplate.init(&self, String template, String tag_start = "{{", Stri
 								.data = (String*)(data + $m.offsetof),
 							};
 						$default:
-							$if $defined(self.data.$eval($m.nameof).as_stream):
+							$if $defined($m.get(self.data).as_stream):
 								return TextTag{
 									.kind = TEMPLATE,
 									.template = self.data.$eval($m.nameof).as_stream(),
diff --git a/test/unit/regression/methodsof.c3 b/test/unit/regression/methodsof.c3
index 695584cee..ecf30caa4 100644
--- a/test/unit/regression/methodsof.c3
+++ b/test/unit/regression/methodsof.c3
@@ -71,6 +71,8 @@ fn void methodsof()
     Foo foo = { .i = 4, .b = true };
     assert(Foo.$eval(Foo.methodsof[2])(&foo) == true); // Foo.xyz
     assert(Foo.$eval(Foo.methodsof[1])(&foo, 2) == 8); // Foo.bar
+    assert(Foo.$eval(Foo.methodsof[2])(&foo) == true); // Foo.xyz
+    assert(Foo.$eval(Foo.methodsof[1])(&foo, 2) == 8); // Foo.bar
 
     Foo foo2 = { .i = 2, .b = false };
     assert(foo2.$eval(Foo.methodsof[2])() == false); // Foo.xyz