[Experimental] Add 'try' and `or_else' built-in procedures

5 files changed, 487 insertions, 50 deletions

diff --git a/src/check_builtin.cpp b/src/check_builtin.cpp
index 378779dc6..23c489482 100644
--- a/src/check_builtin.cpp
+++ b/src/check_builtin.cpp
@@ -47,6 +47,179 @@ BuiltinTypeIsProc *builtin_type_is_procs[BuiltinProc__type_simple_boolean_end -
 	type_has_nil,
 };
 
+void check_promote_optional_ok(CheckerContext *c, Operand *x, Type **val_type_, Type **ok_type_) {
+	switch (x->mode) {
+	case Addressing_MapIndex:
+	case Addressing_OptionalOk:
+	case Addressing_OptionalOkPtr:
+		if (val_type_) *val_type_ = x->type;
+		break;
+	default:
+		if (ok_type_) *ok_type_ = x->type;
+		return;
+	}
+
+	Ast *expr = unparen_expr(x->expr);
+
+	if (expr->kind == Ast_CallExpr) {
+		Type *pt = base_type(type_of_expr(expr->CallExpr.proc));
+		if (is_type_proc(pt)) {
+			Type *tuple = pt->Proc.results;
+			add_type_and_value(&c->checker->info, x->expr, x->mode, tuple, x->value);
+
+			if (pt->Proc.result_count >= 2) {
+				if (ok_type_) *ok_type_ = tuple->Tuple.variables[1]->type;
+			}
+			expr->CallExpr.optional_ok_one = false;
+			x->type = tuple;
+			return;
+		}
+	}
+
+	Type *tuple = make_optional_ok_type(x->type);
+	if (ok_type_) *ok_type_ = tuple->Tuple.variables[1]->type;
+	add_type_and_value(&c->checker->info, x->expr, x->mode, tuple, x->value);
+	x->type = tuple;
+	GB_ASSERT(is_type_tuple(type_of_expr(x->expr)));
+}
+
+void check_try_split_types(CheckerContext *c, Operand *x, String const &name, Type **left_type_, Type **right_type_) {
+	Type *left_type = nullptr;
+	Type *right_type = nullptr;
+	if (x->type->kind == Type_Tuple) {
+		auto const &vars = x->type->Tuple.variables;
+		auto lhs = array_slice(vars, 0, vars.count-1);
+		auto rhs = vars[vars.count-1];
+		if (lhs.count == 1) {
+			left_type = lhs[0]->type;
+		} else if (lhs.count != 0) {
+			left_type = alloc_type_tuple();
+			left_type->Tuple.variables = array_make_from_ptr(lhs.data, lhs.count, lhs.count);
+		}
+
+		right_type = rhs->type;
+	} else {
+		check_promote_optional_ok(c, x, &left_type, &right_type);
+	}
+
+	if (left_type_)  *left_type_  = left_type;
+	if (right_type_) *right_type_ = right_type;
+
+	if (!type_has_nil(right_type) && !is_type_boolean(right_type)) {
+		gbString str = type_to_string(right_type);
+		error(x->expr, "'%.*s' expects an \"optional ok\" like value, or an n-valued expression where the last value is either a boolean or can be compared against 'nil', got %s", LIT(name), str);
+		gb_string_free(str);
+	}
+}
+
+bool check_builtin_try(CheckerContext *c, Operand *operand, String const &name, Ast *call, Type *type_hint) {
+	ast_node(ce, CallExpr, call);
+
+	Operand x = {};
+	check_multi_expr_with_type_hint(c, &x, ce->args[0], type_hint);
+	if (x.mode == Addressing_Invalid) {
+		return false;
+	}
+
+	if (c->in_defer) {
+		error(call, "'%.*s' cannot be used within a defer statement", LIT(name));
+	}
+
+	Type *left_type = nullptr;
+	Type *right_type = nullptr;
+	check_try_split_types(c, &x, name, &left_type, &right_type);
+	add_type_and_value(&c->checker->info, ce->args[0], x.mode, x.type, x.value);
+
+	if (c->curr_proc_sig == nullptr) {
+		error(call, "'%.*s' can only be used within a procedure", LIT(name));
+	}
+	Type *proc_type = base_type(c->curr_proc_sig);
+	GB_ASSERT(proc_type->kind == Type_Proc);
+	Type *result_type = proc_type->Proc.results;
+	if (result_type == nullptr) {
+		error(call, "'%.*s' requires the current procedure to have at least one return value", LIT(name));
+	} else {
+		GB_ASSERT(result_type->kind == Type_Tuple);
+
+		auto const &vars = result_type->Tuple.variables;
+		Type *end_type = vars[vars.count-1]->type;
+
+		if (vars.count > 1) {
+			if (!proc_type->Proc.has_named_results) {
+				error(call, "'%.*s' within a procedure with more than 1 return value requires that the return values are named, allowing for early return", LIT(name));
+			}
+		}
+
+		Operand rhs = {};
+		rhs.type = right_type;
+		rhs.mode = Addressing_Value;
+
+		// TODO(bill): better error message
+		if (!check_is_assignable_to(c, &rhs, end_type)) {
+			gbString a = type_to_string(right_type);
+			gbString b = type_to_string(end_type);
+			gbString ret_type = type_to_string(result_type);
+			error(call, "Cannot assign end value of type '%s' to '%s' in '%.*s'", a, b, LIT(name));
+			if (vars.count == 1) {
+				error_line("\tProcedure return value type: %s\n", ret_type);
+			} else {
+				error_line("\tProcedure return value types: (%s)\n", ret_type);
+			}
+			gb_string_free(ret_type);
+			gb_string_free(b);
+			gb_string_free(a);
+		}
+	}
+
+
+	if (left_type != nullptr) {
+		operand->mode = Addressing_Value;
+		operand->type = left_type;
+	} else {
+		operand->mode = Addressing_NoValue;
+		operand->type = nullptr;
+	}
+
+	return true;
+}
+
+bool check_builtin_or_else(CheckerContext *c, Operand *operand, String const &name, Ast *call, Type *type_hint) {
+	ast_node(ce, CallExpr, call);
+
+	Operand x = {};
+	Operand y = {};
+	check_multi_expr_with_type_hint(c, &x, ce->args[0], type_hint);
+	if (x.mode == Addressing_Invalid) {
+		return false;
+	}
+
+	check_multi_expr(c, &y, ce->args[1]);
+	error_operand_no_value(&y);
+	if (y.mode == Addressing_Invalid) {
+		return false;
+	}
+
+	Type *left_type = nullptr;
+	Type *right_type = nullptr;
+	check_try_split_types(c, &x, name, &left_type, &right_type);
+	add_type_and_value(&c->checker->info, ce->args[0], x.mode, x.type, x.value);
+
+	if (left_type != nullptr) {
+		check_assignment(c, &y, left_type, name);
+	} else {
+		// TODO(bill): better error message
+		error(call, "'%.*s' does not return a value", LIT(name));
+	}
+
+
+	if (left_type == nullptr) {
+		left_type = t_invalid;
+	}
+	operand->mode = Addressing_Value;
+	operand->type = left_type;
+
+	return true;
+}
 
 
 bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32 id, Type *type_hint) {
@@ -86,6 +259,11 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 		// NOTE(bill): The first arg may be a Type, this will be checked case by case
 		break;
 
+	case BuiltinProc_try:
+	case BuiltinProc_or_else:
+		// NOTE(bill): The first arg may be a tuple
+		break;
+
 	case BuiltinProc_DIRECTIVE: {
 		ast_node(bd, BasicDirective, ce->proc);
 		String name = bd->name.string;
@@ -1713,6 +1891,10 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 		break;
 	}
 
+	case BuiltinProc_try:
+		return check_builtin_try(c, operand, builtin_name, call, type_hint);
+	case BuiltinProc_or_else:
+		return check_builtin_or_else(c, operand, builtin_name, call, type_hint);
 
 	case BuiltinProc_simd_vector: {
 		Operand x = {};
diff --git a/src/check_expr.cpp b/src/check_expr.cpp
index 537fb73cc..57d10f60e 100644
--- a/src/check_expr.cpp
+++ b/src/check_expr.cpp
@@ -111,6 +111,8 @@ Type *make_soa_struct_dynamic_array(CheckerContext *ctx, Ast *array_typ_expr, As
 
 bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32 id, Type *type_hint);
 
+void check_promote_optional_ok(CheckerContext *c, Operand *x, Type **val_type_, Type **ok_type_);
+
 Entity *entity_from_expr(Ast *expr) {
 	expr = unparen_expr(expr);
 	switch (expr->kind) {
@@ -4045,26 +4047,7 @@ bool check_assignment_arguments(CheckerContext *ctx, Array<Operand> const &lhs,
 				val1.mode = Addressing_Value;
 				val1.type = t_untyped_bool;
 
-
-				if (expr->kind == Ast_CallExpr) {
-					Type *pt = base_type(type_of_expr(expr->CallExpr.proc));
-					if (is_type_proc(pt)) {
-						do_normal = false;
-						Type *tuple = pt->Proc.results;
-						add_type_and_value(&c->checker->info, o.expr, o.mode, tuple, o.value);
-
-						if (pt->Proc.result_count >= 2) {
-							Type *t1 = tuple->Tuple.variables[1]->type;
-							val1.type = t1;
-						}
-						expr->CallExpr.optional_ok_one = false;
-					}
-				}
-
-				if (do_normal) {
-					Type *tuple = make_optional_ok_type(o.type);
-					add_type_and_value(&c->checker->info, o.expr, o.mode, tuple, o.value);
-				}
+				check_promote_optional_ok(c, &o, nullptr, &val1.type);
 
 				if (expr->kind == Ast_TypeAssertion &&
 				    (o.mode == Addressing_OptionalOk || o.mode == Addressing_OptionalOkPtr)) {
@@ -4170,26 +4153,7 @@ bool check_unpack_arguments(CheckerContext *ctx, Entity **lhs, isize lhs_count,
 				val1.mode = Addressing_Value;
 				val1.type = t_untyped_bool;
 
-
-				if (expr->kind == Ast_CallExpr) {
-					Type *pt = base_type(type_of_expr(expr->CallExpr.proc));
-					if (is_type_proc(pt)) {
-						do_normal = false;
-						Type *tuple = pt->Proc.results;
-						add_type_and_value(&c->checker->info, o.expr, o.mode, tuple, o.value);
-
-						if (pt->Proc.result_count >= 2) {
-							Type *t1 = tuple->Tuple.variables[1]->type;
-							val1.type = t1;
-						}
-						expr->CallExpr.optional_ok_one = false;
-					}
-				}
-
-				if (do_normal) {
-					Type *tuple = make_optional_ok_type(o.type);
-					add_type_and_value(&c->checker->info, o.expr, o.mode, tuple, o.value);
-				}
+				check_promote_optional_ok(c, &o, nullptr, &val1.type);
 
 				if (expr->kind == Ast_TypeAssertion &&
 				    (o.mode == Addressing_OptionalOk || o.mode == Addressing_OptionalOkPtr)) {
@@ -8192,6 +8156,21 @@ void check_multi_expr(CheckerContext *c, Operand *o, Ast *e) {
 	o->mode = Addressing_Invalid;
 }
 
+void check_multi_expr_with_type_hint(CheckerContext *c, Operand *o, Ast *e, Type *type_hint) {
+	check_expr_base(c, o, e, type_hint);
+	switch (o->mode) {
+	default:
+		return; // NOTE(bill): Valid
+	case Addressing_NoValue:
+		error_operand_no_value(o);
+		break;
+	case Addressing_Type:
+		error_operand_not_expression(o);
+		break;
+	}
+	o->mode = Addressing_Invalid;
+}
+
 void check_not_tuple(CheckerContext *c, Operand *o) {
 	if (o->mode == Addressing_Value) {
 		// NOTE(bill): Tuples are not first class thus never named
@@ -8472,9 +8451,15 @@ gbString write_expr_to_string(gbString str, Ast *node, bool shorthand) {
 
 	case_ast_node(ta, TypeAssertion, node);
 		str = write_expr_to_string(str, ta->expr, shorthand);
-		str = gb_string_appendc(str, ".(");
-		str = write_expr_to_string(str, ta->type, shorthand);
-		str = gb_string_append_rune(str, ')');
+		if (ta->type != nullptr &&
+		    ta->type->kind == Ast_UnaryExpr &&
+		    ta->type->UnaryExpr.op.kind == Token_Question) {
+			str = gb_string_appendc(str, ".?");
+		} else {
+			str = gb_string_appendc(str, ".(");
+			str = write_expr_to_string(str, ta->type, shorthand);
+			str = gb_string_append_rune(str, ')');
+		}
 	case_end;
 
 	case_ast_node(tc, TypeCast, node);
diff --git a/src/check_stmt.cpp b/src/check_stmt.cpp
index 24960b33c..d68524994 100644
--- a/src/check_stmt.cpp
+++ b/src/check_stmt.cpp
@@ -1667,7 +1667,7 @@ void check_stmt_internal(CheckerContext *ctx, Ast *node, u32 flags) {
 		GB_ASSERT(ctx->curr_proc_sig != nullptr);
 
 		if (ctx->in_defer) {
-			error(rs->token, "You cannot 'return' within a defer statement");
+			error(rs->token, "'return' cannot be used within a defer statement");
 			break;
 		}
 
diff --git a/src/checker_builtin_procs.hpp b/src/checker_builtin_procs.hpp
index 57b5d7eb9..a72231f8b 100644
--- a/src/checker_builtin_procs.hpp
+++ b/src/checker_builtin_procs.hpp
@@ -33,6 +33,9 @@ enum BuiltinProcId {
 	BuiltinProc_soa_zip,
 	BuiltinProc_soa_unzip,
 
+	BuiltinProc_try,
+	BuiltinProc_or_else,
+
 	BuiltinProc_DIRECTIVE, // NOTE(bill): This is used for specialized hash-prefixed procedures
 
 	// "Intrinsics"
@@ -263,6 +266,9 @@ gb_global BuiltinProc builtin_procs[BuiltinProc_COUNT] = {
 	{STR_LIT("soa_zip"),          1, true,  Expr_Expr, BuiltinProcPkg_builtin},
 	{STR_LIT("soa_unzip"),        1, false, Expr_Expr, BuiltinProcPkg_builtin},
 
+	{STR_LIT("try"),              1, false, Expr_Expr, BuiltinProcPkg_builtin},
+	{STR_LIT("or_else"),          2, false, Expr_Expr, BuiltinProcPkg_builtin},
+
 	{STR_LIT(""),                 0, true,  Expr_Expr, BuiltinProcPkg_builtin}, // DIRECTIVE
 
 
diff --git a/src/llvm_backend.cpp b/src/llvm_backend.cpp
index bf5f33e4b..f146956c2 100644
--- a/src/llvm_backend.cpp
+++ b/src/llvm_backend.cpp
@@ -5339,14 +5339,14 @@ void lb_build_assignment(lbProcedure *p, Array<lbAddr> &lvals, Slice<Ast *> cons
 	}
 }
 
-void lb_build_return_stmt(lbProcedure *p, AstReturnStmt *rs) {
+void lb_build_return_stmt(lbProcedure *p, Slice<Ast *> const &return_results) {
 	lb_ensure_abi_function_type(p->module, p);
 
 	lbValue res = {};
 
 	TypeTuple *tuple  = &p->type->Proc.results->Tuple;
 	isize return_count = p->type->Proc.result_count;
-	isize res_count = rs->results.count;
+	isize res_count = return_results.count;
 
 	lbFunctionType *ft = lb_get_function_type(p->module, p, p->type);
 	bool return_by_pointer = ft->ret.kind == lbArg_Indirect;
@@ -5365,7 +5365,7 @@ void lb_build_return_stmt(lbProcedure *p, AstReturnStmt *rs) {
 			GB_ASSERT(found);
 			res = lb_emit_load(p, *found);
 		} else {
-			res = lb_build_expr(p, rs->results[0]);
+			res = lb_build_expr(p, return_results[0]);
 			res = lb_emit_conv(p, res, e->type);
 		}
 		if (p->type->Proc.has_named_results) {
@@ -5382,7 +5382,7 @@ void lb_build_return_stmt(lbProcedure *p, AstReturnStmt *rs) {
 
 		if (res_count != 0) {
 			for (isize res_index = 0; res_index < res_count; res_index++) {
-				lbValue res = lb_build_expr(p, rs->results[res_index]);
+				lbValue res = lb_build_expr(p, return_results[res_index]);
 				Type *t = res.type;
 				if (t->kind == Type_Tuple) {
 					for_array(i, t->Tuple.variables) {
@@ -5893,7 +5893,7 @@ void lb_build_stmt(lbProcedure *p, Ast *node) {
 	case_end;
 
 	case_ast_node(rs, ReturnStmt, node);
-		lb_build_return_stmt(p, rs);
+		lb_build_return_stmt(p, rs->results);
 	case_end;
 
 	case_ast_node(is, IfStmt, node);
@@ -9553,6 +9553,257 @@ lbValue lb_soa_unzip(lbProcedure *p, AstCallExpr *ce, TypeAndValue const &tv) {
 	return lb_addr_load(p, res);
 }
 
+lbValue lb_emit_try(lbProcedure *p, AstCallExpr *ce, TypeAndValue const &tv) {
+	Ast *arg = ce->args[0];
+
+	lbValue lhs = {};
+	lbValue rhs = {};
+
+	TypeAndValue const &arg_tav = type_and_value_of_expr(arg);
+	lbValue value = lb_build_expr(p, arg);
+
+	if (is_type_tuple(value.type)) {
+		i32 n = cast(i32)(value.type->Tuple.variables.count-1);
+		if (value.type->Tuple.variables.count == 2) {
+			lhs = lb_emit_struct_ev(p, value, 0);
+		} else {
+			lbAddr lhs_addr = lb_add_local_generated(p, tv.type, false);
+			lbValue lhs_ptr = lb_addr_get_ptr(p, lhs_addr);
+			for (i32 i = 0; i < n; i++) {
+				lb_emit_store(p, lb_emit_struct_ep(p, lhs_ptr, i), lb_emit_struct_ev(p, value, i));
+			}
+			lhs = lb_addr_load(p, lhs_addr);
+		}
+		rhs = lb_emit_struct_ev(p, value, n);
+	} else {
+		rhs = value;
+	}
+
+	GB_ASSERT(rhs.value != nullptr);
+
+	lbValue do_early_return = {};
+	if (is_type_boolean(rhs.type)) {
+		do_early_return = lb_emit_unary_arith(p, Token_Not, rhs, t_bool);
+	} else {
+		GB_ASSERT(type_has_nil(rhs.type));
+		do_early_return = lb_emit_comp_against_nil(p, Token_NotEq, rhs);
+	}
+
+	GB_ASSERT(do_early_return.value != nullptr);
+
+
+	lbBlock *return_block = lb_create_block(p, "try.return", false);
+	lbBlock *continue_block = lb_create_block(p, "try.continue", false);
+	lb_emit_if(p, do_early_return, return_block, continue_block);
+	lb_start_block(p, return_block);
+
+	{
+		Type *proc_type = base_type(p->type);
+		// TODO(bill): multiple return values
+		Type *results = proc_type->Proc.results;
+		GB_ASSERT(results != nullptr && results->kind == Type_Tuple);
+		TypeTuple *tuple = &results->Tuple;
+
+		isize return_count = tuple->variables.count;
+		// TODO(bill) multiple
+		GB_ASSERT(return_count != 0);
+
+		lbFunctionType *ft = lb_get_function_type(p->module, p, proc_type);
+		bool return_by_pointer = ft->ret.kind == lbArg_Indirect;
+
+		lbValue res = {};
+		if (return_count == 1) {
+			Entity *e = tuple->variables[0];
+			res = lb_emit_conv(p, rhs, e->type);
+
+			if (p->type->Proc.has_named_results) {
+				// NOTE(bill): store the named values before returning
+				if (e->token.string != "") {
+					lbValue *found = map_get(&p->module->values, hash_entity(e));
+					GB_ASSERT(found != nullptr);
+					lb_emit_store(p, *found, lb_emit_conv(p, res, e->type));
+				}
+			}
+		} else {
+			GB_ASSERT(p->type->Proc.has_named_results);
+			auto results = array_make<lbValue>(permanent_allocator(), 0, return_count);
+
+			for (isize res_index = 0; res_index < return_count; res_index++) {
+				Entity *e = tuple->variables[res_index];
+				lbValue *found = map_get(&p->module->values, hash_entity(e));
+				GB_ASSERT(found);
+				lbValue res = lb_emit_load(p, *found);
+				array_add(&results, res);
+			}
+
+			GB_ASSERT(results.count == return_count);
+
+			auto named_results = slice_make<lbValue>(temporary_allocator(), results.count);
+			auto values = slice_make<lbValue>(temporary_allocator(), results.count);
+
+			// NOTE(bill): store the named values before returning
+			for_array(i, p->type->Proc.results->Tuple.variables) {
+				Entity *e = p->type->Proc.results->Tuple.variables[i];
+				if (e->kind != Entity_Variable) {
+					continue;
+				}
+
+				if (e->token.string == "") {
+					continue;
+				}
+				lbValue *found = map_get(&p->module->values, hash_entity(e));
+				GB_ASSERT(found != nullptr);
+				named_results[i] = *found;
+				values[i] = lb_emit_conv(p, results[i], e->type);
+			}
+
+			for_array(i, named_results) {
+				lb_emit_store(p, named_results[i], values[i]);
+			}
+
+			Type *ret_type = p->type->Proc.results;
+
+			// NOTE(bill): Doesn't need to be zero because it will be initialized in the loops
+			if (return_by_pointer) {
+				res = p->return_ptr.addr;
+			} else {
+				res = lb_add_local_generated(p, ret_type, false).addr;
+			}
+
+			auto result_values = slice_make<lbValue>(temporary_allocator(), results.count);
+			auto result_eps = slice_make<lbValue>(temporary_allocator(), results.count);
+
+			for_array(i, results) {
+				result_values[i] = lb_emit_conv(p, results[i], tuple->variables[i]->type);
+			}
+			for_array(i, results) {
+				result_eps[i] = lb_emit_struct_ep(p, res, cast(i32)i);
+			}
+			for_array(i, result_values) {
+				lb_emit_store(p, result_eps[i], result_values[i]);
+			}
+
+			if (return_by_pointer) {
+				lb_emit_defer_stmts(p, lbDeferExit_Return, nullptr);
+				LLVMBuildRetVoid(p->builder);
+				goto end;
+			}
+
+			res = lb_emit_load(p, res);
+		}
+
+
+		if (return_by_pointer) {
+			if (res.value != nullptr) {
+				LLVMBuildStore(p->builder, res.value, p->return_ptr.addr.value);
+			} else {
+				LLVMBuildStore(p->builder, LLVMConstNull(p->abi_function_type->ret.type), p->return_ptr.addr.value);
+			}
+
+			lb_emit_defer_stmts(p, lbDeferExit_Return, nullptr);
+
+			LLVMBuildRetVoid(p->builder);
+		} else {
+			LLVMValueRef ret_val = res.value;
+			ret_val = OdinLLVMBuildTransmute(p, ret_val, p->abi_function_type->ret.type);
+			if (p->abi_function_type->ret.cast_type != nullptr) {
+				ret_val = OdinLLVMBuildTransmute(p, ret_val, p->abi_function_type->ret.cast_type);
+			}
+
+			lb_emit_defer_stmts(p, lbDeferExit_Return, nullptr);
+			LLVMBuildRet(p->builder, ret_val);
+		}
+	}
+
+end:;
+	lb_start_block(p, continue_block);
+
+	if (tv.type != nullptr) {
+		return lb_emit_conv(p, lhs, tv.type);
+	}
+	return {};
+}
+
+
+lbValue lb_emit_or_else(lbProcedure *p, AstCallExpr *ce, TypeAndValue const &tv) {
+	Ast *arg = ce->args[0];
+	Ast *else_value = ce->args[1];
+
+	lbValue lhs = {};
+	lbValue rhs = {};
+
+	TypeAndValue const &arg_tav = type_and_value_of_expr(arg);
+	if (unparen_expr(arg)->kind == Ast_TypeAssertion) {
+		GB_ASSERT_MSG(is_type_tuple(arg_tav.type), "%s", type_to_string(arg_tav.type));
+	}
+	lbValue value = lb_build_expr(p, arg);
+
+	if (is_type_tuple(value.type)) {
+		i32 end_index = cast(i32)(value.type->Tuple.variables.count-1);
+		if (value.type->Tuple.variables.count == 2) {
+			lhs = lb_emit_struct_ev(p, value, 0);
+		} else {
+			lbAddr lhs_addr = lb_add_local_generated(p, tv.type, false);
+			lbValue lhs_ptr = lb_addr_get_ptr(p, lhs_addr);
+			for (i32 i = 0; i < end_index; i++) {
+				lb_emit_store(p, lb_emit_struct_ep(p, lhs_ptr, i), lb_emit_struct_ev(p, value, i));
+			}
+			lhs = lb_addr_load(p, lhs_addr);
+		}
+		rhs = lb_emit_struct_ev(p, value, end_index);
+	} else {
+		rhs = value;
+	}
+
+	GB_ASSERT(rhs.value != nullptr);
+
+	lbValue has_value = {};
+	if (is_type_boolean(rhs.type)) {
+		has_value = rhs;
+	} else {
+		GB_ASSERT_MSG(type_has_nil(rhs.type), "%s", type_to_string(rhs.type));
+		has_value = lb_emit_comp_against_nil(p, Token_CmpEq, rhs);
+	}
+
+	GB_ASSERT(has_value.value != nullptr);
+
+	LLVMValueRef incoming_values[2] = {};
+	LLVMBasicBlockRef incoming_blocks[2] = {};
+
+	GB_ASSERT(else_value != nullptr);
+	lbBlock *then  = lb_create_block(p, "or_else.then");
+	lbBlock *done  = lb_create_block(p, "or_else.done"); // NOTE(bill): Append later
+	lbBlock *else_ = lb_create_block(p, "or_else.else");
+
+	lb_emit_if(p, has_value, then, else_);
+	lb_start_block(p, then);
+
+	Type *type = default_type(tv.type);
+
+	incoming_values[0] = lb_emit_conv(p, lhs, type).value;
+
+	lb_emit_jump(p, done);
+	lb_start_block(p, else_);
+
+	incoming_values[1] = lb_emit_conv(p, lb_build_expr(p, else_value), type).value;
+
+	lb_emit_jump(p, done);
+	lb_start_block(p, done);
+
+	lbValue res = {};
+	res.value = LLVMBuildPhi(p->builder, lb_type(p->module, type), "");
+	res.type = type;
+
+	GB_ASSERT(p->curr_block->preds.count >= 2);
+	incoming_blocks[0] = p->curr_block->preds[0]->block;
+	incoming_blocks[1] = p->curr_block->preds[1]->block;
+
+	LLVMAddIncoming(res.value, incoming_values, incoming_blocks, 2);
+
+	return res;
+}
+
+
 
 lbValue lb_build_builtin_proc(lbProcedure *p, Ast *expr, TypeAndValue const &tv, BuiltinProcId id) {
 	ast_node(ce, CallExpr, expr);
@@ -9942,6 +10193,12 @@ lbValue lb_build_builtin_proc(lbProcedure *p, Ast *expr, TypeAndValue const &tv,
 	case BuiltinProc_soa_unzip:
 		return lb_soa_unzip(p, ce, tv);
 
+	case BuiltinProc_try:
+		return lb_emit_try(p, ce, tv);
+
+	case BuiltinProc_or_else:
+		return lb_emit_or_else(p, ce, tv);
+
 
 	// "Intrinsics"
 
@@ -11132,7 +11389,14 @@ lbValue lb_emit_comp_against_nil(lbProcedure *p, TokenKind op_kind, lbValue x) {
 	lbValue res = {};
 	res.type = t_llvm_bool;
 	Type *t = x.type;
-	if (is_type_pointer(t)) {
+	if (is_type_enum(t)) {
+		if (op_kind == Token_CmpEq) {
+			res.value = LLVMBuildIsNull(p->builder, x.value, "");
+		} else if (op_kind == Token_NotEq) {
+			res.value = LLVMBuildIsNotNull(p->builder, x.value, "");
+		}
+		return res;
+	} else if (is_type_pointer(t)) {
 		if (op_kind == Token_CmpEq) {
 			res.value = LLVMBuildIsNull(p->builder, x.value, "");
 		} else if (op_kind == Token_NotEq) {