Make begin optional in procedures with only return

boot/stage13.elna

@@ -6,6 +6,7 @@
 
 (* - Multiline comments. *)
 (* - elsif conditions. *)
+(* - Optional "begin" if the procedure body is a single return statement. *)
 
 const
 	symbol_builtin_name_int := "Int";
@@ -71,7 +72,7 @@ begin
 
 	if _load_byte(string) <> '"' then
 		counter := counter + 1;
-		goto .string_length_loop;
+		goto .string_length_loop
 	end;
 
 	return counter
@@ -100,9 +101,9 @@ begin
 		contents := contents + 1;
 
 		if current_byte <> '\\' then
-			compiler_strings_length := compiler_strings_length + 1;
+			compiler_strings_length := compiler_strings_length + 1
 		end;
-		goto .add_string_loop;
+		goto .add_string_loop
 	end;
 
 	return result
@@ -145,10 +146,10 @@ begin
 	local_buffer := @result + 11;
 
 	if number >= 0 then
-		is_negative := 0;
+		is_negative := 0
 	else
 		number = -number;
-		is_negative := 1;
+		is_negative := 1
 	end;
 
 	.print_i_digit10;
@@ -159,11 +160,11 @@ begin
 	local_buffer := local_buffer + -1;
 
 	if number <> 0 then
-		goto .print_i_digit10;
+		goto .print_i_digit10
 	end;
 	if is_negative = 1 then
 		_store_byte('-', local_buffer);
-		local_buffer := local_buffer + -1;
+		local_buffer := local_buffer + -1
 	end;
 	result := @result + 11;
 	result := result + -local_buffer;
@@ -210,7 +211,7 @@ begin
 		_write_c(next_byte);
 
 		(* Advance the input string by one byte. *)
-		_write_z(string + 1);
+		_write_z(string + 1)
 	end;
 end;
 
@@ -314,8 +315,8 @@ begin
 		count := count + -1;
 
 		if result = 0 then
-			goto .memcmp_loop;
-		end;
+			goto .memcmp_loop
+		end
 	end;
 
 	return result
@@ -341,7 +342,7 @@ begin
 		destination := destination + 1;
 		source := source + 1;
 		count := count + -1;
-		goto .memcpy_loop;
+		goto .memcpy_loop
 	end;
 
 	return destination
@@ -383,7 +384,7 @@ begin
 	character := _load_byte(source_code_position);
 	if character = '\\' then
 		_write_c('\\');
-		source_code_position := source_code_position + 1;
+		source_code_position := source_code_position + 1
 	end;
 	_write_s(source_code_position, 1);
 	_write_s("'\n", 2);
@@ -981,9 +982,14 @@ end;
 proc _skip_spaces();
 var
 	current_byte: Word;
+	lhs: Word;
+	rhs: Word;
 begin
 	current_byte := _load_byte(source_code_position);
-	if current_byte = '\t' then
+	lhs := current_byte = '\t';
+	rhs := current_byte = ' ';
+
+	if lhs or rhs then
 		source_code_position := source_code_position + 1;
 		_skip_spaces();
 	end;
@@ -1194,9 +1200,14 @@ begin
 	_read_procedure_temporaries();
 
 	(* Skip semicolon, "begin" and newline. *)
-	source_code_position := source_code_position + 6;
-
-	_compile_procedure_body();
+	_lexer_read_token(@token_kind);
+	if token_kind = _lexer_token_kind_begin() then
+		_lexer_skip_token();
+		_compile_procedure_body();
+	end;
+	if token_kind = _lexer_token_kind_return() then
+		_compile_return_statement();
+	end;
 
 	(* Write the epilogue. *)
 	_write_z("\tlw ra, 124(sp)\n\tlw s0, 120(sp)\n\taddi sp, sp, 128\n\tret\n\0");