Unexpected empty source error improved

include/musique.hh

@@ -41,6 +41,47 @@ using i64 = std::int64_t;
 using usize = std::size_t;
 using isize = std::ptrdiff_t;
 
+/// \brief Location describes code position in `file line column` format.
+///        It's used both to represent position in source files provided
+//         to interpreter and internal interpreter usage.
+struct Location
+{
+	std::string_view filename = "<unnamed>"; ///< File that location is pointing to
+	usize line   = 1;                        ///< Line number (1 based) that location is pointing to
+	usize column = 1;                        ///< Column number (1 based) that location is pointing to
+
+	/// Advances line and column numbers based on provided rune
+	///
+	/// If rune is newline, then column is reset to 1, and line number is incremented.
+	/// Otherwise column number is incremented.
+	///
+	/// @param rune Rune from which column and line numbers advancements are made.
+	Location& advance(u32 rune);
+
+	bool operator==(Location const& rhs) const = default;
+
+	//! Creates location at default filename with specified line and column number
+	static Location at(usize line, usize column);
+
+	// Used to describe location of function call in interpreter (internal use only)
+#if defined(__cpp_lib_source_location)
+	static Location caller(std::source_location loc = std::source_location::current());
+#elif (__has_builtin(__builtin_FILE) and __has_builtin(__builtin_LINE))
+	static Location caller(char const* file = __builtin_FILE(), usize line = __builtin_LINE());
+#else
+#error Cannot implement Location::caller function
+	/// Returns location of call in interpreter source code.
+	///
+	/// Example of reporting where `foo()` was beeing called:
+	/// @code
+	/// void foo(Location loc = Location::caller()) { std::cout << loc << '\n'; }
+	/// @endcode
+	static Location caller();
+#endif
+};
+
+std::ostream& operator<<(std::ostream& os, Location const& location);
+
 /// Error handling related functions and definitions
 namespace errors
 {
@@ -53,6 +94,8 @@ namespace errors
 	/// When parser was expecting code but encountered end of file
 	struct Unexpected_Empty_Source
 	{
+		enum { Block_Without_Closing_Bracket } reason;
+		std::optional<Location> start;
 	};
 
 	/// When user passed numeric literal too big for numeric type
@@ -183,47 +226,6 @@ namespace pretty
 template<typename ...Lambdas>
 struct Overloaded : Lambdas... { using Lambdas::operator()...; };
 
-/// \brief Location describes code position in `file line column` format.
-///        It's used both to represent position in source files provided
-//         to interpreter and internal interpreter usage.
-struct Location
-{
-	std::string_view filename = "<unnamed>"; ///< File that location is pointing to
-	usize line   = 1;                        ///< Line number (1 based) that location is pointing to
-	usize column = 1;                        ///< Column number (1 based) that location is pointing to
-
-	/// Advances line and column numbers based on provided rune
-	///
-	/// If rune is newline, then column is reset to 1, and line number is incremented.
-	/// Otherwise column number is incremented.
-	///
-	/// @param rune Rune from which column and line numbers advancements are made.
-	Location& advance(u32 rune);
-
-	bool operator==(Location const& rhs) const = default;
-
-	//! Creates location at default filename with specified line and column number
-	static Location at(usize line, usize column);
-
-	// Used to describe location of function call in interpreter (internal use only)
-#if defined(__cpp_lib_source_location)
-	static Location caller(std::source_location loc = std::source_location::current());
-#elif (__has_builtin(__builtin_FILE) and __has_builtin(__builtin_LINE))
-	static Location caller(char const* file = __builtin_FILE(), usize line = __builtin_LINE());
-#else
-#error Cannot implement Location::caller function
-	/// Returns location of call in interpreter source code.
-	///
-	/// Example of reporting where `foo()` was beeing called:
-	/// @code
-	/// void foo(Location loc = Location::caller()) { std::cout << loc << '\n'; }
-	/// @endcode
-	static Location caller();
-#endif
-};
-
-std::ostream& operator<<(std::ostream& os, Location const& location);
-
 /// Guards that program exits if condition does not hold
 void assert(bool condition, std::string message, Location loc = Location::caller());
 

src/errors.cc

@@ -155,7 +155,7 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
 	error_heading(os, err.location, Error_Level::Error, short_description);
 
 	auto const loc = err.location;
-	auto const print_error_line = [&] {
+	auto const print_error_line = [&] (std::optional<Location> loc) {
 		if (loc) {
 			Lines::the.print(os, std::string(loc->filename), loc->line, loc->line);
 			os << '\n';
@@ -167,7 +167,7 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
 			os << "I cannot '" << err.name << "' due to lack of MIDI " << (err.is_input ? "input" : "output") << "connection\n";
 			os << "\n";
 
-			print_error_line();
+			print_error_line(loc);
 
 			os << "You can connect to given MIDI device by specifing port when running musique command like:\n";
 			os << (err.is_input ? "  --input" : "  --output") << " PORT\n";
@@ -178,7 +178,7 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
 			os << "I can't find it in surrounding scope or in one of parent's scopes\n";
 			os << "\n";
 
-			print_error_line();
+			print_error_line(loc);
 
 			os << "Variables can only be references in scope (block) where they been created\n";
 			os << "or from parent blocks to variable block\n";
@@ -189,7 +189,7 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
 			os << "  Character printed: '" << utf8::Print{err.invalid_character} << "'\n";
 			os << "\n";
 
-			print_error_line();
+			print_error_line(loc);
 
 			os << "Musique only accepts characters that are unicode letters or ascii numbers and punctuation\n";
 		},
@@ -199,7 +199,7 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
 			constexpr auto Min = std::numeric_limits<decltype(Number::num)>::min();
 			os << "I tried to parse numeric literal, but I failed.\n\n";
 
-			print_error_line();
+			print_error_line(loc);
 
 			if (err.reason == std::errc::result_out_of_range) {
 				os << "Declared number is outside of valid range of numbers that can be represented.\n";
@@ -212,7 +212,7 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
 			os << "  Token type: " << ut.type << '\n';
 			os << "  Token source: " << ut.source << "\n\n";
 
-			print_error_line();
+			print_error_line(loc);
 
 			os << pretty::begin_comment << "This error is considered an internal one. It should not be displayed to the end user.\n";
 			os << "\n";
@@ -223,7 +223,7 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
 		[&](errors::Expected_Expression_Separator_Before const& err) {
 			os << "I failed to parse following code, due to missing semicolon before it!\n\n";
 
-			print_error_line();
+			print_error_line(loc);
 
 			if (err.what == "var") {
 				os << "If you want to create variable inside expression try wrapping them inside parentheses like this:\n";
@@ -234,7 +234,7 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
 		[&](errors::Literal_As_Identifier const& err) {
 			os << "I expected an identifier in " << err.context << ", but found" << (err.type_name.empty() ? "" : " ") << err.type_name << " value = '" << err.source << "'\n\n";
 
-			print_error_line();
+			print_error_line(loc);
 
 			if (err.type_name == "chord") {
 				os << "Try renaming to different name or appending with something that is not part of chord literal like 'x'\n";
@@ -252,7 +252,7 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
 				{
 					os << "I tried to call function '" << err.name << "' but you gave me wrong types for it!\n";
 
-					print_error_line();
+					print_error_line(loc);
 
 					os << "Make sure that all values matches one of supported signatures listed below!\n";
 					os << '\n';
@@ -267,7 +267,7 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
 					os << "I tried and failed to evaluate operator '" << err.name << "' due to values with wrong types provided\n";
 					os << "Make sure that both values matches one of supported signatures listed below!\n";
 					os << '\n';
-					print_error_line();
+					print_error_line(loc);
 
 
 					if (err.name == "+") { os << "Addition only supports:\n"; }
@@ -285,7 +285,7 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
 			os << "Value of type " << err.type << " cannot be called.\n";
 			os << "\n";
 
-			print_error_line();
+			print_error_line(loc);
 
 			os << "Only values of this types can be called:\n";
 			os << "  - musical values like c, c47, (c&g) can be called to provide octave and duration\n";
@@ -299,9 +299,21 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
 			os << "when correct code for such expression would be [4;3]\n";
 			os << pretty::end;
 		},
+		[&](errors::Unexpected_Empty_Source const& err) {
+			switch (err.reason) {
+			break; case errors::Unexpected_Empty_Source::Block_Without_Closing_Bracket:
+				os << "Reached end of input when waiting for closing of a block ']'\n";
+				os << "Expected block end after:\n\n";
+				print_error_line(loc);
+
+				if (err.start) {
+					os << "Which was introduced by block starting here:\n\n";
+					print_error_line(err.start);
+				}
+			}
+		},
 		[&](errors::Undefined_Operator const&)               { unimplemented(); },
 		[&](errors::Unexpected_Keyword const&)               { unimplemented(); },
-		[&](errors::Unexpected_Empty_Source const&)          { unimplemented(); }
 	}, err.details);
 
 	return os;

src/parser.cc

@@ -272,8 +272,11 @@ Result<Ast> Parser::parse_atomic_expression()
 						}
 					}
 					return Error {
-						.details = errors::Unexpected_Empty_Source {},
+						.details = errors::Unexpected_Empty_Source {
-						.location = {}
+							.reason = errors::Unexpected_Empty_Source::Block_Without_Closing_Bracket,
+							.start = opening.location
+						},
+						.location = tokens.back().location
 					};
 				}
 				consume();