unicode support & location in errors

src/errors.cc

@@ -5,7 +5,24 @@ bool Error::operator==(errors::Type type)
 	return this->type == type;
 }
 
-std::ostream& operator<<(std::ostream& os, Error const&)
+std::ostream& operator<<(std::ostream& os, Error const& err)
 {
-	return os << "generic error";
+	if (err.location) {
+		os << *err.location;
+	} else {
+		os << "musique";
+	}
+
+	os << ": error: ";
+
+	switch (err.type) {
+	case errors::End_Of_File:
+		return os << "end of file\n";
+
+	case errors::Unrecognized_Character:
+		return os << "unrecognized charater 0x" << std::hex << err.invalid_character
+			<< "(char: '" << utf8::Print(err.invalid_character) << "')\n";
+	}
+
+	return os << "unrecognized error type\n";
 }

src/lexer.cc

@@ -2,8 +2,7 @@
 
 auto Lexer::next_token() -> Result<Token>
 {
-	while (consume_if(unicode::is_space)) {
-	}
+	while (consume_if(unicode::is_space)) {}
 	start();
 
 	if (peek() == 0) {

src/musique.hh

@@ -2,9 +2,11 @@
 
 #include <cassert>
 #include <cstdint>
+#include <optional>
 #include <ostream>
 #include <string_view>
 #include <tl/expected.hpp>
+#include <variant>
 
 using u8  = std::uint8_t;
 using u16 = std::uint16_t;
@@ -53,7 +55,8 @@ std::ostream& operator<<(std::ostream& os, Location const& location);
 struct Error
 {
 	errors::Type type;
-	Error *child = nullptr;
+	std::optional<Location> location = std::nullopt;
+	u32 invalid_character = 0;
 
 	bool operator==(errors::Type);
 };
@@ -102,9 +105,14 @@ namespace utf8
 	using namespace unicode::special_runes;
 
 	// Decodes rune and returns remaining string
-	auto decode(std::string_view str) -> std::pair<u32, std::string_view>;
+	auto decode(std::string_view s) -> std::pair<u32, std::string_view>;
+	auto length(std::string_view s) -> usize;
+
+	struct Print { u32 rune; };
 }
 
+std::ostream& operator<<(std::ostream& os, utf8::Print const& print);
+
 struct Token
 {
 	enum class Type

src/tests/unicode.cc

@@ -0,0 +1,21 @@
+#include <boost/ut.hpp>
+#include <musique.hh>
+
+using namespace boost::ut;
+using namespace std::string_view_literals;
+
+suite utf8_test = [] {
+	"UTF-8 Character length"_test = [] {
+		expect(utf8::length(" ")          == 1_u);
+		expect(utf8::length("ą")          == 2_u);
+		expect(utf8::length("\u2705")     == 3_u);
+		expect(utf8::length("\U000132d1") == 4_u);
+	};
+
+	"UTF-8 Character decoding"_test = [] {
+		expect(eq(utf8::decode(" ").first,          0x20u));
+		expect(eq(utf8::decode("ą").first,          0x105u));
+		expect(eq(utf8::decode("\u2705").first,     0x2705u));
+		expect(eq(utf8::decode("\U000132d1").first, 0x132d1u));
+	};
+};

src/unicode.cc

@@ -1,7 +1,5 @@
 #include "musique.hh"
 
-auto utf8::decode(std::string_view s) -> std::pair<u32, std::string_view>
-{
 static constexpr std::array<u8, 4> payloads {
 	0b0111'1111, 0b0001'1111, 0b0000'1111, 0b0000'0111
 };
@@ -13,18 +11,25 @@ auto utf8::decode(std::string_view s) -> std::pair<u32, std::string_view>
 constexpr auto payload_cont  = 0b0011'1111;
 constexpr auto pattern_cont  = 0b1000'0000;
 
+auto utf8::length(std::string_view s) -> usize
+{
+	if (not s.empty()) {
+		for (auto i = 0u; i < payloads.size(); ++i) {
+			if ((u8(s.front()) & ~payloads[i]) == patterns[i]) {
+				return i+1;
+			}
+		}
+	}
+	return 0;
+}
+
+auto utf8::decode(std::string_view s) -> std::pair<u32, std::string_view>
+{
 	if (s.empty()) {
 		return { utf8::Rune_Error, s };
 	}
 
-	usize length = 0;
-
-	for (auto i = 0u; i < payloads.size(); ++i) {
-		if ((s.front() & ~payloads[i]) == patterns[i]) {
-			length = i+1;
-			break;
-		}
-	}
+	usize length = utf8::length(s);
 
 	if (length == 0 || s.size() < length) {
 		return { utf8::Rune_Error, s };
@@ -34,9 +39,9 @@ auto utf8::decode(std::string_view s) -> std::pair<u32, std::string_view>
 
 	while (--length > 0) {
 		s.remove_prefix(1);
-		if ((s.front() & ~payload_cont) == pattern_cont)
+		if ((s.front() & ~payload_cont) == pattern_cont) {
 			return { utf8::Rune_Error, s };
-
+		}
 		result <<= 6;
 		result |= u32(s.front() & payload_cont);
 	}
@@ -46,6 +51,34 @@ auto utf8::decode(std::string_view s) -> std::pair<u32, std::string_view>
 	return { result, s };
 }
 
+std::ostream& operator<<(std::ostream& os, utf8::Print const& print)
+{
+	auto r = print.rune;
+	std::array<u8, utf8::Max_Bytes> buffer;
+	unsigned length = 0;
+
+	if (r <= 0x7f) {
+		buffer[0] = r;
+		length = 1;
+	} else if (r <= 0x07'ff) {
+		buffer[0] = ((r >> 6) & 0x1f) | 0xc0;
+		buffer[1] = ((r >> 0) & 0x3f) | 0x80;
+		length = 2;
+	} else if (r <= 0xff'ff) {
+		buffer[0] = ((r >> 12) & 0x0f) | 0xe0;
+		buffer[1] = ((r >>  6) & 0x3f) | 0x80;
+		buffer[2] = ((r >>  0) & 0x3f) | 0x80;
+		length = 3;
+	} else {
+		buffer[0] = ((r >> 18) & 0x07) | 0xf0;
+		buffer[1] = ((r >> 12) & 0x3f) | 0x80;
+		buffer[2] = ((r >>  6) & 0x3f) | 0x80;
+		buffer[3] = ((r >>  0) & 0x3f) | 0x80;
+		length = 4;
+	}
+	return os.write((char const*)buffer.data(), length);
+}
+
 bool unicode::is_digit(u32 digit)
 {
 	return digit >= '0' && digit <= '9';