ladybird/Libraries/LibCpp/Lexer.cpp
Itamar bf53d7ff64 LibCpp: Add library for working with c++ code
Moved the C++ Lexer we have from LibGUI to here, so that other
components could use it without linking with LibGUI.
2020-09-30 21:46:59 +02:00

790 lines
22 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "Lexer.h"
#include <AK/HashTable.h>
#include <AK/StdLibExtras.h>
#include <AK/String.h>
#include <ctype.h>
namespace Cpp {
Lexer::Lexer(const StringView& input)
: m_input(input)
{
}
char Lexer::peek(size_t offset) const
{
if ((m_index + offset) >= m_input.length())
return 0;
return m_input[m_index + offset];
}
char Lexer::consume()
{
ASSERT(m_index < m_input.length());
char ch = m_input[m_index++];
m_previous_position = m_position;
if (ch == '\n') {
m_position.line++;
m_position.column = 0;
} else {
m_position.column++;
}
return ch;
}
static bool is_valid_first_character_of_identifier(char ch)
{
return isalpha(ch) || ch == '_' || ch == '$';
}
static bool is_valid_nonfirst_character_of_identifier(char ch)
{
return is_valid_first_character_of_identifier(ch) || isdigit(ch);
}
constexpr const char* s_known_keywords[] = {
"alignas",
"alignof",
"and",
"and_eq",
"asm",
"bitand",
"bitor",
"bool",
"break",
"case",
"catch",
"class",
"compl",
"const",
"const_cast",
"constexpr",
"continue",
"decltype",
"default",
"delete",
"do",
"dynamic_cast",
"else",
"enum",
"explicit",
"export",
"extern",
"false",
"final",
"for",
"friend",
"goto",
"if",
"inline",
"mutable",
"namespace",
"new",
"noexcept",
"not",
"not_eq",
"nullptr",
"operator",
"or",
"or_eq",
"override",
"private",
"protected",
"public",
"register",
"reinterpret_cast",
"return",
"signed",
"sizeof",
"static",
"static_assert",
"static_cast",
"struct",
"switch",
"template",
"this",
"thread_local",
"throw",
"true",
"try",
"typedef",
"typeid",
"typename",
"union",
"using",
"virtual",
"volatile",
"while",
"xor",
"xor_eq"
};
constexpr const char* s_known_types[] = {
"ByteBuffer",
"CircularDeque",
"CircularQueue",
"Deque",
"DoublyLinkedList",
"FileSystemPath",
"Array",
"Function",
"HashMap",
"HashTable",
"IPv4Address",
"InlineLinkedList",
"IntrusiveList",
"JsonArray",
"JsonObject",
"JsonValue",
"MappedFile",
"NetworkOrdered",
"NonnullOwnPtr",
"NonnullOwnPtrVector",
"NonnullRefPtr",
"NonnullRefPtrVector",
"Optional",
"OwnPtr",
"RefPtr",
"Result",
"ScopeGuard",
"SinglyLinkedList",
"String",
"StringBuilder",
"StringImpl",
"StringView",
"Utf8View",
"Vector",
"WeakPtr",
"auto",
"char",
"char16_t",
"char32_t",
"char8_t",
"double",
"float",
"i16",
"i32",
"i64",
"i8",
"int",
"int",
"long",
"short",
"signed",
"u16",
"u32",
"u64",
"u8",
"unsigned",
"void",
"wchar_t"
};
static bool is_keyword(const StringView& string)
{
static HashTable<String> keywords(array_size(s_known_keywords));
if (keywords.is_empty()) {
keywords.set_from(s_known_keywords);
}
return keywords.contains(string);
}
static bool is_known_type(const StringView& string)
{
static HashTable<String> types(array_size(s_known_types));
if (types.is_empty()) {
types.set_from(s_known_types);
}
return types.contains(string);
}
Vector<Token> Lexer::lex()
{
Vector<Token> tokens;
size_t token_start_index = 0;
Position token_start_position;
auto emit_token = [&](auto type) {
Token token;
token.m_type = type;
token.m_start = m_position;
token.m_end = m_position;
tokens.append(token);
consume();
};
auto begin_token = [&] {
token_start_index = m_index;
token_start_position = m_position;
};
auto commit_token = [&](auto type) {
Token token;
token.m_type = type;
token.m_start = token_start_position;
token.m_end = m_previous_position;
tokens.append(token);
};
auto emit_token_equals = [&](auto type, auto equals_type) {
if (peek(1) == '=') {
begin_token();
consume();
consume();
commit_token(equals_type);
return;
}
emit_token(type);
};
auto match_escape_sequence = [&]() -> size_t {
switch (peek(1)) {
case '\'':
case '"':
case '?':
case '\\':
case 'a':
case 'b':
case 'f':
case 'n':
case 'r':
case 't':
case 'v':
return 2;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7': {
size_t octal_digits = 1;
for (size_t i = 0; i < 2; ++i) {
char next = peek(2 + i);
if (next < '0' || next > '7')
break;
++octal_digits;
}
return 1 + octal_digits;
}
case 'x': {
size_t hex_digits = 0;
while (isxdigit(peek(2 + hex_digits)))
++hex_digits;
return 2 + hex_digits;
}
case 'u':
case 'U': {
bool is_unicode = true;
size_t number_of_digits = peek(1) == 'u' ? 4 : 8;
for (size_t i = 0; i < number_of_digits; ++i) {
if (!isxdigit(peek(2 + i))) {
is_unicode = false;
break;
}
}
return is_unicode ? 2 + number_of_digits : 0;
}
default:
return 0;
}
};
auto match_string_prefix = [&](char quote) -> size_t {
if (peek() == quote)
return 1;
if (peek() == 'L' && peek(1) == quote)
return 2;
if (peek() == 'u') {
if (peek(1) == quote)
return 2;
if (peek(1) == '8' && peek(2) == quote)
return 3;
}
if (peek() == 'U' && peek(1) == quote)
return 2;
return 0;
};
while (m_index < m_input.length()) {
auto ch = peek();
if (isspace(ch)) {
begin_token();
while (isspace(peek()))
consume();
commit_token(Token::Type::Whitespace);
continue;
}
if (ch == '(') {
emit_token(Token::Type::LeftParen);
continue;
}
if (ch == ')') {
emit_token(Token::Type::RightParen);
continue;
}
if (ch == '{') {
emit_token(Token::Type::LeftCurly);
continue;
}
if (ch == '}') {
emit_token(Token::Type::RightCurly);
continue;
}
if (ch == '[') {
emit_token(Token::Type::LeftBracket);
continue;
}
if (ch == ']') {
emit_token(Token::Type::RightBracket);
continue;
}
if (ch == '<') {
begin_token();
consume();
if (peek() == '<') {
consume();
if (peek() == '=') {
consume();
commit_token(Token::Type::LessLessEquals);
continue;
}
commit_token(Token::Type::LessLess);
continue;
}
if (peek() == '=') {
consume();
commit_token(Token::Type::LessEquals);
continue;
}
if (peek() == '>') {
consume();
commit_token(Token::Type::LessGreater);
continue;
}
commit_token(Token::Type::Less);
continue;
}
if (ch == '>') {
begin_token();
consume();
if (peek() == '>') {
consume();
if (peek() == '=') {
consume();
commit_token(Token::Type::GreaterGreaterEquals);
continue;
}
commit_token(Token::Type::GreaterGreater);
continue;
}
if (peek() == '=') {
consume();
commit_token(Token::Type::GreaterEquals);
continue;
}
commit_token(Token::Type::Greater);
continue;
}
if (ch == ',') {
emit_token(Token::Type::Comma);
continue;
}
if (ch == '+') {
begin_token();
consume();
if (peek() == '+') {
consume();
commit_token(Token::Type::PlusPlus);
continue;
}
if (peek() == '=') {
consume();
commit_token(Token::Type::PlusEquals);
continue;
}
commit_token(Token::Type::Plus);
continue;
}
if (ch == '-') {
begin_token();
consume();
if (peek() == '-') {
consume();
commit_token(Token::Type::MinusMinus);
continue;
}
if (peek() == '=') {
consume();
commit_token(Token::Type::MinusEquals);
continue;
}
if (peek() == '>') {
consume();
if (peek() == '*') {
consume();
commit_token(Token::Type::ArrowAsterisk);
continue;
}
commit_token(Token::Type::Arrow);
continue;
}
commit_token(Token::Type::Minus);
continue;
}
if (ch == '*') {
emit_token_equals(Token::Type::Asterisk, Token::Type::AsteriskEquals);
continue;
}
if (ch == '%') {
emit_token_equals(Token::Type::Percent, Token::Type::PercentEquals);
continue;
}
if (ch == '^') {
emit_token_equals(Token::Type::Caret, Token::Type::CaretEquals);
continue;
}
if (ch == '!') {
emit_token_equals(Token::Type::ExclamationMark, Token::Type::ExclamationMarkEquals);
continue;
}
if (ch == '=') {
emit_token_equals(Token::Type::Equals, Token::Type::EqualsEquals);
continue;
}
if (ch == '&') {
begin_token();
consume();
if (peek() == '&') {
consume();
commit_token(Token::Type::AndAnd);
continue;
}
if (peek() == '=') {
consume();
commit_token(Token::Type::AndEquals);
continue;
}
commit_token(Token::Type::And);
continue;
}
if (ch == '|') {
begin_token();
consume();
if (peek() == '|') {
consume();
commit_token(Token::Type::PipePipe);
continue;
}
if (peek() == '=') {
consume();
commit_token(Token::Type::PipeEquals);
continue;
}
commit_token(Token::Type::Pipe);
continue;
}
if (ch == '~') {
emit_token(Token::Type::Tilde);
continue;
}
if (ch == '?') {
emit_token(Token::Type::QuestionMark);
continue;
}
if (ch == ':') {
begin_token();
consume();
if (peek() == ':') {
consume();
if (peek() == '*') {
consume();
commit_token(Token::Type::ColonColonAsterisk);
continue;
}
commit_token(Token::Type::ColonColon);
continue;
}
commit_token(Token::Type::Colon);
continue;
}
if (ch == ';') {
emit_token(Token::Type::Semicolon);
continue;
}
if (ch == '.') {
begin_token();
consume();
if (peek() == '*') {
consume();
commit_token(Token::Type::DotAsterisk);
continue;
}
commit_token(Token::Type::Dot);
continue;
}
if (ch == '#') {
begin_token();
consume();
if (is_valid_first_character_of_identifier(peek()))
while (peek() && is_valid_nonfirst_character_of_identifier(peek()))
consume();
auto directive = StringView(m_input.characters_without_null_termination() + token_start_index, m_index - token_start_index);
if (directive == "#include") {
commit_token(Token::Type::IncludeStatement);
begin_token();
while (isspace(peek()))
consume();
commit_token(Token::Type::Whitespace);
begin_token();
if (peek() == '<' || peek() == '"') {
char closing = consume() == '<' ? '>' : '"';
while (peek() && peek() != closing && peek() != '\n')
consume();
if (peek() && consume() == '\n') {
commit_token(Token::Type::IncludePath);
continue;
}
commit_token(Token::Type::IncludePath);
begin_token();
}
}
while (peek() && peek() != '\n')
consume();
commit_token(Token::Type::PreprocessorStatement);
continue;
}
if (ch == '/' && peek(1) == '/') {
begin_token();
while (peek() && peek() != '\n')
consume();
commit_token(Token::Type::Comment);
continue;
}
if (ch == '/' && peek(1) == '*') {
begin_token();
consume();
consume();
bool comment_block_ends = false;
while (peek()) {
if (peek() == '*' && peek(1) == '/') {
comment_block_ends = true;
break;
}
consume();
}
if (comment_block_ends) {
consume();
consume();
}
commit_token(Token::Type::Comment);
continue;
}
if (ch == '/') {
emit_token_equals(Token::Type::Slash, Token::Type::SlashEquals);
continue;
}
if (size_t prefix = match_string_prefix('"'); prefix > 0) {
begin_token();
for (size_t i = 0; i < prefix; ++i)
consume();
while (peek()) {
if (peek() == '\\') {
if (size_t escape = match_escape_sequence(); escape > 0) {
commit_token(Token::Type::DoubleQuotedString);
begin_token();
for (size_t i = 0; i < escape; ++i)
consume();
commit_token(Token::Type::EscapeSequence);
begin_token();
continue;
}
}
if (consume() == '"')
break;
}
commit_token(Token::Type::DoubleQuotedString);
continue;
}
if (size_t prefix = match_string_prefix('R'); prefix > 0 && peek(prefix) == '"') {
begin_token();
for (size_t i = 0; i < prefix + 1; ++i)
consume();
size_t prefix_start = m_index;
while (peek() && peek() != '(')
consume();
StringView prefix_string = m_input.substring_view(prefix_start, m_index - prefix_start);
while (peek()) {
if (consume() == '"') {
ASSERT(m_index >= prefix_string.length() + 2);
ASSERT(m_input[m_index - 1] == '"');
if (m_input[m_index - 1 - prefix_string.length() - 1] == ')') {
StringView suffix_string = m_input.substring_view(m_index - 1 - prefix_string.length(), prefix_string.length());
if (prefix_string == suffix_string)
break;
}
}
}
commit_token(Token::Type::RawString);
continue;
}
if (size_t prefix = match_string_prefix('\''); prefix > 0) {
begin_token();
for (size_t i = 0; i < prefix; ++i)
consume();
while (peek()) {
if (peek() == '\\') {
if (size_t escape = match_escape_sequence(); escape > 0) {
commit_token(Token::Type::SingleQuotedString);
begin_token();
for (size_t i = 0; i < escape; ++i)
consume();
commit_token(Token::Type::EscapeSequence);
begin_token();
continue;
}
}
if (consume() == '\'')
break;
}
commit_token(Token::Type::SingleQuotedString);
continue;
}
if (isdigit(ch) || (ch == '.' && isdigit(peek(1)))) {
begin_token();
consume();
auto type = ch == '.' ? Token::Type::Float : Token::Type::Integer;
bool is_hex = false;
bool is_binary = false;
auto match_exponent = [&]() -> size_t {
char ch = peek();
if (ch != 'e' && ch != 'E' && ch != 'p' && ch != 'P')
return 0;
type = Token::Type::Float;
size_t length = 1;
ch = peek(length);
if (ch == '+' || ch == '-') {
++length;
}
for (ch = peek(length); isdigit(ch); ch = peek(length)) {
++length;
}
return length;
};
auto match_type_literal = [&]() -> size_t {
size_t length = 0;
for (;;) {
char ch = peek(length);
if ((ch == 'u' || ch == 'U') && type == Token::Type::Integer) {
++length;
} else if ((ch == 'f' || ch == 'F') && !is_binary) {
type = Token::Type::Float;
++length;
} else if (ch == 'l' || ch == 'L') {
++length;
} else
return length;
}
};
if (peek() == 'b' || peek() == 'B') {
consume();
is_binary = true;
for (char ch = peek(); ch == '0' || ch == '1' || (ch == '\'' && peek(1) != '\''); ch = peek()) {
consume();
}
} else {
if (peek() == 'x' || peek() == 'X') {
consume();
is_hex = true;
}
for (char ch = peek(); (is_hex ? isxdigit(ch) : isdigit(ch)) || (ch == '\'' && peek(1) != '\'') || ch == '.'; ch = peek()) {
if (ch == '.') {
if (type == Token::Type::Integer) {
type = Token::Type::Float;
} else
break;
};
consume();
}
}
if (!is_binary) {
size_t length = match_exponent();
for (size_t i = 0; i < length; ++i)
consume();
}
size_t length = match_type_literal();
for (size_t i = 0; i < length; ++i)
consume();
commit_token(type);
continue;
}
if (is_valid_first_character_of_identifier(ch)) {
begin_token();
while (peek() && is_valid_nonfirst_character_of_identifier(peek()))
consume();
auto token_view = StringView(m_input.characters_without_null_termination() + token_start_index, m_index - token_start_index);
if (is_keyword(token_view))
commit_token(Token::Type::Keyword);
else if (is_known_type(token_view))
commit_token(Token::Type::KnownType);
else
commit_token(Token::Type::Identifier);
continue;
}
dbg() << "Unimplemented token character: " << ch;
emit_token(Token::Type::Unknown);
}
return tokens;
}
}