LibGUi: Rework GML parser into a lexer+parser

This will make it easier to add GML syntax highlighting. :^)

Libraries/LibGUI/CMakeLists.txt

@@ -30,6 +30,7 @@ set(SOURCES
  FileSystemModel.cpp
  FilteringProxyModel.cpp
  Frame.cpp
+ GMLLexer.cpp
  GMLParser.cpp
  GroupBox.cpp
  HeaderView.cpp

Libraries/LibGUI/GMLLexer.cpp

@@ -0,0 +1,180 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <[email protected]>
+ * 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 "GMLLexer.h"
+#include <AK/Vector.h>
+#include <ctype.h>
+
+namespace GUI {
+
+GMLLexer::GMLLexer(const StringView& input)
+ : m_input(input)
+{
+}
+
+char GMLLexer::peek(size_t offset) const
+{
+ if ((m_index + offset) >= m_input.length())
+ return 0;
+ return m_input[m_index + offset];
+}
+
+char GMLLexer::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_identifier_start(char ch)
+{
+ return isalpha(ch) || ch == '_';
+}
+
+static bool is_valid_identifier_character(char ch)
+{
+ return isalnum(ch) || ch == '_';
+}
+
+static bool is_valid_class_start(char ch)
+{
+ return isalpha(ch) || ch == '_';
+}
+
+static bool is_valid_class_character(char ch)
+{
+ return isalnum(ch) || ch == '_' || ch == ':';
+}
+
+Vector<GMLToken> GMLLexer::lex()
+{
+ Vector<GMLToken> tokens;
+
+ size_t token_start_index = 0;
+ GMLPosition token_start_position;
+
+ auto begin_token = [&] {
+ token_start_index = m_index;
+ token_start_position = m_position;
+ };
+
+ auto commit_token = [&](auto type) {
+ GMLToken token;
+ token.m_view = m_input.substring_view(token_start_index, m_index - token_start_index);
+ token.m_type = type;
+ token.m_start = token_start_position;
+ token.m_end = m_previous_position;
+ tokens.append(token);
+ };
+
+ auto consume_class = [&] {
+ begin_token();
+ consume();
+ commit_token(GMLToken::Type::ClassMarker);
+ begin_token();
+ while (is_valid_class_character(peek()))
+ consume();
+ commit_token(GMLToken::Type::ClassName);
+ };
+
+ while (m_index < m_input.length()) {
+ if (isspace(peek(0))) {
+ begin_token();
+ while (isspace(peek()))
+ consume();
+ continue;
+ }
+
+ // C++ style comments
+ if (peek(0) && peek(0) == '/' && peek(1) == '/') {
+ begin_token();
+ while (peek() && peek() != '\n')
+ consume();
+ commit_token(GMLToken::Type::Comment);
+ continue;
+ }
+
+ if (peek(0) == '{') {
+ begin_token();
+ consume();
+ commit_token(GMLToken::Type::LeftCurly);
+ continue;
+ }
+
+ if (peek(0) == '}') {
+ begin_token();
+ consume();
+ commit_token(GMLToken::Type::RightCurly);
+ continue;
+ }
+
+ if (peek(0) == '@' && is_valid_class_start(peek(1))) {
+ consume_class();
+ continue;
+ }
+
+ if (is_valid_identifier_start(peek(0))) {
+ begin_token();
+ consume();
+ while (is_valid_identifier_character(peek(0)))
+ consume();
+ commit_token(GMLToken::Type::Identifier);
+ continue;
+ }
+
+ if (peek(0) == ':') {
+ begin_token();
+ consume();
+ commit_token(GMLToken::Type::Colon);
+
+ while (isspace(peek()))
+ consume();
+
+ if (peek(0) == '@' && is_valid_class_start(peek(1))) {
+ consume_class();
+ } else {
+ begin_token();
+ while (peek() && peek() != '\n')
+ consume();
+ commit_token(GMLToken::Type::JsonValue);
+ }
+ continue;
+ }
+
+ consume();
+ commit_token(GMLToken::Type::Unknown);
+ }
+ return tokens;
+}
+
+}

Libraries/LibGUI/GMLLexer.h

@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <[email protected]>
+ * 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.
+ */
+
+#pragma once
+
+#include <AK/StringView.h>
+
+namespace GUI {
+
+#define FOR_EACH_TOKEN_TYPE \
+ __TOKEN(Unknown) \
+ __TOKEN(Comment) \
+ __TOKEN(ClassMarker) \
+ __TOKEN(ClassName) \
+ __TOKEN(LeftCurly) \
+ __TOKEN(RightCurly) \
+ __TOKEN(Identifier) \
+ __TOKEN(Colon) \
+ __TOKEN(JsonValue)
+
+struct GMLPosition {
+ size_t line;
+ size_t column;
+};
+
+struct GMLToken {
+ enum class Type {
+#define __TOKEN(x) x,
+ FOR_EACH_TOKEN_TYPE
+#undef __TOKEN
+ };
+
+ const char* to_string() const
+ {
+ switch (m_type) {
+#define __TOKEN(x) \
+ case Type::x: \
+ return #x;
+ FOR_EACH_TOKEN_TYPE
+#undef __TOKEN
+ }
+ ASSERT_NOT_REACHED();
+ }
+
+ Type m_type { Type::Unknown };
+ StringView m_view;
+ GMLPosition m_start;
+ GMLPosition m_end;
+};
+
+class GMLLexer {
+public:
+ GMLLexer(const StringView&);
+
+ Vector<GMLToken> lex();
+
+private:
+ char peek(size_t offset = 0) const;
+ char consume();
+
+ StringView m_input;
+ size_t m_index { 0 };
+ GMLPosition m_previous_position { 0, 0 };
+ GMLPosition m_position { 0, 0 };
+};
+
+}