Libraries: Move to Userland/Libraries/

Userland/Libraries/LibGUI/GMLLexer.cpp

@@ -0,0 +1,175 @@
+/*
+ * Copyright (c) 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 "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_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) == '@') {
+            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) == '@') {
+                consume_class();
+            } else {
+                begin_token();
+                while (peek() && peek() != '\n')
+                    consume();
+                commit_token(GMLToken::Type::JsonValue);
+            }
+            continue;
+        }
+
+        consume();
+        commit_token(GMLToken::Type::Unknown);
+    }
+    return tokens;
+}
+
+}