Repo created

srcs/juloo.keyboard2/KeyValueParser.java

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+package juloo.keyboard2;
+
+import java.util.ArrayList;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+Parse a key definition. The syntax for a key definition is:
+- [(symbol):(key_action)]
+- [:(kind) (attributes):(payload)].
+- If [str] doesn't start with a [:] character, it is interpreted as an
+  arbitrary string key.
+
+[key_action] is:
+- ['Arbitrary string']
+- [(key_action),(key_action),...]
+- [keyevent:(code)]
+- [(key_name)]
+
+For the different kinds and attributes, see doc/Possible-key-values.md.
+
+Examples:
+- [:str flags=dim,small symbol='MyKey':'My arbitrary string'].
+- [:str:'My arbitrary string'].
+
+*/
+public final class KeyValueParser
+{
+  static Pattern KEYDEF_TOKEN;
+  static Pattern QUOTED_PAT;
+  static Pattern WORD_PAT;
+
+  static public KeyValue parse(String input) throws ParseError
+  {
+    int symbol_ends = 0;
+    final int input_len = input.length();
+    while (symbol_ends < input_len && input.charAt(symbol_ends) != ':')
+        symbol_ends++;
+    if (symbol_ends == 0) // Old syntax
+      return Starting_with_colon.parse(input);
+    if (symbol_ends == input_len) // String key
+      return KeyValue.makeStringKey(input);
+    String symbol = input.substring(0, symbol_ends);
+    init();
+    Matcher m = KEYDEF_TOKEN.matcher(input);
+    m.region(symbol_ends + 1, input_len);
+    KeyValue first_key = parse_key_def(m);
+    if (!parse_comma(m)) // Input is a single key def with a specified symbol
+      return first_key.withSymbol(symbol);
+    // Input is a macro
+    ArrayList<KeyValue> keydefs = new ArrayList<KeyValue>();
+    keydefs.add(first_key);
+    do { keydefs.add(parse_key_def(m)); }
+    while (parse_comma(m));
+    return KeyValue.makeMacro(symbol, keydefs.toArray(new KeyValue[]{}), 0);
+  }
+
+  static void init()
+  {
+    if (KEYDEF_TOKEN != null)
+      return;
+    KEYDEF_TOKEN = Pattern.compile("'|,|keyevent:|(?:[^\\\\',]+|\\\\.)+");
+    QUOTED_PAT = Pattern.compile("((?:[^'\\\\]+|\\\\')*)'");
+    WORD_PAT = Pattern.compile("[a-zA-Z0-9_]+|.");
+  }
+
+  static KeyValue key_by_name_or_str(String str)
+  {
+    KeyValue k = KeyValue.getSpecialKeyByName(str);
+    if (k != null)
+      return k;
+    return KeyValue.makeStringKey(str);
+  }
+
+  static KeyValue parse_key_def(Matcher m) throws ParseError
+  {
+    if (!match(m, KEYDEF_TOKEN))
+      parseError("Expected key definition", m);
+    String token = m.group(0);
+    switch (token)
+    {
+      case "'": return parse_string_keydef(m);
+      case ",": parseError("Unexpected comma", m); return null;
+      case "keyevent:": return parse_keyevent_keydef(m);
+      default: return key_by_name_or_str(remove_escaping(token));
+    }
+  }
+
+  static KeyValue parse_string_keydef(Matcher m) throws ParseError
+  {
+    if (!match(m, QUOTED_PAT))
+      parseError("Unterminated quoted string", m);
+    return KeyValue.makeStringKey(remove_escaping(m.group(1)));
+  }
+
+  static KeyValue parse_keyevent_keydef(Matcher m) throws ParseError
+  {
+    if (!match(m, WORD_PAT))
+      parseError("Expected keyevent code", m);
+    int eventcode = 0;
+    try { eventcode = Integer.parseInt(m.group(0)); }
+    catch (Exception _e)
+    { parseError("Expected an integer payload", m); }
+    return KeyValue.keyeventKey("", eventcode, 0);
+  }
+
+  /** Returns [true] if the next token is a comma, [false] if it is the end of the input. Throws an error otherwise. */
+  static boolean parse_comma(Matcher m) throws ParseError
+  {
+    if (!match(m, KEYDEF_TOKEN))
+      return false;
+    String token = m.group(0);
+    if (!token.equals(","))
+      parseError("Expected comma instead of '"+ token + "'", m);
+    return true;
+  }
+
+  static String remove_escaping(String s)
+  {
+    if (!s.contains("\\"))
+      return s;
+    StringBuilder out = new StringBuilder(s.length());
+    final int len = s.length();
+    int prev = 0, i = 0;
+    for (; i < len; i++)
+      if (s.charAt(i) == '\\')
+      {
+        out.append(s, prev, i);
+        prev = i + 1;
+      }
+    out.append(s, prev, i);
+    return out.toString();
+  }
+
+  /**
+    Parse a key definition starting with a [:]. This is the old syntax and is
+    kept for compatibility.
+    */
+  final static class Starting_with_colon
+  {
+    static Pattern START_PAT;
+    static Pattern ATTR_PAT;
+    static Pattern QUOTED_PAT;
+    static Pattern PAYLOAD_START_PAT;
+    static Pattern WORD_PAT;
+
+    static public KeyValue parse(String str) throws ParseError
+    {
+      String symbol = null;
+      int flags = 0;
+      init();
+      // Kind
+      Matcher m = START_PAT.matcher(str);
+      if (!m.lookingAt())
+        parseError("Expected kind, for example \":str ...\".", m);
+      String kind = m.group(1);
+      // Attributes
+      while (true)
+      {
+        if (!match(m, ATTR_PAT))
+          break;
+        String attr_name = m.group(1);
+        String attr_value = parseSingleQuotedString(m);
+        switch (attr_name)
+        {
+          case "flags":
+            flags = parseFlags(attr_value, m);
+            break;
+          case "symbol":
+            symbol = attr_value;
+            break;
+
+          default:
+            parseError("Unknown attribute "+attr_name, m);
+        }
+      }
+      // Payload
+      if (!match(m, PAYLOAD_START_PAT))
+        parseError("Unexpected character", m);
+      String payload;
+      switch (kind)
+      {
+        case "str":
+          payload = parseSingleQuotedString(m);
+          if (symbol == null)
+            return KeyValue.makeStringKey(payload, flags);
+          return KeyValue.makeStringKey(payload, flags).withSymbol(symbol);
+
+        case "char":
+          payload = parsePayloadWord(m);
+          if (payload.length() != 1)
+            parseError("Expected a single character payload", m);
+          return KeyValue.makeCharKey(payload.charAt(0), symbol, flags);
+
+        case "keyevent":
+          payload = parsePayloadWord(m);
+          int eventcode = 0;
+          try { eventcode = Integer.parseInt(payload); }
+          catch (Exception _e)
+          { parseError("Expected an integer payload", m); }
+          if (symbol == null)
+            symbol = String.valueOf(eventcode);
+          return KeyValue.keyeventKey(symbol, eventcode, flags);
+
+        default: break;
+      }
+      parseError("Unknown kind '"+kind+"'", m, 1);
+      return null; // Unreachable
+    }
+
+    static String parseSingleQuotedString(Matcher m) throws ParseError
+    {
+      if (!match(m, QUOTED_PAT))
+        parseError("Expected quoted string", m);
+      return m.group(1).replace("\\'", "'");
+    }
+
+    static String parsePayloadWord(Matcher m) throws ParseError
+    {
+      if (!match(m, WORD_PAT))
+        parseError("Expected a word after ':' made of [a-zA-Z0-9_]", m);
+      return m.group(0);
+    }
+
+    static int parseFlags(String s, Matcher m) throws ParseError
+    {
+      int flags = 0;
+      for (String f : s.split(","))
+      {
+        switch (f)
+        {
+          case "dim": flags |= KeyValue.FLAG_SECONDARY; break;
+          case "small": flags |= KeyValue.FLAG_SMALLER_FONT; break;
+          default: parseError("Unknown flag "+f, m);
+        }
+      }
+      return flags;
+    }
+
+    static boolean match(Matcher m, Pattern pat)
+    {
+      try { m.region(m.end(), m.regionEnd()); } catch (Exception _e) {}
+      m.usePattern(pat);
+      return m.lookingAt();
+    }
+
+    static void init()
+    {
+      if (START_PAT != null)
+        return;
+      START_PAT = Pattern.compile(":(\\w+)");
+      ATTR_PAT = Pattern.compile("\\s*(\\w+)\\s*=");
+      QUOTED_PAT = Pattern.compile("'(([^'\\\\]+|\\\\')*)'");
+      PAYLOAD_START_PAT = Pattern.compile("\\s*:");
+      WORD_PAT = Pattern.compile("[a-zA-Z0-9_]*");
+    }
+  }
+
+  static boolean match(Matcher m, Pattern pat)
+  {
+    try { m.region(m.end(), m.regionEnd()); } catch (Exception _e) {}
+    m.usePattern(pat);
+    return m.lookingAt();
+  }
+
+  static void parseError(String msg, Matcher m) throws ParseError
+  {
+    parseError(msg, m, m.regionStart());
+  }
+
+  static void parseError(String msg, Matcher m, int i) throws ParseError
+  {
+    StringBuilder msg_ = new StringBuilder("Syntax error");
+    try
+    {
+      msg_.append(" at token '").append(m.group(0)).append("'");
+    } catch (IllegalStateException _e) {}
+    msg_.append(" at position ");
+    msg_.append(i);
+    msg_.append(": ");
+    msg_.append(msg);
+    throw new ParseError(msg_.toString());
+  }
+
+  public static class ParseError extends Exception
+  {
+    public ParseError(String msg) { super(msg); }
+  };
+}