12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879808182838485 |
- /*
- * Copyright (c) 2006-2017 DMDirc Developers
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
- * documentation files (the "Software"), to deal in the Software without restriction, including without limitation the
- * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
- * permit persons to whom the Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the
- * Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
- * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
- * OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
- * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
- */
-
- package com.dmdirc.addons.calc;
-
- import java.text.ParseException;
- import java.util.ArrayList;
- import java.util.Arrays;
- import java.util.List;
-
- /**
- * The lexer takes a String input and produces an ordered list of {@link Token}s corresponding to
- * the input.
- */
- public class Lexer {
-
- /** The input string. */
- private final String input;
-
- /**
- * Creates a new lexer for the specified input string.
- *
- * @param input The string to be tokenised
- */
- public Lexer(final String input) {
- this.input = input.replaceAll("\\s+", "");
- }
-
- /**
- * Tokenises the input string into an ordered list of tokens.
- *
- * @return A list of tokens corresponding to the input string
- *
- * @throws ParseException If an expected token is not found
- */
- public List<Token> tokenise() throws ParseException {
- final List<Token> res = new ArrayList<>();
- List<TokenType> possibles = Arrays.asList(TokenType.values());
-
- boolean cont = true;
- int i = 0;
-
- do {
- boolean found = false;
-
- for (TokenType type : possibles) {
- final int match = type.match(input, i);
-
- if (match > -1) {
- res.add(new Token(type, input.substring(i, match)));
-
- possibles = type.getFollowers();
- i = match;
- found = true;
- cont = type != TokenType.END;
-
- break;
- }
- }
-
- if (!found) {
- throw new ParseException("No legal token found at offset "
- + i + ". Expecting one of: "
- + Arrays.toString(possibles.toArray()), i);
- }
- } while (cont);
-
- return res;
- }
-
- }
|