315 lines
10 KiB
Java
315 lines
10 KiB
Java
package carpet.script;
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import carpet.script.exception.ExpressionException;
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import carpet.script.exception.InternalExpressionException;
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import java.util.ArrayList;
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import java.util.Iterator;
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import java.util.List;
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/**
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* Expression tokenizer that allows to iterate over a {@link String}
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* expression token by token. Blank characters will be skipped.
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*/
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public class Tokenizer implements Iterator<Tokenizer.Token>
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{
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/** What character to use for decimal separators. */
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private static final char decimalSeparator = '.';
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/** What character to use for minus sign (negative values). */
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private static final char minusSign = '-';
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/** Actual position in expression string. */
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private int pos = 0;
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private int lineno = 0;
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private int linepos = 0;
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/** The original input expression. */
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private String input;
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/** The previous token or <code>null</code> if none. */
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private Token previousToken;
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private Expression expression;
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Tokenizer(Expression expr, String input)
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{
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this.input = input;
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this.expression = expr;
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}
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@Override
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public boolean hasNext()
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{
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return (pos < input.length());
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}
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/**
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* Peek at the next character, without advancing the iterator.
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*
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* @return The next character or character 0, if at end of string.
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*/
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private char peekNextChar()
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{
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return (pos < (input.length() - 1)) ? input.charAt(pos + 1) : 0;
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}
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private boolean isHexDigit(char ch)
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{
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return ch == 'x' || ch == 'X' || (ch >= '0' && ch <= '9') || (ch >= 'a' && ch <= 'f')
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|| (ch >= 'A' && ch <= 'F');
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}
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public static List<Token> simplepass(String input)
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{
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Tokenizer tok = new Tokenizer(null, input);
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List<Token> res = new ArrayList<>();
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while (tok.hasNext()) res.add(tok.next());
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return res;
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}
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@Override
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public Token next()
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{
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Token token = new Token();
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if (pos >= input.length())
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{
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return previousToken = null;
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}
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char ch = input.charAt(pos);
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while (Character.isWhitespace(ch) && pos < input.length())
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{
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linepos++;
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if (ch=='\n')
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{
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lineno++;
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linepos = 0;
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}
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ch = input.charAt(++pos);
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}
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token.pos = pos;
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token.lineno = lineno;
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token.linepos = linepos;
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boolean isHex = false;
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if (Character.isDigit(ch) || (ch == decimalSeparator && Character.isDigit(peekNextChar())))
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{
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if (ch == '0' && (peekNextChar() == 'x' || peekNextChar() == 'X'))
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isHex = true;
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while ((isHex
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&& isHexDigit(
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ch))
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|| (Character.isDigit(ch) || ch == decimalSeparator || ch == 'e' || ch == 'E'
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|| (ch == minusSign && token.length() > 0
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&& ('e' == token.charAt(token.length() - 1)
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|| 'E' == token.charAt(token.length() - 1)))
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|| (ch == '+' && token.length() > 0
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&& ('e' == token.charAt(token.length() - 1)
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|| 'E' == token.charAt(token.length() - 1))))
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&& (pos < input.length()))
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{
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token.append(input.charAt(pos++));
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linepos++;
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ch = pos == input.length() ? 0 : input.charAt(pos);
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}
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token.type = isHex ? Token.TokenType.HEX_LITERAL : Token.TokenType.LITERAL;
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}
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else if (ch == '\'')
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{
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pos++;
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linepos++;
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if (pos == input.length())
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{
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token.type = Token.TokenType.STRINGPARAM;
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if (expression != null)
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throw new ExpressionException(this.expression, token, "Program truncated");
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}
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ch = input.charAt(pos);
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while (ch != '\'')
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{
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if (ch == '\\')
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{
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pos++;
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linepos++;
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if (pos == input.length())
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{
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token.type = Token.TokenType.STRINGPARAM;
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if (expression != null)
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throw new ExpressionException(this.expression, token, "Program truncated");
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}
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}
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token.append(input.charAt(pos++));
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linepos++;
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ch = pos == input.length() ? 0 : input.charAt(pos);
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}
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pos++;
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linepos++;
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token.type = Token.TokenType.STRINGPARAM;
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}
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else if (Character.isLetter(ch) || "_".indexOf(ch) >= 0)
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{
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while ((Character.isLetter(ch) || Character.isDigit(ch) || "_".indexOf(ch) >= 0
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|| token.length() == 0 && "_".indexOf(ch) >= 0) && (pos < input.length()))
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{
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token.append(input.charAt(pos++));
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linepos++;
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ch = pos == input.length() ? 0 : input.charAt(pos);
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}
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// Remove optional white spaces after function or variable name
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if (Character.isWhitespace(ch))
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{
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while (Character.isWhitespace(ch) && pos < input.length())
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{
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ch = input.charAt(pos++);
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linepos++;
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if (ch=='\n')
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{
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lineno++;
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linepos = 0;
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}
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}
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pos--;
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linepos--;
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}
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token.type = ch == '(' ? Token.TokenType.FUNCTION : Token.TokenType.VARIABLE;
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}
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else if (ch == '(' || ch == ')' || ch == ',')
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{
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if (ch == '(')
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{
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token.type = Token.TokenType.OPEN_PAREN;
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}
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else if (ch == ')')
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{
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token.type = Token.TokenType.CLOSE_PAREN;
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}
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else
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{
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token.type = Token.TokenType.COMMA;
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}
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token.append(ch);
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pos++;
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linepos++;
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if (expression != null && previousToken != null && previousToken.type == Token.TokenType.OPERATOR && (ch == ')' || ch == ',') )
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{
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if (previousToken.surface.equalsIgnoreCase(";"))
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throw new ExpressionException(this.expression, previousToken,
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"Cannot have semicolon at the end of the expression");
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throw new ExpressionException(this.expression, previousToken,
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"Can't have operator "+previousToken.surface+" at the end of a subexpression");
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}
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}
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else
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{
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String greedyMatch = "";
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int initialPos = pos;
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int initialLinePos = linepos;
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ch = input.charAt(pos);
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int validOperatorSeenUntil = -1;
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while (!Character.isLetter(ch) && !Character.isDigit(ch) && "_".indexOf(ch) < 0
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&& !Character.isWhitespace(ch) && ch != '(' && ch != ')' && ch != ','
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&& (pos < input.length()))
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{
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greedyMatch += ch;
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pos++;
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linepos++;
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if (Expression.none.isAnOperator(greedyMatch))
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{
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validOperatorSeenUntil = pos;
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}
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ch = pos == input.length() ? 0 : input.charAt(pos);
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}
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if (validOperatorSeenUntil != -1)
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{
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token.append(input.substring(initialPos, validOperatorSeenUntil));
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pos = validOperatorSeenUntil;
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linepos = initialLinePos+validOperatorSeenUntil-initialPos;
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}
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else
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{
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token.append(greedyMatch);
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}
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if (previousToken == null || previousToken.type == Token.TokenType.OPERATOR
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|| previousToken.type == Token.TokenType.OPEN_PAREN || previousToken.type == Token.TokenType.COMMA)
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{
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token.surface += "u";
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token.type = Token.TokenType.UNARY_OPERATOR;
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}
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else
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{
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token.type = Token.TokenType.OPERATOR;
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}
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}
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if (expression != null && previousToken != null &&
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(
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token.type == Token.TokenType.LITERAL ||
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token.type == Token.TokenType.HEX_LITERAL ||
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token.type == Token.TokenType.VARIABLE ||
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token.type == Token.TokenType.STRINGPARAM ||
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token.type == Token.TokenType.FUNCTION
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) &&(
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previousToken.type == Token.TokenType.VARIABLE ||
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previousToken.type == Token.TokenType.FUNCTION ||
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previousToken.type == Token.TokenType.LITERAL ||
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previousToken.type == Token.TokenType.CLOSE_PAREN ||
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previousToken.type == Token.TokenType.HEX_LITERAL ||
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previousToken.type == Token.TokenType.STRINGPARAM
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)
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)
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{
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throw new ExpressionException(this.expression, previousToken, "'"+token.surface +"' is not allowed after '"+previousToken.surface+"'");
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}
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return previousToken = token;
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}
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@Override
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public void remove()
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{
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throw new InternalExpressionException("remove() not supported");
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}
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public static class Token
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{
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enum TokenType
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{
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VARIABLE, FUNCTION, LITERAL, OPERATOR, UNARY_OPERATOR,
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OPEN_PAREN, COMMA, CLOSE_PAREN, HEX_LITERAL, STRINGPARAM
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}
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public String surface = "";
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public TokenType type;
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public int pos;
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public int linepos;
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public int lineno;
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public void append(char c)
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{
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surface += c;
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}
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public void append(String s)
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{
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surface += s;
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}
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public char charAt(int pos)
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{
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return surface.charAt(pos);
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}
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public int length()
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{
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return surface.length();
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}
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@Override
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public String toString()
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{
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return surface;
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}
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}
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}
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