Package jflex.core

Class LexScan

  • All Implemented Interfaces:
    java_cup.runtime.Scanner, sym, ILexScan
    public final class LexScan
extends AbstractLexScan
implements sym, java_cup.runtime.Scanner

    • Constructor Detail

      • LexScan

        public LexScan​(Reader in)
        Creates a new scanner
        Parameters:
        in - the java.io.Reader to read input from.

    • Method Detail

      • yyclose

        public final void yyclose()
                   throws IOException
        Closes the input reader.
        Throws:
        IOException - if the reader could not be closed.

      • yypushStream

        public final void yypushStream​(Reader reader)
        Stores the current input stream on a stack, and reads from a new stream. Lexical state, line, char, and column counting remain untouched. The current input stream can be restored with yypopStream (usually in an <<EOF>> action).
        Parameters:
        reader - the new input stream to read from
        See Also:
        yypopStream()

      • yymoreStreams

        public final boolean yymoreStreams()
        Returns true iff there are still streams left to read from on the stream stack.

      • yyreset

        public final void yyreset​(Reader reader)
        Resets the scanner to read from a new input stream. Does not close the old reader. All internal variables are reset, the old input stream cannot be reused (internal buffer is discarded and lost). Lexical state is set to ZZ_INITIAL. Internal scan buffer is resized down to its initial length, if it has grown.
        Parameters:
        reader - the new input stream
        See Also:
        yypushStream(java.io.Reader), yypopStream()

      • yyatEOF

        public final boolean yyatEOF()
        Returns whether the scanner has reached the end of the reader it reads from.
        Returns:
        whether the scanner has reached EOF.

      • yystate

        public final int yystate()
        Returns the current lexical state.
        Returns:
        the current lexical state.

      • yybegin

        public final void yybegin​(int newState)
        Enters a new lexical state
        Parameters:
        newState - the new lexical state

      • yytext

        public final String yytext()
        Returns the text matched by the current regular expression.
        Returns:
        the matched text.

      • yycharat

        public final char yycharat​(int pos)
        Returns the character at position pos from the matched text. It is equivalent to yytext().charAt(pos), but faster
        Parameters:
        pos - the position of the character to fetch. A value from 0 to yylength()-1.
        Returns:
        the character at position pos

      • yylength

        public final int yylength()
        How many characters were matched.
        Returns:
        the length of the matched text region.

      • yypushback

        public void yypushback​(int number)
        Pushes the specified amount of characters back into the input stream. They will be read again by then next call of the scanning method
        Parameters:
        number - the number of characters to be read again. This number must not be greater than yylength()!

      • next_token

        public java_cup.runtime.Symbol next_token()
                                   throws IOException
        Resumes scanning until the next regular expression is matched, the end of input is encountered or an I/O-Error occurs.
        Specified by:
        next_token in interface java_cup.runtime.Scanner
        Returns:
        the next token
        Throws:
        IOException - if any I/O-Error occurs

      • debug_next_token

        public java_cup.runtime.Symbol debug_next_token()
                                         throws IOException
        Same as next_token but also prints the token to standard out for debugging.
        Throws:
        IOException

      • main

        public static void main​(String[] argv)
        Runs the scanner on input files. This main method is the debugging routine for the scanner. It prints debugging information about each returned token to System.out until the end of file is reached, or an error occured.
        Parameters:
        argv - the command line, contains the filenames to run the scanner on.