Package org.fife.ui.rsyntaxtextarea.modes

Class JavaScriptTokenMaker

  • All Implemented Interfaces:
    TokenMaker
    public class JavaScriptTokenMaker
extends AbstractJFlexCTokenMaker
    Scanner for JavaScript files. Its states could be simplified, but are kept the way they are to keep a degree of similarity (i.e. copy/paste) between it and HTML/JSP/PHPTokenMaker. This should cause no difference in performance.

    This implementation was created using JFlex 1.4.1; however, the generated file was modified for performance. Memory allocation needs to be almost completely removed to be competitive with the handwritten lexers (subclasses of AbstractTokenMaker, so this class has been modified so that Strings are never allocated (via yytext()), and the scanner never has to worry about refilling its buffer (needlessly copying chars around). We can achieve this because RText always scans exactly 1 line of tokens at a time, and hands the scanner this line as an array of characters (a Segment really). Since tokens contain pointers to char arrays instead of Strings holding their contents, there is no need for allocating new memory for Strings.

    The actual algorithm generated for scanning has, of course, not been modified.

    If you wish to regenerate this file yourself, keep in mind the following:

    • The generated JavaScriptTokenMaker.java file will contain two definitions of both zzRefill and yyreset. You should hand-delete the second of each definition (the ones generated by the lexer), as these generated methods modify the input buffer, which we'll never have to do.
    • You should also change the declaration/definition of zzBuffer to NOT be initialized. This is a needless memory allocation for us since we will be pointing the array somewhere else anyway.
    • You should NOT call yylex() on the generated scanner directly; rather, you should use getTokenList as you would with any other TokenMaker instance.

    • Constructor Detail

      • JavaScriptTokenMaker

        public JavaScriptTokenMaker()
        Constructor. This must be here because JFlex does not generate a no-parameter constructor.

      • JavaScriptTokenMaker

        public JavaScriptTokenMaker​(Reader in)
        Creates a new scanner There is also a java.io.InputStream version of this constructor.
        Parameters:
        in - the java.io.Reader to read input from.

      • JavaScriptTokenMaker

        public JavaScriptTokenMaker​(InputStream in)
        Creates a new scanner. There is also java.io.Reader version of this constructor.
        Parameters:
        in - the java.io.Inputstream to read input from.

    • Method Detail

      • addToken

        public void addToken​(char[] array,
                     int start,
                     int end,
                     int tokenType,
                     int startOffset)
        Adds the token specified to the current linked list of tokens.
        Specified by:
        addToken in interface TokenMaker
        Overrides:
        addToken in class TokenMakerBase
        Parameters:
        array - The character array.
        start - The starting offset in the array.
        end - The ending offset in the array.
        tokenType - The token's type.
        startOffset - The offset in the document at which this token occurs.

      • getJavaScriptVersion

        public static String getJavaScriptVersion()
        Returns the JavaScript version being highlighted.
        Returns:
        Supported JavaScript version.
        See Also:
        isJavaScriptCompatible(String)

      • getLineCommentStartAndEnd

        public String[] getLineCommentStartAndEnd​(int languageIndex)
        Returns the text to place at the beginning and end of a line to "comment" it in this programming language.
        Specified by:
        getLineCommentStartAndEnd in interface TokenMaker
        Overrides:
        getLineCommentStartAndEnd in class TokenMakerBase
        Parameters:
        languageIndex - The language index at the offset in question. Since some TokenMakers effectively have nested languages (such as JavaScript in HTML), this parameter tells the TokenMaker what sub-language to look at.
        Returns:
        The start and end strings to add to a line to "comment" it out. A null value for either means there is no string to add for that part. A value of null for the array means this language does not support commenting/uncommenting lines.

      • getTokenList

        public Token getTokenList​(Segment text,
                          int initialTokenType,
                          int startOffset)
        Returns the first token in the linked list of tokens generated from text. This method must be implemented by subclasses so they can correctly implement syntax highlighting.
        Parameters:
        text - The text from which to get tokens.
        initialTokenType - The token type we should start with.
        startOffset - The offset into the document at which text starts.
        Returns:
        The first Token in a linked list representing the syntax highlighted text.

      • isE4xSupported

        public static boolean isE4xSupported()
        Returns whether e4x is being highlighted.
        Returns:
        Whether e4x is being highlighted.
        See Also:
        setE4xSupported(boolean)

      • isJavaScriptCompatible

        public static boolean isJavaScriptCompatible​(String version)
        Returns whether features for a specific JS version should be honored while highlighting.
        Parameters:
        version - JavaScript version required
        Returns:
        Whether the JavaScript version is the same or greater than version required.

      • setE4xSupported

        public static void setE4xSupported​(boolean supported)
        Sets whether e4x should be highlighted. A repaint should be forced on all RSyntaxTextAreas editing JavaScript if this property is changed to see the difference.
        Parameters:
        supported - Whether e4x should be highlighted.
        See Also:
        isE4xSupported()

      • setJavaScriptVersion

        public static void setJavaScriptVersion​(String javaScriptVersion)
        Set the supported JavaScript version because some keywords were introduced on or after this version.
        Parameters:
        javaScriptVersion - The version of JavaScript to support, such as "1.5" or "1.6".
        See Also:
        isJavaScriptCompatible(String), getJavaScriptVersion()

      • 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 YY_INITIAL.
        Parameters:
        reader - the new input stream

      • yystate

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

      • yybegin

        public final void yybegin​(int newState)
        Enters a new lexical state
        Specified by:
        yybegin in class AbstractJFlexTokenMaker
        Parameters:
        newState - the new lexical state

      • yytext

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

      • 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()
        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()!

      • yylex

        public Token yylex()
            throws IOException
        Resumes scanning until the next regular expression is matched, the end of input is encountered or an I/O-Error occurs.
        Returns:
        the next token
        Throws:
        IOException - if any I/O-Error occurs