[antlr-interest] Visually display the DFA ANTLR generates

[Geoffrey Zhu]

Does anyone know how to visually display the DFA ANTLR generates?

For example, ANTLR generates the following DFA, but it is just too
difficult for me to figure out what it is doing.


    protected DFA4 dfa4 =3D new DFA4(this);
    static final String DFA4_eotS =3D
        "\2\uffff\1\6\1\uffff\1\5\2\uffff\4\5\1\14\1\uffff";
    static final String DFA4_eofS =3D
        "\15\uffff";
    static final String DFA4_minS =3D
 
"\1\50\1\uffff\2\11\1\145\2\uffff\1\154\1\145\1\143\1\164\1\141\1"+
        "\uffff";
    static final String DFA4_maxS =3D
 
"\1\172\1\uffff\2\172\1\145\2\uffff\1\154\1\145\1\143\1\164\1\172"+
        "\1\uffff";
    static final String DFA4_acceptS =3D
        "\1\uffff\1\1\3\uffff\1\4\1\2\5\uffff\1\3";
    static final String DFA4_specialS =3D
        "\15\uffff}>";
    static final String[] DFA4_transitionS =3D {
            "\1\2\70\uffff\32\1",
            "",
            "\1\3\26\uffff\1\3\100\uffff\22\5\1\4\7\5",
            "\1\3\26\uffff\1\3\100\uffff\22\5\1\4\7\5",
            "\1\7",
            "",
            "",
            "\1\10",
            "\1\11",
            "\1\12",
            "\1\13",
            "\32\5",
            ""
    };

    static final short[] DFA4_eot =3D DFA.unpackEncodedString(DFA4_eotS);
    static final short[] DFA4_eof =3D DFA.unpackEncodedString(DFA4_eofS);
    static final char[] DFA4_min =3D
DFA.unpackEncodedStringToUnsignedChars(DFA4_minS);
    static final char[] DFA4_max =3D
DFA.unpackEncodedStringToUnsignedChars(DFA4_maxS);
    static final short[] DFA4_accept =3D
DFA.unpackEncodedString(DFA4_acceptS);
    static final short[] DFA4_special =3D
DFA.unpackEncodedString(DFA4_specialS);
    static final short[][] DFA4_transition;

    static {
        int numStates =3D DFA4_transitionS.length;
        DFA4_transition =3D new short[numStates][];
        for (int i=3D0; i<numStates; i++) {
            DFA4_transition[i] =3D
DFA.unpackEncodedString(DFA4_transitionS[i]);
        }
    }

    class DFA4 extends DFA {

        public DFA4(BaseRecognizer recognizer) {
            this.recognizer =3D recognizer;
            this.decisionNumber =3D 4;
            this.eot =3D DFA4_eot;
            this.eof =3D DFA4_eof;
            this.min =3D DFA4_min;
            this.max =3D DFA4_max;
            this.accept =3D DFA4_accept;
            this.special =3D DFA4_special;
            this.transition =3D DFA4_transition;
        }
        public String getDescription() {
            return "1:1: Tokens : ( ID | LPAREN | LP_SELECT | LP_OTHER
);";
        }
    }
 

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