Parsing.java

/*
 * Vitry, copyright (C) Hans Hoglund 2011
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * See COPYING.txt for details.
 */
package vitry.runtime.parse;

import static vitry.runtime.util.Arrays.linearSearch;

import vitry.runtime.*;
import vitry.runtime.error.*;


public class Parsing
{

    /*
     * Terminals used in the token stream generated by the lexer.
     * These do (should?) not exist in the AST.
     */
    public static final int PL       = findToken("(");
    public static final int PR       = findToken(")");
    public static final int BL       = findToken("[");
    public static final int BR       = findToken("]");
    public static final int AL       = findToken("{");
    public static final int AR       = findToken("}");

    public static final int EQ       = findToken("=");

    public static final int FN       = findToken("fn");
    public static final int LET      = findToken("let");
    public static final int DO       = findToken("do");
    public static final int MATCH    = findToken("match");

    public static final int IF       = findToken("if");
    public static final int ELSE     = findToken("else");
    public static final int MODULE   = findToken("module");

    public static final int IMPORT   = findToken("import");
    public static final int AS       = findToken("as");
    public static final int TYPE     = findToken("type");
    public static final int IMPLICIT = findToken("implicit");
    public static final int INFIX    = findToken("infix");

    /*
     * Syntactic tokens used in the AST.
     * Do not exist in the token stream generated by the lexer.
     */
    static
    {
        def("Ang", VitryParser.Ang);
        def("Apply", VitryParser.Apply);
        def("Assign", VitryParser.Assign);
        def("Bra", VitryParser.Bra);
        def("Do", VitryParser.Do);
        def("Delay", VitryParser.Delay);
        def("Fn", VitryParser.Fn);
        def("If", VitryParser.If);
        def("Left", VitryParser.Left);
        def("Let", VitryParser.Let);
        def("Match", VitryParser.Match);
        def("Module", VitryParser.Module);
        def("Op", VitryParser.Op);
        def("Ops", VitryParser.Ops);
        def("Par", VitryParser.Par);
        def("Quote", VitryParser.Quote);
        def("Type", VitryParser.Type);
        def("Import", VitryParser.Import);
        def("TypeDecl", VitryParser.TypeDecl);
        def("Implicit", VitryParser.Implicit);
        def("Fixity", VitryParser.Fixity);
    }


    public static final int getTokenType(Object p)
    {
        try
        {
            try
            {
                return getParserTokenType(p);
            } catch (Exception _)
            {
                return getSymbolicTokenType(p);
            }
        } catch (VitryError e)
        {
            throw e;
        }
    }

    public static final int getParserTokenType(Object p)
    {
        return ((VitryToken) p).getTokenType();
    }


    public static final int getSymbolicTokenType(Object p)
    {
        try
        {
            return table.lookup(p);
        } catch (Exception e)
        {
            throw new ParseError("Unknown form: " + p);
        }
    }


    private static int findToken(String t)
    {
        int res = linearSearch(VitryParser.tokenNames, "'" + t + "'");
        if (res < 0)
            throw new AssertionError("Token type of " + t + "is < 0");
        return res;
    }

    private static HashEnv<Object, Integer> table;

    private static void def(String sym, int type)
    {
        if (table == null)
            table = new HashEnv<Object, Integer>();
        table.define(Symbol.intern(sym), type);
    }
}