ParserState.java

package org.xmlsh.sh.grammar;

import static org.xmlsh.sh.grammar.ParserState.TokenEnum.COLON;
import static org.xmlsh.sh.grammar.ParserState.TokenEnum.COMMA;

import java.util.EnumMap;
import java.util.EnumSet;

import org.xmlsh.sh.grammar.ShellParserUtils.TokenValue;

class ParserState {


  public static enum StateEnum {
    START ,
    BRACE_GROUP,
    FUNCTION_CALL,
    FUNCTION_DECL,
    ARRAY_LIST ,
    SEQUENCE_LIST ,
    BRACE_WORD ;
  }


  private static EnumMap<StateEnum, ParserState > mStateMap = new EnumMap<StateEnum,ParserState>(StateEnum.class);


  public static
  enum TokenEnum {
    COMMA( new TokenValue( ShellParserConstants.WORD , ",")) ,
    NL( new TokenValue( ShellParserConstants.NL , null )),
    SEMI( new TokenValue( ShellParserConstants.SEMI , null)),
    RPAREN( new TokenValue( ShellParserConstants.RPAREN , null)),
    COLON(  new TokenValue( ShellParserConstants.WORD , ":"))
    ;

    TokenValue value ;
    TokenEnum( TokenValue v ){
      value  = v ;
    }

    TokenValue getValue() {
      return value ;
    }
  }

  private EnumSet<TokenEnum> mDelims ;


  private static ParserState newInstance( StateEnum s ) {
    switch( s )  {
    case BRACE_GROUP :
    case FUNCTION_CALL :
    case ARRAY_LIST :
    case SEQUENCE_LIST :
    case FUNCTION_DECL :
      return new ParserState( EnumSet.of( COMMA ));

    case BRACE_WORD :
      return new ParserState( EnumSet.of( COMMA  , COLON ));

    default :
    case START :
      return new ParserState( EnumSet.noneOf(TokenEnum.class));
    }
  }



  public static ParserState instanceOf( StateEnum s ) {
    ParserState state = mStateMap.get(s);
    if( state == null )
      mStateMap.put( s , state = newInstance(s));
    return state ;
  }


  private ParserState( ) {
    mDelims = EnumSet.noneOf(TokenEnum.class);
  }

  private ParserState( EnumSet<TokenEnum> delims ) {
    mDelims = delims ;
  }

  public boolean isDelim( Token t ) {
    TokenEnum te = ShellParserUtils.tokenEnum(t);
    return mDelims.contains(te);
  }
}