docs: public PatternDescr getBasePattern() {
          if ( this.patterns.size() > 1 ) {
              return (PatternDescr) this.patterns.get( 0 );
          } else if ( this.patterns.size() == 1 ) {
              // in case there is only one pattern, we do a rewrite, so:
              // forall( Cheese( type == "stilton" ) )
              // becomes
              // forall( BASE_IDENTIFIER : Cheese() Cheese( this == BASE_IDENTIFIER, type == "stilton" ) )
              PatternDescr original = (PatternDescr) this.patterns.get( 0 );
              PatternDescr base = (PatternDescr) original.clone();
              base.getDescrs().clear();
              base.setIdentifier( BASE_IDENTIFIER );
              base.setResource(original.getResource());
              return base;
          }
          return null;
      }