type.java

Java编写的编译器前端

package lexer;		// File Type.java
public class Type extends Word {
	public int width = 0;
	public Type(String s, int tag, int w) { super(s, tag); width = w; }
	public static final Type
		Int    = new Type( "int",    Tag.BASIC, 4 ),
		Double = new Type( "double", Tag.BASIC, 8 ),
	        Char   = new Type( "char",   Tag.BASIC, 1 ),
		Bool   = new Type( "bool",   Tag.BASIC, 1 );
	public static boolean numeric(Type p){
		if (p == Type.Char || p == Type.Int || p == Type.Double) return true;
		else return false;
	}
	public static Type max(Type p1, Type p2) {
		if ( !numeric(p1) || !numeric(p2) ) return null;
		else if (p1 == Type.Double || p2 == Type.Double ) return Type.Double;
		else if (p1 == Type.Int || p2 == Type.Int ) return Type.Int;
		else return Type.Char;
	}
}