assnode.java

来自「一个JAVA编写的简单编译器」· Java 代码 · 共 33 行

package ast.binaryExpr;


public class AssNode extends ast.JSubNode {
  public AssNode (ast.IJSubNode n) {
    super (n);
  }
  
  public String toString () {
    return "=";
  }    
  
  public void codegen () {
    int k = getNumChildren ();
    ast.IJSubNode rvalue = (ast.IJSubNode)getChild (k-1);
    rvalue.codegen ();
    for (int i = k-1; i > 0; i--) {
      ast.IJSubNode lvalue = (ast.IJSubNode)getChild (i-1);
      if (i > 1)
        codegen.WriteCode.genInstruction ("dup");
      if (lvalue instanceof ast.Leaf) {
        ast.Leaf leaf = (ast.Leaf)lvalue;
        codegen.WriteCode.genStore (leaf.getDeclaration());
      } else
        util.Error.e2 ("L-Value in = expected");
    }      
  }  
  
  public String getXMLType () {
    return "assign";
  }
}