The R Project SVN – R – Diff – /trunk/src/main/subset.c

     dims = getAttrib(x, R_DimSymbol);
     ndims = length(dims);
     if(nsubs > 1 && nsubs != ndims)
 	errorcall(call, "incorrect number of subscripts");
+    /* split out ENVSXP for now */
+    if( TYPEOF(x) == ENVSXP ) {
+      if( nsubs != 1 || !isString(CAR(subs)) || length(CAR(subs)) != 1 )
+	error("wrong arguments for subsetting an environment");
+      ans = findVarInFrame(x, install(CHAR(STRING_ELT(CAR(subs),
+))));
+      UNPROTECT(1);
+      if(ans == R_UnboundValue )
+        return(R_NilValue);
+      return(ans);
+    }
+    /* back to the regular program */
     if (!(isVector(x) || isList(x) || isLanguage(x)))
 	errorcall(call, R_MSG_ob_nonsub);
     if(nsubs == 1) { /* vector indexing */
 	SEXP thesub = CAR(subs);
 		SET_NAMED(y, NAMED(x));
 	    return y;
+	}
 	return R_NilValue;
+    }
+    else if( isEnvironment(x) ){
+      UNPROTECT(2);
+      y = findVarInFrame(x, install(CHAR(input)));
+      if( y != R_UnboundValue )
+	return(y);
+      return R_NilValue;
+    }
     UNPROTECT(2);
     return R_NilValue;
+}

The R Project SVN R