Bind merge(Bind b) {
for (Enumeration<String> en = b.keys(); en.hasMoreElements(); ) {
String var = en.nextElement();
this.put(var, var);
}
return this;
}
/** for all var in env2 if var !in env1 && var in this : error exp1 optional exp2 */
boolean check(Bind env1, Bind env2) {
for (Enumeration<String> en = env2.keys(); en.hasMoreElements(); ) {
String var = en.nextElement();
if (!env1.contains(var) && this.contains(var)) {
return false;
}
}
return true;
}