private static Expr define(boolean isGlobal, Interpreter interpreter, Scope scope, Expr argExpr) {
if (!(argExpr instanceof ListExpr))
return interpreter.error("def:is: needs more than one argument.");
ListExpr args = (ListExpr) argExpr;
if (args.getList().size() != 2) return interpreter.error("def:is: expects two arguments.");
// get the list of names being defined
Expr nameArg = args.getList().get(0);
List<String> names = new ArrayList<String>();
if (nameArg.getType() == ExprType.NAME) {
// defining a single name
names.add(((NameExpr) nameArg).getName());
} else if (nameArg.getType() == ExprType.LIST) {
// defining a list of names
ListExpr namesList = (ListExpr) nameArg;
for (Expr name : namesList.getList()) {
if (name.getType() != ExprType.NAME) {
return interpreter.error("First argument to def:is: must be a name, list, or call.");
}
names.add(((NameExpr) name).getName());
}
} else {
return interpreter.error("First argument to def:is: must be a name, list, or call.");
}
// evaluate the value(s)
Expr body = args.getList().get(1);
Expr value = interpreter.eval(scope, body);
// make sure the body matches the names
if (names.size() > 1) {
if (value.getType() != ExprType.LIST)
return interpreter.error("When defining multiple names, the value must be a list.");
ListExpr valueList = (ListExpr) value;
if (names.size() != valueList.getList().size())
return interpreter.error(
"When defining multiple names, the number of names and values must match.");
}
// define the names in the correct scope
if (names.size() == 1) {
defineName(isGlobal, interpreter, scope, names.get(0), value);
} else {
ListExpr values = (ListExpr) value;
for (int i = 0; i < names.size(); i++) {
defineName(isGlobal, interpreter, scope, names.get(i), values.getList().get(i));
}
}
return Expr.unit();
}
private static Expr createFunction(boolean isMacro, Scope scope, Expr arg) {
// ### bob: need lots of error-handling here
ListExpr argList = (ListExpr) arg;
// get the parameter name(s)
List<String> paramNames = new ArrayList<String>();
Expr parameters = argList.getList().get(0);
if (parameters.getType() == ExprType.LIST) {
ListExpr paramList = (ListExpr) parameters;
for (Expr param : paramList.getList()) {
paramNames.add(((NameExpr) param).getName());
}
} else {
// not a list, so assume it's a single name
paramNames.add(((NameExpr) parameters).getName());
}
// create the function
return new FunctionExpr(scope, isMacro, paramNames, argList.getList().get(1));
// ### bob: need to support closures at some point
}
