Co<Expression> ExpressionFor::evaluate(Environment &env) const {
Co<Expression> start_value = start->evaluate(env);
Co<Expression> end_value = end->evaluate(env);
Co<Expression> delta_value = delta->evaluate(env);
ExpressionInteger *start_ivalue = dynamic_cast<ExpressionInteger *>(start_value.GetPointer());
ExpressionInteger *end_ivalue = dynamic_cast<ExpressionInteger *>(end_value.GetPointer());
ExpressionInteger *delta_ivalue = dynamic_cast<ExpressionInteger *>(delta_value.GetPointer());
if (!start_ivalue) {
throw MessagedException(start->getSourceLocation().toAnchor() + ": A for loop's starting value must be an integer. " + start->getSource() + " is not an integer.");
}
if (!end_ivalue) {
throw MessagedException(end->getSourceLocation().toAnchor() + ": A for loop's ending value must be an integer. " + end->getSource() + " is not an integer.");
}
if (!delta_ivalue) {
throw MessagedException(delta->getSourceLocation().toAnchor() + ": A for loop's increment value must be an integer. " + delta->getSource() + " is not an integer.");
}
int a = start_ivalue->toInteger();
int b = end_ivalue->toInteger();
int idelta = delta_ivalue->toInteger();
Co<Expression> value = ExpressionUnit::getSingleton();
if (idelta > 0) {
if (is_inclusive) {
++b;
}
for (int i = a; i < b; i += idelta) {
env.checkTimeout(getSourceLocation());
iterator->assign(env, Co<Expression>(new ExpressionInteger(i)));
value = body->evaluate(env);
}
} else {
if (is_inclusive) {
--b;
}
for (int i = a; i > b; i += idelta) {
env.checkTimeout(getSourceLocation());
iterator->assign(env, Co<Expression>(new ExpressionInteger(i)));
value = body->evaluate(env);
}
}
return value;
}
Co<Expression> ExpressionCallWithNamedParameters::evaluate(Environment &env) const {
env.checkTimeout(getSourceLocation());
Co<ExpressionClosure> closure = env[name];
/* std::cout << "getSource(): " << getSource() << std::endl; */
/* std::cout << "getSourceLocation(): " << getSourceLocation().toAnchor() << std::endl; */
/* std::cout << "closure->getSourceLocation(): " << closure->getSourceLocation().toAnchor() << std::endl; */
if (closure.IsNull()) {
throw MessagedException(getSourceLocation().toAnchor() + ": No function named " + name + " is defined.");
}
/* closure->setSource(getSource(), getSourceLocation()); */
Co<ExpressionDefine> define = closure->getDefine();
Co<Environment> closure_env(new Environment(*closure->getEnvironment()));
// Before trying to execute this business, let's make certain the user didn't
// pass any named parameters that don't apply. Having extras isn't going to
// stop us from executing the function, but it probably means the caller has
// some different intent.
set<string> formal_names = define->getFormalNames();
for (bindings_t::const_iterator i = bindings.begin();
i != bindings.end();
++i) {
if (formal_names.find(i->first) == formal_names.end()) {
throw MessagedException(getSourceLocation().toAnchor() + ": I saw that you passed a parameter named " + i->first + " to function " + define->getName() + ", but " + define->getName() + " doesn't accept a parameter named " + i->first + ".");
}
}
// Having cleared the appropriateness of the bindings, let's start evaluating.
for (unsigned int i = 0; i < define->getArity(); ++i) {
const FormalParameter &formal = define->getFormal(i);
bool is_lazy = formal.getEvaluationMode() == FormalParameter::LAZY;
// Look up parameter name in enumerated bindings first. If we find an
// explicit parameter with that name, use its value.
bindings_t::const_iterator match = bindings.find(formal.getName());
Co<ExpressionDefine> parameter_define;
Co<ExpressionDefine> parameter_closure;
if (match != bindings.end()) {
parameter_define = Co<ExpressionDefine>(new ExpressionDefine(formal.getName(), is_lazy ? match->second : match->second->evaluate(env)));
parameter_closure = Co<ExpressionClosure>(new ExpressionClosure(parameter_define, is_lazy ? env : Environment()));
parameter_closure->setSource(match->second->getSource(), match->second->getSourceLocation());
} else if (!formal.getDefaultValue().IsNull()) {
parameter_define = Co<ExpressionDefine>(new ExpressionDefine(formal.getName(), formal.getDefaultValue()->evaluate(env)));
parameter_closure = Co<ExpressionClosure>(new ExpressionClosure(parameter_define, Environment()));
parameter_closure->setSource(formal.getDefaultValue()->getSource(), formal.getDefaultValue()->getSourceLocation());
// UPDATE: disallow implicits. They work, but their benefit is small and
// risk of confusion is too high.
// If no such parameter was enumerated, checking for a binding with that
// name in the surrounding environment at the time of the call.
/* else if (env.isBound(formal.getName())) { */
/* Co<Expression> closure = env[formal.getName()]; */
/* parameter_define = Co<ExpressionDefine>(new ExpressionDefine(formal.getName(), is_lazy ? closure : closure->evaluate(env))); */
/* parameter_closure = Co<ExpressionClosure>(new ExpressionClosure(parameter_define, is_lazy ? env : Environment())); */
/* parameter_closure->setSource(closure->getSource(), closure->getSourceLocation()); */
} else {
throw MessagedException(getSourceLocation().toAnchor() + ": Function " + define->getName() + " expects a parameter named " + formal.getName() + ". No such parameter was provided and no variable with that name was defined.");
}
closure_env->replace(define->getFormal(i).getName(), parameter_closure);
}
try {
return closure->evaluate(*closure_env);
} catch (Co<Expression> return_value) {
return return_value;
} catch (UnlocatedException e) {
throw MessagedException(getSourceLocation().toAnchor() + ": " + e.GetMessage());
}
}