musique/src/value.cc
2022-05-21 23:12:50 +02:00

146 lines
2.8 KiB
C++

#include <musique.hh>
Result<Value> Value::from(Token t)
{
switch (t.type) {
case Token::Type::Numeric:
return Value::number(Try(Number::from(std::move(t))));
case Token::Type::Symbol:
if (t.source == "true")
return Value::boolean(true);
if (t.source == "false")
return Value::boolean(false);
if (t.source == "nil")
return Value{};
return Value::symbol(std::string(t.source));
default:
unimplemented();
}
}
Value Value::boolean(bool b)
{
Value v;
v.type = Value::Type::Bool;
v.b = b;
return v;
}
Value Value::number(Number n)
{
Value v;
v.type = Type::Number;
v.n = std::move(n).simplify();
return v;
}
Value Value::symbol(std::string s)
{
Value v;
v.type = Type::Symbol;
v.s = std::move(s);
return v;
}
Value Value::lambda(Function f)
{
Value v;
v.type = Type::Lambda;
v.f = std::move(f);
return v;
}
Result<Value> Value::operator()(Interpreter &i, std::vector<Value> args)
{
if (type == Type::Lambda) {
return f(i, std::move(args));
}
// TODO Fill location
return errors::not_callable(std::nullopt, type);
}
bool Value::truthy() const
{
switch (type) {
case Type::Bool: return b;
case Type::Nil: return false;
case Type::Number: return n != Number(0);
case Type::Lambda:
case Type::Symbol: return true;
}
unreachable();
}
bool Value::falsy() const
{
return not truthy();
}
bool Value::operator==(Value const& other) const
{
if (type != other.type)
return false;
switch (type) {
case Type::Nil: return true;
case Type::Number: return n == other.n;
case Type::Symbol: return s == other.s;
case Type::Lambda: return false; // TODO Reconsider if functions are comparable
case Type::Bool: return b == other.b;
}
unreachable();
}
std::ostream& operator<<(std::ostream& os, Value const& v)
{
switch (v.type) {
case Value::Type::Nil:
return os << "nil";
case Value::Type::Number:
return os << v.n;
case Value::Type::Symbol:
return os << v.s;
case Value::Type::Bool:
return os << (v.b ? "true" : "false");
case Value::Type::Lambda:
return os << "<lambda>";
}
unreachable();
}
std::string_view type_name(Value::Type t)
{
switch (t) {
case Value::Type::Bool: return "bool";
case Value::Type::Lambda: return "lambda";
case Value::Type::Nil: return "nil";
case Value::Type::Number: return "number";
case Value::Type::Symbol: return "symbol";
}
unreachable();
}
Result<Value> Lambda::operator()(Interpreter &i, std::vector<Value> arguments)
{
i.current_env = ++i.env();
assert(parameters.size() == arguments.size(), "wrong number of arguments");
auto &env = i.env();
for (usize j = 0; j < parameters.size(); ++j) {
env.force_define(parameters[j], std::move(arguments[j]));
}
Ast body_copy = body;
auto result = i.eval(std::move(body_copy));
i.current_env = --i.env();
return result;
}