rand works for doubles

src/environment.rs

@@ -74,6 +74,7 @@ impl Environment {
  let subtract_fn = rust_core::SubtractFn {};
  let multiply_fn = rust_core::MultiplyFn {};
  let divide_fn = rust_core::DivideFn {};
+ let rand_fn = rust_core::RandFn {};
  let str_fn = rust_core::StrFn {};
  let do_fn = rust_core::DoFn {};
  let nth_fn = rust_core::NthFn {};
@@ -105,6 +106,7 @@ impl Environment {
  environment.insert(Symbol::intern("-"), subtract_fn.to_rc_value());
  environment.insert(Symbol::intern("*"), multiply_fn.to_rc_value());
  environment.insert(Symbol::intern("_slash_"), divide_fn.to_rc_value());
+ environment.insert(Symbol::intern("rand"), rand_fn.to_rc_value());
  environment.insert(Symbol::intern("let"), let_macro.to_rc_value());
  environment.insert(Symbol::intern("str"), str_fn.to_rc_value());
  environment.insert(Symbol::intern("quote"), quote_macro.to_rc_value());

src/rust_core.rs

@@ -22,6 +22,10 @@ pub use self::_divide_::*;
 pub(crate) mod _multiply_;
 pub use self::_multiply_::*;
 
+pub(crate) mod rand;
+pub use self::rand::*;
+
+
 // string
 pub(crate) mod str;
 pub use self::str::*;

src/rust_core/rand.rs

@@ -0,0 +1,35 @@
+use crate::ifn::IFn;
+use crate::value::{Value, ToValue};
+use std::rc::Rc;
+use rand::{random, thread_rng, Rng};
+use crate::error_message;
+use std::any::Any;
+
+/// (rand) or (rand n)
+///
+#[derive(Debug, Clone)]
+pub struct RandFn {}
+impl ToValue for RandFn {
+ fn to_value(&self) -> Value {
+ Value::IFn(Rc::new(self.clone()))
+ }
+}
+impl IFn for RandFn {
+ fn invoke(&self, args: Vec<Rc<Value>>) -> Value {
+ match args.len() {
+ 0 => Value::F64(thread_rng().gen()),
+ 1 => {
+ let arg = args.get(0).unwrap().to_value();
+ match arg {
+ Value::I32(i_) => Value::F64(thread_rng().gen_range(0.0, i_ as f64)),
+ Value::F64(f_) => Value::F64(thread_rng().gen_range(0.0, f_)),
+ _ => Value::Condition(format!( // TODO: what error message should be returned regarding using typetags?
+ "Type mismatch; Expecting: (i32 | i64 | f32 | f64), Found: {}",
+ arg.type_tag()
+ ))
+ }
+ },
+ _ => error_message::wrong_varg_count(&[0, 1], args.len())
+ }
+ }
+}