remove java implementation, was merely a book copy

rust/rox/src/native_functions.rs

@@ -1,44 +0,0 @@
-use std::{
-    rc::Rc,
-    time::{SystemTime, UNIX_EPOCH},
-};
-
-use ordered_float::OrderedFloat;
-
-use crate::{
-    callable::{Callable, CallingError},
-    interpreter::Interpreter,
-    value::{CallableType, Value},
-};
-
-struct Clock;
-
-impl Callable for Clock {
-    fn name(&self) -> String {
-        "clock".into()
-    }
-
-    fn arity(&self) -> usize {
-        0
-    }
-
-    fn call(
-        &self,
-        _interpreter: &mut Interpreter,
-        _args: Vec<crate::value::Value>,
-    ) -> Result<Value, CallingError> {
-        let start = SystemTime::now();
-        let since_the_epoch = start
-            .duration_since(UNIX_EPOCH)
-            .map_err(|e| CallingError::CallFailed(e.to_string()))?;
-
-        Ok(Value::Number(OrderedFloat(since_the_epoch.as_secs_f64())))
-    }
-}
-
-pub fn all() -> Vec<(String, Value)> {
-    vec![(
-        "clock".into(),
-        Value::Callable((Rc::new(Clock {}), CallableType::Function)),
-    )]
-}