Can now create simple hardcoded IFn functions and invoke them

Author: Tko1

src/main.rs

@@ -0,0 +1,63 @@
+use std::any::{Any, TypeId};
+use std::collections::HashMap;
+use std::hash::{Hash,Hasher};
+use dyn_clone::DynClone;
+
+#[derive(Hash,PartialEq,Eq,Copy,Clone)]
+struct Symbol {
+    name: &'static str
+}
+
+trait IFn: DynClone {
+    fn invoke(&self,args: &[&dyn Any]) -> Box<dyn Any>;
+}
+dyn_clone::clone_trait_object!(IFn);
+
+#[derive(Clone)]
+struct AddFn {
+}
+impl IFn for AddFn {
+    fn invoke(&self,args: &[&dyn Any]) -> Box<dyn Any>
+    {
+	Box::new(args.into_iter().fold(0,|a,b|  {
+	    let _a = a as i64;
+	    if let Some(_b) = b.downcast_ref::<i64>() {
+		_a + *_b
+	    }
+	    else {
+		_a
+	    }
+	    
+	}))
+    }
+}
+use crate::Expr::*;
+#[derive(Clone)]
+enum Expr {
+    SymbolExpr(Symbol),
+    FnExpr(Box<dyn IFn>),
+    i32Expr(i32),
+    nilExpr 
+}
+impl Expr {
+    fn eval(&self,environment: &HashMap<Symbol,Expr>) -> Expr{
+	match self {
+	    SymbolExpr(sym) => match environment.get(&sym) {
+		Some(expr) => expr.clone(),
+		_ => nilExpr
+	    },
+	    _ => nilExpr 
+	}
+	    
+    }
+}
+
+fn main() {
+    let add = AddFn{};
+    let answer = add.invoke(&[&(1 as i64) as &dyn Any ,&(2 as i64) as &dyn Any]);
+    let answer_as_num = answer.downcast_ref::<i64>();// as Box<i64>;
+    
+    println!("Start:");
+    println!("{:?}",answer_as_num);
+    println!("Edn:");
+}