add variable export function

src/vars.rs

@@ -18,8 +18,8 @@
 use std::cell::RefCell;
 use std::rc::Rc;
 use std::collections::HashMap;
-use crate::segment::{Ctr};
-
+use crate::segment::{Ctr, Ast};
+use crate::func::{Function, Operation, Args, FTable};
 /* Mapping between a string token and a tree of Segments
  * The string token can be found in any Ctr::Symbol value
  * it is expected that the trees stored are already evaluated
@@ -36,3 +36,27 @@ pub fn define(
         drop(rc_segment);
     }
 }
+
+pub fn get_export() -> Function {
+    return Function{
+        name: String::from("export"),
+        loose_syms: true,
+        eval_lazy: false,
+        args: Args::Lazy(2),
+        function: Operation::Internal(
+            |a: Ast, b: Rc<RefCell<VTable>>, _c: Rc<RefCell<FTable>>| -> Ctr {
+                let inner = a.borrow_mut();
+                match &inner.car {
+                    Ctr::Symbol(identifier) => {
+                        define(b, identifier.to_string(), Rc::new(inner.cdr.clone()));
+                        return Ctr::None;
+                    },
+                    _ => {
+                        eprintln!("first argument to export must be a symbol");
+                        return Ctr::None;
+                    }
+                }
+            }
+        )
+    };
+}