add append function

src/append.rs

@@ -0,0 +1,68 @@
+/* relish: versatile lisp shell
+ * Copyright (C) 2021 Aidan Hahn
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+use crate::func::{FTable, Function, Args, Operation};
+use crate::vars::{VTable};
+use crate::segment::{Ctr, Ast, circuit, list_idx, list_append, new_ast};
+use std::rc::Rc;
+use std::cell::RefCell;
+
+pub fn get_append() -> Function {
+    return Function{
+        name: String::from("append"),
+        loose_syms: false,
+        eval_lazy: false,
+        args: Args::Lazy(-1),
+        function: Operation::Internal(
+            |a: Ast, _b: Rc<RefCell<VTable>>, _c: Rc<RefCell<FTable>>| -> Ctr {
+                let ptr = list_idx(a.clone(), 0);
+                match ptr {
+                    Ctr::Seg(ref c) => {
+                        let acpy = a.clone();
+                        match acpy.borrow().cdr.clone() {
+                            Ctr::Seg(cn) => {
+                                // append to list case
+                                if !circuit(cn, &mut |arg: &Ctr| -> bool {
+                                    list_append(c.clone(), arg.clone());
+                                    return true;
+                                }) {
+                                    eprintln!("get_append circuit loop should not have returned false");
+                                }
+                            },
+                            _ => {
+                                eprintln!("get_append args somehow not in standard form");
+                            }
+                        }
+
+                        return ptr;
+                    },
+                    _ => {
+                        let n = new_ast(Ctr::None, Ctr::None);
+                        if !circuit(a, &mut |arg: &Ctr| -> bool {
+                            list_append(n.clone(), arg.clone());
+                            return true;
+                        }) {
+                            eprintln!("get_append circuit loop should not have returned false");
+                        }
+
+                        return Ctr::Seg(n);
+                    }
+                }
+            }
+        )
+    };
+}