mod eval_tests {
    use relish::ast::{eval, lex, SymTable};
    use relish::ast::{Args, Ctr, Seg, Symbol, UserFn, ValueType};

    #[test]
    fn eval_simple() {
        let test_doc = "(1 2)".to_string();
        let mut syms = SymTable::new();
        let doc_tree = lex(&test_doc).unwrap();
        let reduced = *eval(&doc_tree, &mut syms).unwrap();
        assert_eq!(reduced.to_string(), test_doc);
    }

    #[test]
    fn eval_embedded_lists_no_funcs() {
        let test_doc = "(1 (1 2 3 4 5) 5)".to_string();
        let mut syms = SymTable::new();
        let doc_tree = lex(&test_doc).unwrap();
        let reduced = *eval(&doc_tree, &mut syms).unwrap();
        assert_eq!(reduced.to_string(), test_doc);
    }

    #[test]
    fn eval_function_call() {
        let test_doc = "('one' (echo 'unwrap_me'))".to_string();
        let output = "('one' 'unwrap_me')";
        let mut syms = SymTable::new();

        let test_external_func: Symbol = Symbol {
            name: String::from("echo"),
            args: Args::Lazy(1),
            conditional_branches: false,
            docs: String::new(),
            value: ValueType::FuncForm(UserFn {
                arg_syms: vec!["input".to_string()],
                ast: Box::new(Seg::from(
                    Box::from(Ctr::Symbol("input".to_string())),
                    Box::from(Ctr::None),
                )),
            }),
            ..Default::default()
        };

        syms.insert(String::from("echo"), test_external_func);
        let doc_tree = lex(&test_doc).unwrap();
        let reduced = *eval(&doc_tree, &mut syms).unwrap();
        assert_eq!(reduced.to_string(), output);
    }

    #[test]
    fn eval_embedded_func_calls() {
        let test_doc = "('one' (echo (echo 'unwrap_me')))".to_string();
        let output = "('one' 'unwrap_me')";
        let mut syms = SymTable::new();

        let test_external_func: Symbol = Symbol {
            name: String::from("echo"),
            args: Args::Lazy(1),
            conditional_branches: false,
            docs: String::new(),
            value: ValueType::FuncForm(UserFn {
                arg_syms: vec!["input".to_string()],
                ast: Box::new(Seg::from(
                    Box::from(Ctr::Symbol("input".to_string())),
                    Box::from(Ctr::None),
                )),
            }),
            ..Default::default()
        };

        syms.insert(String::from("echo"), test_external_func);
        let doc_tree = lex(&test_doc).unwrap();
        let reduced = *eval(&doc_tree, &mut syms).unwrap();
        assert_eq!(reduced.to_string(), output);
    }

    #[test]
    fn eval_bad_syms() {
        let test_doc = "(undefined)".to_string();
        let mut syms = SymTable::new();
        let doc_tree = lex(&test_doc).unwrap();
        match eval(&doc_tree, &mut syms) {
            Err(e) => {
                assert_eq!(e.0.first().unwrap().message,
                           "(is an undefined symbol)")
            }

            Ok(reduced) => {
                println!("Eval succeeded when it shouldnt have");
                println!("see: {}", reduced);
                assert!(false)
            }
        }
    }
}