diff --git a/SConstruct b/SConstruct
index f713843..b86d426 100644
--- a/SConstruct
+++ b/SConstruct
@@ -11,21 +11,22 @@ src_dir = "src/"
 
 program_sources = ["src/main.c"]
 lib_srcs = [
-    "src/parse.c",
-    "src/memory.c",
     "src/builtins.c",
     "src/evaluate.c",
-    "src/utility.c",
+    "src/memory.c",
+    "src/special.c",
     "src/state.c",
+    "src/utility.c",
+    "src/parse.c",
 ]
 lib_includes = ["src/"]
 
 
 test_srcs = [
-    "test/test_parse.c",
-    "test/test_utility.c",
-    "test/test_state.c",
     "test/test_e2e.c",
+    "test/test_parse.c",
+    "test/test_state.c",
+    "test/test_utility.c",
 ]
 test_lib_srcs = ["third-party/unity/src/unity.c"]
 test_lib_includes = ["third-party/unity/src/"]
diff --git a/src/builtins.c b/src/builtins.c
index acdfd9a..2be67ad 100644
--- a/src/builtins.c
+++ b/src/builtins.c
@@ -3,6 +3,7 @@
 #include "utility.h"
 #include "builtins.h"
 #include "state.h"
+#include "lisp.h"
 
 #include <assert.h>
 #include <stddef.h>
@@ -24,6 +25,8 @@ LISP_FUNC_1(ucl_builtin_type, state, arg) {
             return ucl_symbol_create("error");
         case UCL_TYPE_BUILTIN:
             return ucl_symbol_create("builtin");
+        case UCL_TYPE_SPECIAL:
+            return ucl_symbol_create("special");
         case UCL_TYPE_COUNT:
             assert(0);
             return NULL;
@@ -192,41 +195,6 @@ LISP_FUNC_1(ucl_builtin_print, state, arg0) {
     return ucl_nil_create();
 }
 
-struct ucl_object *ucl_builtin_let(struct ucl_state *state, struct ucl_object *args) {
-    // TODO: Check arguments
-    struct ucl_object *assignments = ucl_car(args);
-    struct ucl_object *expressions = ucl_cdr(args);
-    struct ucl_state *let_state = ucl_state_create_child(state);
-
-    FOREACH_LIST(assignments, iter, item) {
-        // TODO: Check arguments
-        struct ucl_object *sym = ucl_car(item);
-        struct ucl_object *expr = ucl_car(ucl_cdr(item));
-        struct ucl_object *value = ucl_evaluate(let_state, expr);
-
-        assert(sym->type == UCL_TYPE_SYMBOL);
-        //assert(ucl_list_length(expr)->integer == 1);
-
-        if (value->type == UCL_TYPE_ERROR) {
-            // TODO cleanup
-            return value;
-        }
-        ucl_state_put(let_state, sym->symbol, value);
-    }
-
-    struct ucl_object *result = NULL;
-    FOREACH_LIST(expressions, iter, item) {
-        result = ucl_evaluate(let_state, item);
-        if (result->type == UCL_TYPE_ERROR) {
-            return result;
-        }
-    }
-
-
-    ucl_state_delete(let_state);
-    return result;
-}
-
 struct ucl_object *ucl_builtin_list(struct ucl_state *state, struct ucl_object *args) {
     struct ucl_object *head = ucl_nil_create();
     FOREACH_LIST(args, iter, item) {
diff --git a/src/builtins.h b/src/builtins.h
index 4468a4d..f51ae7c 100644
--- a/src/builtins.h
+++ b/src/builtins.h
@@ -3,49 +3,6 @@
 
 #include "utility.h"
 
-#define LISP_FUNC_0(func_name, state_name)                              \
-    static struct ucl_object *func_name##_impl();                       \
-    struct ucl_object *func_name(struct ucl_state *state, struct ucl_object *args) { \
-        if (args->cell.car != NULL) {                                   \
-            return NULL;                                                \
-        }                                                               \
-        return func_name##_impl(state_name);                            \
-    }                                                                   \
-    static struct ucl_object *func_name##_impl(struct ucl_state *state)
-
-#define LISP_FUNC_1(func_name, state_name, arg0_name)                   \
-    static struct ucl_object *func_name##_impl(struct ucl_state *state, struct ucl_object *arg0_name); \
-    struct ucl_object *func_name(struct ucl_state *state, struct ucl_object *args) { \
-        struct ucl_object *len_obj = ucl_list_length(args);             \
-        if (len_obj->type != UCL_TYPE_INT) {                            \
-            return NULL;                                                \
-        }                                                               \
-        if (len_obj->integer != 1) {                                    \
-            return NULL;                                                \
-        }                                                               \
-        struct ucl_object *arg0 = ucl_car(args);                        \
-        return func_name##_impl(state_name, arg0);                      \
-    }                                                                   \
-    static struct ucl_object *func_name##_impl(struct ucl_state *state, struct ucl_object *arg0_name)
-
-// TODO: Unroll the args more efficiently, this is O(n^2)
-#define LISP_FUNC_2(func_name, state_name, arg0_name, arg1_name)         \
-    static struct ucl_object *func_name##_impl(struct ucl_state *state, struct ucl_object *arg0_name, struct ucl_object *arg1_name); \
-    struct ucl_object *func_name(struct ucl_state *state, struct ucl_object *args) { \
-        struct ucl_object *len_obj = ucl_list_length(args);             \
-        if (len_obj->type != UCL_TYPE_INT) {                            \
-            return NULL;                                                \
-        }                                                               \
-        if (len_obj->integer != 2) {                                    \
-            return NULL;                                                \
-        }                                                               \
-        struct ucl_object *arg0 = ucl_list_nth(args, 0);                \
-        struct ucl_object *arg1 = ucl_list_nth(args, 1);                \
-        return func_name##_impl(state_name, arg0, arg1);                \
-    }                                                                   \
-    static struct ucl_object *func_name##_impl(struct ucl_state *state, struct ucl_object *arg0_name, struct ucl_object *arg1_name)
-
-
 struct ucl_object *ucl_builtin_error(struct ucl_state *state, struct ucl_object *args);
 struct ucl_object *ucl_builtin_type(struct ucl_state *state, struct ucl_object *args);
 struct ucl_object *ucl_builtin_symbol_p(struct ucl_state *state, struct ucl_object *args);
@@ -62,7 +19,6 @@ struct ucl_object *ucl_builtin_concat(struct ucl_state *state, struct ucl_object
 
 struct ucl_object *ucl_builtin_now_millis_mono(struct ucl_state *state, struct ucl_object *args);
 
-struct ucl_object *ucl_builtin_let(struct ucl_state *state, struct ucl_object *args);
 struct ucl_object *ucl_builtin_list(struct ucl_state *state, struct ucl_object *args);
 struct ucl_object *ucl_builtin_print(struct ucl_state *state, struct ucl_object *args);
 
diff --git a/src/evaluate.c b/src/evaluate.c
index 30b302e..9d6f358 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -9,11 +9,7 @@
 // TODO: remove string.h
 #include <string.h>
 
-struct ucl_object *ucl_evaluate_list(struct ucl_state *state, struct ucl_object *list) {
-    if (list->cell.car == NULL) {
-        return list;
-    }
-
+struct ucl_object *ucl_evaluate_builtin_form(struct ucl_state *state, struct ucl_object *list) {
     // TODO: Recursively eval args
     struct ucl_object *evaluated_list = ucl_nil_create();
 
@@ -31,8 +27,6 @@ struct ucl_object *ucl_evaluate_list(struct ucl_state *state, struct ucl_object
         result = fun->builtin(state, args);
     }
 
-    // TODO: Non-builtins
-
     // TODO: cleanup
 
     return result;
@@ -42,29 +36,45 @@ struct ucl_object *ucl_evaluate_special_form(struct ucl_state *state, struct ucl
     // TODO: Recursively eval args
     const char *fun_sym = ucl_car(list)->symbol;
 
-    if (strcmp(fun_sym, "let")) {
-        return ucl_evaluate_list(state, list);
-    }
-
     struct ucl_object *fun = ucl_state_get(state, ucl_car(list)->symbol);
     struct ucl_object *args = ucl_cdr(list);
     struct ucl_object *result = NULL;
 
-    assert(fun->type == UCL_TYPE_BUILTIN);
-    if (fun->type == UCL_TYPE_BUILTIN) {
-        // TODO: check for errors
-        result = fun->builtin(state, args);
-    }
+    result = fun->special(state, args);
 
     return result;
 }
 
+
+
+struct ucl_object *ucl_evaluate_list(struct ucl_state *state, struct ucl_object *list) {
+    if (list->cell.car == NULL) {
+        return list;
+    }
+
+    struct ucl_object *fun_sym = ucl_car(list);
+    if (fun_sym->type != UCL_TYPE_SYMBOL) {
+        return ucl_error_create("Unknown function symbol");
+    }
+    struct ucl_object *fun = ucl_state_get(state, fun_sym->symbol);
+    UCL_RET_IF_ERROR(fun);
+
+    if (fun->type == UCL_TYPE_SPECIAL) {
+        return ucl_evaluate_special_form(state, list);
+    } else if (fun->type == UCL_TYPE_BUILTIN) {
+        return ucl_evaluate_builtin_form(state, list);
+    } else {
+        assert(0);
+        // TODO: Lisp functions and other errors
+    }
+}
+
 struct ucl_object *ucl_evaluate(struct ucl_state *state, struct ucl_object *obj) {
     assert(obj != NULL);
 
     switch (obj->type) {
         case UCL_TYPE_CELL:
-            return ucl_evaluate_special_form(state, obj);
+            return ucl_evaluate_list(state, obj);
         case UCL_TYPE_SYMBOL:
             return ucl_state_get(state, obj->symbol);
         case UCL_TYPE_INT:
@@ -72,6 +82,7 @@ struct ucl_object *ucl_evaluate(struct ucl_state *state, struct ucl_object *obj)
         case UCL_TYPE_ERROR:
             return obj;
         case UCL_TYPE_BUILTIN:
+        case UCL_TYPE_SPECIAL:
         case UCL_TYPE_COUNT:
             assert(0);
             return NULL;
diff --git a/src/internal.h b/src/internal.h
index 9ff9d04..42db698 100644
--- a/src/internal.h
+++ b/src/internal.h
@@ -18,7 +18,8 @@ struct ucl_object *ucl_int_create(int integer);
 struct ucl_object *ucl_symbol_create(const char* symbol);
 struct ucl_object *ucl_string_create(const char* string);
 struct ucl_object *ucl_error_create(const char* error);
-struct ucl_object *ucl_builtin_create(ucl_builtin builtin);
+struct ucl_object *ucl_builtin_create(ucl_lisp builtin);
+struct ucl_object *ucl_special_create(ucl_lisp special);
 
 void ucl_object_delete(struct ucl_object *obj);
 
diff --git a/src/lisp.h b/src/lisp.h
new file mode 100644
index 0000000..76b470b
--- /dev/null
+++ b/src/lisp.h
@@ -0,0 +1,49 @@
+#ifndef _UCLISP_LISP_H_
+#define _UCLISP_LISP_H_
+
+#include "uclisp.h"
+#include "utility.h"
+
+#define LISP_FUNC_0(func_name, state_name)                              \
+    static struct ucl_object *func_name##_impl();                       \
+    struct ucl_object *func_name(struct ucl_state *state, struct ucl_object *args) { \
+        if (args->cell.car != NULL) {                                   \
+            return NULL;                                                \
+        }                                                               \
+        return func_name##_impl(state_name);                            \
+    }                                                                   \
+    static struct ucl_object *func_name##_impl(struct ucl_state *state)
+
+#define LISP_FUNC_1(func_name, state_name, arg0_name)                   \
+    static struct ucl_object *func_name##_impl(struct ucl_state *state, struct ucl_object *arg0_name); \
+    struct ucl_object *func_name(struct ucl_state *state, struct ucl_object *args) { \
+        struct ucl_object *len_obj = ucl_list_length(args);             \
+        if (len_obj->type != UCL_TYPE_INT) {                            \
+            return NULL;                                                \
+        }                                                               \
+        if (len_obj->integer != 1) {                                    \
+            return NULL;                                                \
+        }                                                               \
+        struct ucl_object *arg0 = ucl_car(args);                        \
+        return func_name##_impl(state_name, arg0);                      \
+    }                                                                   \
+    static struct ucl_object *func_name##_impl(struct ucl_state *state, struct ucl_object *arg0_name)
+
+// TODO: Unroll the args more efficiently, this is O(n^2)
+#define LISP_FUNC_2(func_name, state_name, arg0_name, arg1_name)        \
+    static struct ucl_object *func_name##_impl(struct ucl_state *state, struct ucl_object *arg0_name, struct ucl_object *arg1_name); \
+    struct ucl_object *func_name(struct ucl_state *state, struct ucl_object *args) { \
+        struct ucl_object *len_obj = ucl_list_length(args);             \
+        if (len_obj->type != UCL_TYPE_INT) {                            \
+            return NULL;                                                \
+        }                                                               \
+        if (len_obj->integer != 2) {                                    \
+            return NULL;                                                \
+        }                                                               \
+        struct ucl_object *arg0 = ucl_list_nth(args, 0);                \
+        struct ucl_object *arg1 = ucl_list_nth(args, 1);                \
+        return func_name##_impl(state_name, arg0, arg1);                \
+    }                                                                   \
+    static struct ucl_object *func_name##_impl(struct ucl_state *state, struct ucl_object *arg0_name, struct ucl_object *arg1_name)
+
+#endif
diff --git a/src/main.c b/src/main.c
index 17b24ba..8e76b9d 100644
--- a/src/main.c
+++ b/src/main.c
@@ -2,16 +2,21 @@
 #include <stdio.h>
 
 #include "uclisp.h"
-#include "state.h"
-#include "internal.h"
-#include "utility.h"
+
 #include "builtins.h"
+#include "internal.h"
+#include "special.h"
+#include "state.h"
+#include "utility.h"
 
 int main(int argc, const char **argv) {
     (void) argc, (void) argv;
     struct ucl_state *state = ucl_state_create();
 
-    ucl_state_put(state, "let", ucl_builtin_create(ucl_builtin_let));
+    ucl_state_put(state, "let", ucl_special_create(ucl_special_let));
+    ucl_state_put(state, "if", ucl_special_create(ucl_special_if));
+
+
     ucl_state_put(state, "print", ucl_builtin_create(ucl_builtin_print));
     ucl_state_put(state, "list", ucl_builtin_create(ucl_builtin_list));
 
diff --git a/src/memory.c b/src/memory.c
index 631d490..7adb695 100644
--- a/src/memory.c
+++ b/src/memory.c
@@ -49,7 +49,7 @@ struct ucl_object *ucl_error_create(const char *error)
 }
 
 
-struct ucl_object *ucl_builtin_create(ucl_builtin builtin)
+struct ucl_object *ucl_builtin_create(ucl_lisp builtin)
 {
     struct ucl_object* obj = ucl_object_alloc();
     obj->type = UCL_TYPE_BUILTIN;
@@ -57,6 +57,15 @@ struct ucl_object *ucl_builtin_create(ucl_builtin builtin)
     return obj;
 }
 
+struct ucl_object *ucl_special_create(ucl_lisp special)
+{
+    struct ucl_object* obj = ucl_object_alloc();
+    obj->type = UCL_TYPE_SPECIAL;
+    obj->special = special;
+    return obj;
+}
+
+
 static struct ucl_object* ucl_object_alloc() {
     return malloc(sizeof(struct ucl_object));
 }
diff --git a/src/special.c b/src/special.c
new file mode 100644
index 0000000..531e31d
--- /dev/null
+++ b/src/special.c
@@ -0,0 +1,86 @@
+#include "state.h"
+#include "lisp.h"
+#include "utility.h"
+#include "internal.h"
+
+#include <assert.h>
+
+struct ucl_object *ucl_special_let(struct ucl_state *state, struct ucl_object *args) {
+    // TODO: Check arguments
+    struct ucl_object *assignments = ucl_car(args);
+    struct ucl_object *expressions = ucl_cdr(args);
+    struct ucl_state *let_state = ucl_state_create_child(state);
+
+    FOREACH_LIST(assignments, iter, item) {
+        // TODO: Check arguments
+        struct ucl_object *sym = ucl_car(item);
+        struct ucl_object *expr = ucl_car(ucl_cdr(item));
+        struct ucl_object *value = ucl_evaluate(let_state, expr);
+
+        assert(sym->type == UCL_TYPE_SYMBOL);
+        //assert(ucl_list_length(expr)->integer == 1);
+
+        if (value->type == UCL_TYPE_ERROR) {
+            // TODO cleanup
+            return value;
+        }
+        ucl_state_put(let_state, sym->symbol, value);
+    }
+
+    struct ucl_object *result = NULL;
+    FOREACH_LIST(expressions, iter, item) {
+        result = ucl_evaluate(let_state, item);
+        if (result->type == UCL_TYPE_ERROR) {
+            return result;
+        }
+    }
+
+
+    ucl_state_delete(let_state);
+    return result;
+}
+
+struct ucl_object *ucl_special_if(struct ucl_state *state, struct ucl_object *args) {
+    // TODO: Check arguments
+    struct ucl_object *cond = ucl_car(args);
+    struct ucl_object *true_form = ucl_list_nth(args, 1);
+    struct ucl_object *false_forms = ucl_cdr(ucl_cdr(args));
+
+    struct ucl_object *cond_result = ucl_evaluate(state, cond);
+    UCL_RET_IF_ERROR(cond_result);
+    if (ucl_truthy(cond_result)->type == UCL_TYPE_SYMBOL) {
+        return ucl_evaluate(state, true_form);
+    }
+
+    struct ucl_object *result = NULL;
+
+    FOREACH_LIST(false_forms, iter, form) {
+        result = ucl_evaluate(state, form);
+    }
+
+    return (result == NULL) ? ucl_nil_create() : result;
+}
+
+
+struct ucl_object *ucl_special_defun(struct ucl_state *state, struct ucl_object *args) {
+   // TODO: Check arguments
+    struct ucl_object *fun_sym = ucl_car(args);
+    if (fun_sym->type != UCL_TYPE_SYMBOL) {
+        return ucl_error_create("First argument to defun must be a symbol");
+    }
+
+    struct ucl_object *fun_args = ucl_list_nth(args, 1);
+    if (fun_args->type != UCL_TYPE_CELL) {
+        // TODO: Check that the list contains only symbols
+        return ucl_error_create("Second argument to defun must be a list of symbols");
+    }
+
+    // For now, other elements are just forms to be evaluated. Maybe one day
+    // there will be docstrings, maybe not!
+
+    // Functions are added to the root scope
+    ucl_state_put(ucl_state_get_root(state), fun_sym->symbol, ucl_cdr(args));
+
+    return fun_sym;
+
+}
diff --git a/src/special.h b/src/special.h
new file mode 100644
index 0000000..6d049a3
--- /dev/null
+++ b/src/special.h
@@ -0,0 +1,10 @@
+#ifndef _UCLISP_SPECIAL_H_
+#define _UCLISP_SPECIAL_H_
+
+#include "uclisp.h"
+
+struct ucl_object *ucl_special_let(struct ucl_state *state, struct ucl_object *args);
+struct ucl_object *ucl_special_if(struct ucl_state *state, struct ucl_object *args);
+struct ucl_object *ucl_special_defun(struct ucl_state *state, struct ucl_object *args);
+
+#endif
diff --git a/src/state.c b/src/state.c
index 94845ae..8b2bb55 100644
--- a/src/state.c
+++ b/src/state.c
@@ -69,6 +69,13 @@ struct ucl_state *ucl_state_create_child(struct ucl_state *parent) {
     return state;
 }
 
+struct ucl_state *ucl_state_get_root(struct ucl_state *state) {
+    while (state->parent != NULL) {
+        state = state->parent;
+    }
+    return state;
+}
+
 void ucl_state_delete(struct ucl_state *state) {
     // TODO: Cleanup
     // ucl_object_delete(state->list);
diff --git a/src/state.h b/src/state.h
index 1328c5c..322195d 100644
--- a/src/state.h
+++ b/src/state.h
@@ -10,5 +10,6 @@ void ucl_state_delete(struct ucl_state *state);
 
 struct ucl_object *ucl_state_get(struct ucl_state *state, const char *name);
 void ucl_state_put(struct ucl_state *state, const char *name, struct ucl_object *obj);
+struct ucl_state *ucl_state_get_root(struct ucl_state *state);
 
 #endif
diff --git a/src/uclisp.h b/src/uclisp.h
index 8143ffc..9a24014 100644
--- a/src/uclisp.h
+++ b/src/uclisp.h
@@ -8,7 +8,8 @@ enum ucl_type {
     UCL_TYPE_STRING = 3,
     UCL_TYPE_ERROR = 4,
     UCL_TYPE_BUILTIN = 5,
-    UCL_TYPE_COUNT = 6,
+    UCL_TYPE_SPECIAL = 6, // Like builtins, but special forms where arguments are not necessarily evaluated
+    UCL_TYPE_COUNT = 7,
 };
 
 struct ucl_cell {
@@ -17,7 +18,7 @@ struct ucl_cell {
 };
 
 struct ucl_state;
-typedef struct ucl_object *(*ucl_builtin)(struct ucl_state* state, struct ucl_object *args);
+typedef struct ucl_object *(*ucl_lisp)(struct ucl_state* state, struct ucl_object *args);
 
 struct ucl_object {
     enum ucl_type type;
@@ -27,7 +28,8 @@ struct ucl_object {
         int integer;
         const char *string;
         const char *error;
-        ucl_builtin builtin;
+        ucl_lisp builtin;
+        ucl_lisp special;
     };
 };
 
diff --git a/src/utility.c b/src/utility.c
index 5e4f171..eba225b 100644
--- a/src/utility.c
+++ b/src/utility.c
@@ -1,5 +1,6 @@
-#include "uclisp.h"
 #include "internal.h"
+#include "lisp.h"
+#include "uclisp.h"
 #include "utility.h"
 
 #include <stddef.h>
@@ -84,7 +85,14 @@ struct ucl_object *ucl_list_nth(struct ucl_object *list, int n) {
 }
 
 struct ucl_object *ucl_truthy(struct ucl_object *obj) {
-    // TODO: Implement me
+    // TODO: Implement me better
+    if (obj->type == UCL_TYPE_INT) {
+        return ucl_predicate(obj->integer);
+    } else if (obj->type == UCL_TYPE_SYMBOL) {
+        return ucl_predicate(true);
+    } else if (obj->type == UCL_TYPE_CELL) {
+        return ucl_predicate(obj->cell.car != NULL);
+    }
     return ucl_error_create("Unimplemented function 'ucl_truthy'");
 }
 
diff --git a/src/utility.h b/src/utility.h
index 030535e..3a06f91 100644
--- a/src/utility.h
+++ b/src/utility.h
@@ -21,8 +21,9 @@ struct ucl_object* ucl_tuple_create(struct ucl_object *obj0, struct ucl_object *
 
 #define UCL_RET_IF_ERROR(obj)                   \
     do {                                        \
-    if ((obj)->type == UCL_TYPE_ERROR) {        \
-        return obj;                             \
+        if ((obj)->type == UCL_TYPE_ERROR) {    \
+            return obj;                         \
+        }                                       \
     } while(0)
 
 #define UCL_COND_OR_RET_ERROR(cond, msg)        \
diff --git a/test/test_e2e.c b/test/test_e2e.c
index 923169e..19c8b88 100644
--- a/test/test_e2e.c
+++ b/test/test_e2e.c
@@ -8,6 +8,7 @@
 #include "testing_helpers.h"
 #include "state.h"
 #include "builtins.h"
+#include "special.h"
 
 static struct ucl_object *input;
 static struct ucl_object *response;
@@ -18,7 +19,8 @@ void setUp(void) {
     response = NULL;
 
     state = ucl_state_create();
-    ucl_state_put(state, "let", ucl_builtin_create(ucl_builtin_let));
+    ucl_state_put(state, "let", ucl_special_create(ucl_special_let));
+    ucl_state_put(state, "defun", ucl_special_create(ucl_special_defun));
     ucl_state_put(state, "+", ucl_builtin_create(ucl_builtin_add));
     ucl_state_put(state, "error", ucl_builtin_create(ucl_builtin_error));
     ucl_state_put(state, "list", ucl_builtin_create(ucl_builtin_list));
@@ -39,77 +41,77 @@ static struct ucl_object *eval (const char *code) {
     return ucl_evaluate(state, ucl_car(sexp));
 }
 
-static void test_simple_add(void) {
+void test_simple_add(void) {
     ucl_state_put(state, "+", ucl_builtin_create(ucl_builtin_add));
     response = eval("(+ 2 3)");
     TEST_ASSERT_OBJ_INT(response);
     TEST_ASSERT_EQUAL(response->integer, 5);
 }
 
-static void test_simple_let(void) {
+void test_simple_let(void) {
     response = eval("(let ((x 2)) (+ x 3))");
     TEST_ASSERT_OBJ_INT(response);
     TEST_ASSERT_EQUAL(response->integer, 5);
 }
 
-static void test_let_assignment_error(void) {
+void test_let_assignment_error(void) {
     response = eval("(let ((x (error \"foo\"))) (+ x 3))");
     TEST_ASSERT_OBJ_ERROR(response);
 }
 
-static void test_nested_let(void) {
+void test_nested_let(void) {
     response = eval("(let ((x 2)) (let ((y 5)) (+ x y)))");
     TEST_ASSERT_OBJ_INT(response);
     TEST_ASSERT_EQUAL(response->integer, 7);
 }
 
-static void test_nested_let_scope(void) {
+void test_nested_let_scope(void) {
     response = eval("(let ((x 2)) (let ((y 5)) (+ x y)) y)");
     TEST_ASSERT_OBJ_ERROR(response);
 }
 
-static void test_multi_let(void) {
+void test_multi_let(void) {
     response = eval("(let ((x 2)(y 5)) (+ x y))");
     TEST_ASSERT_OBJ_INT(response);
     TEST_ASSERT_EQUAL(response->integer, 7);
 }
 
-static void test_let_return_sym(void) {
+void test_let_return_sym(void) {
     response = eval("(let ((x 2)) x)");
     TEST_ASSERT_OBJ_INT(response);
     TEST_ASSERT_EQUAL(response->integer, 2);
 }
 
-static void test_eval_int(void) {
+void test_eval_int(void) {
     response = eval("2");
     TEST_ASSERT_OBJ_INT(response);
     TEST_ASSERT_EQUAL(response->integer, 2);
 }
 
-static void test_eval_string(void) {
+void test_eval_string(void) {
     response = eval("\"foo\"");
     TEST_ASSERT_OBJ_STRING(response);
     TEST_ASSERT_EQUAL_STRING(response->string, "foo");
 }
 
-static void test_eval_sym_defined(void) {
+void test_eval_sym_defined(void) {
     ucl_state_put(state, "foo", ucl_int_create(2));
     response = eval("foo");
     TEST_ASSERT_OBJ_INT(response);
     TEST_ASSERT_EQUAL(response->integer, 2);
 }
 
-static void test_eval_sym_undefined(void) {
+void test_eval_sym_undefined(void) {
     response = eval("foo");
     TEST_ASSERT_OBJ_ERROR(response);
 }
 
-static void test_eval_nested_error(void) {
+void test_eval_nested_error(void) {
     response = eval("(+ (error \"foo\") 3)");
     TEST_ASSERT_OBJ_ERROR(response);
 }
 
-static void test_eval_list(void) {
+void test_eval_list(void) {
     response = eval("(list 1 2 3)");
     TEST_ASSERT_OBJ_LIST(response);
     TEST_ASSERT_EQUAL(ucl_list_length(response)->integer, 3);
@@ -121,6 +123,12 @@ static void test_eval_list(void) {
     }
 }
 
+void test_eval_defun(void) {
+    response = eval("(defun foo (a b) (+ a b))");
+
+    TEST_ASSERT_OBJ_SYMBOL(response);
+    TEST_ASSERT_EQUAL_STRING(response->symbol, "foo");
+}
 
 int main(void) {
     UNITY_BEGIN();
@@ -138,6 +146,7 @@ int main(void) {
     RUN_TEST(test_eval_sym_undefined);
     RUN_TEST(test_eval_nested_error);
     RUN_TEST(test_eval_list);
+    RUN_TEST(test_eval_defun);
 
     return UNITY_END();
 }
diff --git a/test/test_utility.c b/test/test_utility.c
index 7dd49f1..452f8d6 100644
--- a/test/test_utility.c
+++ b/test/test_utility.c
@@ -5,6 +5,7 @@
 #include "uclisp.h"
 #include "internal.h"
 #include "utility.h"
+#include "state.h"
 #include "testing_helpers.h"
 
 static struct ucl_object *input;
@@ -194,6 +195,38 @@ static void test_list_nth_bounds_2() {
     TEST_ASSERT_OBJ_ERROR(response);
 }
 
+static void test_truthy_0() {
+    response = ucl_truthy(ucl_int_create(0));
+
+    TEST_ASSERT_NIL(response);
+}
+
+static void test_truthy_1() {
+    response = ucl_truthy(ucl_int_create(1));
+
+    TEST_ASSERT_T(response);
+}
+
+static void test_truthy_nil() {
+    response = ucl_truthy(ucl_nil_create());
+
+    TEST_ASSERT_NIL(response);
+}
+
+static void test_truthy_list_w_elem() {
+    struct ucl_object *list = ucl_nil_create();
+    ucl_list_append(list, ucl_int_create(0));
+    response = ucl_truthy(list);
+
+    TEST_ASSERT_T(response);
+}
+
+static void test_truthy_sym() {
+    response = ucl_truthy(ucl_symbol_create("t"));
+
+    TEST_ASSERT_T(response);
+}
+
 
 int main(void) {
     UNITY_BEGIN();
@@ -221,6 +254,11 @@ int main(void) {
     RUN_TEST(test_list_nth_bounds_0);
     RUN_TEST(test_list_nth_bounds_1);
     RUN_TEST(test_list_nth_bounds_2);
+    RUN_TEST(test_truthy_0);
+    RUN_TEST(test_truthy_1);
+    RUN_TEST(test_truthy_nil);
+    RUN_TEST(test_truthy_list_w_elem);
+    RUN_TEST(test_truthy_sym);
 
     return UNITY_END();
 }