From ed1f406102738812fafa5e49ee131fe06c177687 Mon Sep 17 00:00:00 2001
From: Bad Diode <bd@badd10de.dev>
Date: Wed, 13 Oct 2021 16:44:17 +0200
Subject: Add a lot of primitive types

---
 src/bootstrap/primitives.c | 900 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 900 insertions(+)
 create mode 100644 src/bootstrap/primitives.c

(limited to 'src/bootstrap/primitives.c')

diff --git a/src/bootstrap/primitives.c b/src/bootstrap/primitives.c
new file mode 100644
index 0000000..8369fa8
--- /dev/null
+++ b/src/bootstrap/primitives.c
@@ -0,0 +1,900 @@
+Object *
+eval(Environment* env, Object *root) {
+    switch (root->type) {
+        case OBJ_TYPE_FIXNUM:
+        case OBJ_TYPE_BOOL:
+        case OBJ_TYPE_NIL:
+        case OBJ_TYPE_STRING: {
+            return root;
+        } break;
+        case OBJ_TYPE_SYMBOL: {
+            Object *val = env_lookup(env, root);
+            if (val == obj_err) {
+                error_push((Error){
+                    .type = ERR_TYPE_RUNTIME,
+                    .value = ERR_SYMBOL_NOT_FOUND,
+                });
+                return obj_err;
+            }
+            return val;
+        } break;
+        case OBJ_TYPE_PAIR: {
+            if (root->car->type == OBJ_TYPE_SYMBOL) {
+                Object *val = env_lookup(env, root->car);
+                if (val == obj_err) {
+                    error_push((Error){
+                        .type = ERR_TYPE_RUNTIME,
+                        .value = ERR_SYMBOL_NOT_FOUND,
+                    });
+                    return obj_err;
+                }
+                if (val->type == OBJ_TYPE_PROCEDURE) {
+                    return val->proc(env, root->cdr);
+                }
+                error_push((Error){
+                    .type = ERR_TYPE_RUNTIME,
+                    .value = ERR_OBJ_NOT_CALLABLE,
+                });
+                return obj_err;
+            }
+        } break;
+        default: {
+            break;
+        } break;
+    }
+
+    printf("DING\n");
+    display(root);
+    printf("\nTYPE: %d\n", root->type);
+
+    error_push((Error){
+        .type = ERR_TYPE_RUNTIME,
+        .value = ERR_UNKNOWN_OBJ_TYPE,
+    });
+    return obj_err;
+}
+
+Object *
+proc_quote(Environment *env, Object *obj) {
+    (void)env;
+    return obj->car;
+}
+
+//
+// Arithmetic procedures.
+//
+
+Object *
+proc_sum(Environment *env, Object *obj) {
+    // First argument.
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    Object *car = eval(env, obj->car);
+    if (car == obj_err) {
+        return obj_err;
+    }
+    if (car->type != OBJ_TYPE_FIXNUM) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_WRONG_ARG_TYPE,
+        });
+        return obj_err;
+    }
+
+    // Traverse the list.
+    obj = obj->cdr;
+    ssize_t tot = car->fixnum;
+    while (obj != obj_nil) {
+        car = eval(env, obj->car);
+        if (car == obj_err) {
+            return obj_err;
+        }
+        if (car->type != OBJ_TYPE_FIXNUM) {
+            error_push((Error){
+                .type = ERR_TYPE_RUNTIME,
+                .value = ERR_WRONG_ARG_TYPE,
+            });
+            return obj_err;
+        }
+        tot += car->fixnum;
+        obj = obj->cdr;
+    }
+    return make_fixnum(tot);
+}
+
+Object *
+proc_sub(Environment *env, Object *obj) {
+    // First argument.
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    Object *car = eval(env, obj->car);
+    if (car == obj_err) {
+        return obj_err;
+    }
+    if (car->type != OBJ_TYPE_FIXNUM) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_WRONG_ARG_TYPE,
+        });
+        return obj_err;
+    }
+
+    // Traverse the list.
+    obj = obj->cdr;
+    ssize_t tot = car->fixnum;
+    while (obj != obj_nil) {
+        car = eval(env, obj->car);
+        if (car == obj_err) {
+            return obj_err;
+        }
+        if (car->type != OBJ_TYPE_FIXNUM) {
+            error_push((Error){
+                .type = ERR_TYPE_RUNTIME,
+                .value = ERR_WRONG_ARG_TYPE,
+            });
+            return obj_err;
+        }
+        tot -= car->fixnum;
+        obj = obj->cdr;
+    }
+    return make_fixnum(tot);
+}
+
+Object *
+proc_mul(Environment *env, Object *obj) {
+    // First argument.
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    Object *car = eval(env, obj->car);
+    if (car == obj_err) {
+        return obj_err;
+    }
+    if (car->type != OBJ_TYPE_FIXNUM) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_WRONG_ARG_TYPE,
+        });
+        return obj_err;
+    }
+
+    // Traverse the list.
+    obj = obj->cdr;
+    ssize_t tot = car->fixnum;
+    while (obj != obj_nil) {
+        Object *car = eval(env, obj->car);
+        if (car == obj_err) {
+            return obj_err;
+        }
+        if (car->type != OBJ_TYPE_FIXNUM) {
+            error_push((Error){
+                .type = ERR_TYPE_RUNTIME,
+                .value = ERR_WRONG_ARG_TYPE,
+            });
+            return obj_err;
+        }
+        tot *= car->fixnum;
+        obj = obj->cdr;
+    }
+    return make_fixnum(tot);
+}
+
+Object *
+proc_div(Environment *env, Object *obj) {
+    // First argument.
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    Object *car = eval(env, obj->car);
+    if (car == obj_err) {
+        return obj_err;
+    }
+    if (car->type != OBJ_TYPE_FIXNUM) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_WRONG_ARG_TYPE,
+        });
+        return obj_err;
+    }
+
+    // Traverse the list.
+    obj = obj->cdr;
+    ssize_t tot = car->fixnum;
+    while (obj != obj_nil) {
+        Object *car = eval(env, obj->car);
+        if (car == obj_err) {
+            return obj_err;
+        }
+        if (car->type != OBJ_TYPE_FIXNUM) {
+            error_push((Error){
+                .type = ERR_TYPE_RUNTIME,
+                .value = ERR_WRONG_ARG_TYPE,
+            });
+            return obj_err;
+        }
+        if (car->fixnum == 0) {
+            error_push((Error){
+                .type = ERR_TYPE_RUNTIME,
+                .value = ERR_DIVISION_BY_ZERO,
+            });
+            return obj_err;
+        }
+        tot /= car->fixnum;
+        obj = obj->cdr;
+    }
+    return make_fixnum(tot);
+}
+
+Object *
+proc_mod(Environment *env, Object *obj) {
+    // First argument.
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    Object *car = eval(env, obj->car);
+    if (car == obj_err) {
+        return obj_err;
+    }
+    if (car->type != OBJ_TYPE_FIXNUM) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_WRONG_ARG_TYPE,
+        });
+        return obj_err;
+    }
+
+    // Traverse the list.
+    obj = obj->cdr;
+    ssize_t tot = car->fixnum;
+    while (obj != obj_nil) {
+        Object *car = eval(env, obj->car);
+        if (car == obj_err) {
+            return obj_err;
+        }
+        if (car->type != OBJ_TYPE_FIXNUM) {
+            error_push((Error){
+                .type = ERR_TYPE_RUNTIME,
+                .value = ERR_WRONG_ARG_TYPE,
+            });
+            return obj_err;
+        }
+        if (car->fixnum == 0) {
+            error_push((Error){
+                .type = ERR_TYPE_RUNTIME,
+                .value = ERR_DIVISION_BY_ZERO,
+            });
+            return obj_err;
+        }
+        tot %= car->fixnum;
+        obj = obj->cdr;
+    }
+    return make_fixnum(tot);
+}
+
+//
+// Display/Evaluation procedues.
+//
+
+Object *
+proc_display(Environment *env, Object *obj) {
+    display(eval(env, obj->car));
+    return obj_nil;
+}
+
+Object *
+proc_print(Environment *env, Object *obj) {
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    Object *car = eval(env, obj->car);
+    if (car == obj_err) {
+        return obj_err;
+    }
+    if (car->type != OBJ_TYPE_STRING) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_WRONG_ARG_TYPE,
+        });
+        return obj_err;
+    }
+
+    StringView scanner = (StringView) {
+        .start = car->string,
+        .n = car->string_n,
+    };
+    while (scanner.n != 0) {
+        char c = sv_next(&scanner);
+        if (c == '\\' && sv_peek(&scanner) == 'n') {
+            putchar('\n');
+            sv_next(&scanner);
+            continue;
+        }
+        if (c == '\\' && sv_peek(&scanner) == '"') {
+            putchar('"');
+            sv_next(&scanner);
+            continue;
+        }
+        putchar(c);
+    }
+    return obj_nil;
+}
+
+Object *
+proc_newline(Environment *env, Object *obj) {
+    printf("\n");
+    (void)env;
+    (void)obj;
+    return obj_nil;
+}
+
+//
+// Type info procedures.
+//
+
+Object *
+proc_is_boolean(Environment *env, Object *obj) {
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    obj = eval(env, obj->car);
+    if (obj == obj_err) {
+        return obj_err;
+    }
+    return (obj == obj_true || obj == obj_false) ? obj_true : obj_false;
+}
+
+Object *
+proc_is_nil(Environment *env, Object *obj) {
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    obj = eval(env, obj->car);
+    if (obj == obj_err) {
+        return obj_err;
+    }
+    return obj == obj_nil ? obj_true : obj_false;
+}
+
+Object *
+proc_is_symbol(Environment *env, Object *obj) {
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    obj = eval(env, obj->car);
+    if (obj == obj_err) {
+        return obj_err;
+    }
+    return obj->type == OBJ_TYPE_SYMBOL ? obj_true : obj_false;
+}
+
+Object *
+proc_is_string(Environment *env, Object *obj) {
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    obj = eval(env, obj->car);
+    if (obj == obj_err) {
+        return obj_err;
+    }
+    return obj->type == OBJ_TYPE_STRING ? obj_true : obj_false;
+}
+
+Object *
+proc_is_fixnum(Environment *env, Object *obj) {
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    obj = eval(env, obj->car);
+    if (obj == obj_err) {
+        return obj_err;
+    }
+    return obj->type == OBJ_TYPE_FIXNUM ? obj_true : obj_false;
+}
+
+Object *
+proc_is_pair(Environment *env, Object *obj) {
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    obj = eval(env, obj->car);
+    if (obj == obj_err) {
+        return obj_err;
+    }
+    return obj->type == OBJ_TYPE_PAIR ? obj_true : obj_false;
+}
+
+Object *
+proc_is_procedure(Environment *env, Object *obj) {
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    obj = eval(env, obj->car);
+    if (obj == obj_err) {
+        return obj_err;
+    }
+    return obj->type == OBJ_TYPE_PROCEDURE ? obj_true : obj_false;
+}
+
+//
+// Boolean/conditional procedures.
+//
+
+Object *
+proc_not(Environment *env, Object *obj) {
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    obj = eval(env, obj->car);
+    if (obj == obj_err) {
+        return obj_err;
+    }
+    return obj == obj_false ? obj_true : obj_false;
+}
+
+Object *
+proc_and(Environment *env, Object *obj) {
+    while (obj != obj_nil) {
+        if (proc_not(env, obj) == obj_true) {
+            return obj_false;
+        }
+        obj = obj->cdr;
+    }
+    return obj_true;
+}
+
+Object *
+proc_or(Environment *env, Object *obj) {
+    while (obj != obj_nil) {
+        if (proc_not(env, obj) == obj_false) {
+            return obj_true;
+        }
+        obj = obj->cdr;
+    }
+    return obj_false;
+}
+
+Object *
+proc_if(Environment *env, Object *obj) {
+    if (obj == obj_nil || obj->cdr == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    Object *car = obj->car;
+    Object *cdr = obj->cdr;
+    Object *clause = eval(env, car);
+    if (obj == obj_err) {
+        return obj_err;
+    }
+    if (clause == obj_true) {
+        return eval(env, cdr->car);
+    }
+    if (obj->cdr->cdr != obj_nil) {
+        return eval(env, cdr->cdr->car);
+    }
+
+    return obj_nil;
+}
+
+Object *
+proc_cond(Environment *env, Object *obj) {
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+
+    if (obj->car->type != OBJ_TYPE_PAIR) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_WRONG_ARG_TYPE,
+        });
+        return obj_err;
+    }
+
+    // TODO: review this, the cdr->car could cause issues?
+    while (obj != obj_nil) {
+        Object *clause = obj->car;
+        Object *result = eval(env, clause->car);
+        if (result == obj_err) {
+            return obj_err;
+        }
+        if (result == obj_true) {
+            return eval(env, clause->cdr->car);
+        }
+        obj = obj->cdr;
+    }
+    return obj_nil;
+}
+
+Object *
+proc_num_less_than(Environment *env, Object *obj) {
+    // First argument.
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    Object *car = eval(env, obj->car);
+    if (car == obj_err) {
+        return obj_err;
+    }
+    if (car->type != OBJ_TYPE_FIXNUM) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_WRONG_ARG_TYPE,
+        });
+        return obj_err;
+    }
+
+    // Traverse the list.
+    obj = obj->cdr;
+    ssize_t prev = car->fixnum;
+    while (obj != obj_nil) {
+        car = eval(env, obj->car);
+        if (car == obj_err) {
+            return obj_err;
+        }
+        if (car->type != OBJ_TYPE_FIXNUM) {
+            error_push((Error){
+                .type = ERR_TYPE_RUNTIME,
+                .value = ERR_WRONG_ARG_TYPE,
+            });
+            return obj_err;
+        }
+        if (prev >= car->fixnum) {
+            return obj_false;
+        }
+        prev = car->fixnum;
+        obj = obj->cdr;
+    }
+    return obj_true;
+}
+
+Object *
+proc_num_greater_than(Environment *env, Object *obj) {
+    // First argument.
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    Object *car = eval(env, obj->car);
+    if (car == obj_err) {
+        return obj_err;
+    }
+    if (car->type != OBJ_TYPE_FIXNUM) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_WRONG_ARG_TYPE,
+        });
+        return obj_err;
+    }
+
+    // Traverse the list.
+    obj = obj->cdr;
+    ssize_t prev = car->fixnum;
+    while (obj != obj_nil) {
+        car = eval(env, obj->car);
+        if (car == obj_err) {
+            return obj_err;
+        }
+        if (car->type != OBJ_TYPE_FIXNUM) {
+            error_push((Error){
+                .type = ERR_TYPE_RUNTIME,
+                .value = ERR_WRONG_ARG_TYPE,
+            });
+            return obj_err;
+        }
+        if (prev <= car->fixnum) {
+            return obj_false;
+        }
+        prev = car->fixnum;
+        obj = obj->cdr;
+    }
+    return obj_true;
+}
+
+Object *
+proc_num_lesseq_than(Environment *env, Object *obj) {
+    // First argument.
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    Object *car = eval(env, obj->car);
+    if (car == obj_err) {
+        return obj_err;
+    }
+    if (car->type != OBJ_TYPE_FIXNUM) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_WRONG_ARG_TYPE,
+        });
+        return obj_err;
+    }
+
+    // Traverse the list.
+    obj = obj->cdr;
+    ssize_t prev = car->fixnum;
+    while (obj != obj_nil) {
+        car = eval(env, obj->car);
+        if (car == obj_err) {
+            return obj_err;
+        }
+        if (car->type != OBJ_TYPE_FIXNUM) {
+            error_push((Error){
+                .type = ERR_TYPE_RUNTIME,
+                .value = ERR_WRONG_ARG_TYPE,
+            });
+            return obj_err;
+        }
+        if (prev > car->fixnum) {
+            return obj_false;
+        }
+        prev = car->fixnum;
+        obj = obj->cdr;
+    }
+    return obj_true;
+}
+
+Object *
+proc_num_greatereq_than(Environment *env, Object *obj) {
+    // First argument.
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    Object *car = eval(env, obj->car);
+    if (car == obj_err) {
+        return obj_err;
+    }
+    if (car->type != OBJ_TYPE_FIXNUM) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_WRONG_ARG_TYPE,
+        });
+        return obj_err;
+    }
+
+    // Traverse the list.
+    obj = obj->cdr;
+    ssize_t prev = car->fixnum;
+    while (obj != obj_nil) {
+        car = eval(env, obj->car);
+        if (car == obj_err) {
+            return obj_err;
+        }
+        if (car->type != OBJ_TYPE_FIXNUM) {
+            error_push((Error){
+                .type = ERR_TYPE_RUNTIME,
+                .value = ERR_WRONG_ARG_TYPE,
+            });
+            return obj_err;
+        }
+        if (prev < car->fixnum) {
+            return obj_false;
+        }
+        prev = car->fixnum;
+        obj = obj->cdr;
+    }
+    return obj_true;
+}
+
+Object *
+proc_num_equal(Environment *env, Object *obj) {
+    // First argument.
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    Object *car = eval(env, obj->car);
+    if (car == obj_err) {
+        return obj_err;
+    }
+    if (car->type != OBJ_TYPE_FIXNUM) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_WRONG_ARG_TYPE,
+        });
+        return obj_err;
+    }
+
+    // Traverse the list.
+    obj = obj->cdr;
+    ssize_t prev = car->fixnum;
+    while (obj != obj_nil) {
+        car = eval(env, obj->car);
+        if (car == obj_err) {
+            return obj_err;
+        }
+        if (car->type != OBJ_TYPE_FIXNUM) {
+            error_push((Error){
+                .type = ERR_TYPE_RUNTIME,
+                .value = ERR_WRONG_ARG_TYPE,
+            });
+            return obj_err;
+        }
+        if (prev != car->fixnum) {
+            return obj_false;
+        }
+        prev = car->fixnum;
+        obj = obj->cdr;
+    }
+    return obj_true;
+}
+
+//
+// List operation procedures.
+//
+
+Object *
+proc_car(Environment *env, Object *obj) {
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    obj = eval(env, obj->car);
+    if (obj == obj_err) {
+        return obj_err;
+    }
+    if (obj->type != OBJ_TYPE_PAIR) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_WRONG_ARG_TYPE,
+        });
+        return obj_err;
+    }
+    return obj->car;
+}
+
+Object *
+proc_cdr(Environment *env, Object *obj) {
+    if (obj == obj_nil) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_NOT_ENOUGH_ARGS,
+        });
+        return obj_err;
+    }
+    obj = eval(env, obj->car);
+    if (obj == obj_err) {
+        return obj_err;
+    }
+    if (obj->type != OBJ_TYPE_PAIR) {
+        error_push((Error){
+            .type = ERR_TYPE_RUNTIME,
+            .value = ERR_WRONG_ARG_TYPE,
+        });
+        return obj_err;
+    }
+    return obj->cdr;
+}
+
+Object *
+proc_cons(Environment *env, Object *obj) {
+    if (obj == obj_nil || obj->cdr == obj_nil) {
+        fprintf(stderr, "error: not enough arguments\n");
+        return obj_nil;
+    }
+    Object *a = eval(env, obj->car);
+    Object *b = eval(env, obj->cdr->car);
+    return make_pair(a, b);
+}
+
+Object *
+proc_list(Environment *env, Object *obj) {
+    if (obj == obj_nil) {
+        return obj_nil;
+    }
+    Object *head = make_pair(eval(env, obj->car), obj_nil);
+    Object *curr = head;
+    obj = obj->cdr;
+    while (obj != obj_nil) {
+        curr->cdr = make_pair(eval(env, obj->car), obj_nil);
+        curr = curr->cdr;
+        obj = obj->cdr;
+    }
+    return head;
+}
+
+//
+// Polymorphic procedures.
+//
+
+//Object *
+//proc_equal(Object *args) {
+//    // TODO: stub
+//    (void) args;
+//    return NULL;
+//}
+
+//// TODO: fixnum left/right shift, mask, invert
+//// TODO: implement and test missing procedures
+//// TODO: add primitives for type transforms: string->symbol, symbol->string, etc
+//// TODO: properly implement nested environments
+//// TODO: implement support for quotes and semi-quotes
+//// TODO: LAMBDA
+//// TODO: let
+//// TODO: better error handling?
+//// TODO: Revise all instances where we are returning an object, since currently
+//// we may be returning a pointer to an object instead of a new one. Check also
+//// on eval function and everytime we do make_xxx(obj).
-- 
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