diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4547d95..b630868 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -8,7 +8,7 @@ project(libabacus)
 
 add_compile_options(-pedantic -Wall)
 
-add_library(abacus STATIC src/lexer.c src/util.c src/table.c src/parser.c src/libabacus.c src/tree.c src/debug.c src/parsetype.c src/reserved.c src/trie.c src/refcount.c src/ref_vec.c src/ref_trie.c)
+add_library(abacus STATIC src/lexer.c src/util.c src/table.c src/parser.c src/libabacus.c src/tree.c src/debug.c src/parsetype.c src/reserved.c src/trie.c src/refcount.c src/ref_vec.c src/ref_trie.c src/basetype.c)
 add_executable(libabacus src/main.c)
 add_subdirectory(external/liblex)
 
diff --git a/include/basetype.h b/include/basetype.h
new file mode 100644
index 0000000..1ccbade
--- /dev/null
+++ b/include/basetype.h
@@ -0,0 +1,65 @@
+#ifndef LIBABACUS_BASETYPE_H
+#define LIBABACUS_BASETYPE_H
+
+#include "vec.h"
+#include "result.h"
+
+/**
+ * An enum that represents the various
+ * types of the basetype parameters.
+ */
+enum libab_basetype_variant_e {
+    BT_EMPTY,
+    BT_NAME,
+    BT_LIST
+};
+
+/**
+ * A struct that holds information about the basetype
+ * parameter, such as a type name or a "..." (called a list).
+ */
+struct libab_basetype_param_s {
+    /**
+     * The variant of this type parameter.
+     */
+    enum libab_basetype_variant_e variant;
+    /**
+     * The name of the parameter, if one is appropriate.
+     */
+    const char* name;
+};
+
+/**
+ * A struct that holds all the information about a base type.
+ */
+struct libab_basetype_s {
+    /**
+     * The function used to free the value.
+     */
+    void (*free_function)(void*);
+    /**
+     * The parameters of the type. This is a constant array, and
+     * doesn't need memory allocation.
+     */
+    const struct libab_basetype_param_s* params;
+    /**
+     * The size of the param aray.
+     */
+    int count;
+};
+
+typedef enum libab_basetype_variant_e libab_basetype_variant;
+typedef struct libab_basetype_param_s libab_basetype_param;
+typedef struct libab_basetype_s libab_basetype;
+
+/**
+ * Initializes a base type, including all the parameters that it needs
+ * to take.
+ * @param basetype the type that is being initialized.
+ * @param n the number of type parameters it has.
+ * @param params the parameters this basetype accepts.
+ */
+void libab_basetype_init(libab_basetype* basetype, int n, 
+        const libab_basetype_param params[]);
+
+#endif
diff --git a/src/basetype.c b/src/basetype.c
new file mode 100644
index 0000000..2b121a1
--- /dev/null
+++ b/src/basetype.c
@@ -0,0 +1,10 @@
+#include "basetype.h"
+#include "util.h"
+#include <stdlib.h>
+
+void libab_basetype_init(libab_basetype* basetype,
+        int n, const libab_basetype_param params[]) {
+    basetype->params = params;
+    basetype->count = n;
+}
+