1 files changed, 33 insertions, 0 deletions
diff --git a/inc/term.h b/inc/term.h
new file mode 100644
index 0000000..0dd472f
--- /dev/null
+++ b/inc/term.h
@@ -0,0 +1,33 @@
+// Copyright (c) 2023, Marvin Borner <dev@marvinborner.de>
+// SPDX-License-Identifier: MIT
+
+#ifndef SHARING_TERM_H
+#define SHARING_TERM_H
+
+#include <stddef.h>
+
+typedef enum { INV, ABS, APP, VAR } term_type_t;
+
+struct term {
+	term_type_t type;
+	size_t refs;
+	size_t depth;
+	union {
+		struct {
+			struct term *term;
+		} abs;
+		struct {
+			struct term *lhs;
+			struct term *rhs;
+		} app;
+		struct {
+			size_t index;
+		} var;
+	} u;
+};
+
+struct term *term_new(term_type_t type);
+void term_free(struct term *term);
+void term_print(struct term *term);
+
+#endif