1 files changed, 27 insertions, 0 deletions

diff --git a/src/treewalk/environment.h b/src/treewalk/environment.h
new file mode 100644
index 0000000..5ee21ad
--- /dev/null
+++ b/src/treewalk/environment.h
@@ -0,0 +1,27 @@
+#ifndef BDL_ENVIRONMENT_H
+#define BDL_ENVIRONMENT_H
+
+#include "objects.h"
+
+typedef struct Environment {
+    struct Environment *parent;
+    HashTable *table;
+    bool marked;
+} Environment;
+
+Environment * env_create(Environment *parent);
+void env_add_symbol(Environment *env, Object *symbol, Object *value);
+Object * env_lookup(Environment *env, Object *symbol);
+Object * env_update(Environment *env, Object *symbol, Object *value);
+ssize_t env_index_current(Environment *env, Object *symbol);
+void env_add_or_update_current(Environment *env, Object *symbol, Object *value);
+Environment * env_extend(Environment *parent, Environment *extra);
+
+#define MAKE_ENV_VAR(ENV,STR,VAR) \
+    (env_add_symbol((ENV), MAKE_SYM(STR), (VAR)))
+#define MAKE_ENV_PROC(ENV,STR,FUN) \
+    (env_add_symbol((ENV), MAKE_SYM(STR), make_procedure(FUN)))
+
+#define ENV_BUF_CAP 8
+
+#endif // BDL_ENVIRONMENT_H