From 48300cd86ea0313778a4f703aae404e81574a653 Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Thu, 21 Jun 2018 19:00:45 -0700
Subject: [PATCH] Implement reserved operators.

---
 include/reserved.h |  5 +++++
 src/interpreter.c  |  8 ++++++++
 src/reserved.c     | 29 ++++++++++++++++++++++++++++-
 3 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/include/reserved.h b/include/reserved.h
index cd2ae3f..2d9d692 100644
--- a/include/reserved.h
+++ b/include/reserved.h
@@ -23,6 +23,11 @@ struct libab_reserved_operator_s {
      * The associativity of this operator.
      */
     int associativity;
+    /**
+     * The function this operator performs.
+     */
+    libab_result (*function)(libab*, libab_ref*, libab_tree*, 
+                             libab_tree*, libab_ref*);
 };
 
 typedef struct libab_reserved_operator_s libab_reserved_operator;
diff --git a/src/interpreter.c b/src/interpreter.c
index 9140712..a6fb3e7 100644
--- a/src/interpreter.c
+++ b/src/interpreter.c
@@ -2,6 +2,7 @@
 #include "util.h"
 #include "value.h"
 #include "free_functions.h"
+#include "reserved.h"
 
 libab_result libab_interpreter_init(libab_interpreter* intr, libab* ab) {
     libab_result result;
@@ -1163,6 +1164,13 @@ libab_result _interpreter_run(struct interpreter_state* state, libab_tree* tree,
 
         libab_ref_copy(&function, into);
         libab_ref_free(&function);
+    } else if(tree->variant == TREE_RESERVED_OP) {
+        const libab_reserved_operator* op = 
+            libab_find_reserved_operator(tree->string_value);
+        result = op->function(state->ab, scope,
+                vec_index(&tree->children, 0),
+                vec_index(&tree->children, 1),
+                into);
     } else {
         libab_get_unit_value(state->ab, into);
     }
diff --git a/src/reserved.c b/src/reserved.c
index 04983ce..43f13b0 100644
--- a/src/reserved.c
+++ b/src/reserved.c
@@ -2,11 +2,38 @@
 #include "string.h"
 #include "util.h"
 
+libab_result _behavior_assign(libab* ab, libab_ref* scope, 
+                              libab_tree* left, libab_tree* right,
+                              libab_ref* into) {
+    libab_result result = LIBAB_SUCCESS;
+
+    if(left->variant == TREE_ID) {
+        result = libab_run_tree_scoped(ab, right, scope, into);
+        if(result == LIBAB_SUCCESS) {
+            result = libab_put_table_value(libab_ref_get(scope), left->string_value, into);
+        }
+
+        if(result != LIBAB_SUCCESS) {
+            libab_ref_free(into);
+        }
+    } else {
+        result = LIBAB_UNEXPECTED;
+    }
+
+    if(result != LIBAB_SUCCESS) {
+        libab_ref_null(into);
+    }
+
+    return result;
+}
+
 static const libab_reserved_operator libab_reserved_operators[] = {{
     "=", /* Assignment */
     0,   /* Lowest precedence */
-    1    /* Right associative, a = b = 6 should be a = (b = 6) */
+    1,   /* Right associative, a = b = 6 should be a = (b = 6) */
+    _behavior_assign
 }};
+
 static const size_t element_count =
     sizeof(libab_reserved_operators) / sizeof(libab_reserved_operator);