Add unit value to interpreter.

include/interpreter.h

@@ -14,6 +14,10 @@ struct libab_s;
  */
 struct libab_interpreter_s {
     struct libab_s* ab;
+    /**
+     * The unit value, which doesn't need more than one instance.
+     */
+    libab_ref value_unit;
 };
 
 typedef struct libab_interpreter_s libab_interpreter;
@@ -23,7 +27,7 @@ typedef struct libab_interpreter_s libab_interpreter;
  * @param intr the interpreter to initialize.
  * @param ab the libabacus instance this interpreter belongs to.
  */
-void libab_interpreter_init(libab_interpreter* intr, struct libab_s* ab);
+libab_result libab_interpreter_init(libab_interpreter* intr, struct libab_s* ab);
 /**
  * Uses the interpreter to run the given parse tree.
  * @param intr the interpreter to use to run the code.
@@ -46,6 +50,12 @@ libab_result libab_interpreter_run_function(libab_interpreter* intr,
                                             const char* function,
                                             libab_ref_vec* params,
                                             libab_ref* into);
+/**
+ * Gets the unit value from this interpreter.
+ * @param intr the interpreter from which to get the unit value.
+ * @param into the reference into which to store the unit value.
+ */
+void libab_interpreter_unit_value(libab_interpreter* intr, libab_ref* into);
 /**
  * Frees the given interpreter.
  * @param intr the interpreter to free.

src/interpreter.c

@@ -2,8 +2,16 @@
 #include "util.h"
 #include "value.h"
 
-void libab_interpreter_init(libab_interpreter* intr, libab* ab) {
+libab_result libab_interpreter_init(libab_interpreter* intr, libab* ab) {
+    libab_result result;
+    libab_ref unit_data;
     intr->ab = ab;
+
+    libab_ref_null(&unit_data);
+    result = libab_create_value_ref(&intr->value_unit, &unit_data, &ab->type_unit);
+    libab_ref_free(&unit_data);
+
+    return result;
 }
 
 struct interpreter_state {
@@ -844,4 +852,10 @@ libab_result libab_interpreter_run_function(libab_interpreter* intr,
     return result;
 }
 
-void libab_interpreter_free(libab_interpreter* intr) {}
+void libab_interpreter_unit_value(libab_interpreter* intr, libab_ref* into) {
+    libab_ref_copy(&intr->value_unit, into);
+}
+
+void libab_interpreter_free(libab_interpreter* intr) {
+    libab_ref_free(&intr->value_unit);
+}

src/libabacus.c

@@ -35,6 +35,7 @@ libab_result libab_init(libab* ab, void* (*parse_function)(const char*),
                         void (*free_function)(void*)) {
     int parser_initialized = 0;
     int lexer_initialized = 0;
+    int interpreter_initialized = 0;
     libab_ref null_ref;
     libab_result result;
     libab_ref_null(&null_ref);
@@ -55,7 +56,11 @@ libab_result libab_init(libab* ab, void* (*parse_function)(const char*),
     if (result == LIBAB_SUCCESS) {
         parser_initialized = 1;
         libab_parser_init(&ab->parser, ab);
-        libab_interpreter_init(&ab->intr, ab);
+        result = libab_interpreter_init(&ab->intr, ab);
+    }
+
+    if(result == LIBAB_SUCCESS) {
+        interpreter_initialized = 1;
         result = libab_lexer_init(&ab->lexer);
     }
 
@@ -72,6 +77,9 @@ libab_result libab_init(libab* ab, void* (*parse_function)(const char*),
 
         if (parser_initialized) {
             libab_parser_free(&ab->parser);
+        }
+
+        if (interpreter_initialized) {
             libab_interpreter_free(&ab->intr);
         }