Remove in-memory duplication of pebbles' code text

src/calc.c

@@ -24,11 +24,9 @@ int current_script_num;
 // PebbLisp environment
 static struct Environment env;
 
-// Live code text
+// The displayed/processed code text
-char current_code_text[SMAX_LENGTH] = "";
-
-// The actual displayed code text
 char displayed_code[SMAX_LENGTH] = "";
+int excess_chars = 1;
 
 // The result of execution
 #define RESULT_PREFIX "R:"
@@ -54,9 +52,7 @@ const char *tokens[] = {
 static int8_t selected_token = 1;
 
 const char *func_tokens[] = {
-    "spent ", "window ",
+    "window ",
-    "max ", "min ",
-    "sq ", "cube ", "exp ",
     "sc ", "cw ", "pw ", "rw ", "atl ", "utl ",
     "sec ", "mnt ", "hr ", "hrt ", "vibe ", "sub "
 };
@@ -73,8 +69,8 @@ const uint32_t outbox_size = 1024;
 static inline int8_t tokenCount()
 {
     return using_func_tokens?
-            sizeof(func_tokens) / sizeof(func_tokens[0]) :
+        sizeof(func_tokens) / sizeof(func_tokens[0]) :
-            sizeof(tokens) / sizeof(tokens[0]);
+        sizeof(tokens) / sizeof(tokens[0]);
 }
 
 // Get current token from tokens[] or func_tokens[], as appropriate
@@ -84,19 +80,28 @@ static inline const char* getToken(int8_t n)
     return using_func_tokens? func_tokens[t] : tokens[t];
 }
 
+static void trim(size_t len)
+{
+    size_t end = strlen(displayed_code) - 1;
+    for (size_t i = 0; i < len; i++) {
+        displayed_code[end - i] = '\0';
+    }
+}
+
 // Update the current code text with the contents of `current_code_text`,
 // and add the current selected_token to the end
 static void updateText()
 {
+    trim(excess_chars);
     const char *token = getToken(selected_token);
 
-    strcpy(displayed_code, current_code_text);
+    const char* add =
-
-    strcat(displayed_code,
         token[0] == ' ' ? "_":   // Display space as underscore
         token[0] == '\n'? "\\n": // Display newline as \n
-        token                    // Display others literally
+        token;                   // Display others literally
-    );
+
+    strcat(displayed_code, add);
+    excess_chars = strlen(add);
 
     text_layer_set_text(s_input_text_layer, displayed_code);
 }
@@ -174,10 +179,11 @@ static void click_backspace(ClickRecognizerRef recognizer, void *context)
     }
 
     if(!using_func_tokens) {
-        if(current_code_text[0] == '\0') {
+        if(displayed_code[0] == '\0') {
             window_stack_remove(window_stack_get_top_window(), true);
         } else {
-            current_code_text[strlen(current_code_text) - 1] = '\0';
+            trim(excess_chars + 1);
+            excess_chars = 0;
             updateText();
         }
     } else {
@@ -190,7 +196,7 @@ static void click_backspace(ClickRecognizerRef recognizer, void *context)
 // Adds the current token string to the main code string
 static void add_token()
 {
-    strcat(current_code_text, getToken(selected_token));
+    strcat(displayed_code, getToken(selected_token));
     selected_token = 0;
     if(using_func_tokens) {
         using_func_tokens = false;
@@ -205,9 +211,13 @@ static void add_token()
 // Calculate result, display it and reset
 static void calculate()
 {
-    Object obj = parseEval(current_code_text, &env);
     char temp[RESULT_LENGTH + 2] = "";
 
+    trim(excess_chars);
+    excess_chars = 0;
+    Object obj = parseEval(displayed_code, &env);
+    updateText();
+
     stringNObj(temp, &obj, RESULT_LENGTH);
     if(obj.type == TYPE_ERROR) {
         text_layer_set_font(s_result_text_layer, fonts_get_system_font(FONT_KEY_GOTHIC_14_BOLD));
@@ -307,12 +317,12 @@ static void code_window_load(Window *window)
 
     // If possible, load the previous code text
     #ifdef FORCE_TEXT
-    strncpy(current_code_text, FORCE_TEXT, SMAX_LENGTH);
+    strncpy(displayed_code, FORCE_TEXT, SMAX_LENGTH);
     updateText();
     adjustFont();
     #else
     if(persist_exists(current_script_num)) {
-        persist_read_string(current_script_num, current_code_text, SMAX_LENGTH);
+        persist_read_string(current_script_num, displayed_code, SMAX_LENGTH);
         updateText();
         adjustFont();
     }
@@ -469,7 +479,6 @@ static void inbox_received_callback(DictionaryIterator *iter, void *context) {
         }
         char *script_text = script_tuple->value->cstring;
         snprintf(displayed_code, sizeof(displayed_code), "%s", script_text);
-        snprintf(current_code_text, sizeof(current_code_text), "%s", script_text);
         updateText();
     }
 }