From 2844d7db698bcafa835beba937c9ee7a2eb3d5a9 Mon Sep 17 00:00:00 2001
From: Chris Warren-Smith <cwarrensmith@gmail.com>
Date: Sat, 6 Jan 2024 12:31:36 +1030
Subject: [PATCH 1/3] COMMON: Allow modules to return objects with methods that
 take arguments

---
 ChangeLog                      |   3 +
 src/common/blib.c              |  18 +++-
 src/common/eval.c              |   2 +-
 src/common/plugins.c           | 148 ++++++++++++++++-----------------
 src/common/plugins.h           |  12 ++-
 src/include/module.h           |   8 --
 src/include/var.h              |  12 ++-
 src/platform/console/image.cpp |  30 ++++---
 src/ui/form.cpp                |  21 ++---
 src/ui/image.cpp               |  42 +++++-----
 src/ui/window.cpp              |  77 ++++++++++-------
 11 files changed, 202 insertions(+), 171 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 6d857ee3..7eb7e802 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,6 @@
+2024-01-06 (12.27)
+	COMMON: Allow modules to return objects with methods that take arguments
+
 2023-08-27 (12.27)
 	COMMON: Fix parameter number error when calling a unit sub/func
 	COMMON: Show a runtime error if a module calls exit()
diff --git a/src/common/blib.c b/src/common/blib.c
index 6902ab94..b24c9625 100644
--- a/src/common/blib.c
+++ b/src/common/blib.c
@@ -12,6 +12,7 @@
 #include "common/fmt.h"
 #include "common/keymap.h"
 #include "common/messages.h"
+#include "common/plugins.h"
 
 #define STR_INIT_SIZE 256
 #define PKG_INIT_SIZE 5
@@ -2881,12 +2882,21 @@ void cmd_call_vfunc() {
       rt_raise(ERR_NO_FUNC);
     }
   } else {
+    slib_par_t *ptable;
+    int pcount;
     if (code_peek() == kwTYPE_LEVEL_BEGIN) {
-      code_skipnext();
+      ptable = (slib_par_t *)malloc(sizeof(slib_par_t) * MAX_PARAMS);
+      pcount = plugin_build_ptable(ptable, MAX_PARAMS);
+    } else {
+      ptable = NULL;
+      pcount = 0;
     }
-    v_func->v.fn.cb(map, NULL);
-    if (code_peek() == kwTYPE_LEVEL_END) {
-      code_skipnext();
+    if (!prog_error) {
+      v_func->v.fn.cb(map, pcount, ptable, NULL);
+    }
+    if (ptable) {
+      plugin_free_ptable(ptable, pcount);
+      free(ptable);
     }
   }
 }
diff --git a/src/common/eval.c b/src/common/eval.c
index 52fe12d0..dab6c3ce 100644
--- a/src/common/eval.c
+++ b/src/common/eval.c
@@ -786,7 +786,7 @@ static inline void eval_var(var_t *r, var_t *var_p) {
     v_set(r, var_p);
     break;
   case V_FUNC:
-    var_p->v.fn.cb(var_p, r);
+    var_p->v.fn.cb(var_p, 0, NULL, r);
     break;
   case V_NIL:
     r->type = V_NIL;
diff --git a/src/common/plugins.c b/src/common/plugins.c
index 0e5159b3..cd5c4b5a 100644
--- a/src/common/plugins.c
+++ b/src/common/plugins.c
@@ -358,80 +358,6 @@ static void slib_import_routines(slib_t *lib, int comp) {
   }
 }
 
-//
-// build parameter table
-//
-static int slib_build_ptable(slib_par_t *ptable) {
-  int pcount = 0;
-  var_t *arg;
-  bcip_t ofs;
-
-  if (code_peek() == kwTYPE_LEVEL_BEGIN) {
-    code_skipnext();
-    byte ready = 0;
-    do {
-      byte code = code_peek();
-      switch (code) {
-      case kwTYPE_EOC:
-        code_skipnext();
-        break;
-      case kwTYPE_SEP:
-        code_skipsep();
-        break;
-      case kwTYPE_LEVEL_END:
-        ready = 1;
-        break;
-      case kwTYPE_VAR:
-        // variable
-        ofs = prog_ip;
-        if (code_isvar()) {
-          // push parameter
-          ptable[pcount].var_p = code_getvarptr();
-          ptable[pcount].byref = 1;
-          pcount++;
-          break;
-        }
-
-        // restore IP
-        prog_ip = ofs;
-        // no 'break' here
-      default:
-        // default --- expression (BYVAL ONLY)
-        arg = v_new();
-        eval(arg);
-        if (!prog_error) {
-          // push parameter
-          ptable[pcount].var_p = arg;
-          ptable[pcount].byref = 0;
-          pcount++;
-        } else {
-          v_free(arg);
-          v_detach(arg);
-          return pcount;
-        }
-      }
-      if (pcount == MAX_PARAM) {
-        err_parm_limit(MAX_PARAM);
-      }
-    } while (!ready && !prog_error);
-    // kwTYPE_LEVEL_END
-    code_skipnext();
-  }
-  return pcount;
-}
-
-//
-// free parameter table
-//
-static void slib_free_ptable(slib_par_t *ptable, int pcount) {
-  for (int i = 0; i < pcount; i++) {
-    if (ptable[i].byref == 0) {
-      v_free(ptable[i].var_p);
-      v_detach(ptable[i].var_p);
-    }
-  }
-}
-
 //
 // execute a function or procedure
 //
@@ -440,13 +366,13 @@ static int slib_exec(slib_t *lib, var_t *ret, int index, int proc) {
   int pcount;
   if (code_peek() == kwTYPE_LEVEL_BEGIN) {
     ptable = (slib_par_t *)malloc(sizeof(slib_par_t) * MAX_PARAM);
-    pcount = slib_build_ptable(ptable);
+    pcount = plugin_build_ptable(ptable, MAX_PARAM);
   } else {
     ptable = NULL;
     pcount = 0;
   }
   if (prog_error) {
-    slib_free_ptable(ptable, pcount);
+    plugin_free_ptable(ptable, pcount);
     free(ptable);
     return 0;
   }
@@ -470,7 +396,7 @@ static int slib_exec(slib_t *lib, var_t *ret, int index, int proc) {
 
   // clean-up
   if (ptable) {
-    slib_free_ptable(ptable, pcount);
+    plugin_free_ptable(ptable, pcount);
     free(ptable);
   }
 
@@ -643,3 +569,71 @@ int plugin_funcexec(int lib_id, int index, var_t *ret) { return -1; }
 void plugin_free(int lib_id, int cls_id, int id) {}
 void plugin_close() {}
 #endif
+
+int plugin_build_ptable(slib_par_t *ptable, int size) {
+  int pcount = 0;
+  var_t *arg;
+  bcip_t ofs;
+
+  if (code_peek() == kwTYPE_LEVEL_BEGIN) {
+    code_skipnext();
+    byte ready = 0;
+    do {
+      byte code = code_peek();
+      switch (code) {
+      case kwTYPE_EOC:
+        code_skipnext();
+        break;
+      case kwTYPE_SEP:
+        code_skipsep();
+        break;
+      case kwTYPE_LEVEL_END:
+        ready = 1;
+        break;
+      case kwTYPE_VAR:
+        // variable
+        ofs = prog_ip;
+        if (code_isvar()) {
+          // push parameter
+          ptable[pcount].var_p = code_getvarptr();
+          ptable[pcount].byref = 1;
+          pcount++;
+          break;
+        }
+
+        // restore IP
+        prog_ip = ofs;
+        // no 'break' here
+      default:
+        // default --- expression (BYVAL ONLY)
+        arg = v_new();
+        eval(arg);
+        if (!prog_error) {
+          // push parameter
+          ptable[pcount].var_p = arg;
+          ptable[pcount].byref = 0;
+          pcount++;
+        } else {
+          v_free(arg);
+          v_detach(arg);
+          return pcount;
+        }
+      }
+      if (pcount == size) {
+        err_parm_limit(size);
+      }
+    } while (!ready && !prog_error);
+    // kwTYPE_LEVEL_END
+    code_skipnext();
+  }
+  return pcount;
+}
+
+void plugin_free_ptable(slib_par_t *ptable, int pcount) {
+  for (int i = 0; i < pcount; i++) {
+    if (ptable[i].byref == 0) {
+      v_free(ptable[i].var_p);
+      v_detach(ptable[i].var_p);
+    }
+  }
+}
diff --git a/src/common/plugins.h b/src/common/plugins.h
index a4dd16bd..ceac683c 100644
--- a/src/common/plugins.h
+++ b/src/common/plugins.h
@@ -44,7 +44,7 @@ int plugin_get_kid(int lib_id, const char *keyword);
 // returns the function pointer for the given function name
 //
 void *plugin_get_func(const char *name);
-  
+
 //
 // executes the plugin procedure at the given index
 //
@@ -65,6 +65,16 @@ void plugin_free(int lib_id, int cls_id, int id);
 //
 void plugin_close();
 
+//
+// build parameter table
+//
+int plugin_build_ptable(slib_par_t *ptable, int size);
+
+//
+// free parameter table
+//
+void plugin_free_ptable(slib_par_t *ptable, int pcount);
+
 #if defined(__cplusplus)
 }
 #endif
diff --git a/src/include/module.h b/src/include/module.h
index 451e24e2..d27ea522 100644
--- a/src/include/module.h
+++ b/src/include/module.h
@@ -16,14 +16,6 @@
 extern "C" {
 #endif
 
-typedef struct {
-  // the parameter
-  var_t *var_p;
-
-  // whether the parameter can be used by reference
-  uint8_t byref;
-} slib_par_t;
-
 /**
  * @ingroup modstd
  *
diff --git a/src/include/var.h b/src/include/var.h
index 003e7949..eb347c2e 100644
--- a/src/include/var.h
+++ b/src/include/var.h
@@ -47,7 +47,17 @@ extern "C" {
 #endif
 
 struct var_s;
-typedef void (*method) (struct var_s *self, struct var_s *retval);
+
+typedef struct {
+  // the parameter
+  struct var_s *var_p;
+
+  // whether the parameter can be used by reference
+  uint8_t byref;
+} slib_par_t;
+
+// object method signature
+typedef void (*method) (struct var_s *self, int param_count, slib_par_t *params, struct var_s *retval);
 
 typedef struct var_s {
   union {
diff --git a/src/platform/console/image.cpp b/src/platform/console/image.cpp
index 527a539d..b5837fff 100644
--- a/src/platform/console/image.cpp
+++ b/src/platform/console/image.cpp
@@ -245,10 +245,15 @@ ImageBuffer *load_xpm_image(char **data) {
 //
 // png.clip(10, 10, 10, 10)
 //
-void cmd_image_clip(var_s *self, var_s *) {
-  var_int_t left, top, right, bottom;
+void cmd_image_clip(var_s *self, int param_count, slib_par_t *params, var_s *) {
   ImageBuffer *image = load_image(self);
-  if (par_massget("iiii", &left, &top, &right, &bottom) == 4) {
+  if (param_count != 4) {
+    err_parm_num(param_count, 4);
+  } else {
+    var_int_t left = v_getint(params[0].var_p);
+    var_int_t top = v_getint(params[1].var_p);
+    var_int_t right = v_getint(params[2].var_p);
+    var_int_t bottom = v_getint(params[3].var_p);
     int w = image->_width - (right + left);
     int h = image->_height - (bottom + top);
     int size = w * h * 4;
@@ -277,8 +282,6 @@ void cmd_image_clip(var_s *self, var_s *) {
       map_set_int(self, IMG_WIDTH, w);
       map_set_int(self, IMG_HEIGHT, h);
     }
-  } else {
-    err_throw(ERR_PARAM);
   }
 }
 
@@ -290,7 +293,7 @@ void cmd_image_clip(var_s *self, var_s *) {
 // end
 // png.filter(use colorToAlpha(x))
 //
-void cmd_image_filter(var_s *self, var_s *) {
+void cmd_image_filter(var_s *self, int param_count, slib_par_t *params, var_s *) {
   ImageBuffer *image_buffer = load_image(self);
   if (code_peek() == kwUSE && image_buffer != nullptr) {
     code_skipnext();
@@ -326,19 +329,22 @@ void cmd_image_filter(var_s *self, var_s *) {
 // png2 = image(w, h)
 // png2.paste(png1, 0, 0)
 //
-void cmd_image_paste(var_s *self, var_s *) {
-  var_int_t x, y;
-  var_t *var;
+void cmd_image_paste(var_s *self, int param_count, slib_par_t *params, var_s *) {
   ImageBuffer *image = load_image(self);
-  int count = par_massget("Piiii", &var, &x, &y);
-  if (image != nullptr && (count == 1 || count == 3)) {
+  if (image != nullptr && (param_count == 1 || param_count == 3)) {
+    var_t *var = params[0].var_p;
     ImageBuffer *srcImage = load_image(var);
     if (srcImage == nullptr) {
       err_throw(ERR_PARAM);
     } else {
+      var_int_t x;
+      var_int_t y;
       if (count == 1) {
         x = 0;
         y = 0;
+      } else {
+        x = v_getint(params[1].var_p);
+        y = v_getint(params[2].var_p);
       }
       int dw = image->_width;
       int dh = image->_height;
@@ -370,7 +376,7 @@ void cmd_image_paste(var_s *self, var_s *) {
 // png.save("horse1.png")
 // png.save(#1)
 //
-void cmd_image_save(var_s *self, var_s *) {
+void cmd_image_save(var_s *self, int param_count, slib_par_t *params, var_s *) {
   ImageBuffer *image = load_image(self);
   dev_file_t *filep = nullptr;
   byte code = code_peek();
diff --git a/src/ui/form.cpp b/src/ui/form.cpp
index 8cd9a85f..444fad94 100644
--- a/src/ui/form.cpp
+++ b/src/ui/form.cpp
@@ -116,29 +116,20 @@ void FormLink::clicked(int x, int y, bool pressed) {
   }
 }
 
-void cmd_form_close(var_s *self, var_s *) {
+void cmd_form_close(var_s *self, int param_count, slib_par_t *params, var_s *) {
   g_system->getOutput()->removeInputs();
   g_system->getOutput()->resetScroll();
-
-  var_t arg;
-  v_init(&arg);
-  eval(&arg);
-  if (arg.type == V_STR) {
-    g_system->setLoadBreak(arg.v.p.ptr);
+  if (param_count == 1 && params[0].var_p->type == V_STR) {
+    g_system->setLoadBreak(params[0].var_p->v.p.ptr);
   }
-  v_free(&arg);
 }
 
-void cmd_form_refresh(var_s *self, var_s *) {
-  var_t arg;
-  v_init(&arg);
-  eval(&arg);
-  bool setVars = v_getint(&arg) != 0;
-  v_free(&arg);
+void cmd_form_refresh(var_s *self, int param_count, slib_par_t *params, var_s *) {
+  bool setVars = param_count == 1 && v_getint(params[0].var_p) != 0;
   g_system->getOutput()->updateInputs(self, setVars);
 }
 
-void cmd_form_do_events(var_s *self, var_s *) {
+void cmd_form_do_events(var_s *self, int param_count, slib_par_t *params, var_s *) {
   // apply any variable changes onto attached widgets
   if (g_system->isRunning()) {
     AnsiWidget *out = g_system->getOutput();
diff --git a/src/ui/image.cpp b/src/ui/image.cpp
index b0797ceb..1cb4fbbc 100644
--- a/src/ui/image.cpp
+++ b/src/ui/image.cpp
@@ -370,7 +370,7 @@ ImageBuffer *load_xpm_image(char **data) {
   return result;
 }
 
-void get_image_display(var_s *self, ImageDisplay *image) {
+void get_image_display(var_s *self, int param_count, slib_par_t *params, ImageDisplay *image) {
   image->_bid = map_get_int(self, IMG_BID, -1);
 
   List_each(ImageBuffer *, it, buffers) {
@@ -381,14 +381,13 @@ void get_image_display(var_s *self, ImageDisplay *image) {
     }
   }
 
-  var_int_t x, y, z, op;
-  int count = par_massget("iiii", &x, &y, &z, &op);
-
-  if (prog_error || image->_buffer == nullptr || count == 1 || count > 4) {
+  if (prog_error || image->_buffer == nullptr || param_count == 1 || param_count > 4) {
     err_throw(ERR_PARAM);
   } else {
     // 0, 2, 3, 4 arguments accepted
-    if (count >= 2) {
+    if (param_count >= 2) {
+      var_int_t x = v_getint(params[0].var_p);
+      var_int_t y = v_getint(params[1].var_p);
       image->_x = x;
       image->_y = y;
       map_set_int(self, IMG_X, x);
@@ -397,13 +396,15 @@ void get_image_display(var_s *self, ImageDisplay *image) {
       image->_x = map_get_int(self, IMG_X, -1);
       image->_y = map_get_int(self, IMG_Y, -1);
     }
-    if (count >= 3) {
+    if (param_count >= 3) {
+      var_int_t z = v_getint(params[2].var_p);
       image->_zIndex = z;
       map_set_int(self, IMG_ZINDEX, z);
     } else {
       image->_zIndex = map_get_int(self, IMG_ZINDEX, -1);
     }
-    if (count == 4) {
+    if (param_count == 4) {
+      var_int_t op = v_getint(params[3].var_p);
       image->_opacity = op;
       map_set_int(self, IMG_OPACITY, op);
     } else {
@@ -421,9 +422,9 @@ void get_image_display(var_s *self, ImageDisplay *image) {
 //
 // png.show(x, y, zindex, opacity)
 //
-void cmd_image_show(var_s *self, var_s *) {
+void cmd_image_show(var_s *self, int param_count, slib_par_t *params, var_s *) {
   ImageDisplay image;
-  get_image_display(self, &image);
+  get_image_display(self, param_count, params, &image);
   if (!prog_error) {
     g_system->getOutput()->addImage(image);
   }
@@ -432,9 +433,9 @@ void cmd_image_show(var_s *self, var_s *) {
 //
 // png.draw(x, y, opacity)
 //
-void cmd_image_draw(var_s *self, var_s *) {
+void cmd_image_draw(var_s *self, int param_count, slib_par_t *params, var_s *) {
   ImageDisplay image;
-  get_image_display(self, &image);
+  get_image_display(self, param_count, params, &image);
   if (!prog_error) {
     image._opacity = image._zIndex;
     g_system->getOutput()->drawImage(image);
@@ -444,7 +445,7 @@ void cmd_image_draw(var_s *self, var_s *) {
 //
 // png.hide()
 //
-void cmd_image_hide(var_s *self, var_s *) {
+void cmd_image_hide(var_s *self, int param_count, slib_par_t *params, var_s *) {
   int id = map_get_int(self, IMG_ID, -1);
   g_system->getOutput()->removeImage(id);
 }
@@ -455,7 +456,7 @@ void cmd_image_hide(var_s *self, var_s *) {
 // png.save("horse1.png")
 // png.save(#1)
 //
-void cmd_image_save(var_s *self, var_s *) {
+void cmd_image_save(var_s *self, int param_count, slib_par_t *params, var_s *) {
   unsigned id = map_get_int(self, IMG_BID, -1);
   ImageBuffer *image = get_image(id);
   dev_file_t *file;
@@ -516,17 +517,16 @@ void cmd_image_save(var_s *self, var_s *) {
 //
 // png.clip(10, 10, 10, 10)
 //
-void cmd_image_clip(var_s *self, var_s *) {
+void cmd_image_clip(var_s *self, int param_count, slib_par_t *params, var_s *) {
   if (self->type == V_MAP) {
     int bid = map_get_int(self, IMG_BID, -1);
     if (bid != -1) {
       ImageBuffer *image = get_image((unsigned)bid);
-      var_int_t left, top, right, bottom;
-      if (image != nullptr && par_massget("iiii", &left, &top, &right, &bottom)) {
-        map_set_int(self, IMG_OFFSET_LEFT, left);
-        map_set_int(self, IMG_OFFSET_TOP, top);
-        map_set_int(self, IMG_WIDTH, right);
-        map_set_int(self, IMG_HEIGHT, bottom);
+      if (image != nullptr && param_count == 4) {
+        map_set_int(self, IMG_OFFSET_LEFT, v_getint(params[0].var_p));
+        map_set_int(self, IMG_OFFSET_TOP, v_getint(params[1].var_p));
+        map_set_int(self, IMG_WIDTH, v_getint(params[2].var_p));
+        map_set_int(self, IMG_HEIGHT, v_getint(params[3].var_p));
       }
     }
   }
diff --git a/src/ui/window.cpp b/src/ui/window.cpp
index 7f31b125..2bebe619 100644
--- a/src/ui/window.cpp
+++ b/src/ui/window.cpp
@@ -62,30 +62,34 @@ StringList *get_items() {
   return items;
 }
 
-void cmd_window_select_screen1(var_s *self, var_s *) {
+void cmd_window_select_screen1(var_s *self, int param_count, slib_par_t *params, var_s *) {
   g_system->getOutput()->selectScreen(USER_SCREEN1);
 }
 
-void cmd_window_select_screen2(var_s *self, var_s *) {
+void cmd_window_select_screen2(var_s *self, int param_count, slib_par_t *params, var_s *) {
   g_system->getOutput()->selectScreen(USER_SCREEN2);
 }
 
-void cmd_window_select_screen3(var_s *self, var_s *) {
+void cmd_window_select_screen3(var_s *self, int param_count, slib_par_t *params, var_s *) {
   g_system->getOutput()->selectScreen(TEXT_SCREEN);
 }
 
-void cmd_window_show_keypad(var_s *self, var_s *) {
+void cmd_window_show_keypad(var_s *self, int param_count, slib_par_t *params, var_s *) {
   maShowVirtualKeyboard();
 }
 
-void cmd_window_hide_keypad(var_s *self, var_s *) {
+void cmd_window_hide_keypad(var_s *self, int param_count, slib_par_t *params, var_s *) {
   maHideVirtualKeyboard();
 }
 
-void cmd_window_inset(var_s *self, var_s *) {
-  var_int_t x, y, w, h;
-  par_massget("IIII", &x, &y, &w, &h);
-  if (!prog_error) {
+void cmd_window_inset(var_s *self, int param_count, slib_par_t *params, var_s *) {
+  if (param_count != 4) {
+    err_parm_num(param_count, 4);
+  } else {
+    var_int_t x = v_getint(params[0].var_p);
+    var_int_t y = v_getint(params[1].var_p);
+    var_int_t w = v_getint(params[2].var_p);
+    var_int_t h = v_getint(params[3].var_p);
     if (x < 0 || x > 100 ||
         y < 0 || y > 100 ||
         w < 1 || x + w > 100 ||
@@ -97,31 +101,42 @@ void cmd_window_inset(var_s *self, var_s *) {
   }
 }
 
-void cmd_window_set_font(var_s *self, var_s *) {
-  var_num_t size;
-  var_int_t bold, italic;
-  char *unit = nullptr;
-  par_massget("FSII", &size, &unit, &bold, &italic);
-  if (unit != nullptr && strcmp(unit, "em") == 0) {
-    size *= g_system->getOutput()->getFontSize();
+void cmd_window_set_font(var_s *self, int param_count, slib_par_t *params, var_s *) {
+  if (param_count != 4) {
+    err_parm_num(param_count, 4);
+  } else {
+    var_num_t size = v_getreal(params[0].var_p);
+    const char *unit = v_getstr(params[1].var_p);
+    var_int_t bold = v_getint(params[2].var_p);
+    var_int_t italic = v_getint(params[3].var_p);
+    if (unit != nullptr && strcmp(unit, "em") == 0) {
+      size *= g_system->getOutput()->getFontSize();
+    }
+    g_system->getOutput()->setFont(size, bold, italic);
   }
-  g_system->getOutput()->setFont(size, bold, italic);
-  pfree(unit);
 }
 
-void cmd_window_set_size(var_s *self, var_s *) {
-  var_int_t width, height;
-  par_massget("II", &width, &height);
-  g_system->setWindowRect(-1, -1, width, height);
+void cmd_window_set_size(var_s *self, int param_count, slib_par_t *params, var_s *) {
+  if (param_count != 2) {
+    err_parm_num(param_count, 2);
+  } else {
+    var_int_t width = v_getint(params[0].var_p);
+    var_int_t height = v_getint(params[1].var_p);
+    g_system->setWindowRect(-1, -1, width, height);
+  }
 }
 
-void cmd_window_set_location(var_s *self, var_s *) {
-  var_int_t x, y;
-  par_massget("II", &x, &y);
-  g_system->setWindowRect(x, y, -1, -1);
+void cmd_window_set_location(var_s *self, int param_count, slib_par_t *params, var_s *) {
+  if (param_count != 2) {
+    err_parm_num(param_count, 2);
+  } else {
+    var_int_t x = v_getint(params[0].var_p);
+    var_int_t y = v_getint(params[1].var_p);
+    g_system->setWindowRect(x, y, -1, -1);
+  }
 }
 
-void cmd_window_get_theme(var_s *, var_s *retval) {
+void cmd_window_get_theme(var_s *self, int param_count, slib_par_t *params, var_s *retval) {
   if (retval != nullptr) {
     EditTheme theme;
     theme.setId(g_themeId);
@@ -137,7 +152,7 @@ void cmd_window_get_theme(var_s *, var_s *retval) {
   }
 }
 
-void cmd_window_alert(var_s *self, var_s *) {
+void cmd_window_alert(var_s *self, int param_count, slib_par_t *params, var_s *) {
   StringList *items = get_items();
   if (!prog_error && items->size() > 0) {
     const char *message = items->size() > 0 ? (*items)[0]->c_str() : "";
@@ -147,7 +162,7 @@ void cmd_window_alert(var_s *self, var_s *) {
   delete items;
 }
 
-void cmd_window_ask(var_s *self, var_s *retval) {
+void cmd_window_ask(var_s *self, int param_count, slib_par_t *params, var_s *retval) {
   StringList *items = get_items();
   if (!prog_error && items->size() > 0) {
     const char *message = items->size() > 0 ? (*items)[0]->c_str() : "";
@@ -161,7 +176,7 @@ void cmd_window_ask(var_s *self, var_s *retval) {
   delete items;
 }
 
-void cmd_window_menu(var_s *self, var_s *) {
+void cmd_window_menu(var_s *self, int param_count, slib_par_t *params, var_s *) {
   StringList *items = get_items();
   if (!prog_error && items->size() > 0) {
     g_system->optionsBox(items);
@@ -169,7 +184,7 @@ void cmd_window_menu(var_s *self, var_s *) {
   delete items;
 }
 
-void cmd_window_message(var_s *self, var_s *) {
+void cmd_window_message(var_s *self, int param_count, slib_par_t *params, var_s *) {
   var_t arg;
   v_init(&arg);
   eval(&arg);

From 5adc663b3a5103b83ea3b50487fba5c3b8231306 Mon Sep 17 00:00:00 2001
From: Chris Warren-Smith <cwarrensmith@gmail.com>
Date: Sat, 6 Jan 2024 20:49:10 +1030
Subject: [PATCH 2/3] COMMON: Allow modules to return objects with methods that
 take arguments

---
 src/common/blib.c              | 21 ++--------
 src/common/eval.c              |  2 +-
 src/common/var.c               |  1 +
 src/common/var_eval.c          | 47 ++++++++++++++++++++-
 src/common/var_eval.h          |  7 ++++
 src/include/var.h              |  8 +++-
 src/platform/console/image.cpp | 30 ++++++-------
 src/ui/form.cpp                | 21 +++++++---
 src/ui/image.cpp               | 42 +++++++++----------
 src/ui/window.cpp              | 77 ++++++++++++++--------------------
 10 files changed, 144 insertions(+), 112 deletions(-)

diff --git a/src/common/blib.c b/src/common/blib.c
index b24c9625..d3e10fcc 100644
--- a/src/common/blib.c
+++ b/src/common/blib.c
@@ -12,7 +12,6 @@
 #include "common/fmt.h"
 #include "common/keymap.h"
 #include "common/messages.h"
-#include "common/plugins.h"
 
 #define STR_INIT_SIZE 256
 #define PKG_INIT_SIZE 5
@@ -2882,22 +2881,10 @@ void cmd_call_vfunc() {
       rt_raise(ERR_NO_FUNC);
     }
   } else {
-    slib_par_t *ptable;
-    int pcount;
-    if (code_peek() == kwTYPE_LEVEL_BEGIN) {
-      ptable = (slib_par_t *)malloc(sizeof(slib_par_t) * MAX_PARAMS);
-      pcount = plugin_build_ptable(ptable, MAX_PARAMS);
-    } else {
-      ptable = NULL;
-      pcount = 0;
-    }
-    if (!prog_error) {
-      v_func->v.fn.cb(map, pcount, ptable, NULL);
-    }
-    if (ptable) {
-      plugin_free_ptable(ptable, pcount);
-      free(ptable);
-    }
+    var_t result;
+    v_init(&result);
+    v_eval_func(map, v_func, &result);
+    v_free(&result);
   }
 }
 
diff --git a/src/common/eval.c b/src/common/eval.c
index dab6c3ce..52fe12d0 100644
--- a/src/common/eval.c
+++ b/src/common/eval.c
@@ -786,7 +786,7 @@ static inline void eval_var(var_t *r, var_t *var_p) {
     v_set(r, var_p);
     break;
   case V_FUNC:
-    var_p->v.fn.cb(var_p, 0, NULL, r);
+    var_p->v.fn.cb(var_p, r);
     break;
   case V_NIL:
     r->type = V_NIL;
diff --git a/src/common/var.c b/src/common/var.c
index 05017773..3574840d 100644
--- a/src/common/var.c
+++ b/src/common/var.c
@@ -800,5 +800,6 @@ void v_create_func(var_p_t map, const char *name, method cb) {
   var_p_t v_func = map_add_var(map, name, 0);
   v_func->type = V_FUNC;
   v_func->v.fn.cb = cb;
+  v_func->v.fn.mcb = NULL;
   v_func->v.fn.id = 0;
 }
diff --git a/src/common/var_eval.c b/src/common/var_eval.c
index 4509fef9..aa6912ed 100644
--- a/src/common/var_eval.c
+++ b/src/common/var_eval.c
@@ -5,7 +5,7 @@
 // This program is distributed under the terms of the GPL v2.0 or later
 // Download the GNU Public License (GPL) from www.gnu.org
 //
-// Copyright(C) 2010-2014 Chris Warren-Smith. [http://tinyurl.com/ja2ss]
+// Copyright(C) 2010-2024 Chris Warren-Smith. [http://tinyurl.com/ja2ss]
 
 #include "common/sys.h"
 #include "common/kw.h"
@@ -14,6 +14,44 @@
 #include "common/smbas.h"
 #include "common/var.h"
 #include "common/var_eval.h"
+#include "common/plugins.h"
+
+void v_eval_func(var_p_t self, var_p_t v_func, var_p_t result) {
+  if (v_func->v.fn.cb != NULL) {
+    // internal object method
+    if (code_peek() == kwTYPE_LEVEL_BEGIN) {
+      code_skipnext();
+    }
+    v_func->v.fn.cb(self, NULL);
+    if (code_peek() == kwTYPE_LEVEL_END) {
+      code_skipnext();
+    }
+  } else {
+    // module callback
+    slib_par_t *ptable;
+    int pcount;
+    if (code_peek() == kwTYPE_LEVEL_BEGIN) {
+      ptable = (slib_par_t *)malloc(sizeof(slib_par_t) * MAX_PARAMS);
+      pcount = plugin_build_ptable(ptable, MAX_PARAMS);
+    } else {
+      ptable = NULL;
+      pcount = 0;
+    }
+    if (!prog_error) {
+      if (!v_func->v.fn.mcb(self, pcount, ptable, result)) {
+        if (result->type == V_STR) {
+          err_throw(result->v.p.ptr);
+        } else {
+          err_throw("Undefined");
+        }
+      }
+    }
+    if (ptable) {
+      plugin_free_ptable(ptable, pcount);
+      free(ptable);
+    }
+  }
+}
 
 /**
  * Convert multi-dim index to one-dim index
@@ -159,6 +197,13 @@ var_t *code_get_map_element(var_t *map, var_t *field) {
     }
   } else if (field->type == V_ARRAY) {
     result = code_getvarptr_arridx(field);
+  } else if (field->type == V_FUNC) {
+    result = map_get(map, MAP_TMP_FIELD);
+    if (result == NULL) {
+      result = map_add_var(map, MAP_TMP_FIELD, 0);
+    }
+    v_init(result);
+    v_eval_func(map, field, result);
   } else {
     code_skipnext();
     var_t var;
diff --git a/src/common/var_eval.h b/src/common/var_eval.h
index 9ba681ef..6daee18a 100644
--- a/src/common/var_eval.h
+++ b/src/common/var_eval.h
@@ -67,6 +67,13 @@ int code_isvar(void);
  */
 void v_eval_str(var_p_t v);
 
+/**
+ * @ingroup var
+ *
+ * invokes the virtual function
+ */
+void v_eval_func(var_p_t self, var_p_t v_func, var_p_t result);
+
 #if defined(__cplusplus)
 }
 #endif
diff --git a/src/include/var.h b/src/include/var.h
index eb347c2e..8ea30f90 100644
--- a/src/include/var.h
+++ b/src/include/var.h
@@ -56,8 +56,11 @@ typedef struct {
   uint8_t byref;
 } slib_par_t;
 
-// object method signature
-typedef void (*method) (struct var_s *self, int param_count, slib_par_t *params, struct var_s *retval);
+// signature for module callback/virtual functions
+typedef int (*callback) (struct var_s *self, int param_count, slib_par_t *params, struct var_s *retval);
+
+// signature for internal v_funcs
+typedef void (*method) (struct var_s *self, struct var_s *retval);
 
 typedef struct var_s {
   union {
@@ -93,6 +96,7 @@ typedef struct var_s {
     // object method
     struct {
       method cb;
+      callback mcb;
       uint32_t id;
     } fn;
 
diff --git a/src/platform/console/image.cpp b/src/platform/console/image.cpp
index b5837fff..527a539d 100644
--- a/src/platform/console/image.cpp
+++ b/src/platform/console/image.cpp
@@ -245,15 +245,10 @@ ImageBuffer *load_xpm_image(char **data) {
 //
 // png.clip(10, 10, 10, 10)
 //
-void cmd_image_clip(var_s *self, int param_count, slib_par_t *params, var_s *) {
+void cmd_image_clip(var_s *self, var_s *) {
+  var_int_t left, top, right, bottom;
   ImageBuffer *image = load_image(self);
-  if (param_count != 4) {
-    err_parm_num(param_count, 4);
-  } else {
-    var_int_t left = v_getint(params[0].var_p);
-    var_int_t top = v_getint(params[1].var_p);
-    var_int_t right = v_getint(params[2].var_p);
-    var_int_t bottom = v_getint(params[3].var_p);
+  if (par_massget("iiii", &left, &top, &right, &bottom) == 4) {
     int w = image->_width - (right + left);
     int h = image->_height - (bottom + top);
     int size = w * h * 4;
@@ -282,6 +277,8 @@ void cmd_image_clip(var_s *self, int param_count, slib_par_t *params, var_s *) {
       map_set_int(self, IMG_WIDTH, w);
       map_set_int(self, IMG_HEIGHT, h);
     }
+  } else {
+    err_throw(ERR_PARAM);
   }
 }
 
@@ -293,7 +290,7 @@ void cmd_image_clip(var_s *self, int param_count, slib_par_t *params, var_s *) {
 // end
 // png.filter(use colorToAlpha(x))
 //
-void cmd_image_filter(var_s *self, int param_count, slib_par_t *params, var_s *) {
+void cmd_image_filter(var_s *self, var_s *) {
   ImageBuffer *image_buffer = load_image(self);
   if (code_peek() == kwUSE && image_buffer != nullptr) {
     code_skipnext();
@@ -329,22 +326,19 @@ void cmd_image_filter(var_s *self, int param_count, slib_par_t *params, var_s *)
 // png2 = image(w, h)
 // png2.paste(png1, 0, 0)
 //
-void cmd_image_paste(var_s *self, int param_count, slib_par_t *params, var_s *) {
+void cmd_image_paste(var_s *self, var_s *) {
+  var_int_t x, y;
+  var_t *var;
   ImageBuffer *image = load_image(self);
-  if (image != nullptr && (param_count == 1 || param_count == 3)) {
-    var_t *var = params[0].var_p;
+  int count = par_massget("Piiii", &var, &x, &y);
+  if (image != nullptr && (count == 1 || count == 3)) {
     ImageBuffer *srcImage = load_image(var);
     if (srcImage == nullptr) {
       err_throw(ERR_PARAM);
     } else {
-      var_int_t x;
-      var_int_t y;
       if (count == 1) {
         x = 0;
         y = 0;
-      } else {
-        x = v_getint(params[1].var_p);
-        y = v_getint(params[2].var_p);
       }
       int dw = image->_width;
       int dh = image->_height;
@@ -376,7 +370,7 @@ void cmd_image_paste(var_s *self, int param_count, slib_par_t *params, var_s *)
 // png.save("horse1.png")
 // png.save(#1)
 //
-void cmd_image_save(var_s *self, int param_count, slib_par_t *params, var_s *) {
+void cmd_image_save(var_s *self, var_s *) {
   ImageBuffer *image = load_image(self);
   dev_file_t *filep = nullptr;
   byte code = code_peek();
diff --git a/src/ui/form.cpp b/src/ui/form.cpp
index 444fad94..8cd9a85f 100644
--- a/src/ui/form.cpp
+++ b/src/ui/form.cpp
@@ -116,20 +116,29 @@ void FormLink::clicked(int x, int y, bool pressed) {
   }
 }
 
-void cmd_form_close(var_s *self, int param_count, slib_par_t *params, var_s *) {
+void cmd_form_close(var_s *self, var_s *) {
   g_system->getOutput()->removeInputs();
   g_system->getOutput()->resetScroll();
-  if (param_count == 1 && params[0].var_p->type == V_STR) {
-    g_system->setLoadBreak(params[0].var_p->v.p.ptr);
+
+  var_t arg;
+  v_init(&arg);
+  eval(&arg);
+  if (arg.type == V_STR) {
+    g_system->setLoadBreak(arg.v.p.ptr);
   }
+  v_free(&arg);
 }
 
-void cmd_form_refresh(var_s *self, int param_count, slib_par_t *params, var_s *) {
-  bool setVars = param_count == 1 && v_getint(params[0].var_p) != 0;
+void cmd_form_refresh(var_s *self, var_s *) {
+  var_t arg;
+  v_init(&arg);
+  eval(&arg);
+  bool setVars = v_getint(&arg) != 0;
+  v_free(&arg);
   g_system->getOutput()->updateInputs(self, setVars);
 }
 
-void cmd_form_do_events(var_s *self, int param_count, slib_par_t *params, var_s *) {
+void cmd_form_do_events(var_s *self, var_s *) {
   // apply any variable changes onto attached widgets
   if (g_system->isRunning()) {
     AnsiWidget *out = g_system->getOutput();
diff --git a/src/ui/image.cpp b/src/ui/image.cpp
index 1cb4fbbc..b0797ceb 100644
--- a/src/ui/image.cpp
+++ b/src/ui/image.cpp
@@ -370,7 +370,7 @@ ImageBuffer *load_xpm_image(char **data) {
   return result;
 }
 
-void get_image_display(var_s *self, int param_count, slib_par_t *params, ImageDisplay *image) {
+void get_image_display(var_s *self, ImageDisplay *image) {
   image->_bid = map_get_int(self, IMG_BID, -1);
 
   List_each(ImageBuffer *, it, buffers) {
@@ -381,13 +381,14 @@ void get_image_display(var_s *self, int param_count, slib_par_t *params, ImageDi
     }
   }
 
-  if (prog_error || image->_buffer == nullptr || param_count == 1 || param_count > 4) {
+  var_int_t x, y, z, op;
+  int count = par_massget("iiii", &x, &y, &z, &op);
+
+  if (prog_error || image->_buffer == nullptr || count == 1 || count > 4) {
     err_throw(ERR_PARAM);
   } else {
     // 0, 2, 3, 4 arguments accepted
-    if (param_count >= 2) {
-      var_int_t x = v_getint(params[0].var_p);
-      var_int_t y = v_getint(params[1].var_p);
+    if (count >= 2) {
       image->_x = x;
       image->_y = y;
       map_set_int(self, IMG_X, x);
@@ -396,15 +397,13 @@ void get_image_display(var_s *self, int param_count, slib_par_t *params, ImageDi
       image->_x = map_get_int(self, IMG_X, -1);
       image->_y = map_get_int(self, IMG_Y, -1);
     }
-    if (param_count >= 3) {
-      var_int_t z = v_getint(params[2].var_p);
+    if (count >= 3) {
       image->_zIndex = z;
       map_set_int(self, IMG_ZINDEX, z);
     } else {
       image->_zIndex = map_get_int(self, IMG_ZINDEX, -1);
     }
-    if (param_count == 4) {
-      var_int_t op = v_getint(params[3].var_p);
+    if (count == 4) {
       image->_opacity = op;
       map_set_int(self, IMG_OPACITY, op);
     } else {
@@ -422,9 +421,9 @@ void get_image_display(var_s *self, int param_count, slib_par_t *params, ImageDi
 //
 // png.show(x, y, zindex, opacity)
 //
-void cmd_image_show(var_s *self, int param_count, slib_par_t *params, var_s *) {
+void cmd_image_show(var_s *self, var_s *) {
   ImageDisplay image;
-  get_image_display(self, param_count, params, &image);
+  get_image_display(self, &image);
   if (!prog_error) {
     g_system->getOutput()->addImage(image);
   }
@@ -433,9 +432,9 @@ void cmd_image_show(var_s *self, int param_count, slib_par_t *params, var_s *) {
 //
 // png.draw(x, y, opacity)
 //
-void cmd_image_draw(var_s *self, int param_count, slib_par_t *params, var_s *) {
+void cmd_image_draw(var_s *self, var_s *) {
   ImageDisplay image;
-  get_image_display(self, param_count, params, &image);
+  get_image_display(self, &image);
   if (!prog_error) {
     image._opacity = image._zIndex;
     g_system->getOutput()->drawImage(image);
@@ -445,7 +444,7 @@ void cmd_image_draw(var_s *self, int param_count, slib_par_t *params, var_s *) {
 //
 // png.hide()
 //
-void cmd_image_hide(var_s *self, int param_count, slib_par_t *params, var_s *) {
+void cmd_image_hide(var_s *self, var_s *) {
   int id = map_get_int(self, IMG_ID, -1);
   g_system->getOutput()->removeImage(id);
 }
@@ -456,7 +455,7 @@ void cmd_image_hide(var_s *self, int param_count, slib_par_t *params, var_s *) {
 // png.save("horse1.png")
 // png.save(#1)
 //
-void cmd_image_save(var_s *self, int param_count, slib_par_t *params, var_s *) {
+void cmd_image_save(var_s *self, var_s *) {
   unsigned id = map_get_int(self, IMG_BID, -1);
   ImageBuffer *image = get_image(id);
   dev_file_t *file;
@@ -517,16 +516,17 @@ void cmd_image_save(var_s *self, int param_count, slib_par_t *params, var_s *) {
 //
 // png.clip(10, 10, 10, 10)
 //
-void cmd_image_clip(var_s *self, int param_count, slib_par_t *params, var_s *) {
+void cmd_image_clip(var_s *self, var_s *) {
   if (self->type == V_MAP) {
     int bid = map_get_int(self, IMG_BID, -1);
     if (bid != -1) {
       ImageBuffer *image = get_image((unsigned)bid);
-      if (image != nullptr && param_count == 4) {
-        map_set_int(self, IMG_OFFSET_LEFT, v_getint(params[0].var_p));
-        map_set_int(self, IMG_OFFSET_TOP, v_getint(params[1].var_p));
-        map_set_int(self, IMG_WIDTH, v_getint(params[2].var_p));
-        map_set_int(self, IMG_HEIGHT, v_getint(params[3].var_p));
+      var_int_t left, top, right, bottom;
+      if (image != nullptr && par_massget("iiii", &left, &top, &right, &bottom)) {
+        map_set_int(self, IMG_OFFSET_LEFT, left);
+        map_set_int(self, IMG_OFFSET_TOP, top);
+        map_set_int(self, IMG_WIDTH, right);
+        map_set_int(self, IMG_HEIGHT, bottom);
       }
     }
   }
diff --git a/src/ui/window.cpp b/src/ui/window.cpp
index 2bebe619..7f31b125 100644
--- a/src/ui/window.cpp
+++ b/src/ui/window.cpp
@@ -62,34 +62,30 @@ StringList *get_items() {
   return items;
 }
 
-void cmd_window_select_screen1(var_s *self, int param_count, slib_par_t *params, var_s *) {
+void cmd_window_select_screen1(var_s *self, var_s *) {
   g_system->getOutput()->selectScreen(USER_SCREEN1);
 }
 
-void cmd_window_select_screen2(var_s *self, int param_count, slib_par_t *params, var_s *) {
+void cmd_window_select_screen2(var_s *self, var_s *) {
   g_system->getOutput()->selectScreen(USER_SCREEN2);
 }
 
-void cmd_window_select_screen3(var_s *self, int param_count, slib_par_t *params, var_s *) {
+void cmd_window_select_screen3(var_s *self, var_s *) {
   g_system->getOutput()->selectScreen(TEXT_SCREEN);
 }
 
-void cmd_window_show_keypad(var_s *self, int param_count, slib_par_t *params, var_s *) {
+void cmd_window_show_keypad(var_s *self, var_s *) {
   maShowVirtualKeyboard();
 }
 
-void cmd_window_hide_keypad(var_s *self, int param_count, slib_par_t *params, var_s *) {
+void cmd_window_hide_keypad(var_s *self, var_s *) {
   maHideVirtualKeyboard();
 }
 
-void cmd_window_inset(var_s *self, int param_count, slib_par_t *params, var_s *) {
-  if (param_count != 4) {
-    err_parm_num(param_count, 4);
-  } else {
-    var_int_t x = v_getint(params[0].var_p);
-    var_int_t y = v_getint(params[1].var_p);
-    var_int_t w = v_getint(params[2].var_p);
-    var_int_t h = v_getint(params[3].var_p);
+void cmd_window_inset(var_s *self, var_s *) {
+  var_int_t x, y, w, h;
+  par_massget("IIII", &x, &y, &w, &h);
+  if (!prog_error) {
     if (x < 0 || x > 100 ||
         y < 0 || y > 100 ||
         w < 1 || x + w > 100 ||
@@ -101,42 +97,31 @@ void cmd_window_inset(var_s *self, int param_count, slib_par_t *params, var_s *)
   }
 }
 
-void cmd_window_set_font(var_s *self, int param_count, slib_par_t *params, var_s *) {
-  if (param_count != 4) {
-    err_parm_num(param_count, 4);
-  } else {
-    var_num_t size = v_getreal(params[0].var_p);
-    const char *unit = v_getstr(params[1].var_p);
-    var_int_t bold = v_getint(params[2].var_p);
-    var_int_t italic = v_getint(params[3].var_p);
-    if (unit != nullptr && strcmp(unit, "em") == 0) {
-      size *= g_system->getOutput()->getFontSize();
-    }
-    g_system->getOutput()->setFont(size, bold, italic);
+void cmd_window_set_font(var_s *self, var_s *) {
+  var_num_t size;
+  var_int_t bold, italic;
+  char *unit = nullptr;
+  par_massget("FSII", &size, &unit, &bold, &italic);
+  if (unit != nullptr && strcmp(unit, "em") == 0) {
+    size *= g_system->getOutput()->getFontSize();
   }
+  g_system->getOutput()->setFont(size, bold, italic);
+  pfree(unit);
 }
 
-void cmd_window_set_size(var_s *self, int param_count, slib_par_t *params, var_s *) {
-  if (param_count != 2) {
-    err_parm_num(param_count, 2);
-  } else {
-    var_int_t width = v_getint(params[0].var_p);
-    var_int_t height = v_getint(params[1].var_p);
-    g_system->setWindowRect(-1, -1, width, height);
-  }
+void cmd_window_set_size(var_s *self, var_s *) {
+  var_int_t width, height;
+  par_massget("II", &width, &height);
+  g_system->setWindowRect(-1, -1, width, height);
 }
 
-void cmd_window_set_location(var_s *self, int param_count, slib_par_t *params, var_s *) {
-  if (param_count != 2) {
-    err_parm_num(param_count, 2);
-  } else {
-    var_int_t x = v_getint(params[0].var_p);
-    var_int_t y = v_getint(params[1].var_p);
-    g_system->setWindowRect(x, y, -1, -1);
-  }
+void cmd_window_set_location(var_s *self, var_s *) {
+  var_int_t x, y;
+  par_massget("II", &x, &y);
+  g_system->setWindowRect(x, y, -1, -1);
 }
 
-void cmd_window_get_theme(var_s *self, int param_count, slib_par_t *params, var_s *retval) {
+void cmd_window_get_theme(var_s *, var_s *retval) {
   if (retval != nullptr) {
     EditTheme theme;
     theme.setId(g_themeId);
@@ -152,7 +137,7 @@ void cmd_window_get_theme(var_s *self, int param_count, slib_par_t *params, var_
   }
 }
 
-void cmd_window_alert(var_s *self, int param_count, slib_par_t *params, var_s *) {
+void cmd_window_alert(var_s *self, var_s *) {
   StringList *items = get_items();
   if (!prog_error && items->size() > 0) {
     const char *message = items->size() > 0 ? (*items)[0]->c_str() : "";
@@ -162,7 +147,7 @@ void cmd_window_alert(var_s *self, int param_count, slib_par_t *params, var_s *)
   delete items;
 }
 
-void cmd_window_ask(var_s *self, int param_count, slib_par_t *params, var_s *retval) {
+void cmd_window_ask(var_s *self, var_s *retval) {
   StringList *items = get_items();
   if (!prog_error && items->size() > 0) {
     const char *message = items->size() > 0 ? (*items)[0]->c_str() : "";
@@ -176,7 +161,7 @@ void cmd_window_ask(var_s *self, int param_count, slib_par_t *params, var_s *ret
   delete items;
 }
 
-void cmd_window_menu(var_s *self, int param_count, slib_par_t *params, var_s *) {
+void cmd_window_menu(var_s *self, var_s *) {
   StringList *items = get_items();
   if (!prog_error && items->size() > 0) {
     g_system->optionsBox(items);
@@ -184,7 +169,7 @@ void cmd_window_menu(var_s *self, int param_count, slib_par_t *params, var_s *)
   delete items;
 }
 
-void cmd_window_message(var_s *self, int param_count, slib_par_t *params, var_s *) {
+void cmd_window_message(var_s *self, var_s *) {
   var_t arg;
   v_init(&arg);
   eval(&arg);

From 222d01439925be6b52cf8910ba2ae61600d621e5 Mon Sep 17 00:00:00 2001
From: Chris Warren-Smith <cwarrensmith@gmail.com>
Date: Sun, 7 Jan 2024 11:20:02 +1030
Subject: [PATCH 3/3] COMMON: Allow modules to return objects with methods that
 take arguments

---
 src/common/var.c      |  8 ++++++++
 src/common/var_eval.c | 22 +++++++++++++---------
 src/include/var.h     |  7 +++++++
 3 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/src/common/var.c b/src/common/var.c
index 3574840d..6f46ca7b 100644
--- a/src/common/var.c
+++ b/src/common/var.c
@@ -803,3 +803,11 @@ void v_create_func(var_p_t map, const char *name, method cb) {
   v_func->v.fn.mcb = NULL;
   v_func->v.fn.id = 0;
 }
+
+void v_create_callback(var_p_t map, const char *name, callback cb) {
+  var_p_t v_func = map_add_var(map, name, 0);
+  v_func->type = V_FUNC;
+  v_func->v.fn.cb = NULL;
+  v_func->v.fn.mcb = cb;
+  v_func->v.fn.id = 0;
+}
diff --git a/src/common/var_eval.c b/src/common/var_eval.c
index aa6912ed..7bcec5de 100644
--- a/src/common/var_eval.c
+++ b/src/common/var_eval.c
@@ -16,6 +16,17 @@
 #include "common/var_eval.h"
 #include "common/plugins.h"
 
+//
+// returns a temporary var that can exist in the calling scope
+//
+var_p_t v_get_tmp(var_p_t map) {
+  var_p_t result = map_get(map, MAP_TMP_FIELD);
+  if (result == NULL) {
+    result = map_add_var(map, MAP_TMP_FIELD, 0);
+  }
+  return result;
+}
+
 void v_eval_func(var_p_t self, var_p_t v_func, var_p_t result) {
   if (v_func->v.fn.cb != NULL) {
     // internal object method
@@ -185,11 +196,7 @@ var_t *code_get_map_element(var_t *map, var_t *field) {
       if (udf_rv.type != kwTYPE_RET) {
         err_stackmess();
       } else {
-        // result must exist until processed in eval()
-        var_p_t var = map_get(map, MAP_TMP_FIELD);
-        if (var == NULL) {
-          var = map_add_var(map, MAP_TMP_FIELD, 0);
-        }
+        var_p_t var = v_get_tmp(map);
         v_move(var, udf_rv.x.vdvar.vptr);
         v_detach(udf_rv.x.vdvar.vptr);
         result = var;
@@ -198,10 +205,7 @@ var_t *code_get_map_element(var_t *map, var_t *field) {
   } else if (field->type == V_ARRAY) {
     result = code_getvarptr_arridx(field);
   } else if (field->type == V_FUNC) {
-    result = map_get(map, MAP_TMP_FIELD);
-    if (result == NULL) {
-      result = map_add_var(map, MAP_TMP_FIELD, 0);
-    }
+    result = v_get_tmp(map);
     v_init(result);
     v_eval_func(map, field, result);
   } else {
diff --git a/src/include/var.h b/src/include/var.h
index 8ea30f90..16e0f4d2 100644
--- a/src/include/var.h
+++ b/src/include/var.h
@@ -503,6 +503,13 @@ int v_strlen(const var_t *v);
  */
 void v_create_func(var_p_t map, const char *name, method cb);
 
+/**
+ * @ingroup var
+ *
+ * creates a callback method
+ */
+void v_create_callback(var_p_t map, const char *name, callback cb);
+
 #if defined(__cplusplus)
 }
 #endif