new() with typedesc

README.adoc

@@ -1,6 +1,6 @@
 = High level GTK3 (and GTK4) bindings for the Nim programming language
 (c) Stefan Salewski                                     
-//Version 0.7.2
+//Version 0.7.3
 :experimental:
 :imagesdir: http://ssalewski.de/tmp
 :source-highlighter: pygments
@@ -25,8 +25,14 @@ with code inserted from files directly.
 NOTE: This work is partly based on earlier works of J. Mansour and has been supported by A. Rumpf, E. Bassi and other _Nim_ and _GTK/Gnome_ developers.
 The `combinatorics` module was kindly provided by R. Behrends.
 
+NOTE: Starting with current version v0.7.3 we allow passing a type descriptor as first parameter to the
+new() procs like `newButton(MyButtonSubclass)` to support subclassing and extending Widgets in OOP style.
+See <<Extending or sub-classing Widgets>> for an complete example. The init() procs which were used
+before for this task are now deprecated and will be removed later. This new approach generally saves
+one line of source code, allows using `let` instead of `var`, and the naming of procs is more consistent.
+
 NOTE: Starting with version v0.7.1 we have added destructor support when compiled with `--gc:arc`,
-so we have no memory leak for subclassed objects any more, see the example in `Subclassing` section.
+so we have no memory leak for subclassed objects any more, see the example in <<Extending or sub-classing Widgets>> section.
 When compiled with default (refc) GC finalizers are used as before. And for objects marked with `nullable`
 tag in gobject-introspection we now return nil value for the proxy object when the C lib has returned NULL.
 So according to the C API docs, you can check for nil result for the few functions which may return NULL.
@@ -597,13 +603,17 @@ Remember the GTK `devhelp` tool, and use also `grep` or the `nimgrep` variant.
 
 == Extending or sub-classing Widgets
 
-I may occur that we want to attach additional information to GTK widgets
+It may occur that we want to attach additional information to GTK widgets
-by extending or subclassing them. Doing this is supported
+by extending or subclassing them. [line-through]#Doing this is supported
 by providing for each widget class not only a corresponding new() proc which returns 
 the newly created widget, but also
 a init() proc, which gets an uninitialized variable of the (extended) widget type as argument and
 initializes that variable with a newly created
-GTK widget . Initializing the added fields is
+GTK widget.#
+Doing this is supported
+by providing for each widget class an additional new() proc which takes an type descriptor
+as first argument, like `newButton(CountButton, "Counting down from 100 by 5")` in the example below.
+Initializing the added fields is
 done separately by the user. The following code shows a GTK button, which is
 extended with a counter member field. That counter is decreased for
 each button click. The amount of decrease (5) is passed to the callback as a int parameter.
@@ -621,13 +631,13 @@ to test the destructor behaviour.)
 .count_button.nim
 ----
 # nim c count_button.nim
-import gintro/[gtk, glib, gobject, gio]
+import gintro/[gtk, gobject, gio]
 
 type
   CountButton = ref object of Button
     counter: int
 
-when compileOption("gc", "arc"):
+when defined(gcDestructors):
   proc `=destroy`(x: var typeof(CountButton()[])) =
     gtk.`=destroy`(typeof(Button()[])(x))
 
@@ -637,10 +647,11 @@ proc buttonClicked (button: CountButton; decrement: int) =
   echo "Counter is now: ", button.counter
 
 proc appActivate (app: Application) =
-  var button: CountButton
+  #var button: CountButton
   let window = newApplicationWindow(app)
   window.title = "Count Button"
-  initButton(button, "Counting down from 100 by 5")
+  #initButton(button, "Counting down from 100 by 5") # deprecated
+  let button = newButton(CountButton, "Counting down from 100 by 5")
   button.counter = 100
   window.add(button)
   button.connect("clicked", buttonClicked, 5)

examples/gtk3/count_button.nim

@@ -1,11 +1,11 @@
 # nim c count_button.nim
-import gintro/[gtk, glib, gobject, gio]
+import gintro/[gtk, gobject, gio]
 
 type
   CountButton = ref object of Button
     counter: int
 
-when compileOption("gc", "arc"):
+when defined(gcDestructors):
   proc `=destroy`(x: var typeof(CountButton()[])) =
     gtk.`=destroy`(typeof(Button()[])(x))
 
@@ -15,10 +15,11 @@ proc buttonClicked (button: CountButton; decrement: int) =
   echo "Counter is now: ", button.counter
 
 proc appActivate (app: Application) =
-  var button: CountButton
+  #var button: CountButton
   let window = newApplicationWindow(app)
   window.title = "Count Button"
-  initButton(button, "Counting down from 100 by 5")
+  #initButton(button, "Counting down from 100 by 5") # deprecated
+  let button = newButton(CountButton, "Counting down from 100 by 5")
   button.counter = 100
   window.add(button)
   button.connect("clicked", buttonClicked, 5)

gintro.nimble

@@ -1,6 +1,6 @@
 # Package
 
-version       = "0.7.2"
+version       = "0.7.3"
 author        = "Stefan Salewski"
 description = "High level GObject-Introspection based GTK3/GTK4 bindings"
 license       = "MIT"

tests/gen.nim

@@ -1,6 +1,6 @@
 # High level gobject-introspection based GTK3/GTK4 bindings for the Nim programming language
 # nimpretty --maxLineLen:130 gen.nim
-# v 0.7.2 2020-FEB-23
+# v 0.7.3 2020-MAR-09
 # (c) S. Salewski 2018
 
 # https://wiki.gnome.org/Projects/GObjectIntrospection
@@ -900,21 +900,29 @@ proc writeMethod(info: GIBaseInfo; minfo: GIFunctionInfo) =
           for j in 0.cint ..< gCallableInfoGetNArgs(minfo):
             let arg = gCallableInfoGetArg(minfo, j)
             assert gArgInfoGetDirection(arg) notin {GIDirection.OUT, INOUT} # so we can ignore this case!
-          for i in 0 .. 1: # generate the new() and the init() proc
+          for itt in 0 .. 2: # generate the new(), the new(typedesc) and the init() proc
             var hhh = "\nproc " & asym & EM & plist
-            if i > 0:
+            if itt == 1: # new(typedesc)
+              let semi = if hhh.contains("()"): "" else: "; "
+              let p = hhh.find("): ")
+              hhh.setLen(p + 1)
+              hhh = hhh.replace("*(", "*(tdesc: typedesc" & semi)
+              hhh.add(": tdesc")
+            if itt == 2: # init(), deprecated
               let semi = if hhh.contains("()"): "" else: "; "
               let p = hhh.find("): ")
               hhh.setLen(p + 1)
               hhh = hhh.replace("new", "init")
               hhh = hhh.replace("*(", "*[T](result: var T" & semi)
+            if itt == 2:
+              depStr = " {.deprecated.}"
             methodBuffer.writeLine(hhh & depStr & " =")
             methodBuffer.write(arrLex)
             methodBuffer.write(sss)
             if gCallableInfoCanThrowGerror(minfo):
               methodBuffer.writeLine("  var gerror: ptr glib.Error")
-              if i == 0: arglist.insert(", addr gerror", arglist.high)
+              if itt == 0: arglist.insert(", addr gerror", arglist.high)
-            if i > 0:
+            if itt == 1 or itt == 2:
               methodBuffer.writeLine("  assert(result is $1)" % [manglename(gBaseInfoGetName(info))])
             if isGObject:
               # CAUTION: some procs are advertised as constructor but do not construct new objects,
@@ -2604,4 +2612,4 @@ proc launch() =
     supmod4.close
 
 launch()
-# 2607 lines
+# 2615 lines