[Rust on Classic Mac OS post](@/posts/2023/rust-on-ppc-classic-mac-os/index.md) I continued trying to
find a modern language that I can use to build classic Mac OS software. I've
had some success with [Nim] and built a little
[temperature converter application][nim-temp-src]. As part of this I wanted to be able to use
[ResEdit] to edit the layout of the dialog. The problem was that I need a way
to convert the modified resources back into the textual representation used in
the source code. In this post I describe how I did this with `DeRez`.
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{{ video(video="posts/2023/derez/mac-nim-temp.mp4", height=227, poster="png", preload="auto", alt="Video of the temperature converter application.", caption="Video of the temperature converter application.") }}
To build the temperature converter I started with the [Dialog sample] from
{{ figure(image="posts/2023/derez/Dialog.png", link="posts/2023/derez/Dialog.png", pixelated=true, alt="Screenshot of the Dialog sample from Retro68. It has a static text item, edit text item, check box, two radio buttons, and a Quit button.", caption="Dialog Sample") }}
I opened it up in ResEdit and edited the `DITL` (Dialog Template) resource to
add the icon and temperature fields. I also added a new `ICON` resource and
drew a little thermometer:
{{ figure(image="posts/2023/derez/DITL.png", link="posts/2023/derez/DITL.png", pixelated=true, alt="Screenshot of the ResEdit DITL editor editing the DITL resource for my temperature converter.", caption="Editing DITL resource in ResEdit") }}
With the changes made, I now wanted to convert the binary resources stored in
the resource fork back into the [textual format used in the source code][dialog.r].
I believe the format is called `Rez`, here's a snippet of it:
```
resource 'DITL' (128) {
{
{ 190-10-20, 320-10-80, 190-10, 320-10 },
Button { enabled, "Quit" };
{ 190-10-20-5, 320-10-80-5, 190-10+5, 320-10+5 },
UserItem { enabled };
{ 10, 10, 30, 310 },
StaticText { enabled, "Static Text Item" };
{ 40, 10, 56, 310 },
EditText { enabled, "Edit Text Item" };
{ 70, 10, 86, 310 },
CheckBox { enabled, "Check Box" };
{ 90, 10, 106, 310 },
RadioButton { enabled, "Radio 1" };
{ 110, 10, 126, 310 },
RadioButton { enabled, "Radio 2" };
}
};
```
This turned out to be a bit of journey and the motivation for this blog post.
As part of the [Macintosh Programmers Workshop][mpw] (MPW) theres is a tool
called `DeRez` that does what I want. First up I had to work out how to operate
MPW. It's an editable shell where you run commands with ⌘-Return. Once I worked
that out I could run `DeRez` on my edited application but I only got the
fullback hexadecimal representation of the resources, not the structured output
{{ figure(image="posts/2023/derez/MPW.png", link="posts/2023/derez/MPW.png", pixelated=true, alt="Screenshot of an MPW worksheet on Mac OS 8 showing the output of running DeRez on an application.", caption="DeRez output in MPW") }}
