[squeak-dev] Spry update: Spry goes visual!

Göran Krampe goran at krampe.se
Thu Sep 8 08:21:38 UTC 2016

Hi folks!

Just wanted to give a quick update on where I am (<hint>only me 
still</hint>) on the Spry project. I am taking the liberty to post on 
squeak-dev since I hope Squeakers find it interesting, especially the 
small movie below :) I also have some ideas on Squeak<->Spry interop, if 
anyone is interested - catch me on chat.

I am right now trying to nail down a few language level things, and 
finish the manual. The manual is up on the site and is fairly complete 
now (although needs a few rounds of polish):


...along with other things, like an article about "Smalltalk vs Spry" 
which I have only just started:


But... the most interesting part to tell about is probably the fact that 
Spry is taking its first steps with a user interface! Unless you count 
the command line REPL Spry has had for a long time. Or the "spry REPL in 
a browser page" that you can also find on the website (that is actually 
the real Spry VM compiled to js).

A short 2 min movie I made is here:


I hope you found that movie intriguing!

Because it shows a truly *live* experience, just like traditional 
Smalltalks offer. The code we type in is parsed and evaluated live and 
the IDE itself *is written in Spry* (not Nim). This makes it just as 
malleable as a Smalltalk environment.

To make this I have selected the excellent C library called libui:


There is already a wrapper in Nim (auto generated) for libui which made 
it easy for me to create a Spry VM module with primitives using it, the 
primitives and node types so far are here:


The OO mechanism including polymorphism in Spry is still being worked on 
- so naming for some of those things are needlessly messy (to make each 
unique), but apart from that it's very straight forward.

NOTE: There is also a Nim wxWidgets wrapper, a gtk2 wrapper and a gtk3 
wrapper. But... I wanted native on all 3 desktops and libui looks MUCH 
easier and lightweight than wx.

With that VM module included, we can finally look at the code for the 
IDE shown in the movie:


That's 57 lines of Spry code! ...and a big part is constructing the menu 
which the movie doesn't even show.

Also note how I attach Spry code blocks as handlers for the click 
events, menu items etc, for example:


So what we have are Spry code blocks (they are closures) that gets run 
as callbacks called from the C library. Those of you with a bit of 
history knows this has been a truly sore part of Squeak through the years.

And yes, this means we run in libui's event loop which we enter at the end:


And finally... this runs *natively* in Windows, OSX and Linux (Gtk3). 
The movie was recorded on my Ubuntu so its gtk3 that you see. I have 
tried it on OSX too, looks great!

regards, Göran

PS. I am on #squeak and #sprylang on freenode, but also on gitter which 
I kinda prefer: http://gitter.im/gokr/spry

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