Modules and Run/Liberty BASIC

People have been asking for a way to create code libraries in Liberty BASIC for some time. I have thinking about how to do this using an in-memory model. Over the weekend Scott and I worked on adding some modularity to the Run/Liberty BASIC language. Here's how it works so far. We are open to suggestions.

The RUN statement has a new form. If I want to use mymodule.bas as a module in a program I am writing I would code it like this:

run "mymodule.bas", #myModule

This causes mymodule.bas to be compiled into memory. It will execute code up to the first wait statement. This is how values will be initialized. The program then becomes an object assigned to the #myModule handle.

Then you can call any function on that program from within the calling program, like so:

#myModule myFunction(myParameter)

or even use the invokation in a more complex expression:

print "digits: "; len(#myModule myFunction(myParameter))

You may recognize this syntax as being the same as for controlling widgets. It relies on the same underlying mechanisms to do its work.

When we're done with this, modular programs loaded this way will be cached in memory and will only recompile when the source file changes.

Inkey$ and Liberty BASIC

There has been some discussion in the support forum about extending keyboard handling in Liberty BASIC programs. Currently we only allow doing something like this in the graphics views. Two things (maybe more?) are missing:

• Getting the next character in the mainwindow without stopping the program. Currently only INPUT and INPUT$() are supported. Both stop the program and wait.
• Getting the next character typed for some window or widget that has focus. In other words, reading keypresses for objects with handles (ie. #thisWindow)

What I suggested in the forum is a function called inkey$().

The following would read keypresses for the mainwindow:

print inkey$()

or it could be abbreviated to:

print inkey$

To read keypresses for windows or widgets with handles:

print inkey$(#handle)

I'd like to solicit feedback here. Any ideas? Please leave a comment, and thanks!

BASIC and CSS

One of the important aspects of integrating a programming language with web development is page layout. Until recently this would have meant inserting lots of HTML tags into your source code. You can do this with Run BASIC.

However there is a better way. It is called CSS (Cascading Style Sheets). This provides a way to wrap the things on your web page with tags that you give your own names to, and you defined the appearance of the stuff wrapped in those tags somewhere else. This way your program's code has very little extra stuff in it to clutter up your code. If there is too much clutter it can be very hard to understand what code means, and this can slow you down and lead to bugs.

So, Scott McLaughlin and I have begun to integrate CSS with Run BASIC. We added a CSSID statement (originally this blog entry had this as CSS, but we changed the command), a DIV statement, and an END DIV statement. Here's a very short example:

cssid #myTag, "{ background: #FFDDDD; font-family: tahoma }"

div myTag
print "count to ten"
for x = 1 to 10
print x
next x
end div

Okay, so this displays all the text printed between the DIV and the END DIV with a light red background, and using the tahoma font. The #myFont token isn't a handle like the ones used for files and GUI controls. The # is simply part of CSS syntax.

DIV statements can be nested, and the contents of one DIV block will be rendered on the page nested inside of each other.

There is a lot more that can be done with CSS, and we're trying to explore what are the simplest and most useful things to include in Run BASIC.

We will be posting a screencast in the next few days that shows how this works.

Demo of Run BASIC at Smalltalk Solutions

Wednesday evening I had the priviledge of organizing the Seaside BOF (birds of a feather) session at Smalltalk Solutions. This meant that I was the one up at the microphone (which I pushed aside since the room wasn't big) for most of an hour and a half. It was fun and I didn't feel put on the spot since this was more of a round table than anything. I only had to try and direct the conversation some.

Here is James Robertson's blog entry with a photo of me presenting.

http://www.cincomsmalltalk.com/blog/blogView?entry=3355631481

I'm very small in the frame, but yeah that's me all right. You can make out the Run BASIC web page up on the screen if you look carefully.

The demo was a little bit scary since I was modifying the Run BASIC code almost right up to the last second before the meeting. Scott and I were spending most of our free time at the conference working on some simple CSS integration. I'm hoping to put a screencast up to show how it all works.