[IronPython] Python in the Browser updates

Michael Foord fuzzyman at voidspace.org.uk
Thu Jun 19 11:05:16 CEST 2008

Hello all,

Thanks Jonathan. The approach you suggest has several great advantages. 
The disadvantages are that you lose the ability to copy and paste (I 
think most browsers forbid you from manipulating the clipboard from 
Javascript unless the user has fiddled with some obscure settings).

For the first release I'll stick with a textarea but I'll prototype your 
suggestion for the next release and see what I think.

Michael Foord

Jonathan Slenders wrote:
> 2008/6/18 Michael Foord <fuzzyman at voidspace.org.uk 
> <mailto:fuzzyman at voidspace.org.uk>>:
>     Jimmy Schementi wrote:
>         Michael, question for you:
>             On every keypress Javascript calls into IronPython (via
>             the C#!).
>         How come you used C# to handle the onkeypress event? This
>         should do it in Python:
>     Did you look at the code to see why? I'd be really interested to
>     know if I can do what I'm doing from Python inside Silverlight,
>     but I doubt it. There's not much code in total, so it should be
>     easy to follow.
>     I actually handle the onkeypress event from Javascript
>     (onkeypress.js). This calls into 'getSelection' (cursor_pos.js) to
>     work out the current selection in the textarea. Naturally this is
>     easy to do in Firefox / Safari and scarily awful in IE. :-)
>     Having worked these out (and shortcut a few specific scenarios -
>     like ctrl-A, ctrl-Z and ctrl-C), the Javascript then calls into
>     IronPython with the selection start, selection end, and the
>     character that was pressed. I use C# to expose a scriptable type
>     that Javascript can call.
>     I use attaching events from Python to provide the sample code.
>     There are three links above the console and Python handles the
>     'onclick' event to swap the examples around.
> I think Jimmy is right here. And the parts you did in javascript, 
> could also be done in Silverlight. Some suggestions how I would do this:
> - instead of a text area, I'd use a html <div> , with CSS "overflow: 
> auto;" for the scrollbars.
> - insert a <p> tag for each line into the <div>.
> - capture the body.onkeypress events for input
> - keep a textinput buffer in IronPython, but show the last line by 
> copying it on each keypress to the last <p>
> - The cursor could be <span>, styled in CSS to show a pinking cursor.
> - handle the left/right arrows to shift the cursor
> - handle the up/down arrows to replace the last <p> with the second 
> last executed command
> - on a "enter" press, process that line.
> - when using a <div>, it's even very easy to do syntax highlighting on 
> the fly. Surround known keywords by a <span class="keyword"> and style 
> them.
> That shouldn't be too hard to do. But you should decide whether it's 
> necessary to have this all in IronPython. Probably, it's the cleanest 
> way to do it.
> Jonathan
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