what's the difference between a plug-in and a script?

Let's not forget a major plus point of scripts: they are, or can be made to be, version independent. Older scripts that don't wo

rk

anymore (--please ignore random hard returns, I'm not going to fix jive-ups!) can be made to come alive

by putting them into a "Version xx Scripts" folder -- it works for all but the utmost 'dirty scripted hacks'.

Plugins, on the other hand, are highly version-dependent. And as Adobe publishes a new SDK, with new system and environment demands, per each new version of InDesign, the programmer has to acquire that new programming environs, work through the documentation to find what changed where, and update the source code of his own plugin just to make it work for a newer InDesign. Woe unto them who write plugins for a living if they don't promptly update their plugins to work with the latest version (after all, hey, the client paid for his old one -- and it does not work anymore in the new version so why don't you fix it for free as it is clearly broken -- etc.).

Steven.. wrote: I can't figure how they make a living)

Who says we do?

Harbs

Robin, don't dare to touch the weak spot of Harbs! He insists on the label "plugin" for both ;-)

I'll pick a few features of my plugins where scripts can not compete:

Plugins can be seamlessly integrated in many more places of the UI. I've done fields and icons in the control strip to display warnings or actual values of the selection, a tool for arbitrary work in the layout, the tool is tied to the info palette to show its own information while active. I frequently reuse the native widgets in my palettes (e.g. the tree view) with full drag and drop support if required. Preferences dialog? You get the idea.

Plugins can store their values in private places, in preferences, on every object and also in non-objects such as text, rather than abuse few existing features - the color of the unused paragraph rule above comes to mind. I'd instead create my own attributes and add another sub-dialog to the style options for completeness sake.

When Robin mentions the negative "footprint", that's an issue of badly designed plugins. If the programmer does not take care, you will indeed be confronted with "missing plugin" dialogs. Be assured there are options to suppress the dialog and recover gracefully when the document was modified without the plugin.

A major advantage of plugins is the ability to tap into an enormous range of internal notifications. Follow the selection the same way as the original widgets. You do not need to wait for the user to click a button, you just update your display while the mouse is still dragging the image, or you modify the behaviour of mouse-down on your added page item handles. You can step in between before things are changed that you need to change differently - snap to your own kind of grid.

Another advantage: speed. C++ is just faster, and can itself work on smallest details where scripts have to work their way thru levels of abstraction from the runtime engine thru the scripting object model, further thru high and low level encapsulation to finally flip the single bit in the document's database. Only a small part of internal functionality is really exposed to scripts - we just talked the other day that unused swatches are available but how about styles?

Many places within InDesign are designed to be replaced or extended. Run your own composer if you think you can do better than Adobe, or have to emulate Wor(d)se. Add your own drag and drop flavor. Want an own measurement unit? Implement hyphenation services for the Klingon language. Add support for unknown image formats. Very important are the assignment hooks for interchange with InCopy, as a developer of an editorial system you redirect their function towards your database.

As Loic mentions, plugins can be closed against changes. Nothing but the required development effort prevents them to open their functionality to other plugins, or to scripts. A well known example for extensible plugins is actually Rorohiko's plugin used as the basis for many advanced scripts such as Harb's. I also have plugins that invoke scripts on events such as drag and drop from outside, or that expose their new text attributes as scripting properties.

Dirk

Thanks for the link, Steven. But wow, that guy's podcast is totally over my head.

Please forgive my ignorance. I don't usually involve myself with "behind the scenes" info--I'm only an artist!!-- but tomorrow morning I am teaching some people about "extra cool things InDesign can do" and I just *know* this question will come up.

I guess I just wanted to know: from a user standpoint, what is the difference? why do we sometimes extend functionality with things called "scripts" and other times with "plug-ins"? what makes them different from one another--for example, why do I run a "script" to get cool corner effects and a "plug-in"  to do crop marks?

thanks again