[fractallyte]

The Amiga ecosystem perfected this: most (good) software featured an ARexx 'port' - an API, based on the REXX language, that enabled any one program to communicate with another. Or one could simply write an ARexx script to automate a process.

Here's an example of the first occasion I seriously used this, when producing a 3D anaglyphic animation for video: graphics frames - two images for left and right - were rendered in VistaPro (the original 3D landscape generator); as soon as rendering was complete, ImageFX (image processing software) picked up the output and combined the channels to make an anaglyph; this was then sent to the PAR animation recorder (a video recorder). So, THREE separate large packages from different software companies, working in synchrony with each other via ARexx. The whole operation worked so smoothly and efficiently, first time, that I still recall it with awe.

Sadly, yet another killer Amiga feature that never made it to modern computing...

[pjmlp]

The libraries concept used to extend the OS were another cool Amiga feature.

I would say the closest we have today to ARexx experience are Powershell and AppleScript.