File extensions, pas & pp ?

[PeterBB]

I'm curious about the extension .pp 
I would expect Pascal code files to be .pas

Whats the use case for .pp ?
Are .pas & .pp interchangeable?

I'm aware of
https://wiki.freepascal.org/File_extensions
which suggests .pas for units, implying .pp for programs,
but I've seen many units in Lazarus with extension .pp

I guess the extension is not that important,
I'm just wondering what the best practice is here.

[silvercoder70]

.pp files are the same as .pas files except the extension is typically used to indicate the contents are not delphi compatible - at least that is my understanding.

(It's funny you asked this question as I had created a video for YouTube at the beginning of the week on fpc file types but because I also work and had other commitments in the last days I was only able to edit and upload today.)

[marcov]

Turbo Pascal actually, as Delphi compatibility had barely started when it was introduced.  However it was more a self administrative help tool then a hard rule or so.

[PeterBB]

Thanks for the explanations. Maybe the wiki needs updating then?

I has assumed that .pp related to .ppu, in that a compiled pp gives a ppu,
but I gather now that is not the meaning of .pp.

Cheers,
Peter

[wp]

Maybe the wiki needs updating then?

What's wrong with what's written on https://wiki.freepascal.org/File_extensions?

.pp    Pascal code

[Thaddy]

Note file extensions are basically opaque and do not mean much by itself. It can be even txt....

[marcov]

Note file extensions are basically opaque and do not mean much by itself. It can be even txt....

For units it is more important, as they are autoloaded by the compiler searching one of those extensions