Add a few useful os calls to nimscript

[genotrance]

Added the following procs to nimscript:-

• cpDir() = copyDir() - Feature request: copy dir function in nimscript #7393
• mvDir() = moveDir()
• pwd() = getCurrentDir()
• where() = findExe()

I was going to add some test cases into tests/newconfig/tfoo.nims but realized the nims extension is not covered by testament.

[data-man]

Maybe to rename a functions?
cpDir() -> copyDir()
mvDir() -> moveDir()
pwd() -> getCurrentDir()
where() -> findExe()

For compatibility with stdlib.
And pwd() for Windows-users it's not clear. And where() for *x-users. :)

[genotrance]

@Araq preferred different names which is why I did it this way.

https://irclogs.nim-lang.org/29-03-2018.html#23:33:13

[dom96]

This is unrelated to your PR, but why is this checkOsError needed? Won't movedDir etc. raise OSError?

[genotrance]

The exceptions are caught in template cbos() and errorMsg is set there for checkOsError() to check and re-raise it.

[dom96]

@Araq preferred different names which is why I did it this way.

It has just occurred to me why perhaps following Rust's convention might have made sense, exclamation mark at the end of every compile-time proc. Of course this would have had to be done before Rust was even a thing :)

[Araq]

1. Rust uses the exclamation mark for macros.
2. Exclamation marks are ugly and patronizing. Nim is not patronizing.

[Araq]

Sorry this took so long to review. The names are wrong. NimScript names differ from the stdlib names iff they do different things. rmDir is not an alias for removeDir it logs its action and supports ScriptMode.Whatif. But your where and pwd are just aliases, these should be named findExe and getCurrentDir. Btw getCurrentDir is already supported in nimscript.nim.

[genotrance]

I noticed getCurrentDir() but it isn't exported. I also think it is fair to have unique names in nimscript so that once import os does work in nimscript, it won't be a proc name conflict. Especially for backward compatibility, we won't be able to remove getCurrentDir() from nimscript as existing scripts will break without "import os".

I can change where() and pwd() back to their original names if there's a way to avoid the conflict in the future without requiring any script changes.

[Araq]

Well currently you cannot import os in NimScript and once you can you need to disambiguate via import os except getCurrentDir or similar. Not ideal but better than changing the reasoning behind these names.

[genotrance]

Sounds fair since there's also fileExists(), paramCount() and other such procs which share names so this isn't anything new.

I'll change to getCurrentDir() and findExe() and push.

[genotrance]

Added to changelog under "Library additions".