close #9372 add std/tempfiles

[ringabout]

close #9372 add std/tempfiles

Followup:

• add destructors version that does clean-up works automatically.
• based on patterns(see close #9372 add std/tempfiles #17361 (comment))
• handle edge cases(close #9372 add std/tempfiles #17361 (comment))
• Add optional parameter for the length of random strings(see close #9372 add std/tempfiles #17361 (comment))

D:
https://dlang.org/library/std/stdio/file.tmpfile.html
Python:
https://docs.python.org/3.7/library/tempfile.html
C++/C:
http://www.cplusplus.com/reference/cstdio/tmpfile
Golang:
https://golang.org/pkg/io/ioutil
Ruby:
https://ruby-doc.org/stdlib-2.5.3/libdoc/tempfile/rdoc/Tempfile.html
PHP:
https://www.php.net/manual/en/function.tmpfile.php
Java/Groovy/Kotlin:
https://docs.oracle.com/javase/8/docs/api/java/nio/file/Files.html#createTempFile-java.nio.file.Path-java.lang.String-java.lang.String-java.nio.file.attribute.FileAttribute...-
C#:
https://docs.microsoft.com/en-us/dotnet/api/system.io.path.gettempfilename?view=net-5.0
Perl:
https://perldoc.perl.org/File::Temp
Haskell:
http://hackage.haskell.org/package/temporary-1.3/docs/System-IO-Temp.html
Lua:
io.tmpfile()
OCaml:
http://caml.inria.fr/pub/docs/manual-ocaml/libref/Filename.html#VALtemp_file

[Varriount]

Some general things:

• Documentation is needed
• Rather than sticking to C function names, descriptive names should be used.

[konsumlamm]

Does this really have to be a new module? Can't we put it in system/io or os for example? Even if so, I'd prefer a more general name (std/ioutils?), so that we can add more things in the future without having to make a new module again.

[Clyybber]

It should be added to os where getTempDir also resides in.

[ringabout]

std/tempfile intends to provide both low level and high level wrapper which provides auto cleaning up like Python.

TemporaryFile, NamedTemporaryFile, TemporaryDirectory, and SpooledTemporaryFile are high-level interfaces which provide automatic cleanup and can be used as context managers.

[timotheecour]

std/tempfille is expected to grow more features and deserves its own modules, std/os is too large already. Modules are a cheap abstraction. But this should be std/tempfiles, not std/tempfile
https://nim-lang.github.io/Nim/contributing.html

New module names should prefer plural form whenever possible, e.g.: std/sums.nim instead of std/sum.nim. In particular, this reduces chances of conflicts between module name and the symbols it defines.

Note that even python defines it in its own modules (https://docs.python.org/3/library/tempfile.html)

[ringabout]

"temp" vs "stemp" suffixes for the two different classes of functions.

mktemp is deprecated since version 2.3`

I only implement the safe one(use CREATE_NEW on windows and O_EXCL on posix).

[Varriount]

Is automatic cleanup planned?

[ringabout]

High level API can be implemented in the future PR(by means of destructors)

already added to todo
#17361 (comment)

[ringabout]

The PR is ready to be reviewed.

[timotheecour]

LGTM after remaining comments

[Araq]

Merging this now, can be further improved later.