stdin/stdout input/output

[mtijanic]

Should have a way to print the output to stdout, for composability with other tools (eg nwnt foo.gff | grep bar).
Arguably this should be the default and an argument or pipe redirect (>) would send it to a file, but if the CLI is meant to be stable then a new flag would work.

Should also be able to take input from stdin, especially in nwnt->gff direction, so you could do nwnt | sed | nwnt for quick edits.

[WilliamDraco]

New commit for beta of 1.5.0 which adds

• stdin, which it reverts to if <inputfile> is not a file that exists. (So passing - as a filepath will read stdin
• stdout, either as the default if read from stdin and no -o was specified, or by specifying -o stdout
• The above should mean pretty simple std useage without any breakage or change to existing workflows.

This is not final yet due to a nwn_gff issue, at least on windows, when writing out gff data to stdout (See issue). But my tests on piping gff->nwnt through stdin/out at least appear to be working.

[mtijanic]

Thanks for the speedy impl! I don't think this is right however:

stdin, which it reverts to if <inputfile> is not a file that exists.

If I do nwnt foo.gff and foo.gff doesn't exist, I'd want to get an error and not have the program block on stdin.
IMO:

• nwnt foo.gff should read foo.gff or fail
• nwnt - should read stdin
• nwnt (no file argument) should read stdin.

Also, -o stdout is a bit unfortunate as it doesn't allow you to write to a file called stdout but that's a limitation most can live with (even if not a limitation most tools have)

[WilliamDraco]

As discussed in discord - I was having trouble handling stdin as you describe, but after leaving it a few hours and picking it back up the answer was extremely obvious.
New 1.5.1 beta acts as you describe:
nwnt or nwnt - reads from stdin (only when piped)
nwnt foo.gff attempts to find foo.gff or else quits.

Just to publicise the discussion: -o stdout could be changed to any other string, but stdout was just first-to-mind and extremely unlikely as a genuine filename. 🤷 Will stay as is for now.

Unrelated: Also discovered nwn_gff has issues with piped-in gff data on my machine too. Remains in beta until I determine if it's just me or will require an nwnt-side fix too.