Re: Adding new contructors to IOMode to support "don't overwrite if already exists" behavior

One really important question is what modes are actually promised by actual file systems on every posix or otherwise supported platforms . Table stakes is code should work well on every tier 1 platform and tier 2 as well And it’s been pointed out to me that this is part of the Haskell report so whatever final design is done needs to be excellent Meta aside : on and off I sometimes wonder what the world would be like if file systems weren’t stuck in posix minima tar pits (heck an Mvcc with transactions file system would rock). But that’s unrelated to improving the world we have. Do either way this at least starts a discussion about what we can do better today ! Pardon the slow reply, I think everyone everywhere is having a very strange start to spring. Be well and look forward to improving bits and pieces of how we deal with files on computers ;) -Carter On Tue, Mar 31, 2020 at 5:51 PM Carter Schonwald wrote:

At least naively, this seems like a really good idea.

1) do folks who have more experience across the range of supported platforms have any opinions about these additional semantics ?

2) are these names suitably descriptive / unambiguous and or otherwise widely used / discoverable ?

On Mon, Mar 30, 2020 at 12:22 PM Grey Mitchell wrote:

...

The current behavior for System.IO.openFile will either truncate an existing file (with WriteMode) or append new content to the end (with AppendMode). However, there's another behavior that's available from the underlying API: signal an error when the file already exists. I poked around at the code and i think that with a couple extra variants of IOMode, this behavior could be added with a relatively small patch.

I have a branch pushed where i added this behavior:

https://gitlab.haskell.org/QuietMisdreavus/ghc/-/commit/1ff18d4d3fc63f42c371...

I'm a relative newcomer to contributing to GHC or the base library, so if i'm missing something in my patch please let me know. Specifically, i would like to know is there's a place i can add a test for this behavior. I'm also open to changing the names of the new IOModes - this was just something i wrote in to get something working.

Looking forward to working with maintainers to get this added!

Thanks, Grey Mitchell (@QuietMisdreavus) _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries