An F# example

F# projects here:

• showperms – a simple CLI utility, using F# for maximum readabiilty
• showpermsOld – more complicated and irregular (but it’s shorter! and less readable!)
• DiffResults – test results rendered as a diff

showperms

CLI command to show permissions for all files and directories within the given paths.

Usage looks like this:

Z% showperms notFound testDir
      Error: notFound – No such file or directory
drwxr-xr-x   testDir/
drwxr-xr-x   testDir/1d/
drwxr-xr-x   testDir/2d/
-rw-r--r--   testDir/2d/1f
drwxr-xr-x   testDir/2d/2d/
-rwxr-xr-x   testDir/2d/3f
----------   testDir/2d/4f
dr--------   testDir/3d/
             testDir/3d/1d
             testDir/3d/2f
d--------- ! testDir/4d/

A shebang form is provided: showperms.fsx

Rider IDE files included.

Run createTestData.bash to create a testDir/ folder hierarchy.

Depends on NuGet packages:

• Mono.Posix.NETStandard
• NaturalStringExtensions

I have tried publishing a self-containd binary for osx-x64. It runs but not if copied to /usr/local/bin/. See stackoverflow.

showpermsOld

Earlier version, not taking full advantage of F#. Shorter but more complicated and irregular.

DiffResults

See test failures all at once, with a diff, instead of stopping at the first error.

Instead of an assert for each fact, where you see only the first error, using the DiffResults library, you see a line for each fact, shown as a diff of expected vs actual, like the first column of this table:

 diff      expected                actual
––––––     ––––––––                –––––– 
x not        what                    not
  what       where                   what
√ where      why                     but
x but        when                    why          
  why        [newline after when]    [no newline after why]
√ when      
√ 

Key:
   x = wrong: found in expected; is not in actual
   √ = right: not found in expected; is in actual

Depends on the DiffPlex NuGet package