Stream: show and tell

Topic: Inline debug print helper

Luke Boswell (Jun 01 2024 at 08:13):

Thought I might share something which I've found really useful.

If I define a helper like this... (I'm using the ANSI package to print with colors, but could be simpler)

dbgHelp : Task ok err, Bool -> Task ok err where ok implements Inspect
dbgHelp = \task, shouldDbgPrint ->
    if shouldDbgPrint then
        Task.await task \answer ->
            Str.joinWith ["DEBUG:" |> Color.fg Blue, Inspect.toStr answer] " " |> Stderr.line!
            Task.ok answer
    else
        task

I can use it like this.

user = Sql.getUser args |> dbgHelp! devMode

Basically, just a nice way to log the output of a task inline without adding too much additional ceremony.

Brendan Hansknecht (Jun 09 2024 at 17:10):

Now just need a task to load shouldDbgPrint so you don't have to thread it through the app

Last updated: Jul 06 2025 at 12:14 UTC