On Sun, Jul 29, 2012 at 7:04 PM, Richard Cobbe
I'm working on an application that involves processing a lot of Unicode data, and I'm finding the built-in Show implementation for Char to be really inconvenient. Specifically, it renders all characters at U+0080 and above with decimal escapes:
Prelude> '\x80' '\128'
This is annoying because all of the Unicode charts give the code points in hex, and indeed the charts are split into different PDFs at numbers that are nice and round in hex but not in decimal. So in order to figure out which character I'm looking at, I have to convert back to hex and then look it up in the charts.
Is there any way to ask GHC to render super-ASCII characters with their hexadecimal escapes, instead? I'm perfectly happy to write my own custom Show instance, but I don't know how to hook that into ghci's REPL (or, for that matter, the routines that HUnit uses to generate the messages on failed tests, etc.).
I'm using GHC 7.4.1 on MacOS 10.7.4.
In GHC HEAD there is a new flag -interactive-print that allows to change the function used for printing values in GHCi. It will be in 7.6.1. That won't help with HUnit output, though. BR, Paolo