dhall-io
An unsuccessful attempt putting IO in Dhall
Problem
The current approach uses unsafeIO to execute IO computations in the normalizer. However, the normalization algorithm provides no guaratees about redundant calls to normalize. Indeed, it calls functions in an exponential manner:
1121123112112341121123112112345
The source program was supposed to make 5 write calls, one per digit.
Possible fixes
Check the normalization algorithm (doesn't seem easy). Use an MVar and
sequence numbers in the World structure, ignoring IO/step calls with
numbers <= what's stored in MVar.