Eq constraint is not needed
rename
use Control.Lens
rename
use Control.Lens
eliminate Data.Lens.Common module
eliminate joinRef (step 1)
eliminate joinRef (final step)
complete elimination of action
switch back to direct representation
fix typo
generalize SyntEffRef
simplification
change EqRef definition
change EqReference definition
first try to define IsString instance for ReadRef's
always use EqRefs (step 1)
Revert "always use EqRefs (step 1)"

This reverts commit 428a0e6c4bd87919ada4986ddb38d6a6472a35de.
add CorrRef
generalize evalRegister