Ticket #1506 (closed feature request: wontfix)
Case-insensitive char/string comparison
|Reported by:||Eelis||Owned by:|
|Type of failure:||Difficulty:||Unknown|
|Test Case:||Blocked By:|
Data.Char provides functions to convert case, but does not provide a function to perform case-insensitive char/string comparison. Note that such functionality cannot be obtained by simply comparing for equality after performing toUpper/toLower, because some languages have things like multiple lowercase characters corresponding to the same uppercase character.
For example, in Greek, converting either σ or ς to uppercase yields Σ, while the inverse always yields σ. Consequently, the convert-all-to-uppercase approach would produce a false positive when comparing σ to ς, and the convert-all-to-lowercase approach would produce a false negative when comparing Σ to ς.