Boost
C++ Libraries
...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
This version of Boost is under active development. You are currently in the master branch. The current version is 1.91.0.
The following are treated as valid digraphs when used as a collating name:
"ae", "Ae", "AE", "ch", "Ch", "CH", "ll", "Ll", "LL", "ss", "Ss", "SS", "nj", "Nj", "NJ", "dz", "Dz", "DZ", "lj", "Lj", "LJ".
So for example the expression:
[[.ae.]-c]
will match any character that collates between the digraph "ae" and the character "c".