Robert Harper, one of the authors of Standard ML, has given his reasons for not using Haskell to teach introductory programming. Among these are the difficulty of reasoning about resource use with non-strict evaluation, that lazy evaluation complicates the definition of data types and inductive reasoning, and the "inferiority" of Haskell's (old) class system compared to ML's module system. Haskell's build tool, Cabal, has historically been criticised for poorly handling multiple versions of the same library, a problem known as "Cabal hell". The Stackage server and Stack build tool were made in response to these criticisms. Cabal itself now has a much more sophisticated build system, heavily inspired by Nix, which became the default with version 3.0. Clean is a close, slightly older relative of Haskell. Its biggest deviation from Haskell is in the use of uniqueness types instead of monads for I/O and side-effects. A series of languages inspired by Haskell, but with different type systems, have been developed, including:  Java virtual machine (JVM) based:  Other related languages include:  Haskell has served as a testbed for many new ideas in language design. There have been many Haskell variants produced, exploring new language ideas, including:  The Haskell community meets regularly for research and development activities. The main events are:  Since 2006, a series of organized "hackathons" has occurred, the Hac series, aimed at improving the programming language tools and libraries. Falkland Islands at the 2010 Commonwealth Games  Falkland Islands competed in the 2010 Commonwealth Games held in Delhi. Szalay  Szalay may refer to:      Kresnice  Kresnice (; ) is a settlement on the right bank of the Sava River in the Municipality of Litija in central Slovenia. The area is part of the traditional region of Lower Carniola. It is now included with the rest of the municipality in the Central Sava Statistical Region; until January 2014 the municipality was part of the Central Slovenia Statistical Region. Kresnice was mentioned in written sources ca. 1261 as "villa Grafnitz" (and as "ze Kräznicz" in 1372, "Cråzznicz" in 1380, and "Krasnicz" in 1449). The name is derived from the Slovene common noun "kres" 'summer solstice; solstice bonfire' and may indicate a place where such bonfires were held.