#7870: Compilatio​n errors break the complexity encapsulat​ion on DSLs, impairs success in industry -----------------------------+---------------------------------------------- Reporter: agocorona | Owner: Type: feature request | Status: new Priority: normal | Component: Compiler (Type checker) Version: 7.7 | Keywords: DSL, Error, Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: None/Unknown | Blockedby: Blocking: | Related: -----------------------------+---------------------------------------------- From the paper "Scripting the Type Inference Process" -Bastiaan Heeren Jurriaan Hage S. Doaitse Swierstra: ... Combinator languages are a means of defining domain specific languages embedded within an existing programming language, using the abstraction facilities present in the latter. However, since the domain specific extensions are mapped to constructs present in the underlying language, all type errors are reported in terms of the host language, and not in terms of concepts from the combinator library. In addition, the developer of a combinator library may be aware of various mistakes which users of the library can make, something which he can explain in the documentation for the library, but which he cannot make part of the library itself. ...As a result, the beginning programmer is likely to be discouraged from pro-gramming in a functional language, and may see the rejection of programs as a nuisance instead of a blessing. The experienced user might not look at the messages at all. Definitively this is probably the biggest barrier for the acceptance of Haskell on Industry. We need to start with something not as sophisticated as the Helium paper "Scripting the Type Inference Process", but maybe a partial implementation of the techniques mentioned, so that the development can be enhanced in the future. Maybe some kind of library that permits postprocessing of GHC errors and/or the identification of points in the current type checker where some kind of rules can be defined by the programmer can be the first step. -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/7870 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler