sutton036

Some objective quantitative measurements I once posted on Usenet: Jon Harrop wrote: > Andreas Rossberg wrote: >> That is a wild claim, and I doubt that you have any serious statistics >> to back it up. > > Here are some statistics on the proportion of lines of code devoted to > type annotations from 175kLOC of production OCaml and 5kLOC of production > Haskell: > > OCaml: > Hevea 9.0% > ADVI 8.6% > FFTW3 5.2% > Unison 3.5% > MLDonkey 2.5% > LEdit 1.4% > MTASC 0.0% > HLVM 0.0% > > Haskell: > XMonad 19% > Darcs 12% For further comparison, here are some statistics for compilers written in OCaml and Standard ML: OCaml: 6.3% of 217kLOC MosML: 13% of 69kLOC

Most software developers are now familiar with inheritance and virtual methods as common techniques for extensibility from the object oriented paradigm. When faced with functional programming for the first time, these developers often ask how to write extensible code in this alien paradigm. The functional paradigm actually only provides a single form of extensibility: higher-order functions. These allow you to factor out "inner" functions. For example, code that often appears with the same first and last code blocks: let f x = first x stuff1 x last x let g x = first x stuff2 x last x can be factored into a general higher order function that is reused from the specific cases: let hof stuff x = first x stuff x last x let f = hof stuff1 x let g = hof stuff2 x Applying this aggressively leads to design patterns such as parser combinators and is a very powerful and lightweight technique for making code extensible. However, it does not make data types extensible. Conseque...