nilsson@cs.yale.edu writes:
Moreover, there is only one first line, and assuming some kind of language pragma is introduced, and assuming Simon Marlow goes ahead and introduces GHC_OPTIONS, and the other implementors goes ahead and introduces HUGS_OPTIONS, NHC_OPTIONS, etc., insisting on all of these being on the first line is obviously not going to work.
As it happens, nhc98 already interprets some pragmas in this manner: {-# OPTIONS_COMPILE #-} and {-# OPTIONS_LINK #-} The former gives options for this module alone, whereas the latter are accumulated when linking several modules together into an executable, to permit for instance a binding to a foreign library to be conveniently expressed in the single place where it is most relevant. However, clearly, there are already two of these pragmas, and as Henrik points out they also cannot both be in the first line! The way nhc98 deals with this is to do a quick and dirty parse of the source file in the driver script (i.e. grep "OPTIONS..." or equivalent), which information is then used to turn on/off language features in the invocation of the compiler proper. Seems easy enough. Regards, Malcolm