Idiom: variable names
Now that our build system is one giant
Makefile, all our variables
share the same namespace. Where previously we might have had a
variable that contained a list of the Haskell source files called
HS_SRCS, now we have one of these for each directory (and indeed each build, or distdir) in the source tree,
so we have to give them all different names.
The idiom that we use for distinguishing variable names is to prepend
the directory name and the distdir to the variable. So for example the list of
Haskell sources in the directory
utils/hsc2hs would be in the
utils/hsc2hs_dist_HS_SRCS (make doesn't mind slashes in variable
names). The pattern is: directory_distdir_variable.
See also Idiom: macros where many applications of this naming idiom are necessary.
Variables affecting compilation
The file rules/distdir-way-opts.mk contains a list of the variables affecting compilation, such as