Back ends can still shortcut these and use their own primitives, but
doing things this way gives consistent behaviour between the simple IO
primitives and file IO, and allow us to use stdin/stdout consistently
(e.g. to flush stdout).
This also fixes the behaviour of 'replWith' to be consistent with the
Idris 1 version.
System mostly calls C now, except for getting command line arguments,
which may be too back end dependent so maybe we should think of another
approach here later.
I've also added some windows support headers (taken straight from the
rts/Idris 1) but I have no way to test, and the Makefile doesn't build
them. Please can someone who is familiar with windows fix this? Thanks!
This removes the need for some external primitives, and allows the
details to be shared between all the backends (plus we don't have to do
things a certain way just because Scheme chooses to)
It's slightly different wrt to file reading and writing, and now
requires the created buffer to be explicitly freed (since unlike Idris 1
the run time can't be told to manage C values) but this makes the buffer
code more portable by not requiring it to run via scheme.
Performance appears more or less the same as before.
(Which was commented out anyway)
Three scheme back ends is enough to maintain, and Gambit does the same
job as chicken (fast startup of the interpreter, generating via C) but
seems to deal with the code Idris generates better.
That is, really erase the argument position rather than just putting
'erased there. It doesn't make a huge difference to the generated scheme
performance, but since we can always do this for constructors, we might
as well.
Functions can be declared as %foreign with a list of calling
conventions, which a backend will work through until it finds one it can
understand. Currently implemented only in Chez backend. If this works
out, I'll implement it for Racket too, and remove the old primitive
functions.
There's a bit more boiler plate here than before, but it has the benefit
of being more extensible and portable between different back ends.
Some examples, pending proper documentation:
%foreign "C:puts,libc" "scheme:display"
putline : String -> PrimIO ()
%foreign "C:exp, libm.so.6, math.h"
fexp : Double -> Double
%foreign "C:initscr, ncurses_glue.so, ncurses.h"
prim_initscr : PrimIO ()
