Allow sail to be scripted using sail

Currently the -is option allows a list of interactive commands to be
passed to the interactive toplevel, however this is only capable of
executing a sequential list of instructions which is quite limiting.

This commit allows sail interactive commands to be invoked from sail
functions running in the interpreter which can be freely interleaved
with ordinary sail code, for example one could test an assertion at each
QEMU/GDB breakpoint like so:

$include <aarch64.sail>

function main() -> unit = {
  sail_gdb_start("target-select remote localhost:1234");
  while true do {
    sail_gdb_continue(); // Run until breakpoint
    sail_gdb_sync();     // Sync register state with QEMU
    if not(my_assertion()) {
      print_endline("Assertion failed")
    }
  }
}

1 files changed, 13 insertions, 2 deletions

diff --git a/src/interactive.mli b/src/interactive.mli
index b1df0630..933d0a46 100644
--- a/src/interactive.mli
+++ b/src/interactive.mli
@@ -62,6 +62,17 @@ val env : Env.t ref
 val arg : string -> string
 val command : string -> string
 
-val commands : (string * (string * (string -> unit))) list ref
+type action =
+  | ArgString of string * (string -> action)
+  | ArgInt of string * (int -> action)
+  | Action of (unit -> unit)
 
-val register_command : name:string -> help:string -> (string -> unit) -> unit
+val reflect_typ : action -> typ
+
+val commands : (string * (string * action)) list ref
+
+val register_command : name:string -> help:string -> action -> unit
+
+val generate_help : string -> string -> action -> string
+
+val run_action : string -> string -> action -> unit