fostr/trans/ocaml.str
Glen Whitney 7feddbcfbe Extraction from streams (#25)
Add the ! postfix operator and !! expression.
  Also add the ++ string concatenation operator.
  Also allow specification of standard input in the test scheme.

  Resolves #7, #18.

Co-authored-by: Glen Whitney <glen@studioinfinity.org>
Reviewed-on: glen/fostr#25
Co-Authored-By: Glen Whitney <glen@nobody@nowhere.net>
Co-Committed-By: Glen Whitney <glen@nobody@nowhere.net>
2021-03-13 19:30:23 +00:00

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module ocaml
imports libstrategolib signatures/- util signature/TYPE analysis
/* Note will use bottomup-para to traverse the full AST so that
we have access to the original expression (and can get the
Statix-associated type when we need to).
This means that every one of our local rules must take a pair
of an original term and a term with every child replaced by
its generated code.
*/
rules
ml: (_, TopLevel(x)) -> $[(* fostr preamble *)
type stream = { getS: string -> stream; emitS: unit -> string }
let rec stdio = {
getS = (fun s -> print_string s; stdio);
emitS = (fun () -> (read_line ()) ^ "\n");
};;
(* End of preamble *)
[x]]
ml: (_, Stream()) -> $[stdio]
ml: (_, Int(x)) -> x
ml: (_, LitString(x)) -> $[{|[<un-single-quote>x]|}]
ml: (_, EscString(x)) -> x
ml: (_, Sum(x, y)) -> $[[x] + [y]]
ml: (_, Concat(x, y)) -> $[[x] ^ [y]]
ml: (Gets(_,yn), Gets(x, y))
-> $[([x]).getS ([<ml_str>(yn,y)])]
ml: (To(xn,_), To(x, y))
-> $[let _fto = ([x]) in (ignore (([y]).getS ([<ml_str>(xn,"_fto")])); _fto)]
ml: (_, Emits(s)) -> $[[s].emitS ()]
ml: (_, Terminate(x)) -> x
ml: (_, Sequence(l)) -> <ml_seq>l
ml_seq: [x] -> x
ml_seq: [x | xs ] -> $[ignore ([x]);
[<ml_seq>xs]]
/* One drawback of using paramorphism is we have to handle lists
explicitly:
*/
ml: (_, []) -> []
ml: (_, [x | xs]) -> [x | xs]
/* Another drawback of using paramorphism is at the very leaves we have
to undouble the tuple:
*/
ml: (x, x) -> x where <is-string>x
ml_str: (node, code) -> $[[<ml_string_cast>node]([code])]
strategies
ml_string_cast = get-type; (?INT() < !"string_of_int" + !"")
ocaml = bottomup-para(try(ml))
// Interface ocaml code generation with editor services and file system
to-ocaml: (selected, _, _, path, project-path) -> (filename, result)
with filename := <guarantee-extension(|"ml")> path
; result := <ocaml> selected