Commit 35e59e49 authored by POTTIER Francois's avatar POTTIER Francois
Browse files

Front: implement selective expansion + safety test + full expansion.

parent 82b7a883
......@@ -76,9 +76,21 @@ let sorts =
to obtain a grammar without parameterized nonterminal symbols. *)
let grammar : UnparameterizedSyntax.grammar =
(* TEMPORARY do selective expansion first *)
CheckSafeParameterizedGrammar.check grammar;
Drop.drop (SelectiveExpansion.expand SelectiveExpansion.ExpandAll sorts grammar)
let module S = SelectiveExpansion in
(* First, perform a selective expansion: expand away all parameters of
higher sort, keeping the parameters of sort [*]. This process always
terminates. *)
let grammar1 = S.expand S.ExpandHigherSort sorts grammar in
(* This "first-order parameterized grammar" can then be submitted to
the termination check. *)
CheckSafeParameterizedGrammar.check grammar1;
(* If it passes the check, then full expansion is safe. We drop [grammar1]
and start over from [grammar]. This is required in order to get correct
names. (Expanding [grammar1] would yield an equivalent grammar, with
more complicated names, reflecting the two steps of expansion.) *)
let grammar = S.expand S.ExpandAll sorts grammar in
(* This yields an unparameterized grammar. *)
Drop.drop grammar
let () =
Time.tick "Joining and expanding"
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