[isabelle-dev] NEWS: ML antiquotation "instantiate"

[Makarius]

*** ML ***

* ML antiquotation "instantiate" allows to instantiate formal entities
(types, terms, theorems) with values given ML. This works uniformly for
"typ", "term", "prop", "ctyp", "cterm", "cprop", "lemma" --- given as a
keyword after the instantiation. A mode "(schematic)" behind the keyword
means that some variables may remain uninstantiated (fixed in the
specification and schematic in the result); by default, all variables
need to be instantiated.

Examples in HOL:

  fun make_assoc_type (A, B) =
    \<^instantiate>‹'a = A and 'b = B in typ ‹('a × 'b) list››;

  val make_assoc_list =
    map (fn (x, y) =>
      \<^instantiate>‹'a = ‹fastype_of x› and 'b = ‹fastype_of y› and
        x and y in term ‹(x, y)› for x :: 'a and y :: 'b›);

  fun symmetry x y =
    \<^instantiate>‹'a = ‹Thm.ctyp_of_cterm x› and x and y in
      lemma ‹x = y ⟹ y = x› for x y :: 'a by simp›

  fun symmetry_schematic A =
    \<^instantiate>‹'a = A in
      lemma (schematic) ‹x = y ⟹ y = x› for x y :: 'a by simp›


This refers to Isabelle/54085e37ce4d. Some applications are in the preceeding
changesets.

Proper documentation will follow shortly after Isabelle2021-1-RC1 (start of
next week).


	Makarius