Old stuff.

--- a/doc-src/Pure/theory-extensions	Tue Apr 27 10:52:25 1999 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,104 +0,0 @@
-The new Internal Interface for Theory Extension
-===============================================
-
-MMW 06-Jun-1994
-
-
-In former versions of Isabelle, the interface for theory extension was
-provided by extend_theory. This had many deficiencies and has been removed in
-Isabelle94/2.
-
-Instead of one monolithic function, there is now a host of small functions of
-the form:
-
-  add_XXX: ... -> theory -> theory
-
-These provide an extension mechanism which is:
-
-  - incremental (but non-destructive):
-
-    An extend operation may now involve many functions of the add_XXX kind.
-    These act in a purely functional manner.
-
-  - nameless:
-
-    One no longer needs to invent new theory names for intermediate theories.
-    There's now a notion of _draft_theories_ that behave like ordinary ones
-    in many cases (main exceptions: extensions of drafts are not related (wrt
-    subthy); merges of drafts with unrelated theories are impossible). A
-    draft is "closed" by add_thyname.
-
-  - extendable:
-
-    Package writers simply have to provide add_XXX like functions, which are
-    built using a basic set provided by Pure Isabelle.
-
-
-Here follows a sample interactive session using the new functions:
-
-  > add_consts
-  # [("nand", "[o, o] => o", NoSyn), ("#", "[o, o] => o", Infixl 30)]
-  # FOL.thy;
-  Building new grammar...
-  val it = {Pure, IFOL, FOL, #} : theory   
-  > add_axioms
-  # [("nand_def", "nand(P, Q) == ~(P & Q)"), ("xor_def", "P # Q == P & ~Q | ~P & Q")]
-  # it;
-  val it = {Pure, IFOL, FOL, #} : theory   
-  > add_thyname "Gate" it;
-  val it = {Pure, IFOL, FOL, Gate} : theory   
-
-Note that theories and theorems with a "#" draft stamp are not supposed to
-persist. Typically, there is a final add_thyname somewhere with the "real"
-theory name as supplied by the user.
-
-
-Appendix A: Basic theory extension functions
---------------------------------------------
-
-   val add_classes: (class list * class * class list) list -> theory -> theory
-   val add_defsort: sort -> theory -> theory
-   val add_types: (string * int * mixfix) list -> theory -> theory
-   val add_tyabbrs: (string * string list * string * mixfix) list
-     -> theory -> theory
-   val add_tyabbrs_i: (string * string list * typ * mixfix) list
-     -> theory -> theory
-   val add_arities: (string * sort list * sort) list -> theory -> theory
-   val add_consts: (string * string * mixfix) list -> theory -> theory
-   val add_consts_i: (string * typ * mixfix) list -> theory -> theory
-   val add_syntax: (string * string * mixfix) list -> theory -> theory
-   val add_syntax_i: (string * typ * mixfix) list -> theory -> theory
-   val add_trfuns:
-     (string * (ast list -> ast)) list *
-     (string * (term list -> term)) list *
-     (string * (term list -> term)) list *
-     (string * (ast list -> ast)) list -> theory -> theory
-   val add_trrules: xrule list -> theory -> theory
-   val add_axioms: (string * string) list -> theory -> theory
-   val add_axioms_i: (string * term) list -> theory -> theory
-   val add_thyname: string -> theory -> theory
-
-
-Appendix B: The |> operator
----------------------------
-
-Isabelle now provides an ML infix operator for reverse function application:
-
-  infix |>;
-  fun (x |> f) = f x;
-
-Using this, theory extension really becomes a pleasure, e.g.:
-
-  FOL.thy 
-  |> add_consts
-      [("nand", "[o, o] => o", NoSyn),
-       ("#", "[o, o] => o", Infixl 30)]
-  |> add_axioms
-      [("nand_def", "nand(P, Q) == ~(P & Q)"),
-       ("xor_def", "P # Q == P & ~Q | ~P & Q")]
-  |> add_thyname "Gate";
-
-For a real-world example simply reset delete_tmpfiles, use_thy your favourite
-theory definition file and inspect the generated .XXX.thy.ML file.
-
-=============================================================================