# HG changeset patch
# User haftmann
# Date 1475928593 -7200
# Node ID 86efd3d4dc982f4f2e7ee1a729692f5396f00940
# Parent  84c1ae86b9af4e16ee9b235fe2d672ed1e28190d
dedicated syntax for types with a length

diff -r 84c1ae86b9af -r 86efd3d4dc98 NEWS
--- a/NEWS	Sat Oct 08 17:30:19 2016 +0200
+++ b/NEWS	Sat Oct 08 14:09:53 2016 +0200
@@ -249,6 +249,8 @@
 
 *** HOL ***
 
+* Dedicated syntax LENGTH('a) for length of types.
+
 * New proof method "argo" using the built-in Argo solver based on SMT
 technology. The method can be used to prove goals of quantifier-free
 propositional logic, goals based on a combination of quantifier-free
diff -r 84c1ae86b9af -r 86efd3d4dc98 src/HOL/Library/Type_Length.thy
--- a/src/HOL/Library/Type_Length.thy	Sat Oct 08 17:30:19 2016 +0200
+++ b/src/HOL/Library/Type_Length.thy	Sat Oct 08 14:09:53 2016 +0200
@@ -17,10 +17,22 @@
 class len0 =
   fixes len_of :: "'a itself \<Rightarrow> nat"
 
+syntax "_type_length" :: "type \<Rightarrow> nat" ("(1LENGTH/(1'(_')))")
+
+translations "LENGTH('a)" \<rightharpoonup>
+  "CONST len_of (CONST Pure.type :: 'a itself)"
+
+print_translation \<open>
+  let
+    fun len_of_itself_tr' ctxt [Const (@{const_syntax Pure.type}, Type (_, [T]))] =
+      Syntax.const @{syntax_const "_type_length"} $ Syntax_Phases.term_of_typ ctxt T
+  in [(@{const_syntax len_of}, len_of_itself_tr')] end
+\<close>
+
 text \<open>Some theorems are only true on words with length greater 0.\<close>
 
 class len = len0 +
-  assumes len_gt_0 [iff]: "0 < len_of TYPE ('a)"
+  assumes len_gt_0 [iff]: "0 < LENGTH('a)"
 
 instantiation num0 and num1 :: len0
 begin
@@ -35,8 +47,8 @@
 instantiation bit0 and bit1 :: (len0) len0
 begin
 
-definition len_bit0: "len_of (_ :: 'a::len0 bit0 itself) = 2 * len_of TYPE('a)"
-definition len_bit1: "len_of (_ :: 'a::len0 bit1 itself) = 2 * len_of TYPE('a) + 1"
+definition len_bit0: "len_of (_ :: 'a::len0 bit0 itself) = 2 * LENGTH('a)"
+definition len_bit1: "len_of (_ :: 'a::len0 bit1 itself) = 2 * LENGTH('a) + 1"
 
 instance ..
 
diff -r 84c1ae86b9af -r 86efd3d4dc98 src/HOL/ex/Word_Type.thy
--- a/src/HOL/ex/Word_Type.thy	Sat Oct 08 17:30:19 2016 +0200
+++ b/src/HOL/ex/Word_Type.thy	Sat Oct 08 14:09:53 2016 +0200
@@ -9,21 +9,6 @@
     "~~/src/HOL/Library/Type_Length"
 begin
 
-subsection \<open>Compact syntax for types with a length\<close>
-
-syntax "_type_length" :: "type \<Rightarrow> nat" ("(1LENGTH/(1'(_')))")
-
-translations "LENGTH('a)" \<rightharpoonup>
-  "CONST len_of (CONST Pure.type :: 'a itself)"
-
-print_translation \<open>
-  let
-    fun len_of_itself_tr' ctxt [Const (@{const_syntax Pure.type}, Type (_, [T]))] =
-      Syntax.const @{syntax_const "_type_length"} $ Syntax_Phases.term_of_typ ctxt T
-  in [(@{const_syntax len_of}, len_of_itself_tr')] end
-\<close>
-
-
 subsection \<open>Truncating bit representations of numeric types\<close>
 
 class semiring_bits = semiring_div_parity +