# HG changeset patch # User wenzelm # Date 969554838 -7200 # Node ID 0afe7d9514475bcf666c3b68495c6ce2ce7a1e53 # Parent ef58424d78933280fe9485c69c9fe019bada4e15 renamed to Records.thy; diff -r ef58424d7893 -r 0afe7d951447 src/HOL/ex/Points.thy --- a/src/HOL/ex/Points.thy Thu Sep 21 18:33:48 2000 +0200 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,211 +0,0 @@ -(* Title: HOL/ex/Points.thy - ID: $Id$ - Author: Wolfgang Naraschewski and Markus Wenzel, TU Muenchen - License: GPL (GNU GENERAL PUBLIC LICENSE) -*) - -header {* Points and coloured points --- using extensible records in HOL *} - -theory Points = Main: - - -subsection {* Points *} - -record point = - x :: nat - y :: nat - -text {* - Apart many other things, above record declaration produces the - following theorems: -*} - -thm "point.simps" -thm "point.iffs" -thm "point.update_defs" - -text {* - The set of theorems "point.simps" is added automatically to the - standard simpset, "point.iffs" is added to the claset and simpset. -*} - -text {* - Record declarations define new type abbreviations: - - point = "(| x :: nat, y :: nat |)" - 'a point_scheme = "(| x :: nat, y :: nat, ... :: 'a |)" - - Extensions `...' must be in type class `more'! -*} - -consts foo1 :: point -consts foo2 :: "(| x :: nat, y :: nat |)" -consts foo3 :: "'a => ('a::more) point_scheme" -consts foo4 :: "'a => (| x :: nat, y :: nat, ... :: 'a |)" - - -subsubsection {* Introducing concrete records and record schemes *} - -defs - foo1_def: "foo1 == (| x = 1, y = 0 |)" - foo3_def: "foo3 ext == (| x = 1, y = 0, ... = ext |)" - - -subsubsection {* Record selection and record update *} - -constdefs - getX :: "('a::more) point_scheme => nat" - "getX r == x r" - setX :: "('a::more) point_scheme => nat => 'a point_scheme" - "setX r n == r (| x := n |)" - - -subsubsection {* Some lemmas about records *} - -text {* Basic simplifications *} - -lemma "point.make n p = (| x = n, y = p |)" - by simp - -lemma "x (| x = m, y = n, ... = p |) = m" - by simp - -lemma "(| x = m, y = n, ... = p |) (| x:= 0 |) = (| x = 0, y = n, ... = p |)" - by simp - - -text {* Equality of records *} - -lemma "n = n' ==> p = p' ==> (| x = n, y = p |) = (| x = n', y = p' |)" - -- "introduction of concrete record equality" - by simp - -lemma "(| x = n, y = p |) = (| x = n', y = p' |) ==> n = n'" - -- "elimination of concrete record equality" - by simp - -lemma "r (| x := n |) (| y := m |) = r (| y := m |) (| x := n |)" - -- "introduction of abstract record equality" - by simp - -lemma "r (| x := n |) = r (| x := n' |) ==> n = n'" - -- "elimination of abstract record equality (manual proof)" -proof - - assume "r (| x := n |) = r (| x := n' |)" (is "?lhs = ?rhs") - hence "x ?lhs = x ?rhs" by simp - thus ?thesis by simp -qed - - -text {* Surjective pairing *} - -lemma "r = (| x = x r, y = y r |)" - by simp - -lemma "r = (| x = x r, y = y r, ... = more r |)" - by simp - - -text {* Splitting quantifiers: the !!r is NECESSARY here *} - -lemma "!!r. r (| x := n |) (| y := m |) = r (| y := m |) (| x := n |)" -proof record_split - fix x y more - show "(| x = x, y = y, ... = more |)(| x := n, y := m |) = - (| x = x, y = y, ... = more |)(| y := m, x := n |)" - by simp -qed - -lemma "!!r. r (| x := n |) (| x := m |) = r (| x := m |)" -proof record_split - fix x y more - show "(| x = x, y = y, ... = more |)(| x := n, x := m |) = - (| x = x, y = y, ... = more |)(| x := m |)" - by simp -qed - - - -text {* Concrete records are type instances of record schemes *} - -constdefs - foo5 :: nat - "foo5 == getX (| x = 1, y = 0 |)" - - -text {* Manipulating the `...' (more) part *} - -constdefs - incX :: "('a::more) point_scheme => 'a point_scheme" - "incX r == (| x = Suc (x r), y = y r, ... = point.more r |)" - -lemma "!!r n. incX r = setX r (Suc (getX r))" -proof (unfold getX_def setX_def incX_def) - show "!!r n. (| x = Suc (x r), y = y r, ... = more r |) = r(| x := Suc (x r) |)" - by record_split simp -qed - - -text {* alternative definition *} - -constdefs - incX' :: "('a::more) point_scheme => 'a point_scheme" - "incX' r == r (| x := Suc (x r) |)" - - -subsection {* Coloured points: record extension *} - -datatype colour = Red | Green | Blue - -record cpoint = point + - colour :: colour - - -text {* - The record declaration defines new type constructors: - - cpoint = (| x :: nat, y :: nat, colour :: colour |) - 'a cpoint_scheme = (| x :: nat, y :: nat, colour :: colour, ... :: 'a |) -*} - -consts foo6 :: cpoint -consts foo7 :: "(| x :: nat, y :: nat, colour :: colour |)" -consts foo8 :: "('a::more) cpoint_scheme" -consts foo9 :: "(| x :: nat, y :: nat, colour :: colour, ... :: 'a |)" - - -text {* Functions on point schemes work for cpoints as well *} - -constdefs - foo10 :: nat - "foo10 == getX (| x = 2, y = 0, colour = Blue |)" - - -subsubsection {* Non-coercive structural subtyping *} - -text {* foo11 has type cpoint, not type point --- Great! *} - -constdefs - foo11 :: cpoint - "foo11 == setX (| x = 2, y = 0, colour = Blue |) 0" - - -subsection {* Other features *} - -text {* field names contribute to record identity *} - -record point' = - x' :: nat - y' :: nat - -text {* May not apply @{term getX} to @{term "(| x' = 2, y' = 0 |)"} *} - - -text {* Polymorphic records *} - -record 'a point'' = point + - content :: 'a - -types cpoint'' = "colour point''" - -end