Mercurial > cpdt > repo
changeset 359:059c51227e69
Tweak Generic templating
author | Adam Chlipala <adam@chlipala.net> |
---|---|
date | Tue, 01 Nov 2011 12:34:00 -0400 |
parents | 6cc9a3bbc2c6 |
children | e0d91bcf70ec |
files | src/Generic.v |
diffstat | 1 files changed, 1 insertions(+), 9 deletions(-) [+] |
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--- a/src/Generic.v Mon Oct 31 14:24:16 2011 -0400 +++ b/src/Generic.v Tue Nov 01 12:34:00 2011 -0400 @@ -233,11 +233,8 @@ (** ** Pretty-Printing *) -(* EX: Define a generic pretty-printing function. *) - (** It is also useful to do generic pretty-printing of datatype values, rendering them as human-readable strings. To do so, we will need a bit of metadata for each constructor. Specifically, we need the name to print for the constructor and the function to use to render its non-recursive arguments. Everything else can be done generically. *) -(* begin thide *) Record print_constructor (c : constructor) : Type := PI { printName : string; printNonrec : nonrecursive c -> string @@ -270,7 +267,6 @@ fx string (hmap (B1 := print_constructor) (B2 := constructorDenote string) (fun _ pc x r => printName pc ++ "(" ++ printNonrec pc x ++ foldr (fun s acc => ", " ++ s ++ acc) ")" r) pr). -(* end thide *) (** Some simple tests establish that [print] gets the job done. *) @@ -369,16 +365,12 @@ (** ** Mapping *) -(* EX: Define a generic [map] function. *) - (** By this point, we have developed enough machinery that it is old hat to define a generic function similar to the list [map] function. *) -(* begin thide *) Definition map T dt (dd : datatypeDenote T dt) (fx : fixDenote T dt) (f : T -> T) : T -> T := fx T (hmap (B1 := constructorDenote T) (B2 := constructorDenote T) (fun _ c x r => f (c x r)) dd). -(* end thide *) Eval compute in map Empty_set_den Empty_set_fix. (** %\vspace{-.15in}% [[ @@ -470,7 +462,6 @@ (** We would like to be able to prove theorems about our generic functions. To do so, we need to establish additional well-formedness properties that must hold of pieces of evidence. *) -(* begin thide *) Section ok. Variable T : Type. Variable dt : datatype. @@ -504,6 +495,7 @@ (** We are now ready to prove that the [size] function we defined earlier always returns positive results. First, we establish a simple lemma. *) +(* begin thide *) Lemma foldr_plus : forall n (ils : ilist nat n), foldr plus 1 ils > 0. induction ils; crush.