Conv.RENAME_VARS

STRUCTURE

SYNOPSIS

Renames variables underneath a binder.

LIBRARY

Conv

DESCRIPTION

RENAME_VARS_CONV takes a list of strings specifying new names for variables under a binder. More precisely, it will rename variables in abstractions, or bound by universal, existential, unique existence or the select (or Hilbert-choice) “quantifier”.

More than one variable can be renamed at once. If variables occur past the first, then the renaming continues on the appropriate sub-term of the first. (That is, if the term is an abstraction, then renaming will continue on the body of the abstraction. If it is one of the supported quantifiers, then renaming will continue on the body of the abstraction that is the argument of the “binder constant”.)

If RENAME_VARS_CONV is passed the empty list, it is equivalent to ALL_CONV. The binders do not need to be of the same type all the way into the term.

FAILURE

Fails if an attempt is made to rename a variable in a term that is not an abstraction, or is not one of the accepted quantifiers. Also fails if all of the names in the list are not distinct.

EXAMPLE

- RENAME_VARS_CONV ["a", "b"] ``\x y. x /\ y``;
> val it = |- (\x y. x /\ y) = (\a b. a /\ b) : thm
- RENAME_VARS_CONV ["a", "b"] ``!x:'a y. P x /\ P y``;
> val it = |- (!x y. P x /\ P y) = !a b. P a /\ P b : thm
- RENAME_VARS_CONV ["a", "b"] ``!x:'a. ?y. P x /\ P y``;
> val it = |- (!x. ?y. P x /\ P y) = !a. ?b. P a /\ P b : thm

USES

Post-processing mangling of names in code implementing derived logical procedures to make names look more appropriate. Changing names can only affect the presentation of terms, not their semantics.

SEEALSO

aconv, ALPHA