SET-MEASURE-FUNCTION.html -- ACL2 Version 6.3

## SET-MEASURE-FUNCTION

set the default measure function symbol

    Major Section:  SWITCHES-PARAMETERS-AND-MODES

    Examples:
    (set-measure-function nqthm::count)

Note: This is an event! It does not print the usual event summary but nevertheless changes the ACL2 logical world and is so recorded.

    General Form:
    (set-measure-function name)

where `name` is a function symbol of one argument. This macro is equivalent to `(table acl2-defaults-table :measure-function 'name)`, and hence is `local` to any books and `encapsulate` events in which it occurs; see acl2-defaults-table. Although this is thus an event (see table), nevertheless no output results from a `set-measure-function` event.

This event sets the default measure function to `name`. Subsequently, if a recursively defined function is submitted to `defun` with no explicitly given `:measure` argument, `defun` ``guesses'' the measure `(name var)`, where `name` is the then current default measure function and `var` is the first formal found to be tested along every branch and changed in every recursive call.

Note that if `(table acl2-defaults-table :measure-function 'name)` has its default value of `nil`, then the default measure function is `acl2-count`.