unwindLib.UNWIND_ONCE

`UNWIND_ONCE_CONV`

unwindLib.UNWIND_ONCE_CONV : ((term -> bool) -> conv)

Basic conversion for parallel unwinding of equations defining wire values in a standard device specification.

UNWIND_ONCE_CONV p tm unwinds the conjunction tm using the equations selected by the predicate p. tm should be a conjunction, equivalent under associative-commutative reordering to:

   t1 /\ t2 /\ ... /\ tn

p is used to partition the terms ti for 1 <= i <= n into two disjoint sets:

   REW = {{ti | p ti}}
   OBJ = {{ti | ~p ti}}

The terms ti for which p is true are then used as a set of rewrite rules (thus they should be equations) to do a single top-down parallel rewrite of the remaining terms. The rewritten terms take the place of the original terms in the input conjunction. For example, if tm is:

   t1 /\ t2 /\ t3 /\ t4

and REW = {{t1,t3}} then the result is:

   |- t1 /\ t2 /\ t3 /\ t4 = t1 /\ t2' /\ t3 /\ t4'

where ti' is ti rewritten with the equations REW.

Failure

Never fails.

Example


> unwindLib.UNWIND_ONCE_CONV (fn tm => mem (unwindLib.line_name tm) [`l1`,`l2`])
  “(!(x:num). l1 x = (l2 x) - 1) /\
  (!x. f x = (l2 (x+1)) + (l1 (x+2))) /\
  (!x. l2 x = 7)”;
Exception- Type error in function application.
   Function: mem (unwindLib.line_name tm) : string list -> bool
   Argument: [[QUOTE " (*#loc 1 69*)l1"], [QUOTE " (*#loc 1 74*)l2"]]
      : 'a frag list list
   Reason:
      Can't unify string (*In Basis*) with 'a frag list (*In Basis*)
         (Different type constructors)
Fail "Static Errors" raised

UNWIND_ONCE_CONV

Failure

Example

See also

`UNWIND_ONCE_CONV`