fmod RUNTIME-PRELUDE is

  protecting ORACLE .
  protecting BOOL .
  protecting NAT .
  protecting IDENTICAL .
  protecting ABSTRACT-SYNTAX-RUNTIME .

  sort TrueTrm .
  subsort TrueTrm < Trm .

  protecting RUNTIME-RULES .

  var M N P : Trm .

  cmb ('||{0} P) : TrueTrm if P : TrueTrm .
  cmb ('!!{0} P) : TrueTrm if P : TrueTrm .
  cmb ('??{0} P) : TrueTrm if P : TrueTrm .

  cmb ('EQ{0} M N) : TrueTrm if M == N .

endfm