-- Copyright (c) 1991-2002, The Numerical ALgorithms Group Ltd.
-- All rights reserved.
-- Copyright (C) 2007, Gabriel Dos Reis.
-- All rights reserved.
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import '"sys-macros"
)package "BOOT"

-- This one is not currently in general use, but can be applied
-- to various situations are required
 
minimalise x ==
  $hash:local:=MAKE_-HASHTABLE 'UEQUAL
  min x where
    min x ==
      y:=HGET($hash,x)
      y => y
      PAIRP x =>
        x = '(QUOTE T) => '(QUOTE T)
        -- copes with a particular Lucid-ism, God knows why
        -- This circular way of doing things is an attempt to deal with Lucid
        -- Who may place quoted cells in read-only memory
        z:=min CAR x
        if not EQ(z,CAR x) then RPLACA(x,z)
        z:=min CDR x
        if not EQ(z,CDR x) then RPLACD(x,z)
        HashCheck x
      REFVECP x =>
        for i in 0..MAXINDEX x repeat
          x.i:=min (x.i)
        HashCheck x
      STRINGP x => HashCheck x
      x
    HashCheck x ==
      y:=HGET($hash,x)
      y => y
      HPUT($hash,x,x)
      x
  x