If the expression isn't 'true' or 'false' atoms then we assume it's a comparison expression and try to check its truth value.
If this fails then it will try both branches, to allow for e.g. compilation. THis almost works, but there's a choice point or something that gets hit before it tries the false path,
?- joy(` [32 >] [++] [--] ifte`, Si, So).
Si = [_2076|_2078],
So = [_2076+1|_2078] ;
wtf? +
Si = [_2076|_2078],
So = [[+], 1, _2076|_2078] ;
Si = [_2076|_2078],
So = [_2076-1|_2078] ;
wtf? -
Si = [_2076|_2078],
So = [[-], 1, _2076|_2078] ;
wtf? branch
Si = [_2076|_2078],
So = [[branch], [++], [--], _2076>32, _2076|_2078] ;
wtf? swap
Si = [_2076|_2078],
So = [[swap, branch], [--], [++], _2076>32, _2076|_2078] ;
wtf? first
Si = [_2076|_2078],
So = [[first, [++], [--], swap, branch], [_2076>32|_2078], _2076|_2078]
etc...
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