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Sat Jun 6 08:35:42 CEST 2009

CTM

Section 3.4.3 p.140 mentions the use of Definitive Clause Grammar
(DCG) [1] to hide explicit threading of accumulators.  Immediately
after is mentioned that they no longer use this and prefer explicit
state instead.

Section 3.4.4 p.141 mentions difference lists[2].  These can be used
to prevent consing when manupulating the head of some list.  Also it
is mentioned that this can be used to append in constant time when the
tail of the difference list is an unbound variable.  Apparently used a
lot in Prolog programming.

[1] http://en.wikipedia.org/wiki/Definite_clause_grammar
[2] http://en.wikipedia.org/wiki/Difference_list



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