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<H1><A NAME="SEC141" HREF="ciao_toc.html#TOC141">Basic term manipulation</A></H1>
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<STRONG>Author(s):</STRONG> Daniel Cabeza, Manuel Hermenegildo.
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<STRONG>Version:</STRONG> 1.10#7 (2006/4/26, 19:22:13 CEST)
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<STRONG>Version of last change:</STRONG> 1.9#191 (2003/12/19, 16:47:39 CET)
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This module provides basic term manipulation.
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<LI><A HREF="ciao_20.html#SEC142">Usage and interface (term_basic)</A>
<LI><A HREF="ciao_20.html#SEC143">Documentation on exports (term_basic)</A>
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<H2><A NAME="SEC142" HREF="ciao_toc.html#TOC142">Usage and interface (<CODE>term_basic</CODE>)</A></H2>
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<LI><STRONG>Library usage:</STRONG>
These predicates are builtin in Ciao, so nothing special has to be done to use them.
<LI><STRONG>Exports:</STRONG>
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<LI><EM>Predicates:</EM>
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<CODE>arg/3</CODE>,
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<CODE>functor/3</CODE>,
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<CODE>=../2</CODE>,
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<CODE>copy_term/2</CODE>,
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<CODE>C/3</CODE>.
<LI><EM>Properties:</EM>
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<CODE>=/2</CODE>.
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<H2><A NAME="SEC143" HREF="ciao_toc.html#TOC143">Documentation on exports (<CODE>term_basic</CODE>)</A></H2>
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<DT><span class="define">PROPERTY:</span> <B>=/2:</B>
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<STRONG>Usage:</STRONG> <CODE>X = Y</CODE>
<KBD> * ISO * </KBD>
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<LI><EM>Description:</EM> <CODE>X</CODE> and <CODE>Y</CODE> unify.
<LI><EM>The following properties hold globally:</EM>
This predicate is understood natively by CiaoPP.
(<CODE>basic_props:native/1</CODE>)
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</DL>
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<DT><span class="define">PREDICATE:</span> <B>arg/3:</B>
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<STRONG>Usage:</STRONG> <CODE>arg(+ArgNo, +Term, ?Arg)</CODE>
<KBD> * ISO * </KBD>
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<LI><EM>Description:</EM> Argument <CODE>ArgNo</CODE> of the term <CODE>Term</CODE> is <CODE>Arg</CODE>.
<LI><EM>The following properties should hold at call time:</EM>
<CODE>ArgNo</CODE> is an integer.
(<CODE>basic_props:int/1</CODE>)
<LI><EM>The following properties hold globally:</EM>
This predicate is understood natively by CiaoPP.
(<CODE>basic_props:native/1</CODE>)
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</DL>
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<DT><span class="define">PREDICATE:</span> <B>functor/3:</B>
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<STRONG>Usage:</STRONG> <CODE>functor(?Term, ?Name, ?Arity)</CODE>
<KBD> * ISO * </KBD>
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<LI><EM>Description:</EM> The principal functor of the term <CODE>Term</CODE> has name <CODE>Name</CODE> and arity <CODE>Arity</CODE>.
<LI><EM>The following properties hold upon exit:</EM>
<CODE>Name</CODE> is an atom.
(<CODE>basic_props:atm/1</CODE>)
<CODE>Arity</CODE> is a number.
(<CODE>basic_props:num/1</CODE>)
<LI><EM>The following properties hold globally:</EM>
This predicate is understood natively by CiaoPP.
(<CODE>basic_props:native/1</CODE>)
</UL>
</DL>
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<DT><span class="define">PREDICATE:</span> <B>=../2:</B>
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<STRONG>Usage:</STRONG> <CODE>?Term =.. ?List</CODE>
<KBD> * ISO * </KBD>
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<LI><EM>Description:</EM> The functor and arguments of the term <CODE>Term</CODE> comprise the list <CODE>List</CODE>.
<LI><EM>The following properties hold upon exit:</EM>
<CODE>List</CODE> is a list.
(<CODE>basic_props:list/1</CODE>)
<LI><EM>The following properties hold globally:</EM>
This predicate is understood natively by CiaoPP.
(<CODE>basic_props:native/1</CODE>)
</UL>
</DL>
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<DT><span class="define">PREDICATE:</span> <B>copy_term/2:</B>
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<STRONG>Usage:</STRONG> <CODE>copy_term(Term, Copy)</CODE>
<KBD> * ISO * </KBD>
<UL>
<LI><EM>Description:</EM> <CODE>Copy</CODE> is a renaming of <CODE>Term</CODE>, such that brand new variables have been substituted for all variables in <CODE>Term</CODE>. If any of the variables of <CODE>Term</CODE> have
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attributes, the copied variables will have copies of the attributes as well. It behaves as if defined by:
<PRE>
:- data 'copy of'/1.
copy_term(X, Y) :-
asserta_fact('copy of'(X)),
retract_fact('copy of'(Y)).
</PRE>
<LI><EM>The following properties hold globally:</EM>
This predicate is understood natively by CiaoPP.
(<CODE>basic_props:native/1</CODE>)
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</DL>
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<DT><span class="define">PREDICATE:</span> <B>C/3:</B>
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<STRONG>Usage:</STRONG> <CODE>C(?S1, ?Terminal, ?S2)</CODE>
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<LI><EM>Description:</EM> <CODE>S1</CODE> is connected by the terminal <CODE>Terminal</CODE> to <CODE>S2</CODE>. Internally used in <EM>DCG grammar rules</EM>. Defined as if by the single clause: <CODE>'C'([X|S], X, S).</CODE>
<LI><EM>The following properties hold globally:</EM>
This predicate is understood natively by CiaoPP.
(<CODE>basic_props:native/1</CODE>)
</UL>
</DL>
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