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Predicate information
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<TABLE CELLPADDING=0 CELLSPACING=0 WIDTH="100%">
<TR><TD BGCOLOR="#66dbff"><DIV ALIGN=center><TABLE>
<TR><TD><FONT SIZE=4><B><A NAME="htoc98">7.8</A></B></FONT></TD>
<TD WIDTH="100%" ALIGN=center><FONT SIZE=4><B>Predicate information</B></FONT></TD>
</TR></TABLE></DIV></TD>
</TR></TABLE><UL>
<LI><A HREF="manual031.html#toc69"> <TT>current_predicate/1</TT></A>
<LI><A HREF="manual031.html#toc70"> <TT>predicate_property/2</TT></A>
</UL>
<BR>
<A NAME="toc69"></A><TABLE CELLPADDING=0 CELLSPACING=0 WIDTH="100%">
<TR><TD BGCOLOR="#98e7ff"><DIV ALIGN=center><TABLE>
<TR><TD><B><A NAME="htoc99">7.8.1</A></B></TD>
<TD WIDTH="100%" ALIGN=center><TT><B>current_predicate/1</B></TT></TD>
</TR></TABLE></DIV></TD>
</TR></TABLE>
<A NAME="current-predicate/1"></A>
<BR>
<B>Templates</B>
<DL COMPACT=compact><DT><DD><TT>
current_predicate(?predicate_indicator)</TT></DL>
<B>Description</B><BR>
<BR>
<TT>current_predicate(Pred)</TT> succeeds if there
exists a predicate indicator of a defined procedure that unifies with
<TT>Pred</TT>. All user defined procedures are found, whether static or
dynamic. Internal system procedures whose name begins
with <TT>'$'</TT> are not found. A user-defined procedure is found
even when it has no clauses. A user-defined procedure is not found if
it has been abolished. To conform to the ISO reference, built-in predicates
are not found except if the <TT>strict_iso</TT> Prolog flag is switched off (section <A HREF="manual045.html#set-prolog-flag/2">7.22.1</A>). This predicate is re-executable on
backtracking.<BR>
<BR>
<B>Errors</B><BR>
<TABLE CELLSPACING=2 CELLPADDING=0>
<TR><TD BGCOLOR=black COLSPAN=3><TABLE BORDER=0 WIDTH="100%" CELLSPACING=0 CELLPADDING=1><TR><TD></TD></TR></TABLE></TD>
</TR>
<TR><TD VALIGN=top ALIGN=left><TT>Pred</TT> is neither a variable nor a predicate indicator</TD>
<TD VALIGN=top ALIGN=center NOWRAP> </TD>
<TD VALIGN=top ALIGN=left><TT>type_error(predicate_indicator, Pred)</TT></TD>
</TR>
<TR><TD BGCOLOR=black COLSPAN=3><TABLE BORDER=0 WIDTH="100%" CELLSPACING=0 CELLPADDING=1><TR><TD></TD></TR></TABLE></TD>
</TR>
<TR><TD VALIGN=top ALIGN=left><TT>Pred</TT> is a term <TT>Name/Arity</TT> and <TT>Arity</TT> is
neither a variable nor an integer</TD>
<TD VALIGN=top ALIGN=center NOWRAP> </TD>
<TD VALIGN=top ALIGN=left><TT>type_error(integer, Arity)</TT></TD>
</TR>
<TR><TD BGCOLOR=black COLSPAN=3><TABLE BORDER=0 WIDTH="100%" CELLSPACING=0 CELLPADDING=1><TR><TD></TD></TR></TABLE></TD>
</TR>
<TR><TD VALIGN=top ALIGN=left><TT>Pred</TT> is a term <TT>Name/Arity</TT> and <TT>Name</TT> is
neither a variable nor an atom</TD>
<TD VALIGN=top ALIGN=center NOWRAP> </TD>
<TD VALIGN=top ALIGN=left><TT>type_error(atom, Name)</TT></TD>
</TR>
<TR><TD BGCOLOR=black COLSPAN=3><TABLE BORDER=0 WIDTH="100%" CELLSPACING=0 CELLPADDING=1><TR><TD></TD></TR></TABLE></TD>
</TR>
<TR><TD VALIGN=top ALIGN=left><TT>Pred</TT> is a term <TT>Name/Arity</TT> and <TT>Arity</TT> is
an integer < 0</TD>
<TD VALIGN=top ALIGN=center NOWRAP> </TD>
<TD VALIGN=top ALIGN=left><TT>domain_error(not_less_than_zero, Arity)</TT></TD>
</TR>
<TR><TD BGCOLOR=black COLSPAN=3><TABLE BORDER=0 WIDTH="100%" CELLSPACING=0 CELLPADDING=1><TR><TD></TD></TR></TABLE></TD>
</TR>
<TR><TD VALIGN=top ALIGN=left><TT>Pred</TT> is a term <TT>Name/Arity</TT> and <TT>Arity</TT> is
an integer > <TT>max_arity</TT> flag (section <A HREF="manual045.html#set-prolog-flag/2">7.22.1</A>)</TD>
<TD VALIGN=top ALIGN=center NOWRAP> </TD>
<TD VALIGN=top ALIGN=left><TT>representation_error(max_arity)</TT></TD>
</TR>
<TR><TD BGCOLOR=black COLSPAN=3><TABLE BORDER=0 WIDTH="100%" CELLSPACING=0 CELLPADDING=1><TR><TD></TD></TR></TABLE></TD>
</TR></TABLE><BR>
<B>Portability</B><BR>
<BR>
ISO predicate.<BR>
<BR>
<A NAME="toc70"></A><TABLE CELLPADDING=0 CELLSPACING=0 WIDTH="100%">
<TR><TD BGCOLOR="#98e7ff"><DIV ALIGN=center><TABLE>
<TR><TD><B><A NAME="htoc100">7.8.2</A></B></TD>
<TD WIDTH="100%" ALIGN=center><TT><B>predicate_property/2</B></TT></TD>
</TR></TABLE></DIV></TD>
</TR></TABLE>
<A NAME="predicate-property/2"></A>
<BR>
<B>Templates</B>
<DL COMPACT=compact><DT><DD><TT>
predicate_property(?predicate_indicator, ?predicate_property)</TT></DL>
<B>Description</B><BR>
<BR>
<TT>predicate_property(Pred, Property)</TT> succeeds if there
exists a predicate indicator of a defined procedure that unifies with
<TT>Pred</TT> and if <TT>Property</TT> unifies with one of the properties of
the procedure. All user defined procedures and built-in predicates are
found. Internal system procedures whose name begins with <TT>'$'</TT>
are not found. This predicate is re-executable on backtracking.<BR>
<BR>
<B>Predicate properties</B>:
<UL><LI><TT>static</TT>: if the procedure is static.<BR>
<BR>
<LI><TT>dynamic</TT>: if the procedure is dynamic.<BR>
<BR>
<LI><TT>private</TT>: if the procedure is private.<BR>
<BR>
<LI><TT>public</TT>: if the procedure is public.<BR>
<BR>
<LI><TT>user</TT>: if the procedure is a user-defined procedure.<BR>
<BR>
<LI><TT>built_in</TT>: if the procedure is a Prolog built-in predicate.<BR>
<BR>
<LI><TT>built_in_fd</TT>: if the procedure is an FD built-in predicate.<BR>
<BR>
<LI><TT>native_code</TT>: if the procedure is compiled in native code.<BR>
<BR>
<LI><TT>prolog_file(File)</TT>: source file from which the
predicate has been read.<BR>
<BR>
<LI><TT>prolog_line(Line)</TT>: line number of the source
file.</UL>
<B>Errors</B><BR>
<TABLE CELLSPACING=2 CELLPADDING=0>
<TR><TD BGCOLOR=black COLSPAN=3><TABLE BORDER=0 WIDTH="100%" CELLSPACING=0 CELLPADDING=1><TR><TD></TD></TR></TABLE></TD>
</TR>
<TR><TD VALIGN=top ALIGN=left><TT>Pred</TT> is neither a variable nor a predicate indicator</TD>
<TD VALIGN=top ALIGN=center NOWRAP> </TD>
<TD VALIGN=top ALIGN=left><TT>type_error(predicate_indicator, Pred)</TT></TD>
</TR>
<TR><TD BGCOLOR=black COLSPAN=3><TABLE BORDER=0 WIDTH="100%" CELLSPACING=0 CELLPADDING=1><TR><TD></TD></TR></TABLE></TD>
</TR>
<TR><TD VALIGN=top ALIGN=left><TT>Pred</TT> is a term <TT>Name/Arity</TT> and <TT>Arity</TT> is
neither a variable nor an integer</TD>
<TD VALIGN=top ALIGN=center NOWRAP> </TD>
<TD VALIGN=top ALIGN=left><TT>type_error(integer, Arity)</TT></TD>
</TR>
<TR><TD BGCOLOR=black COLSPAN=3><TABLE BORDER=0 WIDTH="100%" CELLSPACING=0 CELLPADDING=1><TR><TD></TD></TR></TABLE></TD>
</TR>
<TR><TD VALIGN=top ALIGN=left><TT>Pred</TT> is a term <TT>Name/Arity</TT> and <TT>Name</TT> is
neither a variable nor an atom</TD>
<TD VALIGN=top ALIGN=center NOWRAP> </TD>
<TD VALIGN=top ALIGN=left><TT>type_error(atom, Name)</TT></TD>
</TR>
<TR><TD BGCOLOR=black COLSPAN=3><TABLE BORDER=0 WIDTH="100%" CELLSPACING=0 CELLPADDING=1><TR><TD></TD></TR></TABLE></TD>
</TR>
<TR><TD VALIGN=top ALIGN=left><TT>Pred</TT> is a term <TT>Name/Arity</TT> and <TT>Arity</TT> is
an integer < 0</TD>
<TD VALIGN=top ALIGN=center NOWRAP> </TD>
<TD VALIGN=top ALIGN=left><TT>domain_error(not_less_than_zero, Arity)</TT></TD>
</TR>
<TR><TD BGCOLOR=black COLSPAN=3><TABLE BORDER=0 WIDTH="100%" CELLSPACING=0 CELLPADDING=1><TR><TD></TD></TR></TABLE></TD>
</TR>
<TR><TD VALIGN=top ALIGN=left><TT>Pred</TT> is a term <TT>Name/Arity</TT> and <TT>Arity</TT> is
an integer > <TT>max_arity</TT> flag (section <A HREF="manual045.html#set-prolog-flag/2">7.22.1</A>)</TD>
<TD VALIGN=top ALIGN=center NOWRAP> </TD>
<TD VALIGN=top ALIGN=left><TT>representation_error(max_arity)</TT></TD>
</TR>
<TR><TD BGCOLOR=black COLSPAN=3><TABLE BORDER=0 WIDTH="100%" CELLSPACING=0 CELLPADDING=1><TR><TD></TD></TR></TABLE></TD>
</TR>
<TR><TD VALIGN=top ALIGN=left><TT>Property</TT> is neither a variable nor a predicate property
term</TD>
<TD VALIGN=top ALIGN=center NOWRAP> </TD>
<TD VALIGN=top ALIGN=left><TT>domain_error(predicate_property, Property)</TT></TD>
</TR>
<TR><TD BGCOLOR=black COLSPAN=3><TABLE BORDER=0 WIDTH="100%" CELLSPACING=0 CELLPADDING=1><TR><TD></TD></TR></TABLE></TD>
</TR>
<TR><TD VALIGN=top ALIGN=left><TT>Property</TT> = <TT>prolog_file(File)</TT> and <TT>File</TT>
is neither a variable nor an atom</TD>
<TD VALIGN=top ALIGN=center NOWRAP> </TD>
<TD VALIGN=top ALIGN=left><TT>type_error(atom, File)</TT></TD>
</TR>
<TR><TD BGCOLOR=black COLSPAN=3><TABLE BORDER=0 WIDTH="100%" CELLSPACING=0 CELLPADDING=1><TR><TD></TD></TR></TABLE></TD>
</TR>
<TR><TD VALIGN=top ALIGN=left><TT>Property</TT> = <TT>prolog_line(Line)</TT> and <TT>Line</TT>
is neither a variable nor an integer</TD>
<TD VALIGN=top ALIGN=center NOWRAP> </TD>
<TD VALIGN=top ALIGN=left><TT>type_error(integer, Line)</TT></TD>
</TR>
<TR><TD BGCOLOR=black COLSPAN=3><TABLE BORDER=0 WIDTH="100%" CELLSPACING=0 CELLPADDING=1><TR><TD></TD></TR></TABLE></TD>
</TR></TABLE><BR>
<B>Portability</B><BR>
<BR>
GNU Prolog predicate.<BR>
<BR>
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Copyright (C) 1999-2002 Daniel Diaz
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