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<H1> J.7 At Clauses</H1>
<H4 ALIGN=CENTER>Syntax</H4>
<DIV Class="Paranum"><FONT SIZE=-2>1</FONT></DIV>
<DIV Class="SyntaxIndented"><FONT FACE="Arial, Helvetica">at_clause<A NAME="I7337"></A>
::= </FONT><B>for</B> <A NAME="I7338"></A><FONT FACE="Arial, Helvetica">direct_name</FONT> <B>use</B> <B>at</B> <A NAME="I7339"></A><FONT FACE="Arial, Helvetica">expression</FONT>;</DIV>
<H4 ALIGN=CENTER>Static Semantics</H4>
<DIV Class="Paranum"><FONT SIZE=-2>2</FONT></DIV>
<DIV Class="Normal"> An <FONT FACE="Arial, Helvetica">at_clause</FONT>
of the form ``for <I>x</I> use at <I>y</I>;'' is equivalent to an <FONT FACE="Arial, Helvetica">attribute_definition_clause</FONT>
of the form ``for <I>x</I>'Address use <I>y</I>;''. </DIV>
<DIV Class="Paranum"><FONT SIZE=-2>2.a</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1><B>Reason: </B>The preferred syntax
for specifying the address of an entity is an <FONT FACE="Arial, Helvetica">attribute_definition_clause</FONT>
specifying the Address attribute. Therefore, the special-purpose <FONT FACE="Arial, Helvetica">at_clause</FONT>
syntax is now obsolete.</FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>2.b</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1>The above equivalence implies,
for example, that only one <FONT FACE="Arial, Helvetica">at_clause</FONT>
is allowed for a given entity. Similarly, it is illegal to give both
an <FONT FACE="Arial, Helvetica">at_clause</FONT> and an <FONT FACE="Arial, Helvetica">attribute_definition_clause</FONT>
specifying the Address attribute. </FONT></DIV>
<H4 ALIGN=CENTER>Extensions to Ada 83</H4>
<DIV Class="Paranum"><FONT SIZE=-2>2.c</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1><A NAME="I7340"></A>We now allow
to define the address of an entity using an <FONT FACE="Arial, Helvetica">attribute_definition_clause</FONT>.
This is because Ada 83's <FONT FACE="Arial, Helvetica">at_clause</FONT>
is so hard to remember: programmers often tend to write ``for X'Address
use...;''. </FONT></DIV>
<H4 ALIGN=CENTER>Wording Changes from Ada 83</H4>
<DIV Class="Paranum"><FONT SIZE=-2>2.d</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1>Ada 83's <FONT FACE="Arial, Helvetica">address_clause</FONT>
is now called an <FONT FACE="Arial, Helvetica">at_clause</FONT> to avoid
confusion with the new term ``Address clause'' (that is, an <FONT FACE="Arial, Helvetica">attribute_definition_clause</FONT>
for the Address attribute). </FONT></DIV>
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