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<H1> 4.1.1 Indexed Components</H1>
<DIV Class="Paranum"><FONT SIZE=-2>1</FONT></DIV>
<DIV Class="Normal"> [An <FONT FACE="Arial, Helvetica">indexed_component</FONT>
denotes either a component of an array or an entry in a family of entries.
<A NAME="I2283"></A>]</DIV>
<H4 ALIGN=CENTER>Syntax</H4>
<DIV Class="Paranum"><FONT SIZE=-2>2</FONT></DIV>
<DIV Class="SyntaxIndented"><FONT FACE="Arial, Helvetica">indexed_component<A NAME="I2284"></A>
::= </FONT><A NAME="I2285"></A><FONT FACE="Arial, Helvetica">prefix</FONT>(<A NAME="I2286"></A><FONT FACE="Arial, Helvetica">expression</FONT> {, <A NAME="I2287"></A><FONT FACE="Arial, Helvetica">expression</FONT>})</DIV>
<H4 ALIGN=CENTER>Name Resolution Rules</H4>
<DIV Class="Paranum"><FONT SIZE=-2>3</FONT></DIV>
<DIV Class="Normal"> The <FONT FACE="Arial, Helvetica">prefix</FONT>
of an <FONT FACE="Arial, Helvetica">indexed_component</FONT> with a given
number of <FONT FACE="Arial, Helvetica">expression</FONT>s shall resolve
to denote an array (after any implicit dereference) with the corresponding
number of index positions, or shall resolve to denote an entry family
of a task or protected object (in which case there shall be only one
<FONT FACE="Arial, Helvetica">expression</FONT>).</DIV>
<DIV Class="Paranum"><FONT SIZE=-2>4</FONT></DIV>
<DIV Class="Normal"> <A NAME="I2288"></A>The expected type for each
<FONT FACE="Arial, Helvetica">expression</FONT> is the corresponding
index type.</DIV>
<H4 ALIGN=CENTER>Static Semantics</H4>
<DIV Class="Paranum"><FONT SIZE=-2>5</FONT></DIV>
<DIV Class="Normal"> When the <FONT FACE="Arial, Helvetica">prefix</FONT>
denotes an array, the <FONT FACE="Arial, Helvetica">indexed_component</FONT>
denotes the component of the array with the specified index value(s).
<A NAME="I2289"></A>The nominal subtype of the <FONT FACE="Arial, Helvetica">indexed_component</FONT>
is the component subtype of the array type. </DIV>
<DIV Class="Paranum"><FONT SIZE=-2>5.a</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1><B>Ramification: </B>In the case
of an array whose components are aliased, and of an unconstrained discriminated
subtype, the components are constrained even though their nominal subtype
is unconstrained. (This is because all aliased discriminated objects
are constrained. See <A HREF="AA-3-10-2.html">3.10.2</A>.) In all other
cases, an array component is constrained if and only if its nominal subtype
is constrained. </FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>6</FONT></DIV>
<DIV Class="Normal"> When the <FONT FACE="Arial, Helvetica">prefix</FONT>
denotes an entry family, the <FONT FACE="Arial, Helvetica">indexed_component</FONT>
denotes the individual entry of the entry family with the specified index
value.</DIV>
<H4 ALIGN=CENTER>Dynamic Semantics</H4>
<DIV Class="Paranum"><FONT SIZE=-2>7</FONT></DIV>
<DIV Class="Normal"> <A NAME="I2290"></A>For the evaluation of an <FONT FACE="Arial, Helvetica">indexed_component</FONT>,
the <FONT FACE="Arial, Helvetica">prefix</FONT> and the <FONT FACE="Arial, Helvetica">expression</FONT>s
are evaluated in an arbitrary order. The value of each <FONT FACE="Arial, Helvetica">expression</FONT>
is converted to the corresponding index type. <A NAME="I2291"></A><A NAME="I2292"></A><A NAME="I2293"></A>A
check is made that each index value belongs to the corresponding index
range of the array or entry family denoted by the <FONT FACE="Arial, Helvetica">prefix</FONT>.
<A NAME="I2294"></A>Constraint_Error is raised if this check fails.</DIV>
<H4 ALIGN=CENTER>Examples</H4>
<DIV Class="Paranum"><FONT SIZE=-2>8</FONT></DIV>
<DIV Class="Normal" Style="margin-bottom: 0.4em"> <I>Examples of indexed
components:</I> </DIV>
<DIV Class="Paranum"><FONT SIZE=-2>9</FONT></DIV>
<DIV Class="Examples"><TT> My_Schedule(Sat) <I>-- a component of a one-dimensional array (see <A HREF="AA-3-6-1.html">3.6.1</A>)</I><BR>
Page(10) <I>-- a component of a one-dimensional array (see <A HREF="AA-3-6.html">3.6</A>)</I><BR>
Board(M, J + 1) <I>-- a component of a two-dimensional array (see <A HREF="AA-3-6-1.html">3.6.1</A>)</I><BR>
Page(10)(20) <I>-- a component of a component (see <A HREF="AA-3-6.html">3.6</A>)</I><BR>
Request(Medium) <I>-- an entry in a family of entries (see <A HREF="AA-9-1.html">9.1</A>)</I><BR>
Next_Frame(L)(M, N) <I>-- a component of a function call (see <A HREF="AA-6-1.html">6.1</A>)</I></TT></DIV>
<DIV Class="NotesHeader"><FONT SIZE=-1>NOTES</FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>10</FONT></DIV>
<DIV Class="Notes"><FONT SIZE=-1>1 <I>Notes on the examples:</I>
Distinct notations are used for components of multidimensional arrays
(such as Board) and arrays of arrays (such as Page). The components of
an array of arrays are arrays and can therefore be indexed. Thus Page(10)(20)
denotes the 20th component of Page(10). In the last example Next_Frame(L)
is a function call returning an access value that designates a two-dimensional
array.</FONT></DIV>
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