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<H1> 3.6.3 String Types</H1>
<H4 ALIGN=CENTER>Static Semantics</H4>
<DIV Class="Paranum"><FONT SIZE=-2>1</FONT></DIV>
<DIV Class="Normal"> <A NAME="I1906"></A>A one-dimensional array type
whose component type is a character type is called a <I>string</I> type.</DIV>
<DIV Class="Paranum"><FONT SIZE=-2>2</FONT></DIV>
<DIV Class="Normal" Style="margin-bottom: 0.4em"> [There are two predefined
string types, String and Wide_String, each indexed by values of the predefined
subtype Positive; these are declared in the visible part of package Standard:]
</DIV>
<DIV Class="Paranum"><FONT SIZE=-2>3</FONT></DIV>
<DIV Class="Examples"><TT>[<B>subtype</B> Positive <B>is</B> Integer <B>range</B> 1 .. Integer'Last;</TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>4</FONT></DIV>
<DIV Class="Examples"><TT><B>type</B> String <B>is</B> <B>array</B>(Positive <B>range</B> <>) <B>of</B> Character;<BR>
<B>type</B> Wide_String <B>is</B> <B>array</B>(Positive <B>range</B> <>) <B>of</B> Wide_Character;<BR>
]</TT></DIV>
<DIV Class="NotesHeader"><FONT SIZE=-1>NOTES</FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>5</FONT></DIV>
<DIV Class="Notes"><FONT SIZE=-1>49 String literals (see <A HREF="AA-2-6.html">2.6</A>
and <A HREF="AA-4-2.html">4.2</A>) are defined for all string types.
The concatenation operator & is predefined for string types, as for
all nonlimited one-dimensional array types. The ordering operators <,
<=, >, and >= are predefined for string types, as for all one-dimensional
discrete array types; these ordering operators correspond to lexicographic
order (see <A HREF="AA-4-5-2.html">4.5.2</A>).</FONT></DIV>
<H4 ALIGN=CENTER>Examples</H4>
<DIV Class="Paranum"><FONT SIZE=-2>6</FONT></DIV>
<DIV Class="Normal" Style="margin-bottom: 0.4em"> <I>Examples of string
objects:</I> </DIV>
<DIV Class="Paranum"><FONT SIZE=-2>7</FONT></DIV>
<DIV Class="Examples"><TT>Stars : String(1 .. 120) := (1 .. 120 => '*' );<BR>
Question : <B>constant</B> String := "How many characters?";<BR>
<I>-- Question'First = 1, Question'Last = 20</I><BR>
<I>-- Question'Length = 20 (the number of characters)</I></TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>8</FONT></DIV>
<DIV Class="Examples"><TT>Ask_Twice : String := Question & Question; <I>-- constrained to (1..40)</I><BR>
Ninety_Six : <B>constant</B> Roman := "XCVI"; <I>-- see <A HREF="AA-3-5-2.html">3.5.2</A> and <A HREF="AA-3-6.html">3.6</A></I></TT></DIV>
<H4 ALIGN=CENTER>Inconsistencies With Ada 83</H4>
<DIV Class="Paranum"><FONT SIZE=-2>8.a</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1><A NAME="I1907"></A>The declaration
of Wide_String in Standard hides a use-visible declaration with the same
<FONT FACE="Arial, Helvetica">defining_identifier</FONT>. In rare cases,
this might result in an inconsistency between Ada 83 and Ada 95. </FONT></DIV>
<H4 ALIGN=CENTER>Incompatibilities With Ada 83</H4>
<DIV Class="Paranum"><FONT SIZE=-2>8.b</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1><A NAME="I1908"></A>Because both
String and Wide_String are always directly visible, an expression like
</FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>8.c</FONT></DIV>
<DIV Class="SmallExamples"><TT>"a" < "bc"</TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>8.d</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1>is now ambiguous, whereas in Ada
83 both string literals could be resolved to type String. </FONT></DIV>
<H4 ALIGN=CENTER>Extensions to Ada 83</H4>
<DIV Class="Paranum"><FONT SIZE=-2>8.e</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1><A NAME="I1909"></A>The type Wide_String
is new (though it was approved by ARG for Ada 83 compilers as well).
</FONT></DIV>
<H4 ALIGN=CENTER>Wording Changes from Ada 83</H4>
<DIV Class="Paranum"><FONT SIZE=-2>8.f</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1>We define the term <I>string type</I>
as a natural analogy to the term <I>character type</I>. </FONT></DIV>
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