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<H1> 2.2 Lexical Elements, Separators, and Delimiters</H1>
<H4 ALIGN=CENTER>Static Semantics</H4>
<DIV Class="Paranum"><FONT SIZE=-2>1</FONT></DIV>
<DIV Class="Normal"> <A NAME="I1197"></A>The text of a program consists
of the texts of one or more <FONT FACE="Arial, Helvetica">compilation</FONT>s.
<A NAME="I1198"></A><A NAME="I1199"></A>The text of each <FONT FACE="Arial, Helvetica">compilation</FONT>
is a sequence of separate <I>lexical elements</I>. Each lexical element
is formed from a sequence of characters, and is either a delimiter, an
<FONT FACE="Arial, Helvetica">identifier</FONT>, a reserved word, a <FONT FACE="Arial, Helvetica">numeric_literal</FONT>,
a <FONT FACE="Arial, Helvetica">character_literal</FONT>, a <FONT FACE="Arial, Helvetica">string_literal</FONT>,
or a comment. The meaning of a program depends only on the particular
sequences of lexical elements that form its <FONT FACE="Arial, Helvetica">compilation</FONT>s,
excluding <FONT FACE="Arial, Helvetica">comment</FONT>s.</DIV>
<DIV Class="Paranum"><FONT SIZE=-2>2</FONT></DIV>
<DIV Class="Normal"> The text of a <FONT FACE="Arial, Helvetica">compilation</FONT>
is divided into <A NAME="I1200"></A><I>lines</I>. <A NAME="I1201"></A>In
general, the representation for an end of line is implementation defined.
However, a sequence of one or more <FONT FACE="Arial, Helvetica">format_effector</FONT>s
other than character tabulation (HT) signifies at least one end of line.
</DIV>
<DIV Class="Paranum"><FONT SIZE=-2>2.a</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1><B>Implementation defined: </B>The
representation for an end of line.</FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>3</FONT></DIV>
<DIV Class="Normal" Style="margin-bottom: 0.4em"> <A NAME="I1202"></A>[In
some cases an explicit <I>separator</I> is required to separate adjacent
lexical elements.] A separator is any of a space character, a format
effector, or the end of a line, as follows: </DIV>
<DIV Class="Paranum"><FONT SIZE=-2>3.a</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1><B>Discussion: </B>It might be
useful to define ``white space'' and use it here. </FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>4</FONT></DIV>
<UL Class="Bulleted"><LI TYPE=DISC>A space character is a separator except within a <FONT FACE="Arial, Helvetica">comment</FONT>,
a <FONT FACE="Arial, Helvetica">string_literal</FONT>, or a <FONT FACE="Arial, Helvetica">character_literal</FONT>.</LI></UL>
<DIV Class="Paranum"><FONT SIZE=-2>5</FONT></DIV>
<UL Class="Bulleted"><LI TYPE=DISC>Character tabulation (HT) is a separator except within
a <FONT FACE="Arial, Helvetica">comment</FONT>.</LI></UL>
<DIV Class="Paranum"><FONT SIZE=-2>6</FONT></DIV>
<UL Class="Bulleted"><LI TYPE=DISC>The end of a line is always a separator. </LI></UL>
<DIV Class="Paranum"><FONT SIZE=-2>7</FONT></DIV>
<DIV Class="Normal"> One or more separators are allowed between any
two adjacent lexical elements, before the first of each <FONT FACE="Arial, Helvetica">compilation</FONT>,
or after the last. At least one separator is required between an <FONT FACE="Arial, Helvetica">identifier</FONT>,
a reserved word, or a <FONT FACE="Arial, Helvetica">numeric_literal</FONT>
and an adjacent <FONT FACE="Arial, Helvetica">identifier</FONT>, reserved
word, or <FONT FACE="Arial, Helvetica">numeric_literal</FONT>.</DIV>
<DIV Class="Paranum"><FONT SIZE=-2>8</FONT></DIV>
<DIV Class="Normal"> <A NAME="I1203"></A>A <I>delimiter</I> is either
one of the following special characters </DIV>
<DIV Class="Paranum"><FONT SIZE=-2>9</FONT></DIV>
<DIV Class="SyntaxIndented">& ' ( ) * + , - . / : ; < = > |</DIV>
<DIV Class="Paranum"><FONT SIZE=-2>10</FONT></DIV>
<DIV Class="Normal"> <A NAME="I1204"></A>or one of the following <I>compound
delimiters</I> each composed of two adjacent special characters </DIV>
<DIV Class="Paranum"><FONT SIZE=-2>11</FONT></DIV>
<DIV Class="SyntaxIndented">=> .. ** := /= >= <= << >> <></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>12</FONT></DIV>
<DIV Class="Normal"> Each of the special characters listed for single
character delimiters is a single delimiter except if this character is
used as a character of a compound delimiter, or as a character of a <FONT FACE="Arial, Helvetica">comment</FONT>,
<FONT FACE="Arial, Helvetica">string_literal</FONT>, <FONT FACE="Arial, Helvetica">character_literal</FONT>,
or <FONT FACE="Arial, Helvetica">numeric_literal</FONT>.</DIV>
<DIV Class="Paranum"><FONT SIZE=-2>13</FONT></DIV>
<DIV Class="Normal" Style="margin-bottom: 0.4em"> The following names
are used when referring to compound delimiters: </DIV>
<DIV Class="CodeIndented"><TABLE Width="70%">
<TR><TD align="left"> delimiter<TD align="left">name<TD align="left"> <TD align="left"> <TD align="left">
<TR><TD align="left"> <TD align="left"> <TD align="left"> <TD align="left"> <TD align="left">
<TR><TD align="left"> =><TD align="left">arrow<TD align="left"> <TD align="left"> <TD align="left">
<TR><TD align="left"> ..<TD align="left">double dot<TD align="left"> <TD align="left"> <TD align="left">
<TR><TD align="left"> **<TD align="left">double star, exponentiate<TD align="left"> <TD align="left"> <TD align="left">
<TR><TD align="left"> :=<TD align="left">assignment (pronounced:<TD align="left"> <TD align="left"> <TD align="left">
<TR><TD align="left"> <TD align="left"> ``becomes'')<TD align="left"> <TD align="left"> <TD align="left">
<TR><TD align="left"> /=<TD align="left">inequality (pronounced:<TD align="left"> <TD align="left"> <TD align="left">
<TR><TD align="left"> <TD align="left"> ``not equal'')<TD align="left"> <TD align="left"> <TD align="left">
<TR><TD align="left"> >=<TD align="left">greater than or equal<TD align="left"> <TD align="left"> <TD align="left">
<TR><TD align="left"> <=<TD align="left">less than or equal<TD align="left"> <TD align="left"> <TD align="left">
<TR><TD align="left"> <<<TD align="left">left label bracket<TD align="left"> <TD align="left"> <TD align="left">
<TR><TD align="left"> >><TD align="left">right label bracket<TD align="left"> <TD align="left"> <TD align="left">
<TR><TD align="left"> <> <TD align="left">box <TD align="left"> <TD align="left"> <TD align="left">
</TABLE></DIV>
<H4 ALIGN=CENTER>Implementation Requirements</H4>
<DIV Class="Paranum"><FONT SIZE=-2>14</FONT></DIV>
<DIV Class="Normal"> An implementation shall support lines of at least
200 characters in length, not counting any characters used to signify
the end of a line. An implementation shall support lexical elements of
at least 200 characters in length. The maximum supported line length
and lexical element length are implementation defined. </DIV>
<DIV Class="Paranum"><FONT SIZE=-2>14.a</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1><B>Implementation defined: </B>Maximum
supported line length and lexical element length.</FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>14.b</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1><B>Discussion: </B>From URG recommendation.
</FONT></DIV>
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