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<TABLE CELLPADDING=0 CELLSPACING=0 WIDTH="100%">
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<TR><TD BGCOLOR="#66ff66"><DIV ALIGN=center><TABLE>
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<TR><TD><A NAME="htoc50"><B><FONT SIZE=5>6.1</FONT></B></A></TD>
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<TD WIDTH="100%" ALIGN=center><B><FONT SIZE=5>Lexical conventions</FONT></B></TD>
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</TR></TABLE></DIV></TD>
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<TABLE CELLPADDING=0 CELLSPACING=0 WIDTH="100%">
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<TR><TD BGCOLOR="#98ff98"><DIV ALIGN=center><TABLE>
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<TR><TD><B>Blanks</B></TD>
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</TR></TABLE></DIV></TD>
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The following characters are considered as blanks: space, newline,
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horizontal tabulation, carriage return, line feed and form feed. Blanks are
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ignored, but they separate adjacent identifiers, literals and
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keywords that would otherwise be confused as one single identifier,
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literal or keyword.<BR>
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<TABLE CELLPADDING=0 CELLSPACING=0 WIDTH="100%">
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<TR><TD BGCOLOR="#98ff98"><DIV ALIGN=center><TABLE>
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<TR><TD><B>Comments</B></TD>
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</TR></TABLE></DIV></TD>
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Comments are introduced by the two characters <TT>(*</TT>, with no
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intervening blanks, and terminated by the characters <TT>*)</TT>, with
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no intervening blanks. Comments are treated as blank characters.
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Comments do not occur inside string or character literals. Nested
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comments are handled correctly.<BR>
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<TABLE CELLPADDING=0 CELLSPACING=0 WIDTH="100%">
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<TR><TD BGCOLOR="#98ff98"><DIV ALIGN=center><TABLE>
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<TR><TD><B>Identifiers</B></TD>
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</TR></TABLE></DIV></TD>
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<DIV ALIGN=center><TABLE CELLSPACING=2 CELLPADDING=0>
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<TR><TD ALIGN=right NOWRAP>
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<TT><I><FONT COLOR=maroon>ident</FONT></I></TT></TD>
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<TD ALIGN=right NOWRAP>::=</TD>
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<TD ALIGN=left NOWRAP> (<TT><I><FONT COLOR=maroon>letter</FONT></I></TT>| <TT><FONT COLOR=blue>_</FONT></TT>) { <TT><I><FONT COLOR=maroon>letter</FONT></I></TT>| <TT><FONT COLOR=blue>0</FONT></TT>...<TT><FONT COLOR=blue>9</FONT></TT>| <TT><FONT COLOR=blue>_</FONT></TT>| <TT><FONT COLOR=blue>'</FONT></TT> }</TD>
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<TR><TD ALIGN=right NOWRAP>
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<TT><I><FONT COLOR=maroon>letter</FONT></I></TT></TD>
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<TD ALIGN=right NOWRAP>::=</TD>
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<TD ALIGN=left NOWRAP> <TT><FONT COLOR=blue>A</FONT></TT> ... <TT><FONT COLOR=blue>Z</FONT></TT> | <TT><FONT COLOR=blue>a</FONT></TT> ... <TT><FONT COLOR=blue>z</FONT></TT></TD>
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</TR></TABLE></DIV><BR>
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Identifiers are sequences of letters, digits, <TT>_</TT> (the underscore
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character), and <TT>'</TT> (the single quote), starting with a
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letter or an underscore.
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Letters contain at least the 52 lowercase and uppercase
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letters from the ASCII set. The current implementation (except on
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MacOS) also recognizes as letters all accented characters from the ISO
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8859-1 (``ISO Latin 1'') set. All characters in an identifier are
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meaningful. The current implementation places no limits on the number
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of characters of an identifier.<BR>
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<TABLE CELLPADDING=0 CELLSPACING=0 WIDTH="100%">
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<TR><TD BGCOLOR="#98ff98"><DIV ALIGN=center><TABLE>
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<TR><TD><B>Integer literals</B></TD>
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</TR></TABLE></DIV></TD>
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<DIV ALIGN=center><TABLE CELLSPACING=2 CELLPADDING=0>
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<TR><TD ALIGN=right NOWRAP>
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<TT><I><FONT COLOR=maroon>integer-literal</FONT></I></TT></TD>
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<TD ALIGN=right NOWRAP>::=</TD>
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<TD ALIGN=left NOWRAP>
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[<TT><FONT COLOR=blue>-</FONT></TT>] { <TT><FONT COLOR=blue>0</FONT></TT>...<TT><FONT COLOR=blue>9</FONT></TT> }<SUP><FONT SIZE=2>+</FONT></SUP></TD>
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<TR><TD ALIGN=right NOWRAP> </TD>
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<TD ALIGN=right NOWRAP>|</TD>
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<TD ALIGN=left NOWRAP> [<TT><FONT COLOR=blue>-</FONT></TT>] (<TT><FONT COLOR=blue>0x</FONT></TT>| <TT><FONT COLOR=blue>0X</FONT></TT>) { <TT><FONT COLOR=blue>0</FONT></TT>...<TT><FONT COLOR=blue>9</FONT></TT>| <TT><FONT COLOR=blue>A</FONT></TT>...<TT><FONT COLOR=blue>F</FONT></TT>| <TT><FONT COLOR=blue>a</FONT></TT>...<TT><FONT COLOR=blue>f</FONT></TT> }<SUP><FONT SIZE=2>+</FONT></SUP></TD>
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<TR><TD ALIGN=right NOWRAP> </TD>
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<TD ALIGN=right NOWRAP>|</TD>
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<TD ALIGN=left NOWRAP> [<TT><FONT COLOR=blue>-</FONT></TT>] (<TT><FONT COLOR=blue>0o</FONT></TT>| <TT><FONT COLOR=blue>0O</FONT></TT>) { <TT><FONT COLOR=blue>0</FONT></TT>...<TT><FONT COLOR=blue>7</FONT></TT> }<SUP><FONT SIZE=2>+</FONT></SUP></TD>
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<TR><TD ALIGN=right NOWRAP> </TD>
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<TD ALIGN=right NOWRAP>|</TD>
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<TD ALIGN=left NOWRAP> [<TT><FONT COLOR=blue>-</FONT></TT>] (<TT><FONT COLOR=blue>0b</FONT></TT>| <TT><FONT COLOR=blue>0B</FONT></TT>) { <TT><FONT COLOR=blue>0</FONT></TT>...<TT><FONT COLOR=blue>1</FONT></TT> }<SUP><FONT SIZE=2>+</FONT></SUP></TD>
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</TR></TABLE></DIV><BR>
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An integer literal is a sequence of one or more digits, optionally
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preceded by a minus sign. By default, integer literals are in decimal
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(radix 10). The following prefixes select a different radix:
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<DIV ALIGN=center><TABLE BORDER=1 CELLSPACING=0 CELLPADDING=1 WIDTH="80%">
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<TR><TD ALIGN=center NOWRAP><B>Prefix</B></TD>
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<TD ALIGN=center NOWRAP><B>Radix</B></TD>
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<TR><TD ALIGN=left NOWRAP>
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<TT>0x</TT>, <TT>0X</TT></TD>
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<TD ALIGN=left NOWRAP>hexadecimal (radix 16)</TD>
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<TR><TD ALIGN=left NOWRAP><TT>0o</TT>, <TT>0O</TT></TD>
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<TD ALIGN=left NOWRAP>octal (radix 8)</TD>
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<TR><TD ALIGN=left NOWRAP><TT>0b</TT>, <TT>0B</TT></TD>
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<TD ALIGN=left NOWRAP>binary (radix 2)</TD>
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</TR></TABLE></DIV><BR>
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(The initial <TT>0</TT> is the digit zero; the <TT>O</TT> for octal is the letter O.)
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The interpretation of integer literals that fall outside the range of
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representable integer values is undefined.<BR>
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<TABLE CELLPADDING=0 CELLSPACING=0 WIDTH="100%">
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<TR><TD BGCOLOR="#98ff98"><DIV ALIGN=center><TABLE>
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<TR><TD><B>Floating-point literals</B></TD>
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</TR></TABLE></DIV></TD>
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<DIV ALIGN=center><TABLE CELLSPACING=2 CELLPADDING=0>
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<TR><TD ALIGN=right NOWRAP>
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<TT><I><FONT COLOR=maroon>float-literal</FONT></I></TT></TD>
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<TD ALIGN=right NOWRAP>::=</TD>
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<TD ALIGN=left NOWRAP>
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[<TT><FONT COLOR=blue>-</FONT></TT>] { <TT><FONT COLOR=blue>0</FONT></TT>...<TT><FONT COLOR=blue>9</FONT></TT> }<SUP><FONT SIZE=2>+</FONT></SUP> [<TT><FONT COLOR=blue>.</FONT></TT> { <TT><FONT COLOR=blue>0</FONT></TT>...<TT><FONT COLOR=blue>9</FONT></TT> }]
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[(<TT><FONT COLOR=blue>e</FONT></TT>| <TT><FONT COLOR=blue>E</FONT></TT>) [<TT><FONT COLOR=blue>+</FONT></TT>| <TT><FONT COLOR=blue>-</FONT></TT>] { <TT><FONT COLOR=blue>0</FONT></TT>...<TT><FONT COLOR=blue>9</FONT></TT> }<SUP><FONT SIZE=2>+</FONT></SUP>]</TD>
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</TR></TABLE></DIV><BR>
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Floating-point decimals consist in an integer part, a decimal part and
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an exponent part. The integer part is a sequence of one or more
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digits, optionally preceded by a minus sign. The decimal part is a
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decimal point followed by zero, one or more digits.
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The exponent part is the character <TT>e</TT> or <TT>E</TT> followed by an
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optional <TT>+</TT> or <TT>-</TT> sign, followed by one or more digits.
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The decimal part or the exponent part can be omitted, but not both to
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avoid ambiguity with integer literals.
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The interpretation of floating-point literals that fall outside the
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range of representable floating-point values is undefined.<BR>
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<TABLE CELLPADDING=0 CELLSPACING=0 WIDTH="100%">
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<TR><TD BGCOLOR="#98ff98"><DIV ALIGN=center><TABLE>
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<TR><TD><B>Character literals</B></TD>
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</TR></TABLE></DIV></TD>
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<A NAME="s:characterliteral"></A><BR>
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<DIV ALIGN=center><TABLE CELLSPACING=2 CELLPADDING=0>
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<TR><TD ALIGN=right NOWRAP>
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<TT><I><FONT COLOR=maroon>char-literal</FONT></I></TT></TD>
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<TD ALIGN=right NOWRAP>::=</TD>
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<TD ALIGN=left NOWRAP>
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<TT><FONT COLOR=blue>'</FONT></TT> <TT><I><FONT COLOR=maroon>regular-char</FONT></I></TT> <TT><FONT COLOR=blue>'</FONT></TT></TD>
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<TR><TD ALIGN=right NOWRAP> </TD>
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<TD ALIGN=right NOWRAP>|</TD>
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<TD ALIGN=left NOWRAP> <TT><FONT COLOR=blue>'</FONT></TT> <TT><FONT COLOR=blue>\</FONT></TT> (<TT><FONT COLOR=blue>\</FONT></TT> | <TT><FONT COLOR=blue>'</FONT></TT> | <TT><FONT COLOR=blue>n</FONT></TT> | <TT><FONT COLOR=blue>t</FONT></TT> | <TT><FONT COLOR=blue>b</FONT></TT> | <TT><FONT COLOR=blue>r</FONT></TT>) <TT><FONT COLOR=blue>'</FONT></TT></TD>
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<TR><TD ALIGN=right NOWRAP> </TD>
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<TD ALIGN=right NOWRAP>|</TD>
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<TD ALIGN=left NOWRAP> <TT><FONT COLOR=blue>'</FONT></TT> <TT><FONT COLOR=blue>\</FONT></TT> (<TT><FONT COLOR=blue>0</FONT></TT>...<TT><FONT COLOR=blue>9</FONT></TT>) (<TT><FONT COLOR=blue>0</FONT></TT>...<TT><FONT COLOR=blue>9</FONT></TT>) (<TT><FONT COLOR=blue>0</FONT></TT>...<TT><FONT COLOR=blue>9</FONT></TT>) <TT><FONT COLOR=blue>'</FONT></TT></TD>
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</TR></TABLE></DIV><BR>
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Character literals are delimited by <TT>'</TT> (single quote) characters.
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The two single quotes enclose either one character different from
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<TT>'</TT> and <TT>\</TT>, or one of the escape sequences below:
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<DIV ALIGN=center><TABLE BORDER=1 CELLSPACING=0 CELLPADDING=1 WIDTH="80%">
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<TR><TD ALIGN=center NOWRAP><B>Sequence</B></TD>
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<TD ALIGN=center NOWRAP><B>Character denoted</B></TD>
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<TR><TD ALIGN=left NOWRAP>
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<TD ALIGN=left NOWRAP>backslash (<TT>\</TT>)</TD>
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<TR><TD ALIGN=left NOWRAP><TT>\'</TT></TD>
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<TD ALIGN=left NOWRAP>single quote (<TT>'</TT>)</TD>
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<TR><TD ALIGN=left NOWRAP><TT>\n</TT></TD>
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<TD ALIGN=left NOWRAP>linefeed (LF)</TD>
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<TR><TD ALIGN=left NOWRAP><TT>\r</TT></TD>
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<TD ALIGN=left NOWRAP>return (CR)</TD>
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<TR><TD ALIGN=left NOWRAP><TT>\t</TT></TD>
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<TD ALIGN=left NOWRAP>horizontal tabulation (TAB)</TD>
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<TR><TD ALIGN=left NOWRAP><TT>\b</TT></TD>
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<TD ALIGN=left NOWRAP>backspace (BS)</TD>
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<TR><TD ALIGN=left NOWRAP><TT>\</TT><I>ddd</I></TD>
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<TD ALIGN=left NOWRAP>the character with ASCII code <I>ddd</I> in decimal</TD>
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</TR></TABLE></DIV><BR>
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<TABLE CELLPADDING=0 CELLSPACING=0 WIDTH="100%">
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<TR><TD BGCOLOR="#98ff98"><DIV ALIGN=center><TABLE>
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<TR><TD><B>String literals</B></TD>
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</TR></TABLE></DIV></TD>
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<A NAME="s:stringliteral"></A><BR>
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<DIV ALIGN=center><TABLE CELLSPACING=2 CELLPADDING=0>
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<TR><TD ALIGN=right NOWRAP>
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<TT><I><FONT COLOR=maroon>string-literal</FONT></I></TT></TD>
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<TD ALIGN=right NOWRAP>::=</TD>
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<TD ALIGN=left NOWRAP>
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<TT><FONT COLOR=blue>"</FONT></TT> { <TT><I><FONT COLOR=maroon>string-character</FONT></I></TT> } <TT><FONT COLOR=blue>"</FONT></TT></TD>
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<TR><TD ALIGN=right NOWRAP>
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<TT><I><FONT COLOR=maroon>string-character</FONT></I></TT></TD>
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<TD ALIGN=right NOWRAP>::=</TD>
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<TD ALIGN=left NOWRAP>
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<TT><I><FONT COLOR=maroon>regular-char</FONT></I></TT></TD>
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<TR><TD ALIGN=right NOWRAP> </TD>
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<TD ALIGN=right NOWRAP>|</TD>
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<TD ALIGN=left NOWRAP> <TT><FONT COLOR=blue>\</FONT></TT> (<TT><FONT COLOR=blue>\</FONT></TT> | <TT><FONT COLOR=blue>"</FONT></TT> | <TT><FONT COLOR=blue>n</FONT></TT> | <TT><FONT COLOR=blue>t</FONT></TT> | <TT><FONT COLOR=blue>b</FONT></TT> | <TT><FONT COLOR=blue>r</FONT></TT>)</TD>
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<TR><TD ALIGN=right NOWRAP> </TD>
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<TD ALIGN=right NOWRAP>|</TD>
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<TD ALIGN=left NOWRAP> <TT><FONT COLOR=blue>\</FONT></TT> (<TT><FONT COLOR=blue>0</FONT></TT>...<TT><FONT COLOR=blue>9</FONT></TT>) (<TT><FONT COLOR=blue>0</FONT></TT>...<TT><FONT COLOR=blue>9</FONT></TT>) (<TT><FONT COLOR=blue>0</FONT></TT>...<TT><FONT COLOR=blue>9</FONT></TT>)</TD>
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</TR></TABLE></DIV><BR>
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String literals are delimited by <TT>"</TT> (double quote) characters.
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The two double quotes enclose a sequence of either characters
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different from <TT>"</TT> and <TT>\</TT>, or escape sequences from the
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<DIV ALIGN=center><TABLE BORDER=1 CELLSPACING=0 CELLPADDING=1 WIDTH="80%">
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<TR><TD ALIGN=center NOWRAP><B>Sequence</B></TD>
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<TD ALIGN=center NOWRAP><B>Character denoted</B></TD>
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<TR><TD ALIGN=left NOWRAP>
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<TD ALIGN=left NOWRAP>backslash (<TT>\</TT>)</TD>
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<TR><TD ALIGN=left NOWRAP><TT>\"</TT></TD>
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<TD ALIGN=left NOWRAP>double quote (<TT>"</TT>)</TD>
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<TR><TD ALIGN=left NOWRAP><TT>\n</TT></TD>
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<TD ALIGN=left NOWRAP>linefeed (LF)</TD>
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<TR><TD ALIGN=left NOWRAP><TT>\r</TT></TD>
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<TD ALIGN=left NOWRAP>return (CR)</TD>
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<TR><TD ALIGN=left NOWRAP><TT>\t</TT></TD>
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<TD ALIGN=left NOWRAP>horizontal tabulation (TAB)</TD>
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<TR><TD ALIGN=left NOWRAP><TT>\b</TT></TD>
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<TD ALIGN=left NOWRAP>backspace (BS)</TD>
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<TR><TD ALIGN=left NOWRAP><TT>\</TT><I>ddd</I></TD>
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<TD ALIGN=left NOWRAP>the character with ASCII code <I>ddd</I> in decimal</TD>
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</TR></TABLE></DIV><BR>
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To allow splitting long string literals across lines, the sequence
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<TT>\</TT><I>newline</I> <I>blanks</I> (a <TT>\</TT> at end-of-line followed by any
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number of blanks at the beginning of the next line) is ignored inside
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The current implementation places no restrictions on the length of
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<TABLE CELLPADDING=0 CELLSPACING=0 WIDTH="100%">
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<TR><TD BGCOLOR="#98ff98"><DIV ALIGN=center><TABLE>
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<TR><TD><B>Naming labels</B></TD>
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</TR></TABLE></DIV></TD>
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To avoid ambiguities, naming labels cannot just be defined
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syntactically as the sequence of the three tokens <TT>~</TT>, <TT><I><FONT COLOR=maroon>ident</FONT></I></TT> and
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<TT>:</TT>, and have to be defined at the lexical level.<BR>
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<DIV ALIGN=center><TABLE CELLSPACING=2 CELLPADDING=0>
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<TR><TD ALIGN=right NOWRAP>
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<TT><I><FONT COLOR=maroon>label</FONT></I></TT> </TD>
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<TD ALIGN=right NOWRAP>::=</TD>
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<TD ALIGN=left NOWRAP> <TT><FONT COLOR=blue>~</FONT></TT> (<TT><FONT COLOR=blue>a</FONT></TT> ... <TT><FONT COLOR=blue>z</FONT></TT>) { <TT><I><FONT COLOR=maroon>letter</FONT></I></TT>| <TT><FONT COLOR=blue>0</FONT></TT>...<TT><FONT COLOR=blue>9</FONT></TT>| <TT><FONT COLOR=blue>_</FONT></TT>| <TT><FONT COLOR=blue>'</FONT></TT> } <TT><FONT COLOR=blue>:</FONT></TT></TD>
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<TR><TD ALIGN=right NOWRAP>
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<TT><I><FONT COLOR=maroon>optlabel</FONT></I></TT> </TD>
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<TD ALIGN=right NOWRAP>::=</TD>
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<TD ALIGN=left NOWRAP> <TT><FONT COLOR=blue>?</FONT></TT> (<TT><FONT COLOR=blue>a</FONT></TT> ... <TT><FONT COLOR=blue>z</FONT></TT>) { <TT><I><FONT COLOR=maroon>letter</FONT></I></TT>| <TT><FONT COLOR=blue>0</FONT></TT>...<TT><FONT COLOR=blue>9</FONT></TT>| <TT><FONT COLOR=blue>_</FONT></TT>| <TT><FONT COLOR=blue>'</FONT></TT> } <TT><FONT COLOR=blue>:</FONT></TT></TD>
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</TR></TABLE></DIV><BR>
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Naming labels come in two flavours: <TT><I><FONT COLOR=maroon>label</FONT></I></TT> for normal arguments and
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<TT><I><FONT COLOR=maroon>optlabel</FONT></I></TT> for optional ones. They are simply distinguished by their
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first character, either <TT>~</TT> or <TT>?</TT>.<BR>
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<TABLE CELLPADDING=0 CELLSPACING=0 WIDTH="100%">
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<TR><TD BGCOLOR="#98ff98"><DIV ALIGN=center><TABLE>
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<TR><TD><B>Prefix and infix symbols</B></TD>
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</TR></TABLE></DIV></TD>
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<DIV ALIGN=center><TABLE CELLSPACING=2 CELLPADDING=0>
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<TR><TD ALIGN=right NOWRAP>
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<TT><I><FONT COLOR=maroon>infix-symbol</FONT></I></TT></TD>
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<TD ALIGN=right NOWRAP>::=</TD>
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<TD ALIGN=left NOWRAP>
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(<TT><FONT COLOR=blue>=</FONT></TT> | <TT><FONT COLOR=blue><</FONT></TT> | <TT><FONT COLOR=blue>></FONT></TT> | <TT><FONT COLOR=blue>@</FONT></TT> | <TT><FONT COLOR=blue>^</FONT></TT> | <TT><FONT COLOR=blue>|</FONT></TT> | <TT><FONT COLOR=blue>&</FONT></TT> |
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<TT><FONT COLOR=blue>+</FONT></TT> | <TT><FONT COLOR=blue>-</FONT></TT> | <TT><FONT COLOR=blue>*</FONT></TT> | <TT><FONT COLOR=blue>/</FONT></TT> | <TT><FONT COLOR=blue>$</FONT></TT> | <TT><FONT COLOR=blue>%</FONT></TT>) { <TT><I><FONT COLOR=maroon>operator-char</FONT></I></TT> }</TD>
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<TR><TD ALIGN=right NOWRAP>
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<TT><I><FONT COLOR=maroon>prefix-symbol</FONT></I></TT></TD>
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<TD ALIGN=right NOWRAP>::=</TD>
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<TD ALIGN=left NOWRAP>
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(<TT><FONT COLOR=blue>!</FONT></TT> | <TT><FONT COLOR=blue>?</FONT></TT> | <TT><FONT COLOR=blue>~</FONT></TT>) { <TT><I><FONT COLOR=maroon>operator-char</FONT></I></TT> }</TD>
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<TR><TD ALIGN=right NOWRAP>
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<TT><I><FONT COLOR=maroon>operator-char</FONT></I></TT></TD>
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<TD ALIGN=right NOWRAP>::=</TD>
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<TD ALIGN=left NOWRAP>
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<TT><FONT COLOR=blue>!</FONT></TT> | <TT><FONT COLOR=blue>$</FONT></TT> | <TT><FONT COLOR=blue>%</FONT></TT> | <TT><FONT COLOR=blue>&</FONT></TT> | <TT><FONT COLOR=blue>*</FONT></TT> | <TT><FONT COLOR=blue>+</FONT></TT> | <TT><FONT COLOR=blue>-</FONT></TT> | <TT><FONT COLOR=blue>.</FONT></TT> |
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<TT><FONT COLOR=blue>/</FONT></TT> | <TT><FONT COLOR=blue>:</FONT></TT> | <TT><FONT COLOR=blue><</FONT></TT> | <TT><FONT COLOR=blue>=</FONT></TT> | <TT><FONT COLOR=blue>></FONT></TT> | <TT><FONT COLOR=blue>?</FONT></TT> | <TT><FONT COLOR=blue>@</FONT></TT> |
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<TT><FONT COLOR=blue>^</FONT></TT> | <TT><FONT COLOR=blue>|</FONT></TT> | <TT><FONT COLOR=blue>~</FONT></TT></TD>
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</TR></TABLE></DIV><BR>
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Sequences of ``operator characters'', such as <TT><=></TT> or <TT>!!</TT>,
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are read as a single token from the <TT><I><FONT COLOR=maroon>infix-symbol</FONT></I></TT> or <TT><I><FONT COLOR=maroon>prefix-symbol</FONT></I></TT>
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class. These symbols are parsed as prefix and infix operators inside
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expressions, but otherwise behave much as identifiers.
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<TABLE CELLPADDING=0 CELLSPACING=0 WIDTH="100%">
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<TR><TD BGCOLOR="#98ff98"><DIV ALIGN=center><TABLE>
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<TR><TD><B>Keywords</B></TD>
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</TR></TABLE></DIV></TD>
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The identifiers below are reserved as keywords, and cannot be employed
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and as assert asr begin class
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closed constraint do done downto else
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end exception external false for fun
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function functor if in include inherit
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land lazy let lor lsl lsr
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lxor match method mod module mutable
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new of open or parser private
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rec sig struct then to true
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try type val virtual when while
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</PRE>The following character sequences are also keywords:
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# & ' ( ) * , -> ?
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?? . .. .( .[ : :: := ;
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;; <- = [ [| [< {< ] |]
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>] >} _ ` { | } ~
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<TABLE CELLPADDING=0 CELLSPACING=0 WIDTH="100%">
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<TR><TD BGCOLOR="#98ff98"><DIV ALIGN=center><TABLE>
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<TR><TD><B>Ambiguities</B></TD>
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</TR></TABLE></DIV></TD>
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Lexical ambiguities are resolved according to the ``longest match''
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rule: when a character sequence can be decomposed into two tokens in
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several different ways, the decomposition retained is the one with the
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longest first token.<BR>
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<TABLE CELLPADDING=0 CELLSPACING=0 WIDTH="100%">
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<TR><TD BGCOLOR="#98ff98"><DIV ALIGN=center><TABLE>
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<TR><TD><B>Line number directives</B></TD>
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</TR></TABLE></DIV></TD>
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<DIV ALIGN=center><TABLE CELLSPACING=2 CELLPADDING=0>
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<TR><TD ALIGN=right NOWRAP>
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<TT><I><FONT COLOR=maroon>linenum-directive</FONT></I></TT></TD>
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<TD ALIGN=right NOWRAP>::=</TD>
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<TD ALIGN=left NOWRAP>
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<TT><FONT COLOR=blue>#</FONT></TT> {<TT><FONT COLOR=blue>0</FONT></TT> ... <TT><FONT COLOR=blue>9</FONT></TT>}<SUP><FONT SIZE=2>+</FONT></SUP></TD>
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<TR><TD ALIGN=right NOWRAP> </TD>
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<TD ALIGN=right NOWRAP>|</TD>
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<TD ALIGN=left NOWRAP> <TT><FONT COLOR=blue>#</FONT></TT> {<TT><FONT COLOR=blue>0</FONT></TT> ... <TT><FONT COLOR=blue>9</FONT></TT>}<SUP><FONT SIZE=2>+</FONT></SUP> <TT><FONT COLOR=blue>"</FONT></TT> { <TT><I><FONT COLOR=maroon>string-character</FONT></I></TT> } <TT><FONT COLOR=blue>"</FONT></TT></TD>
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</TR></TABLE></DIV><BR>
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Preprocessors that generate Caml source code can insert line number
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directives in their output so that error messages produced by the
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compiler contain line numbers and file names referring to the source
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file before preprocessing, instead of after preprocessing.
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A line number directive is composed of a <TT>#</TT> (sharp sign), followed by
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a positive integer (the source line number), optionally followed by a
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character string (the source file name).
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Line number directives are treated as blank characters during lexical
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