SML# lexical items consist of the following.

keywords

The following are SML# keywords and they cannot be used as identifiers.

abstype and andalso as case datatype do else end eqtype exception fn fun functor handle if in include infix infixr let local nonfix of op open orelse raise rec set sharing sig signature struct structure then type val where while with withtype ( ) [ ] { } , : :> ; ... _ = => -> #

$⟨$alphaId$\mathrm{⟩}$ defined in the identifier section does not contain these keywords.

SQL keywords

The following are keywords used in SQL expressions and cannot be used as identifiers within SQL expressions.

asc all begin by commit cross default delete desc distinct fetch first from group inner insert into is join limit natural next not null offset only on or order rollback row rows select set update values where

These strings are not among the $⟨$alphaId$\mathrm{⟩}$ in the SQL expression that begins with the _sql keyword introduced in Section 19 and defined in Chapter 22. SQL expressions are not expressions in the definition of Standard ML, this restriction preserves the backward compatibility.

Extended keywords

The following names started with _ are keywords used to represent SML# special features. Since they are not lexical items in the definition of Standard ML, introducing them preserves the backward compatibility.

__attribute__ _builtin _foreach _import _interface _join _dynamic _dynamiccase _polyrec _require _sizeof _sql _sqlserver _typeof _use

Identifiers

Identifiers are names used in programs. SML# has the following 7 classes of identifiers defined below. Their classes are determined from their occurring context, so the same name can be used in different identifiers.

name	usage
$⟨$vid$\mathrm{⟩}$	variables, data constructors
$⟨$lab$\mathrm{⟩}$	record labels
$⟨$strid$\mathrm{⟩}$	structure names
$⟨$sigid$\mathrm{⟩}$	signature names
$⟨$funid$\mathrm{⟩}$	functor names
$⟨$tycon$\mathrm{⟩}$	type constructors
$⟨$tyvar$\mathrm{⟩}$	type variables

これら識別子の構造は以下の通りである．

$⟨$vid$\mathrm{⟩}$	::=	$⟨$alphaId$\mathrm{⟩}$  $|$ $⟨$symbolId$\mathrm{⟩}$
$⟨$lab$\mathrm{⟩}$	::=	$⟨$alphaId$\mathrm{⟩}$  $|$ $⟨$string$\mathrm{⟩}$  $|$ $⟨$decimal$\mathrm{⟩}$  $|$ $⟨$decimal$\mathrm{⟩}$ _ $⟨$alphaId$\mathrm{⟩}$	(note *1)
$⟨$strid$\mathrm{⟩}$	::=	$⟨$alphaId$\mathrm{⟩}$
$⟨$sigid$\mathrm{⟩}$	::=	$⟨$alphaId$\mathrm{⟩}$
$⟨$funid$\mathrm{⟩}$	::=	$⟨$alphaId$\mathrm{⟩}$
$⟨$tyvar$\mathrm{⟩}$	::=	’ $⟨$alphaId$\mathrm{⟩}$  $|$ ’’$⟨$alphaId$\mathrm{⟩}$
$⟨$tycon$\mathrm{⟩}$	::=	$⟨$alphaId$\mathrm{⟩}$  $|$ $⟨$symbolId$\mathrm{⟩}$

Note.

1. 1.

   There are the following three kinds of record labels: character string labels（$⟨$alphaId$\mathrm{⟩}$ or $⟨$string$\mathrm{⟩}$）， integer labels($⟨$decimal$\mathrm{⟩}$), ordered character string labels([1-9][0-9]* _ $⟨$alphaId$\mathrm{⟩}$). In SML#, record fields are sorted according to the ordering of their labels. Character string labels are ordered by String.compare. Integer labels are ordered according to the integer they represents. Ordered character string labels are order by the lexicographical pairing of integer labels and character string labels.

The definition of these character classes are given below.

$⟨$alpha$\mathrm{⟩}$	::=	[A-Za-z\127-\255]
$⟨$symbol$\mathrm{⟩}$	::=	! $|$  % $|$  & $|$  $ $|$  + $|$  / $|$  : $|$  < $|$  = $|$  > $|$  ? $|$  @ $|$    $|$  ‘ $|$  | $|$  # $|$  - $|$  ^ $|$  \
$⟨$alphaId$\mathrm{⟩}$	::=	$⟨$alpha$\mathrm{⟩}$ ($⟨$alpha$\mathrm{⟩}$  $|$ [0-9]  $|$ ’  $|$ _ )*	(Note 1)
$⟨$decimal$\mathrm{⟩}$	::=	[1-9] [0-9]*
$⟨$symbolId$\mathrm{⟩}$	::=	$⟨$symbol$\mathrm{⟩}$*	(Note 2)

Note.

1. 1.

   The character class $⟨$alphaId$\mathrm{⟩}$ does not contain keywords. Furthermore, in SQL expressions that begins with _sql, $⟨$alphaId$\mathrm{⟩}$ does not contain SQL keywords.

2. 2.

   $⟨$symbolId$\mathrm{⟩}$ does not contain keywords. Therefore ==> is an instance of $⟨$symbolId$\mathrm{⟩}$ but => is not.

Long identifiers

For $⟨$vid$\mathrm{⟩}$ (variable names and constructor names) and $⟨$strid$\mathrm{⟩}$ (structure names), the following long identifiers are defined.

$⟨$longVid$\mathrm{⟩}$	::=	($⟨$strid$\mathrm{⟩}$ .)* $⟨$vid$\mathrm{⟩}$
$⟨$longTycon$\mathrm{⟩}$	::=	($⟨$strid$\mathrm{⟩}$ .)* $⟨$tycon$\mathrm{⟩}$
$⟨$longStrid$\mathrm{⟩}$	::=	($⟨$strid$\mathrm{⟩}$ .)* $⟨$strid$\mathrm{⟩}$

constant literals $\mathrm{⟨}$scon$\mathrm{⟩}$

Syntax for constant literals are given below.

$⟨$scon$\mathrm{⟩}$	::=	$⟨$int$\mathrm{⟩}$  $|$ $⟨$word$\mathrm{⟩}$  $|$ $⟨$real$\mathrm{⟩}$  $|$ $⟨$string$\mathrm{⟩}$  $|$ $⟨$char$\mathrm{⟩}$	Constant literals
$⟨$int$\mathrm{⟩}$	::=	$($~$)\mathrm{?}$[0-9]$+$	Decimal integers
	$|$	$($~$)\mathrm{?}$0x[0-9a-fA-F]$+$	Hexadecimal integers
$⟨$word$\mathrm{⟩}$	::=	0w[0-9]$+$	unsigned decimal integers
	$|$	0wx[0-9a-fA-F]$+$	unsigned hexadecimal integers
$⟨$real$\mathrm{⟩}$	::=	$($~$)\mathrm{?}$[0-9]$+$ . [0-9]$+$ [Ee]$($~$)\mathrm{?}$[0-9]+	Floating-point numbers
	$|$	$($~$)\mathrm{?}$[0-9]$+$ . [0-9]+
	$|$	$($~$)\mathrm{?}$[0-9]$+$ [Ee]$($~$)\mathrm{?}$[0-9]+
$⟨$char$\mathrm{⟩}$	::=	#" ($⟨$printable$\mathrm{⟩}$ $\mathrm{|}$ $\mathrm{⟨}$escape$\mathrm{⟩}$) "	Character
$⟨$string$\mathrm{⟩}$	::=	" ($⟨$printable$\mathrm{⟩}$ $\mathrm{|}$ $\mathrm{⟨}$escape$\mathrm{⟩}$)$*$ "	String
$⟨$printable$\mathrm{⟩}$	::=	characters except for \ and "
$⟨$escape$\mathrm{⟩}$	::=	\a	The warning character (ASCII 7)
	$|$	\b	Backspace (ASCII 8)
	$|$	\t	Horizontal tab (ASCII 9)
	$|$	\n	New line character (ASCII 10)
	$|$	\v	Vertical tab (ASCII 11)
	$|$	\f	Home feed (ASCII 12)
	$|$	\r	Carriage return (ASCII 13)
	$|$	\^[\064-\095]	Control character represented by [\064-\095]
	$|$	\\	The \ character
	$|$	\"	The " character
	$|$	\$ddd$	The character of decimal code $ddd$
	$|$	\$f$ $\mathrm{\cdots }$ $f$\	ignoring whitespace characters $f\mathrm{\cdots }f$
	$|$	\u$xxxx$	The string of the UTF-8 character of hexadecimal code $xxxx$