X-Git-Url: https://git.distorted.org.uk/~mdw/sod/blobdiff_plain/92e590b029e3cffc62b2876149ab257f0e6d8eb3..e895be217c3be6769708da17c9ae87cb22db040e:/doc/syntax.tex

diff --git a/doc/syntax.tex b/doc/syntax.tex
index 75aa36e..72329a4 100644
--- a/doc/syntax.tex
+++ b/doc/syntax.tex
@@ -51,15 +51,15 @@ could be a token.
 
 <id-start-char> ::= <alpha-char> | "_"
 
-<id-body-char> ::= <id-start-char> @! <digit-char>
+<id-body-char> ::= <id-start-char> | <digit-char>
 
-<alpha-char> ::= "A" | "B" | \dots\ | "Z"
-\alt "a" | "b" | \dots\ | "z"
-\alt <extended-alpha-char>
+<alpha-char> ::= "A" | "B" | $\cdots$ | "Z"
+  | "a" | "b" | $\cdots$ | "z"
+  | <extended-alpha-char>
 
 <digit-char> ::= "0" | <nonzero-digit-char>
 
-<nonzero-digit-char> ::= "1" | "2" $| \ldots |$ "9"
+<nonzero-digit-char> ::= "1" | "2" | $\cdots$ | "9"
 \end{grammar}
 
 The precise definition of @<alpha-char> is left to the function
@@ -80,11 +80,11 @@ level.
 
 <char-literal> ::= "'" <char-literal-char> "'"
 
-<string-literal-char> ::= any character other than "\\" or "\""
-\alt "\\" <char>
+<string-literal-char> :: "\\" <char>
+  | any character other than "\\" or "\""
 
-<char-literal-char> ::= any character other than "\\" or "'"
-\alt "\\" <char>
+<char-literal-char> :: "\\" <char>
+  | any character other than "\\" or "'"
 
 <char> ::= any single character
 \end{grammar}
@@ -101,25 +101,25 @@ discouraged.
 
 \begin{grammar}
 <integer-literal> ::= <decimal-integer>
-\alt <binary-integer>
-\alt <octal-integer>
-\alt <hex-integer>
+  | <binary-integer>
+  | <octal-integer>
+  | <hex-integer>
 
 <decimal-integer> ::= "0" | <nonzero-digit-char> @<digit-char>^*
 
-<binary-integer> ::= "0" @("b"|"B"@) @<binary-digit-char>^+
+<binary-integer> ::= "0" @("b" | "B"@) @<binary-digit-char>^+
 
 <binary-digit-char> ::= "0" | "1"
 
-<octal-integer> ::= "0" @["o"|"O"@] @<octal-digit-char>^+
+<octal-integer> ::= "0" @["o" | "O"@] @<octal-digit-char>^+
 
-<octal-digit-char> ::= "0" | "1" $| \ldots |$ "7"
+<octal-digit-char> ::= "0" | "1" | $\cdots$ | "7"
 
-<hex-integer> ::= "0" @("x"|"X"@) @<hex-digit-char>^+
+<hex-integer> ::= "0" @("x" | "X"@) @<hex-digit-char>^+
 
 <hex-digit-char> ::= <digit-char>
-\alt "A" | "B" | "C" | "D" | "E" | "F"
-\alt "a" | "b" | "c" | "d" | "e" | "f"
+  | "A" | "B" | "C" | "D" | "E" | "F"
+  | "a" | "b" | "c" | "d" | "e" | "f"
 \end{grammar}
 
 Sod understands only integers, not floating-point numbers; its integer syntax
@@ -130,15 +130,16 @@ binary.  However, length and signedness indicators are not permitted.
 \subsection{Punctuation} \label{sec:syntax.lex.punct}
 
 \begin{grammar}
-<punctuation> ::= any nonalphanumeric character other than "_", "\"" or "'"
+<punctuation> ::= "<<" | ">>" | "||" | "&&"
+  | "<=" | ">=" | "==" | "!=" | "\dots"
+\alt any nonalphanumeric character other than "_", "\"", or "'"
 \end{grammar}
 
 
 \subsection{Comments} \label{sec:syntax.lex.comment}
 
 \begin{grammar}
-<comment> ::= <block-comment>
-\alt <line-comment>
+<comment> ::= <block-comment> | <line-comment>
 
 <block-comment> ::=
   "/*"
@@ -323,7 +324,7 @@ defined in the built-in module.
 <abstract-declarator> ::= <declarator>$[\epsilon, \mbox{@<argument-list>}]$
 
 <argument-declarator> ::=
-  <declarator>$[\mbox{@<identifier> @! $\epsilon$}, \mbox{@<argument-list>}]$
+  <declarator>$[\mbox{@<identifier> | $\epsilon$}, \mbox{@<argument-list>}]$
 
 <simple-declarator> ::=
   <declarator>$[\mbox{@<identifier>}, \mbox{@<argument-list>}]$
@@ -351,7 +352,7 @@ keyword arguments.
   @[<list>$[\mbox{@<argument>}]$@]
   "?" @[<list>$[\mbox{@<keyword-argument>}]$@]
 
-<method-argument-list> ::= <argument-list> @! <keyword-argument-list>
+<method-argument-list> ::= <argument-list> | <keyword-argument-list>
 
 <dotted-name> ::= <identifier> "." <identifier>
 
@@ -367,18 +368,53 @@ keyword arguments.
 
 <property> ::= <identifier> "=" <expression>
 
-<expression> ::= <term> | <expression> "+" <term> | <expression> "--" <term>
+<expression> ::= <logical-or>
 
-<term> ::= <factor> | <term> "*" <factor> | <term> "/" <factor>
+<logical-or> ::= <logical-and>
+  | <logical-or> "||" <logical-and>
 
-<factor> ::= <primary> | "+" <factor> | "--" <factor>
+<logical-and> ::= <bitwise-or>
+  | <logical-and> "&&" <bitwise-or>
+
+<bitwise-or> ::= <bitwise-xor>
+  | <bitwise-or> "|" <bitwise-xor>
+
+<bitwise-xor> ::= <bitwise-and>
+  | <bitwise-xor> "^" <bitwise-and>
+
+<bitwise-and> ::= <equality>
+  | <bitwise-and> "&" <equality>
+
+<equality> ::= <ordering>
+  | <equality> "==" <ordering>
+  | <equality> "!=" <ordering>
+
+<ordering> ::= <shift>
+  | <ordering> "<" <shift>
+  | <ordering> "<=" <shift>
+  | <ordering> ">=" <shift>
+  | <ordering> ">" <shift>
+
+<shift> ::= <additive>
+  | <shift> "<<" <additive>
+  | <shift> ">>" <additive>
+
+<additive> ::= <term>
+  | <additive> "+" <term>
+  | <additive> "--" <term>
+
+<term> ::= <factor>
+  | <term> "*" <factor>
+  | <term> "/" <factor>
+
+<factor> ::= <primary>
+  | "!" <factor> | "~" factor
+  | "+" <factor> | "--" <factor>
 
 <primary> ::=
      <integer-literal> | <string-literal> | <char-literal> | <identifier>
-\alt "<" <plain-type> ">"
-\alt "{" <c-fragment> "}"
-\alt "?" <s-expression>
-\alt "(" <expression> ")"
+\alt "<" <plain-type> ">" | "{" <c-fragment> "}" | "?" <s-expression>
+  | "(" <expression> ")"
 \end{grammar}
 
 \emph{Property sets} are a means for associating miscellaneous information
@@ -462,10 +498,10 @@ above, are as follows.
 
 \item The @|boolean| output type denotes a boolean value, which may be either
   true or false.  A value of type @|id| is considered true if it is @|true|,
-  @|t|, @|yes|, @|on|, or @|verily|; or false if it is @|false|, @|nil|,
-  @|no|, @|off|, or @|nowise|; it is erroneous to provide any other
-  identifier where a boolean value is wanted.  A value of type @|int| is
-  considered true if it is nonzero, or false if it is zero.
+  @|t|, @|yes|, @|on|, @|yup|, or @|verily|; or false if it is @|false|,
+  @|nil|, @|no|, @|off|, @|nope|, or @|nowise|; it is erroneous to provide
+  any other identifier where a boolean value is wanted.  A value of type
+  @|int| is considered true if it is nonzero, or false if it is zero.
 
 \item The @|symbol| output type denotes a Lisp symbol.
 
@@ -476,7 +512,7 @@ above, are as follows.
   upper; if the name contains letters of both cases, then it is not changed.
   For example, @|foo45| becomes @|FOO45|, or \emph{vice-versa}; but @|Splat|
   remains as it is.  Second, the name is subjected to \emph{separator
-    switching}: all underscores in the name are replaced with hyphens (and
+  switching}: all underscores in the name are replaced with hyphens (and
   \emph{vice-versa}, though hyphens aren't permitted in identifiers in the
   first place).  Finally, the resulting name is interned in the current
   package, which will usually be @|sod-user| unless changed explicitly by the
@@ -634,14 +670,18 @@ declarations instead.
 
 \begin{grammar}
 <code-definition> ::=
-  "code" <identifier> ":" <item-name> @[<constraints>@]
+  "code" <reason> ":" <item-name> @[<constraints>@]
   "{" <c-fragment> "}"
+\alt
+  "code" <reason> ":" <constraints> ";"
+
+<reason> ::= <identifier>
 
 <constraints> ::= "[" <list>$[\mbox{@<constraint>}]$ "]"
 
 <constraint> ::= @<item-name>^+
 
-<item-name> ::= <identifier> @! "(" @<identifier>^+ ")"
+<item-name> ::= <identifier> | "(" @<identifier>^+ ")"
 \end{grammar}
 
 The @<c-fragment> will be output unchanged to one of the output files.
@@ -726,8 +766,9 @@ The @<list>$[\mbox{@<identifier>}]$ names the direct superclasses for the new
 class.  It is an error if any of these @<identifier>s does not name a defined
 class.  The superclass list is required, and must not be empty; listing
 @|SodObject| as your class's superclass is a good choice if nothing else
-seems suitable.  It's not possible to define a \emph{root class} in the Sod
-language: you must use Lisp to do this, and it's quite involved.
+seems suitable.  A class with no direct superclasses is called a \emph{root
+class}.  It is not possible to define a root class in the Sod language: you
+must use Lisp to do this, and it's quite involved.
 
 The @<properties> provide additional information.  The standard class
 properties are as follows.
@@ -862,6 +903,9 @@ Properties:
 \begin{description}
 \item[@|message_class|] A symbol naming the Lisp class to use to represent
   the message.
+\item[@|readonly|] A boolean indicating whether the message guarantees not to
+  modify its receiver.  If this is true, the receiver will be declared
+  @"const".
 \item[@|combination|] A keyword naming the aggregating method combination to
   use.
 \item[@|most_specific|] A keyword, either @`first' or @`last', according to