X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/sod/blobdiff_plain/020b9e2b4364c61a668d47c4c5405295349817d8..0e5c0b9edba8966aba72acb2b101b7a13d80f45a:/doc/syntax.tex

diff --git a/doc/syntax.tex b/doc/syntax.tex
index 65bd727..0e14e17 100644
--- a/doc/syntax.tex
+++ b/doc/syntax.tex
@@ -25,51 +25,6 @@
 
 \chapter{Module syntax} \label{ch:syntax}
 
-%%%--------------------------------------------------------------------------
-\section{Notation} \label{sec:syntax.notation}
-
-Fortunately, Sod is syntactically quite simple.  The notation is slightly
-unusual in order to make the presentation shorter and easier to read.
-
-Anywhere a simple nonterminal name $x$ may appear in the grammar, an
-\emph{indexed} nonterminal $x[a_1, \ldots, a_n]$ may also appear.  On the
-left-hand side of a production rule, the indices $a_1$, \ldots, $a_n$ are
-variables which vary over all nonterminal and terminal symbols, and the
-variables may also appear on the right-hand side in place of a nonterminal.
-Such a rule stands for a family of rules, in each variable is replaced by
-each possible simple nonterminal or terminal symbol.
-
-The letter $\epsilon$ denotes the empty nonterminal
-\begin{quote}
-  \syntax{$\epsilon$ ::=}
-\end{quote}
-
-The following indexed productions are used throughout the grammar, some often
-enough that they deserve special notation.
-\begin{itemize}
-\item @[$x$@] abbreviates @<optional>$[x]$, denoting an optional occurrence
-  of $x$:
-  \begin{quote}
-    \syntax{@[$x$@] ::= <optional>$[x]$ ::= $\epsilon$ @! $x$}
-  \end{quote}
-\item $x^*$ abbreviates @<zero-or-more>$[x]$, denoting a sequence of zero or
-  more occurrences of $x$:
-  \begin{quote}
-    \syntax{$x^*$ ::= <zero-or-more>$[x]$ ::=
-      $\epsilon$ @! <zero-or-more>$[x]$ $x$}
-  \end{quote}
-\item $x^+$ abbreviates @<one-or-more>$[x]$, denoting a sequence of one or
-  more occurrences of $x$:
-  \begin{quote}
-    \syntax{$x^+$ ::= <one-or-more>$[x]$ ::= <zero-or-more>$[x]$ $x$}
-  \end{quote}
-\item @<list>$[x]$ denotes a sequence of one or more occurrences of $x$
-  separated by commas:
-  \begin{quote}
-    \syntax{<list>$[x]$ ::= $x$ @! <list>$[x]$ "," $x$}
-  \end{quote}
-\end{itemize}
-
 %%%--------------------------------------------------------------------------
 \section{Lexical syntax} \label{sec:syntax.lex}
 
@@ -196,16 +151,16 @@ binary.  However, length and signedness indicators are not permitted.
 
 <not-star-or-slash> ::= any character other than "*" or  "/"
 
-<line-comment> ::= "//" @<not-newline>^* <newline>
+<line-comment> ::= "/\,/" @<not-newline>^* <newline>
 
 <newline> ::= a newline character
 
 <not-newline> ::= any character other than newline
 \end{grammar}
 
-Comments are exactly as in C99: both traditional block comments `\texttt{/*}
-\dots\ \texttt{*/}' and \Cplusplus-style `\texttt{//} \dots' comments are
-permitted and ignored.
+Comments are exactly as in C99: both traditional block comments `@|/*| \dots\
+@|*/|' and \Cplusplus-style `@|/\,/| \dots' comments are permitted and
+ignored.
 
 
 \subsection{Special nonterminals} \label{sec:syntax.lex.special}
@@ -255,6 +210,16 @@ brackets, braces or parenthesis ends the fragment.
 A @<module> is the top-level syntactic item.  A module consists of a sequence
 of definitions.
 
+[FIXME]
+Properties:
+\begin{description}
+\item[@"module_class"] A symbol naming the Lisp class to use to
+  represent the module.
+\item[@"guard"] An identifier to use as the guard symbol used to prevent
+  multiple inclusion in the header file.
+\end{description}
+
+
 \subsection{Simple definitions} \label{sec:syntax.module.simple}
 
 \subsubsection{Importing modules}
@@ -407,14 +372,15 @@ though the only operators currently defined act on integer values only.
 
 \subsubsection{The expression evaluator}
 \begin{grammar}
-<expression> ::= <term> | <expression> "+" <term> | <expression> "-" <term>
+<expression> ::= <term> | <expression> "+" <term> | <expression> "--" <term>
 
 <term> ::= <factor> | <term> "*" <factor> | <term> "/" <factor>
 
-<factor> ::= <primary> | "+" <factor> | "-" <factor>
+<factor> ::= <primary> | "+" <factor> | "--" <factor>
 
 <primary> ::=
      <integer-literal> | <string-literal> | <char-literal> | <identifier>
+\alt "<" <plain-type> ">"
 \alt "?" <s-expression>
 \alt "(" <expression> ")"
 \end{grammar}
@@ -456,8 +422,10 @@ recognized.
 
 <qualifier> ::= <atomic> | "const" | "volatile" | "restrict"
 
+<plain-type> ::= @<declaration-specifier>^+ <abstract-declarator>
+
 <atomic-type> ::=
-  <atomic> "(" @<declaration-specifier>^+ <abstract-declarator> ")"
+  <atomic> "(" <plain-type> ")"
 
 <atomic> ::= "atomic" | "_Atomic"
 
@@ -517,14 +485,15 @@ All of these have their usual C meanings.
 <declarator-suffix>$[a]$ ::= "[" <c-fragment> "]"
 \alt "(" $a$ ")"
 
-<argument-list> ::= $\epsilon$ | "..."
-\alt <list>$[\mbox{@<argument>}]$ @["," "..."@]
+<argument-list> ::= $\epsilon$ | "\dots"
+\alt <list>$[\mbox{@<argument>}]$ @["," "\dots"@]
 
 <argument> ::= @<declaration-specifier>^+ <argument-declarator>
 
 <abstract-declarator> ::= <declarator>$[\epsilon, \mbox{@<argument-list>}]$
 
 <argument-declarator> ::= <declarator>$[\mbox{@<identifier> @! $\epsilon$}]$
+
 <argument-declarator> ::=
   <declarator>$[\mbox{@<identifier> @! $\epsilon$}, \mbox{@<argument-list>}]$
 
@@ -581,11 +550,11 @@ necessary in order to resolve certain kinds of circularity.  For example,
 \begin{prog}
 class Sub;                                                      \\+
 
-class Super : SodObject \{                                      \\ \ind
+class Super: SodObject \{                                       \\ \ind
   Sub *sub;                                                   \-\\
 \};                                                             \\+
 
-class Sub : Super \{                                            \\ \ind
+class Sub: Super \{                                             \\ \ind
   /* \dots\ */                                                \-\\
 \};
 \end{prog}
@@ -634,7 +603,7 @@ properties are as follows.
   which messages it will respond to, and what its behaviour will be when it
   receives them.  The property value must be an identifier naming a defined
   subclass of @"SodClass".  The default metaclass is @"SodClass".
-  %%% FIXME xref to theory
+  See \xref{sec:concepts.metaclasses} for more details.
 \item[@"nick"] A nickname for the class, to be used to distinguish it from
   other classes in various limited contexts.  The property value must be an
   identifier; the default is constructed by forcing the class name to
@@ -661,19 +630,28 @@ It is not possible to declare a slot with function type: such an item is
 interpreted as being a @<message-item> or @<method-item>.  Pointers to
 functions are fine.
 
+Properties:
+\begin{description}
+\item[@"slot_class"] A symbol naming the Lisp class to use to represent the
+  direct slot.
+\item[@"initarg"] An identifier naming an initialization argument which can
+  be used to provide a value for the slot.  See
+  \xref{sec:concepts.lifecycle.birth} for the details.
+\end{description}
+
 An @<initializer>, if present, is treated as if a separate
 @<initializer-item> containing the slot name and initializer were present.
 For example,
 \begin{prog}
 [nick = eg]                                                     \\
-class Example : Super \{                                        \\ \ind
+class Example: Super \{                                         \\ \ind
   int foo = 17;                                               \-\\
 \};
 \end{prog}
 means the same as
 \begin{prog}
 [nick = eg]                                                     \\
-class Example : Super \{                                        \\ \ind
+class Example: Super \{                                         \\ \ind
   int foo;                                                      \\
   eg.foo = 17;                                                \-\\
 \};
@@ -696,10 +674,18 @@ The first component of the @<dotted-name> must be the nickname of one of the
 class's superclasses (including itself); the second must be the name of a
 slot defined in that superclass.
 
-An @|initarg| property may be set on an instance slot initializer (or a
-direct slot definition).  See \xref{sec:concepts.lifecycle.birth} for the
-details.  An initializer item must have either an @|initarg| property, or an
-initializer expression, or both.
+Properties:
+\begin{description}
+\item[@"initializer_class"] A symbol naming the Lisp class to use to
+  represent the initializer.
+\item[@"initarg"] An identifier naming an initialization argument which can
+  be used to provide a value for the slot.  See
+  \xref{sec:concepts.lifecycle.birth} for the details.  An initializer item
+  must have either an @|initarg| property, or an initializer expression, or
+  both.
+\item[@"initarg_class"] A symbol naming the Lisp class to use to represent
+  the initarg.  Only permitted if @"initarg" is also set.
+\end{description}
 
 Each class may define at most one initializer item with an explicit
 initializer expression for a given slot.
@@ -711,6 +697,11 @@ initializer expression for a given slot.
   @<declaration-specifier>^+
   <list>$[\mbox{@<init-declarator>}]$ ";"
 \end{grammar}
+Properties:
+\begin{description}
+\item[@"initarg_class"] A symbol naming the Lisp class to use to represent
+  the initarg.
+\end{description}
 
 \subsubsection{Fragment items}
 \begin{grammar}
@@ -726,6 +717,45 @@ initializer expression for a given slot.
   <keyword-declarator>$[\mbox{@<identifier>}]$
   @[<method-body>@]
 \end{grammar}
+Properties:
+\begin{description}
+\item[@"message_class"] A symbol naming the Lisp class to use to represent
+  the message.
+\item[@"combination"] A keyword naming the aggregating method combination to
+  use.
+\item[@"most_specific"] A keyword, either @`first' or @`last', according to
+  whether the most specific applicable method should be invoked first or
+  last.
+\end{description}
+
+Properties for the @|custom| aggregating method combination:
+\begin{description}
+\item[@"retvar"] An identifier for the return value from the effective
+  method.  The default is @|sod__ret|.  Only permitted if the message return
+  type is not @|void|.
+\item[@"valvar"] An identifier holding each return value from a direct method
+  in the effective method.  The default is @|sod__val|.  Only permitted if
+  the method return type (see @"methty" below) is not @|void|.
+\item[@"methty"] A C type, which is the return type for direct methods of
+  this message.
+\item[@"decls"] A code fragment containing declarations to be inserted at the
+  head of the effective method body.  The default is to insert nothing.
+\item[@"before"] A code fragment containing initialization to be performed at
+  the beginning of the effective method body.  The default is to insert
+  nothing.
+\item[@"first"] A code fragment to set the return value after calling the
+  first applicable direct method.  The default is to use the @"each"
+  fragment.
+\item[@"each"] A code fragment to set the return value after calling a direct
+  method.  If @"first" is also set, then it is used after the first direct
+  method instead of this.  The default is to insert nothing, which is
+  probably not what you want.
+\item[@"after"] A code fragment inserted at the end of the effective method
+  body.  The default is to insert nothing.
+\item[@"count"] An identifier naming a variable to be declared in the
+  effective method body, of type @|size_t|, holding the number of applicable
+  methods.  The default is not to provide such a variable.
+\end{description}
 
 \subsubsection{Method items}
 \begin{grammar}
@@ -736,6 +766,14 @@ initializer expression for a given slot.
 
 <method-body> ::= "{" <c-fragment> "}" | "extern" ";"
 \end{grammar}
+Properties:
+\begin{description}
+\item[@"method_class"] A symbol naming the Lisp class to use to represent
+  the direct method.
+\item[@"role"] A keyword naming the direct method's rÃ´le.  For the built-in
+  `simple' message classes, the acceptable rÃ´le names are @|before|,
+  @|after|, and @|around|.  By default, a primary method is constructed.
+\end{description}
 
 %%%----- That's all, folks --------------------------------------------------
 
