X-Git-Url: https://git.distorted.org.uk/~mdw/sod/blobdiff_plain/9a9a7b35fe696f7dfe041935bf41e89558930aee..2f8a99a834db051434d30471e9cc26a41f6a5fa7:/doc/structures.tex?ds=sidebyside

diff --git a/doc/structures.tex b/doc/structures.tex
index 7121692..a36ae82 100644
--- a/doc/structures.tex
+++ b/doc/structures.tex
@@ -637,13 +637,22 @@ defined for the sake of completeness.
 Finally, the class object is defined as
 \begin{prog}
   extern const struct $R$__ilayout $C$__classobj;               \\
-  \#define $C$__class (\&$C$__classobj.$j$.$r$)
+  \#define $C$__class (\&$C$__classobj.$j$.$r$)                 \\
+  \#define $C$__cls_$k$ (\&$C$__classobj.$k$.$n$)               \\
+  \quad$\vdots$
 \end{prog}
 The exported symbol @|$C$__classobj| contains the entire class instance.
 This is usually rather unwieldy.  The macro @|$C$__class| is usable as a
 pointer of type @|const $R$~*|, where $R$ is the root metaclass of $C$, i.e.,
 the metaclass of the least specific superclass of $C$; usually this is
-@|const SodClass~*|.
+@|const SodClass~*|.  For each chain of $C$'s metaclass, a macro
+@|$C$__cls_$k$| is defined, usable as a pointer of type @|const $N$~*|, where
+$K$ and $N$ are the chain's head and tail classes (i.e., the least- and
+most-specific classes in the chain) respectively; this macro is
+\emph{omitted} if $N = R$, i.e., in the common case where $C$'s metaclass is
+precisely the root metaclass, since the existing @|$C$__class| macro is
+already sufficient.
+
 
 %%%----- That's all, folks --------------------------------------------------
 
