X-Git-Url: https://git.distorted.org.uk/~mdw/sod/blobdiff_plain/faf3eb58d676c3abbef538784e26ca398d339caf..c6b4ed992d81518f240509e6ab212d8fe705485a:/lib/sod-structs.3

diff --git a/lib/sod-structs.3 b/lib/sod-structs.3
index 672fe59..161fc4e 100644
--- a/lib/sod-structs.3
+++ b/lib/sod-structs.3
@@ -692,7 +692,7 @@ will have
 .I different
 structures.
 .PP
-The instance layout split neatly into disjoint chains.
+The instance layout splits neatly into disjoint chains.
 This is necessary because
 each
 .B ichain
@@ -705,7 +705,7 @@ it doesn't matter that there are
 multiple method entry pointers
 for the same effective method
 as long as they all work correctly.
-Indeed, it's essential that they do,
+Indeed, it's essential that there are multiple entry pointers,
 because each chain's method entry function
 will need to apply a different offset to the receiver pointer
 before invoking the effective method.
@@ -869,8 +869,9 @@ be the most specific superclass of
 .I M
 in the same chain as
 .IR J .
-Then, if there is currently no class pointer of type
-.IR Q ,
+If there is currently no class pointer
+for the chain headed by
+.IR J ,
 then add a member
 .RS
 .IP
@@ -883,7 +884,13 @@ pointing to the appropriate
 .B islots
 structure within
 .IR M 's
-class object.
+class object,
+where
+.I Q
+is the most specific superclass of
+.I M
+in the same chain as
+.IR J .
 .RE
 .hP \*o
 Examine the superclass chains of
@@ -1107,6 +1114,12 @@ Finally, the class object is defined as
 .B #define
 .IB C __class
 .BI (& C __classobj. j . r )
+.br
+.B #define
+.IB C __cls_ k
+.BI (& C __classobj. k . n )
+.br
+\&...
 .PP
 The exported symbol
 .IB C __classobj
@@ -1125,7 +1138,32 @@ is the root metaclass of
 i.e., the metaclass of the least specific superclass of
 .IR C ;
 usually this is
-.BR "const SodClass *" .
+.BR "const SodClass\ *" .
+For each chain of
+.IR C 's
+metaclass, a macro
+.IB C __cls_ k
+is defined, usable as a pointer of type
+.B const
+.IR N \ \c
+.BR * ,
+where
+.I K
+and
+.I N
+are the chain's head and tail classes
+(i.e., the least- and most-specific classes in the chain)
+respectively;
+this macro is
+.I omitted
+if
+.IR N "\ =\ " R ,
+i.e., in the common case where
+.IR C 's
+metaclass is precisely the root metaclass,
+since the existing
+.IB C __class
+macro is already sufficient.
 .
 .\"--------------------------------------------------------------------------
 .SH SEE ALSO