.IB cls ,
.IB chead ,
.BI "const void *" obj );
-.PP
-.B const void *\c
-.B SOD_CLASSOF(\c
-.BI "const " cls " *" obj );
.br
.B void *\c
.B SOD_INSTBASE(\c
.BI "const " cls " *" obj );
-.br
-.IB cls " *" \c
-.B SOD_CONVERT(\c
-.IB cls ,
-.BI "const void *" obj );
-.br
-.B SOD_DECL(\c
-.IB cls ,
-.IB var );
.PP
+.B const void *\c
+.B SOD_CLASSOF(\c
+.BI "const " cls " *" obj );
+.br
.B int
.B sod_subclassp(\c
.BI "const SodClass *" sub ,
.BI "const SodClass *" super );
+.PP
+.IB cls " *" \c
+.B SOD_CONVERT(\c
+.IB cls ,
+.BI "const void *" obj );
.br
.B int
.B sod_convert(\c
.BI "const SodClass *" cls ,
.BI "const void *" obj );
+.PP
+.IB cls " *" \c
+.B SOD_INIT(\c
+.IB cls ,
+.BI "void *" p ,
+.IB keywords );
+.br
+.B void *\c
+.B sod_init(\c
+.BI "const SodClass *" cls ,
+.BI "void *" p ,
+.B ...);
+.br
+.B void *\c
+.B sod_initv(\c
+.BI "const SodClass *" cls ,
+.BI "void *" p ,
+.BI "va_list " ap );
+.br
+.B SOD_DECL(\c
+.IB cls ,
+.IB var );
+.PP
.
.\"--------------------------------------------------------------------------
.SH DESCRIPTION
While the translator can (at some effort) support alternative roots,
they will require different run-time support machinery.
.
-.SS Infrastructure macros
-These macros are mostly intended for use in code
-generated by the Sod translator.
+.SS Layout utilities
+The following macros are useful in
+finding one's way around an instance layout structure,
+given various levels of information about
+what kind of object one is dealing with,
+or for computing the tables which are used for
+this kind of navigation.
+.PP
+These macros are mostly intended for use in
+code generated by the Sod translator.
Others may find them useful for special effects,
but they can be tricky to understand and use correctly
and can't really be recommended for general use.
.PP
The
-.B SOD_XCHAIN
-macro performs a `cross-chain upcast'.
-Given a pointer
-.I cls
-.BI * obj
-to an instance of a class of type
-.I cls
-and the nickname
-.I chead
-of the least specific class in one of
-.IR cls 's
-superclass chains which does not contain
-.I cls
-itself,
-.B SOD_XCHAIN(\c
-.IB chead ,
-.IB obj )
-returns the address of that chain's storage
-within the instance layout as a raw
-.B void *
-pointer.
-(Note that
-.I cls
-is not mentioned explicitly.)
-This macro is used by the generated
-.IB CLASS __CONV_ CLS
-conversion macros,
-which you are encouraged to use instead where possible.
-.PP
-The
.B SOD_OFFSETDIFF
macro returns the signed offset between
two members of a structure or union type.
The
.B SOD_INSTBASE
macro (described below) is more suited to general use.
+.PP
+The
+.B SOD_INSTBASE
+macro finds the base address of an instance's layout.
+Given a pointer
+.BI "const " cls " *" obj
+to an instance,
+.BI SOD_INSTBASE( obj )
+returns the base address of the storage allocated to
+.IR obj .
+This is useful if you want to free a dynamically allocated instance,
+for example.
+This macro needs to look up an offset in
+.IR obj 's
+vtable to do its work.
+Compare
+.B SOD_ILAYOUT
+above,
+which is faster but requires
+precise knowledge of the instance's dynamic class.
.
-.SS Utility macros
-The following macros are expected to be useful
-in Sod method definitions and client code.
+.SS Classes
+The following macros and functions
+query the runtime relationhips between
+instances and classes.
.PP
The
.B SOD_CLASSOF
.IB cls __class \fR.)
.PP
The
-.B SOD_INSTBASE
-macro finds the base address of an instance's layout.
+.B sod_subclassp
+function answers whether one class
+.I sub
+is actually a subclass of another class
+.IR super .
+.B sod_subclassp(\c
+.IB sub ,
+.IB super )
+returns nonzero if and only if
+.I sub
+is a subclass of
+.IR super .
+This involves a run-time trawl through the class structures:
+while some effort has been made to make it perform well
+it's still not very fast.
+.
+.SS Conversions
+The following macros and functions are used
+to convert instance pointers of some (static) type
+into instance pointers of other static types
+to the same instance.
+.PP
+The
+.B SOD_XCHAIN
+macro performs a `cross-chain upcast'.
Given a pointer
-.BI "const " cls " *" obj
-to an instance,
-.BI SOD_INSTBASE( obj )
-returns the base address of the storage allocated to
-.IR obj .
-This is useful if you want to free a dynamically allocated instance,
-for example.
-This macro needs to look up an offset in
-.IR obj 's
-vtable to do its work.
-Compare
-.B SOD_ILAYOUT
-above,
-which is faster but requires
-precise knowledge of the instance's dynamic class.
+.I cls
+.BI * obj
+to an instance of a class of type
+.I cls
+and the nickname
+.I chead
+of the least specific class in one of
+.IR cls 's
+superclass chains which does not contain
+.I cls
+itself,
+.B SOD_XCHAIN(\c
+.IB chead ,
+.IB obj )
+returns the address of that chain's storage
+within the instance layout as a raw
+.B void *
+pointer.
+(Note that
+.I cls
+is not mentioned explicitly.)
+This macro is used by the generated
+.IB cls __CONV_ c
+conversion macros,
+which you are encouraged to use instead where possible.
.PP
The
.B SOD_CONVERT
-macro performs general conversions
+macro
+and
+.B sod_convert
+function
+perform general conversions
(up-, down-, and cross-casts) on instance pointers.
-Given a class name
+Given a class
.I cls
and a pointer
.BI "const void *" obj
to an instance,
-.B SOD_CONVERT(\c
-.IB cls ,
-.IB obj )
-returns an appropriately converted pointer to
+they return an appropriately converted pointer to
.I obj
if
.I obj
is indeed an instance of (some subclass of)
.IR cls ;
-otherwise it returns a null pointer.
-This macro is a simple wrapper around the
+otherwise they return a null pointer.
+.PP
+The
+.B SOD_CONVERT
+macro expects
+.I cls
+to be a class name;
+the
+.B sod_convert
+function
+expects a pointer to a class object instead.
+.PP
+This involves a run-time trawl through the class structures:
+while some effort has been made to make it perform well
+it's still not very fast.
+For upcasts (where
+.I cls
+is a superclass of the static type of
+.IR obj )
+the automatically defined conversion macros should be used instead,
+because they're much faster and can't fail.
+.PP
+When the target class is known statically,
+it's slightly more convenient to use the
+.B SOD_CONVERT
+macro rather than the
.B sod_convert
-function described below,
-which is useful in the common case that
-the target class is known statically.
+function,
+since the class object name is longer and uglier,
+and the macro returns a pointer of the correct type.
+.
+.SS Instance lifecycle
+The following macros and functions
+manage the standard steps along
+an instance's lifecycle.
+.PP
+The
+.B SOD_INIT
+macro,
+and the
+.B sod_init
+and
+.B sod_initv
+functions,
+imprint and initialize an instance of a class
+.I cls
+in the storage starting at address
+.IR p .
+.PP
+The direct class for the new instance is specified as
+a class name to
+.BR SOD_INIT ,
+or a pointer to a class object to the functions.
+.PP
+Keyword arguments for the initialization message may be provided.
+The
+.B SOD_INIT
+macro expects a single preprocessor-time argument
+which is a use of one of
+.B KWARGS
+or
+.B NO_KWARGS
+(see
+.BR keyword (3));
+the
+.B sod_init
+function expects the keywords as
+a variable-length argument tail;
+and
+.B sod_initv
+expects the keywords to be passed indirectly,
+through the captured argument-tail cursor
+.IR ap .
+.PP
+The return value is an instance pointer for the class
+.IR cls ;
+the
+.B SOD_INIT
+macro will have converted it to the correct type,
+so it should probably be used where possible.
+In fact, this is guaranteed to be equal to
+.I p
+by the layout rules described in
+.BR sod-structs (3).
.PP
The
.B SOD_DECL
pointers to it will become invalid when control
exits the scope of the declaration.
.
-.SS Functions
-The following functions are provided.
-.PP
-The
-.B sod_subclassp
-function answers whether one class
-.I sub
-is actually a subclass of another class
-.IR super .
-.B sod_subclassp(\c
-.IB sub ,
-.IB super )
-returns nonzero if and only if
-.I sub
-is a subclass of
-.IR super .
-This involves a run-time trawl through the class structures:
-while some effort has been made to make it perform well
-it's still not very fast.
-.PP
-The
-.B sod_convert
-function performs general conversions
-(up-, down-, and cross-casts) on instance pointers.
-Given a class pointer
-.I cls
-and an instance pointer
-.IR obj ,
-.B sod_convert(\c
-.IB cls ,
-.IB obj )
-returns an appropriately converted pointer to
-.I obj
-in the case that
-.I obj
-is an instance of (some subclass of)
-.IR cls ;
-otherwise it returns null.
-This involves a run-time trawl through the class structures:
-while some effort has been made to make it perform well
-it's still not very fast.
-For upcasts (where
-.I cls
-is a superclass of the static type of
-.IR obj )
-the automatically defined conversion macros should be used instead,
-because they're much faster and can't fail.
-When the target class is known statically,
-it's slightly more convenient to use the
-.B SOD_CONVERT
-macro instead.
-.
.\"--------------------------------------------------------------------------
.SH SEE ALSO
+.BR keyword (3),
.BR sod (1),
.BR sod-structs (3).
.
~mdw / sod / blobdiff