Variant Type Checking and Access

Macros
#define	stvarIs(svar, type)   _stvarIs(svar, stType(type))
#define	stvarObj(class, svar)   (objDynCast(class, stvarObjInst(svar)))

Functions
string	stvarString (stvar *svar)
string *	stvarStringPtr (stvar *svar)
ObjInst *	stvarObjInst (stvar *svar)
ObjInst **	stvarObjInstPtr (stvar *svar)

Detailed Description

Functions and macros for checking variant types and extracting values.

Macro Definition Documentation

stvarIs

#define stvarIs	(		svar,
			type
	)		_stvarIs(svar, stType(type))

bool stvarIs(stvar *svar, type)

Check if a variant contains a value of the specified type.

Compares the variant's runtime type descriptor against the specified compile-time type. Returns false for NULL pointers.

Parameters

svar	Pointer to variant to check
type	Type name to check for (e.g., int32, string)

Returns

true if variant contains the specified type, false otherwise

Example:

stvar v = stvar(int32, 42);
if (stvarIs(&v, int32)) {
    int32 val = v.data.st_int32;
}

Definition at line 523 of file stvar.h.

stvarObj

#define stvarObj	(		class,
			svar
	)		(objDynCast(class, stvarObjInst(svar)))

ClassName* stvarObj(ClassName, stvar *svar)

Extract typed object from variant with runtime type checking.

Retrieves the object from the variant and performs a dynamic cast to the specified class type. Returns NULL if the variant does not contain an object or if the object is not compatible with the target class.

Parameters

class	Target class name (e.g., MyClass)
svar	Pointer to variant

Returns

Typed object pointer, or NULL if not compatible

Example:

stvar v = stvar(object, myTestObj);
TestClass *tc = stvarObj(TestClass, &v);
if (tc) {
    // Use typed object
}

Definition at line 642 of file stvar.h.

Function Documentation

stvarObjInst()

ObjInst * stvarObjInst ( stvar *  svar )

inline

ObjInst* stvarObjInst(stvar *svar)

Extract object instance from variant if it contains an object.

Returns the untyped object pointer if the variant contains an object. For typed access, use stvarObj() macro instead.

Parameters

svar	Pointer to variant

Returns

Object instance pointer if variant contains object, NULL otherwise

Example:

stvar v = stvar(object, myObj);
ObjInst *obj = stvarObjInst(&v);
if (obj) {
    // Use untyped object
}

Definition at line 599 of file stvar.h.

References stvarIs.

stvarObjInstPtr()

ObjInst ** stvarObjInstPtr ( stvar *  svar )

inline

ObjInst** stvarObjInstPtr(stvar *svar)

Get pointer to object instance field within variant.

Returns a pointer to the object field inside the variant's data union. Returns NULL if the variant does not contain an object.

Parameters

svar	Pointer to variant

Returns

Pointer to object field, or NULL if not an object variant

Definition at line 615 of file stvar.h.

References stvarIs.

stvarString()

string stvarString ( stvar *  svar )

inline

string stvarString(stvar *svar)

Extract string value from variant if it contains a string.

Convenience accessor that checks the type and returns the string value in one operation. Returns NULL if the variant does not contain a string or if the pointer is NULL.

Parameters

svar	Pointer to variant

Returns

String value if variant contains string, NULL otherwise

Example:

stvar v = stvar(string, _SL("hello"));
string s = stvarString(&v);
if (s) {
    // Use string
}

Definition at line 548 of file stvar.h.

References stvarIs.

stvarStringPtr()

string * stvarStringPtr ( stvar *  svar )

inline

string* stvarStringPtr(stvar *svar)

Get pointer to string value within variant.

Returns a pointer to the string field inside the variant's data union, allowing modification of the stored string. Returns NULL if the variant does not contain a string.

Parameters

svar	Pointer to variant

Returns

Pointer to string field, or NULL if not a string variant

Example:

stvar v = stvar(string, _SL("hello"));
string *ps = stvarStringPtr(&v);
if (ps) {
    strAppend(ps, _SL(" world"));
}

Definition at line 574 of file stvar.h.

References stvarIs.