The Stack

Many API functions can arbitrarily refer to any element in the stack through an index. The stack indexes follow those conventions:

Here an example (let’s pretend that this table is the VM stack)

In this case, the function sq_gettop would return 4;

The API offers several functions to push and retrieve data from the Squirrel stack.

To push a value that is already present in the stack in the top position

void sq_push(HSQUIRRELVM v,SQInteger idx);

To pop an arbitrary number of elements

void sq_pop(HSQUIRRELVM v,SQInteger nelemstopop);

To remove an element from the stack

void sq_remove(HSQUIRRELVM v,SQInteger idx);

To retrieve the top index (and size) of the current virtual stack you must call sq_gettop

SQInteger sq_gettop(HSQUIRRELVM v);

To force the stack to a certain size you can call sq_settop

void sq_settop(HSQUIRRELVM v,SQInteger newtop);

If the newtop is bigger than the previous one, the new posistions in the stack will be filled with null values.

The following function pushes a C value into the stack

void sq_pushstring(HSQUIRRELVM v,const SQChar *s,SQInteger len);
void sq_pushfloat(HSQUIRRELVM v,SQFloat f);
void sq_pushinteger(HSQUIRRELVM v,SQInteger n);
void sq_pushuserpointer(HSQUIRRELVM v,SQUserPointer p);
void sq_pushbool(HSQUIRRELVM v,SQBool b);
			

this function pushes a null into the stack

void sq_pushnull(HSQUIRRELVM v);

returns the type of the value in a arbitrary position in the stack

SQObjectType sq_gettype(HSQUIRRELVM v,SQInteger idx);

the result can be one of the following values:

OT_NULL,OT_INTEGER,OT_FLOAT,OT_STRING,OT_TABLE,OT_ARRAY,OT_USERDATA,
OT_CLOSURE,OT_NATIVECLOSURE,OT_GENERATOR,OT_USERPOINTER,OT_BOOL,OT_INSTANCE,OT_CLASS,OT_WEAKREF
				

The following functions convert a squirrel value in the stack to a C value

SQRESULT sq_getstring(HSQUIRRELVM v,SQInteger idx,const SQChar **c);
SQRESULT sq_getinteger(HSQUIRRELVM v,SQInteger idx,SQInteger *i);
SQRESULT sq_getfloat(HSQUIRRELVM v,SQInteger idx,SQFloat *f);
SQRESULT sq_getuserpointer(HSQUIRRELVM v,SQInteger idx,SQUserPointer *p);
SQRESULT sq_getuserdata(HSQUIRRELVM v,SQInteger idx,SQUserPointer *p,SQUserPointer *typetag);
SQRESULT sq_getbool(HSQUIRRELVM v,SQInteger idx,SQBool *p);
			

The function sq_cmp compares 2 values from the stack and returns their relation (like strcmp() in ANSI C).

SQInteger sq_cmp(HSQUIRRELVM v);