Argument Unpacking Helpers

Variadic helpers for extracting arguments from x-lang arg lists. More...

Functions
static void	__attribute__ ((unused)) x_args(x_obj_t *p_base
	va_start (ap, count)
	for (i=0;i< count;i++)
	va_end (ap)
	x_heap_root_push (p_cell, roots[0])
	x_heap_root_push (p_cell, roots[1])
	x_heap_root_pop (p_cell)

Variables
static void x_obj_t *	p_args
static void x_obj_t int	count
static void x_obj_t int int	i
int	held = 0
x_obj_t **	p_cell = x_heap_root_slot(p_base)
x_spair_t	roots [2]

Detailed Description

Variadic helpers for extracting arguments from x-lang arg lists.

Function Documentation

__attribute__()

static void __attribute__ ( (unused)  )

static

Unpack count elements from an args list into output pointers.

NULL pointers skip that position (like _ in pattern matching).

x_args(p_base, p_args, 3, NULL, &a, &b);  // skip self, extract 2

Parameters

p_base	Base/execution context (for the improper-spine raise).
p_args	Argument list (pair chain).
count	Number of positions to unpack.
...	Pointers to x_obj_t* slots (or NULL to skip).

Note

Walking off the proper prefix of an IMPROPER list used to read the tail atom's value word as a pair pointer (#487). The nil test below ends a proper list; x_eval_spine_guard raises on the atom a dotted tail ends with, which is the same catchable error an applicative already gave for the same call shape.

Unpack and evaluate count elements from an args list.

NULL pointers skip that position without evaluating.

x_eargs(p_base, p_args, 3, NULL, &a, &b);  // skip self, eval+extract 2

Parameters

p_base	Base/execution context.
p_args	Argument list (pair chain).
count	Number of positions to unpack.
...	Pointers to x_obj_t* slots (or NULL to skip).

for()

for

(

)

va_end()

va_end

(

ap

)

va_start()

va_start	(	ap	,
		count
	)

x_heap_root_pop()

x_heap_root_pop

(

p_cell

)

x_heap_root_push() [1/2]

x_heap_root_push	(	p_cell	,
		roots	[0]
	)

x_heap_root_push() [2/2]

x_heap_root_push	(	p_cell	,
		roots	[1]
	)

Variable Documentation

count

static void x_obj_t int count

held

int held = 0

i

static void x_obj_t int int i

Initial value:

{
    va_list ap

p_args

static void x_obj_t * p_args

p_cell

x_obj_t** p_cell = x_heap_root_slot(p_base)

roots

x_spair_t roots[2]

Initial value:

= {
        x_obj_set((x_obj_t *)x_type_pair_obj, X_OBJ_FLAG_NONE,
            { NULL }, { NULL }),
        x_obj_set((x_obj_t *)x_type_pair_obj, X_OBJ_FLAG_NONE,
            { NULL }, { NULL })
    }