Literals and Constructors

The dynamic runtime gives you a Python-flavoured API. Every value is a var (AbsObj *), created through constructor functions. Call abs_init() once before using anything from the runtime (see lifecycle.md).

#include "abscom/abs.h"

The v() literal macro

v(x) is a type-generic constructor that turns C values into var objects:

C argument	Result
int, long	int value
double, float	float value
char *, const char *	string value
bool	bool value

var a = v(42);          /* int   */
var b = v(3.14);        /* float */
var c = v("hello");     /* str   */
var d = v(true);        /* bool  */

Explicit constructors

Function	Description
var abs_new_int(long v)	Int value.
var abs_new_float(double v)	Float value.
var abs_new_str(const char *v)	String value (copied).
var abs_new_bool(bool v)	Bool value.
var abs_new_none(void)	The None value.
var abs_new_list(void)	Empty list.
var abs_new_dict(void)	Empty dict.
var abs_new_set(void)	Empty set.
var abs_new_error(const char *msg)	Error value (see error-handling.md).

Convenience macros

Macro	Expands to
None	abs_new_none()
True	((bool)1)
False	((bool)0)
List()	abs_new_list()
Dict()	abs_new_dict()
Set()	abs_new_set()

abs_init();

var n = None;      /* ABS_NONE     */
var t = v(True);   /* ABS_BOOL 1   */   /* v() wraps the bool literal */

True/False are raw C bools, handy for bool parameters (like sorted(xs, True)). Wrap them with v(...) when you need a var bool.

The AbsType enum

Every object carries a type tag:

Value	Meaning
ABS_INT	64-bit integer (long).
ABS_FLOAT	Double-precision float.
ABS_STR	String.
ABS_BOOL	Boolean.
ABS_LIST	Mutable list.
ABS_DICT	String-keyed dictionary.
ABS_SET	Unique-item set.
ABS_FILE	Open file handle.
ABS_ERROR	Error value.
ABS_NONE	The None value.
ABS_CLASS	A class object.
ABS_INSTANCE	An instance of a class.

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