Closures

Macros
#define	closureCreate(func, ...)   _closureCreate(func, count_macro_args(__VA_ARGS__), (stvar[]) { __VA_ARGS__ })
#define	closureCall(cls, ...)   _closureCall(cls, count_macro_args(__VA_ARGS__), (stvar[]) { __VA_ARGS__ })

Typedefs
typedef struct closure_ref *	closure
	Opaque handle to a closure.
typedef bool(*	closureFunc) (stvlist *cvars, stvlist *args)

Functions
closure	closureClone (closure cls)
void	closureDestroy (closure *cls)

Detailed Description

Function closures that capture environment variables for deferred execution.

A closure packages a function pointer with a list of captured variables (cvars) that act as the function's environment. When the closure is called, these captured variables are passed to the function along with any call-time arguments.

This is useful for:

• Passing context to callbacks without global state
• Implementing event handlers with associated data
• Deferred execution with captured parameters

Basic usage:

bool myCallback(stvlist *cvars, stvlist *args) {
    int captured = stvlNextInt(cvars);
    string arg = stvlNextPtr(string, args);
    // use captured value and argument...
    return true;
}
 
closure cls = closureCreate(myCallback, stvar(int32, 42));
closureCall(cls, stvar(string, myString));
closureDestroy(&cls);

Macro Definition Documentation

closureCall

#define closureCall	(		cls,
			...
	)		_closureCall(cls, count_macro_args(__VA_ARGS__), (stvar[]) { __VA_ARGS__ })

bool closureCall(closure cls, ...)

Call a closure with the given arguments.

Invokes the closure's function, passing both the captured variables (cvars) and the provided call-time arguments.

Parameters

cls	Closure to call
...	Zero or more stvar arguments to pass to the closure function

Returns

Return value from the closure function

Definition at line 86 of file closure.h.

closureCreate

#define closureCreate	(		func,
			...
	)		_closureCreate(func, count_macro_args(__VA_ARGS__), (stvar[]) { __VA_ARGS__ })

closure closureCreate(closureFunc func, ...)

Create a new closure with captured variables.

Captures the provided variables (cvars) which will be available to the function when the closure is called. The variables are copied, so the originals can be safely destroyed.

Parameters

func	Closure function to call
...	Zero or more stvar arguments to capture as the closure's environment

Returns

New closure object (must be freed with closureDestroy())

Definition at line 72 of file closure.h.

Typedef Documentation

closureFunc

typedef bool(* closureFunc) (stvlist *cvars, stvlist *args)

Closure function signature

Closure functions receive two argument lists:

• cvars: Captured variables provided when the closure was created
• args: Arguments provided when the closure is called

Both are accessed using stvlist iteration functions (stvlNext*, stvlNextPtr, etc.)

Parameters

cvars	List of captured variables from closureCreate()
args	List of arguments from closureCall()

Returns

true on success, false on failure

Definition at line 58 of file closure.h.

Function Documentation

closureClone()

closure closureClone

(

closure

cls

)

Create a copy of a closure

Creates a new closure with the same function and captured variables. The captured variables are deep-copied, so modifications to the original won't affect the clone.

Parameters

cls	Closure to clone

Returns

New independent closure (must be freed with closureDestroy())

closureDestroy()

void closureDestroy

(

closure *

cls

)

Destroy a closure and release its resources

Frees the closure and all captured variables. Sets the closure pointer to NULL.

Parameters

cls	Pointer to closure to destroy