From b8e270b9628592441e42555e1cbeb70bdb105aa9 Mon Sep 17 00:00:00 2001
From: Max Wash <mbswash@gmail.com>
Date: Mon, 4 May 2026 22:53:45 +0100
Subject: [PATCH] fx.reflection: function: implementing pre-binding argument
 values to functions

---
 fx.reflection/function.c                      | 79 ++++++++++++++++---
 .../include/fx/reflection/function.h          |  2 +-
 2 files changed, 67 insertions(+), 14 deletions(-)

diff --git a/fx.reflection/function.c b/fx.reflection/function.c
index 73d7626..66d9870 100644
--- a/fx.reflection/function.c
+++ b/fx.reflection/function.c
@@ -15,14 +15,46 @@ struct fx_function_p {
 	 * variable number of arguments, which may be handled differently by the
 	 * ABI */
 	size_t func_nr_args;
+
+	fx_value *func_bound_args;
+	size_t func_nr_bound_args, func_max_bound_args;
 };
 
 /*** PRIVATE FUNCTIONS ********************************************************/
 
-extern intptr_t fx_function_invoke_i(
-	fx_function_impl impl,
-	const fx_value *args,
-	size_t nr_args);
+static fx_status function_bind(
+	struct fx_function_p *func,
+	fx_value *args,
+	size_t nr_args)
+{
+	if (func->func_nr_bound_args) {
+		fx_value_unset_array(
+			func->func_bound_args,
+			func->func_nr_bound_args);
+	}
+
+	if (!args || !nr_args) {
+		func->func_nr_bound_args = 0;
+		return FX_SUCCESS;
+	}
+
+	if (nr_args > func->func_max_bound_args) {
+		fx_value *buf = realloc(
+			func->func_bound_args,
+			nr_args * sizeof *buf);
+		if (!buf) {
+			return FX_ERR_NO_MEMORY;
+		}
+
+		func->func_bound_args = buf;
+		func->func_max_bound_args = nr_args;
+	}
+
+	fx_value_copy_array(func->func_bound_args, args, nr_args);
+	func->func_nr_bound_args = nr_args;
+
+	return FX_SUCCESS;
+}
 
 static fx_status function_invoke(
 	const struct fx_function_p *func,
@@ -30,34 +62,44 @@ static fx_status function_invoke(
 	size_t nr_args,
 	fx_value *return_value)
 {
-	if (nr_args < func->func_nr_args) {
+	size_t total_args = nr_args + func->func_nr_bound_args;
+
+	if (total_args < func->func_nr_args) {
 		return FX_ERR_INVALID_ARGUMENT;
 	}
 
-	if (nr_args > func->func_nr_args
+	if (total_args > func->func_nr_args
 	    && !(func->func_flags & FX_FUNCTION_F_VARARG)) {
 		return FX_ERR_INVALID_ARGUMENT;
 	}
 
 	size_t nr_fixed_args = func->func_nr_args;
-	size_t nr_var_args = nr_args - nr_fixed_args;
+	size_t nr_var_args = total_args - nr_fixed_args;
 
 	struct callvm vm = {0};
 	callvm_reset(&vm, nr_fixed_args);
 
+	for (size_t i = 0; i < func->func_nr_bound_args; i++) {
+		const fx_value *arg = &func->func_bound_args[i];
+		callvm_push(&vm, arg);
+	}
+
 	for (size_t i = 0; i < nr_args; i++) {
 		const fx_value *arg = &args[i];
 		callvm_push(&vm, arg);
 	}
 
-	*return_value
-		= callvm_invoke(&vm, func->func_impl, func->func_return_type);
+	*return_value = callvm_invoke(
+		&vm,
+		func->func_impl,
+		func->func_return_type);
 
 	callvm_reset(&vm, 0);
 	return FX_SUCCESS;
 }
 
-/*** PUBLIC FUNCTIONS *********************************************************/
+/*** PUBLIC FUNCTIONS
+ * *********************************************************/
 
 FX_API fx_function *fx_function_create(
 	const char *name,
@@ -72,8 +114,9 @@ FX_API fx_function *fx_function_create(
 		return NULL;
 	}
 
-	struct fx_function_p *p
-		= fx_object_get_private(func, FX_REFLECTION_TYPE_FUNCTION);
+	struct fx_function_p *p = fx_object_get_private(
+		func,
+		FX_REFLECTION_TYPE_FUNCTION);
 
 	p->func_name = fx_strdup(name);
 	p->func_flags = flags;
@@ -88,7 +131,17 @@ FX_API fx_function *fx_function_create(
 	return func;
 }
 
-FX_API fx_status fx_function_invoke(
+fx_status fx_function_bind(fx_function *func, fx_value *args, size_t nr_args)
+{
+	FX_CLASS_DISPATCH_STATIC(
+		FX_REFLECTION_TYPE_FUNCTION,
+		function_bind,
+		func,
+		args,
+		nr_args);
+}
+
+fx_status fx_function_invoke(
 	const fx_function *func,
 	const fx_value *args,
 	size_t nr_args,
diff --git a/fx.reflection/include/fx/reflection/function.h b/fx.reflection/include/fx/reflection/function.h
index 03d78ec..201fce7 100644
--- a/fx.reflection/include/fx/reflection/function.h
+++ b/fx.reflection/include/fx/reflection/function.h
@@ -67,7 +67,7 @@ FX_API fx_function *fx_function_create(
 	size_t nr_args,
 	fx_value_type return_type);
 FX_API fx_status
-fx_function_bind(const fx_function *func, const fx_value *args, size_t nr_args);
+fx_function_bind(fx_function *func, fx_value *args, size_t nr_args);
 FX_API fx_status fx_function_invoke(
 	const fx_function *func,
 	const fx_value *args,