From 30bb620dba83d9be32db8a0fdf751a800f9a2376 Mon Sep 17 00:00:00 2001
From: Brandon Dyck <brandon@dyck.us>
Date: Sat, 26 Nov 2022 21:45:16 -0700
Subject: [PATCH] Wrapped ph7_create_function

---
 cgo.c  |  4 ++++
 cgo.h  |  3 +++
 ph7.go | 38 +++++++++++++++++++++++++++++++++++++-
 3 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/cgo.c b/cgo.c
index d50841e..03d1175 100644
--- a/cgo.c
+++ b/cgo.c
@@ -11,3 +11,7 @@ int vm_extract_output(ph7_vm *pVm, const char **pzPtr, int *pLen) {
 int vm_set_output_callback(ph7_vm *pVm, void *pUserData) {
 	return ph7_vm_config(pVm, PH7_VM_CONFIG_OUTPUT, &write_vm_output, pUserData);
 }
+
+int vm_create_function(ph7_vm *pVm, const char *zName, void *pUserData) {
+	return ph7_create_function(pVm, zName, call_foreign_function, pUserData);
+}
diff --git a/cgo.h b/cgo.h
index cf529a7..c8576ab 100644
--- a/cgo.h
+++ b/cgo.h
@@ -6,3 +6,6 @@ int vm_extract_output(ph7_vm *pVm, const char **pzPtr, int *pLen);
 
 extern int write_vm_output(void*, unsigned int, void*);
 int vm_set_output_callback(ph7_vm *pVm, void *pUserData);
+
+extern int call_foreign_function(ph7_context *pCtx, int argc, ph7_value **argv);
+int vm_create_function(ph7_vm *pVm, const char *zName, void *pUserData);
diff --git a/ph7.go b/ph7.go
index 2239e9d..113f3e3 100644
--- a/ph7.go
+++ b/ph7.go
@@ -53,6 +53,8 @@ type Error struct {
 	Code ResultCode
 }
 
+// TODO create a CompileError that contains the error log text
+
 func newError(code C.int) error {
 	if code != C.PH7_OK {
 		return Error{
@@ -112,12 +114,17 @@ func (e Engine) Close() error {
 	return newError(C.ph7_release(e.ptr))
 }
 
+type Value C.ph7_value
+
+type Context C.ph7_context
+
 type VM struct {
 	ptr          *C.ph7_vm
 	pointerKey   unsafe.Pointer
 	outputWriter io.Writer
 	// TODO clear outputWriteError when resetting VM
-	outputWriteErr error
+	outputWriteErr   error
+	userFunctionKeys []unsafe.Pointer
 }
 
 func newVM(cvm *C.ph7_vm) *VM {
@@ -170,5 +177,34 @@ func (vm *VM) Reset() error {
 
 func (vm *VM) Close() error {
 	pointer.Unref(vm.pointerKey)
+	for _, key := range vm.userFunctionKeys {
+		pointer.Unref(key)
+	}
 	return newError(C.ph7_vm_release(vm.ptr))
 }
+
+type ForeignFunction interface {
+	Call(ctx *Context, args []*Value) ResultCode
+}
+
+//export call_foreign_function
+func call_foreign_function(ctx *C.ph7_context, argc C.int, argv **C.ph7_value) C.int {
+	fkey := C.ph7_context_user_data(ctx)
+	f := pointer.Restore(fkey).(ForeignFunction)
+	args := make([]*Value, 0, argc)
+	argvSlice := unsafe.Slice(argv, argc)
+	for i := range argvSlice {
+		args = append(args, (*Value)(argvSlice[i]))
+	}
+	return C.int(f.Call((*Context)(ctx), args))
+}
+
+func (vm *VM) CreateFunction(name string, f ForeignFunction) error {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	fkey := pointer.Save(f)
+	vm.userFunctionKeys = append(vm.userFunctionKeys, fkey)
+
+	return newError(C.vm_create_function(vm.ptr, cname, fkey))
+}