Moved external calls to a separate function

src/core/CallExtern.go

@@ -0,0 +1,23 @@
+package core
+
+import (
+	"fmt"
+
+	"git.akyoto.dev/cli/q/src/expression"
+	"git.akyoto.dev/cli/q/src/types"
+	"git.akyoto.dev/cli/q/src/x86"
+)
+
+// CallExtern calls an external function.
+func (f *Function) CallExtern(fn *Function, parameters []*expression.Expression) ([]types.Type, error) {
+	f.DLLs = f.DLLs.Append(fn.Package, fn.Name)
+	registers := x86.WindowsInputRegisters[:len(parameters)]
+	err := f.BeforeCall(fn, parameters, registers)
+
+	if err != nil {
+		return nil, err
+	}
+
+	f.DLLCall(fmt.Sprintf("%s.%s", fn.Package, fn.Name))
+	return fn.OutputTypes, nil
+}