An enhanced integration of spreadsheet environments and external environments is disclosed herein that allows users to enter non-native statements directly into the cells of a worksheet so that external resources can be applied with respect to their values. In addition, a security model is disclosed whereby external functions referenced in the cells of a worksheet are executed in the context of a runtime environment that is secured apart from the spreadsheet application that hosts the worksheet. Various enhancements to the user experience are also disclosed that allow users to enter non-native statements in line with respect to the functional syntax that forms the basis of spreadsheet formulas.