... which, in a weird bit of back-to-the-future, is exactly how Grace Hopper's original "compilers" worked, compiling (hence the term) patched versions of hand-built stencils. (The first few, A-0 and immediate successors, had program text that named the stencils directly, like what we'd now call directives for a macroassembler; later, MATH-MATIC and FLOW-MATIC added what we'd now call front ends which used the stencil language as an internal intermediate code.)