Unless, pipe is reserved for something else why not implement it here? Assuming an english keymap is in use both the : and | require a shiftkey to enter and both use pinky finger to insert. Is the extra bit of reach an issue? Conceptually the|seems more apropos to composition and prob. more accessible to more potential adopters than the :. For me the|is an easier visual parse when scanning multiple lines of code. For me the:isn't as easy a visual parse when scanning multiple lines of code.