I love literate programming, however my main issue with most tools like this one is that they do not properly support compiler/debugger error messages. This is a huge, often unstated caveat. It is very important to be able to read error messages and quickly locate the offending line in the literate source.

For languages that support file/line pragmas like C, literate programming works very well. Alternately, if the language supports goto and can sensibly unravel these statements, one can cobble a weave/tangle script to still have a 1-1 mapping between program and source line numbers.

Otherwise, I find that I need to program in a very functional style in order to force my tangled program to have the exact same line numbers as the literate source. This is possible, but it also negates the advantages of having natural language macro names, since they are essentially equivalent to the function names. In this case, tangle becomes an identity mapping.