Using .12c.

If "#include file.p8" is preceded by whitespace, it will result in a syntax error: unexpected symbol near #.

#include my_stuff.p8    <- works
   #include my_stuff.p8 <- doesn't work

This makes it difficult to embed #includes into "function() end" blocks without disrupting indention for readability.

Perhaps the "#" character is being called upon to do just a little too much work? Maybe "@" for compiler directives would be a better choice.