Yes, PDD 19 can talk about 'subroutines' rather than 'compilation
units'. (I just did a quick skim of the file, and a simple search and
replace changing 'compilation unit' to 'subroutine' will work fine.)
In imcc.y, change 'compilation_unit' and 'compilation_units' to
something more general like
# New Ticket Created by Klaas-Jan Stol
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IMCC's top level non-terminal rule looks something like:
program:
