$(MAKE)
# How do we convert a raw listing into something testable by sage? We
-# append/prepend triple quotes to make the whole thing into a doctest.
+# append/prepend triple quotes to make the whole thing into a doctest,
+# and then we replace any blank lines by "<BLANKLINE>".
sage_listings/%.py: sage_listings/%.listing
- echo '"""' > $@ && cat $< >> $@ && echo '"""' >> $@
+ echo '"""' > $@ && cat $< >> $@ && echo '"""' >> $@ && sed -i 's/^[[:space:]]*$$/<BLANKLINE>/' $@
# Ensure that there are no overfull or underfull boxes in the output
# document by parsing the log for said warnings.