just one alternative proof syntax, which also works for Proof_Syntax.pretty_proof/Proof_Syntax.read_proof roundtrip;
# -*- shell-script -*- :mode=shellscript:
#
# Isabelle user settings sample -- for use in $ISABELLE_HOME_USER/etc/settings
ISABELLE_BUILD_OPTIONS="browser_info document=pdf"
ISABELLE_LOGIC=HOL