doc-src/Intro/bool.thy

renamed 'defns' to 'defs';
removed 'sigclass';
replaced parents by enclose;
exported parens, brackets, mk_list, mk_big_list, mk_pair, mk_triple;
various minor internal changes;

Bool = FOL +
types 	bool 0
arities bool 	:: term
consts tt,ff	:: "bool"
end