doc-src/Intro/list.thy

added ML antiquotation @{make_string}, which produces proper pretty printed version in Poly/ML 5.3.0 or later;

List = FOL +
types   list 1
arities list    :: (term)term
consts  Nil     :: "'a list"
        Cons    :: "['a, 'a list] => 'a list" 
end