Pure/library/enclose, Pure/Syntax/pretty/enclose: renamed from parents
Pure/library/is_blank: now handles form feeds () too, in accordance with
ML definition
Arith = FOL +
classes arith < term
consts "0" :: "'a::arith" ("0")
"1" :: "'a::arith" ("1")
"+" :: "['a::arith,'a] => 'a" (infixl 60)
end