Elan has a constructive type system based on four concrete elementary types and two mechanisms for composing types, and gives to its users the opportunity to add further (abstract) types.
(315,160) (000,150)type-declarer (005,120)(20,20)[rt] (015,120)(0,-1)100 (000,130)(1,0)110060type-name (1,0)110 (025,120)(20,20)[lb] (025,110)(1,0)095040INT (1,0)095 (255,120)(20,20)[rb] (025,100)(20,20)[lb] (025,090)(1,0)095040REAL (1,0)095 (255,100)(20,20)[rb] (025,080)(20,20)[lb] (025,070)(1,0)095040BOOL (1,0)095 (255,080)(20,20)[rb] (025,060)(20,20)[lb] (025,050)(1,0)095040TEXT (1,0)095 (255,060)(20,20)[rb] (025,040)(20,20)[lb] (025,030)(1,0)005040ROW (1,0)030060cardinality (1,0)030060type-declarer (1,0)005 (255,040)(20,20)[rb] (025,020)(20,20)[lb] (025,010)(1,0)020040STRUCT (1,0)030010( (1,0)030040fields (1,0)030010) (1,0)020 (255,020)(20,20)[rb] (265,020)(0,1)100 (275,120)(20,20)[lt]