A type system is a tractable syntactic method for proving the absence of certain program behaviors by classifying phrases according to the kinds of values they compute.
The word “static” is sometimes added explicitly--we speak of a “statically typed programming language,” for example--to distinguish the sorts of compile-time analyses we are considering here from the dynamic or latent typing found in languages such as Scheme (Sussman and Steele, 1975; Kelsey, Clinger, and Rees, 1998; Dybvig, 1996), where run-time type tags are used to distinguish different kinds of structures in the heap. Terms like “dynamically typed” are arguably misnomers and should probably be replaced by “dynamically checked,” but the usage is standard.
Perhaps I should have been more clear that we use the words "dynamically typed" because they have entered the lexicon, but they are misnomers -- they do not properly capture what type theorists mean when they say "type".
A type system is a tractable syntactic method for proving the absence of certain program behaviors by classifying phrases according to the kinds of values they compute.
The word “static” is sometimes added explicitly--we speak of a “statically typed programming language,” for example--to distinguish the sorts of compile-time analyses we are considering here from the dynamic or latent typing found in languages such as Scheme (Sussman and Steele, 1975; Kelsey, Clinger, and Rees, 1998; Dybvig, 1996), where run-time type tags are used to distinguish different kinds of structures in the heap. Terms like “dynamically typed” are arguably misnomers and should probably be replaced by “dynamically checked,” but the usage is standard.
Perhaps I should have been more clear that we use the words "dynamically typed" because they have entered the lexicon, but they are misnomers -- they do not properly capture what type theorists mean when they say "type".