langchart.org

TYPE DISCIPLINE	Clojure	Erlang	F#	Haskell	Java	JavaScript	Python	Scala
strongly typed	yes	yes	yes	yes	yes		yes	yes
statically typed	no	no	yes	yes	yes		no	yes
coercion				no	yes		yes	yes
null reference				no	yes		yes	yes
strict booleans	no			yes	yes		no	yes
most types reified				no	yes		yes	yes
all types reified				no	no		yes	no

Notes: Manifests can prevent type-erasure in Scala in only very limited cases.

STATIC TYPES	F#	Haskell	Java	Scala
type inference	yes	yes	no	yes
path-dependent types				yes
existential types			yes	yes
self types			no	yes
bottom types			no	yes
compound types				yes
higher kinded types			no	yes
structural types			no	yes
sum types
product types
recursive types
type bounds			yes	yes
views				yes
view bounds				yes

OBJECTS	Clojure	Erlang	F#	Haskell	Java	JavaScript	Python	Scala
objects			yes		yes		yes	yes
all values are objects					no		yes	yes
?enforced encapsulation?					yes		no	yes

Notes: Objects are function/data containers that are first-class values.

CLASSES	F#	Java	Python	Scala
class type parameters		yes	no	yes
multiple constructors		yes		yes
anonymous classes		yes		yes
inner classes		yes		yes
reference to current object		yes	no	yes
reference to parent class		yes		yes

INHERITANCE	Clojure	Erlang	F#	Haskell	Java	JavaScript	Python	Scala
abstract functions					yes		no	yes
abstract data					no		no	yes
abstract types					no		no	yes
concrete function inheritance					yes		yes	yes
concrete data inheritance					yes		yes	yes
type aliases					no			yes
multiple abstract inheritance					yes		no	yes
multiple concrete inheritance					no		yes	yes
?virtual functions?

FUNCTIONS	Clojure	Erlang	F#	Haskell	Java	JavaScript	Python	Scala
function type parameters					yes		no	yes
operators evaluate like functions		no			no			yes
operator overloading				yes	no		yes	yes
first-class functions	yes	yes		yes	no		yes	yes
anonymous functions	yes	yes		yes	no		yes	yes
nested named functions					no		yes	yes
currying				yes	no			yes
partial application of functions	yes			yes	no		stdlib	yes
overloading	yes				yes		no	yes
default arguments					no		yes	yes
named arguments					no		yes	yes
variable number arguments					yes			yes
keyword parameter maps					no		yes
unstructured side-effects	yes	yes		no	yes		yes	yes
?dispatch?
?generators?
?continuations?

Notes: Scala’s methods aren’t themselves first-class but can always be treated as such.

BINDINGS & SCOPE	Clojure	Erlang	F#	Haskell	Java	JavaScript	Python	Scala
lexical scope					yes		no	yes
shadowing					no			yes
single assignment variables	no	yes		yes	yes		no	yes
multiple assignment variables	yes	no		no	yes		yes	yes
closures					no			yes
pattern matching	yes	yes		yes	no		no	yes
pattern matching in parameters		yes		yes	no		no	no
mutable state	yes			no	yes		yes	yes
?unmanaged mutable state?	no			no	yes		yes	yes
?forward declarations?
?globals?

Notes: Java only allows shadowing of class members.

CONTROL	Clojure	Erlang	F#	Haskell	Java	JavaScript	Python	Scala
if	yes	yes		yes	yes		yes	yes
if uses strict booleans	no				yes		no	yes
foreach					yes		yes	yes
while					yes		yes	yes
finally on loops					no		yes	no
exceptions	yes				yes		yes	yes
case		yes			no		no	yes
break/continue					yes		yes	no
switch
return					yes		yes	yes

LIBRARY	Clojure	Erlang	F#	Haskell	Java	JavaScript	Python	Scala
user-defined conversion					no			yes
implicit functions					no			yes
implicit parameters					no			yes
first-class modules							yes

Notes: Scala 2.8’s package objects can only add members to a package.

EVALUATION	Clojure	Erlang	F#	Haskell	Java	JavaScript	Python	Scala
?lazy functions?
?lazy expressions?
lazy initialization of fields					no			yes
delayed parameter evaluation					no			yes
eager parameter evaluation					yes		yes	yes
uniform access principle					no		no	yes
atoms	yes	yes			no		no	no

Notes: Only Java’s static fields are initialized lazily.

PROGRAM TEXT	Clojure	Erlang	F#	Haskell	Java	JavaScript	Python	Scala
whitespace significant				yes	no	no	yes	no
homoiconicity	yes	no	no	no	no		no	no
preprocessor	yes				no			no
macros	yes				no		no	no
metaprogramming
regular expressions	yes				no		no	no
reflection					yes

COLLECTIONS SYNTAX	Clojure	Erlang	F#	Haskell	Java	JavaScript	Python	Scala
lists	yes	yes		yes	no		yes	no
cons		yes			no		no
indexes					no		yes	no
ranges				yes	no		no	no
slices					no		yes	no
tuples		yes		yes			yes	yes
comprehensions	yes	yes		yes	no		yes	yes
maps	yes	no			no		yes	no

BASIC TYPES	Clojure	Erlang	F#	Haskell	Java	JavaScript	Python	Scala
integers are arbitrary-size	yes	yes		yes	no			no
strings are sequences	yes			yes	no		yes	yes

IMPLEMENTATION	Clojure	Erlang	F#	Haskell	Java	JavaScript	Python	Scala
true parallelism	yes	yes	yes	yes	yes		no	yes
full tail call optimization	no	yes		yes	no		no	no

Notes: CPython’s global interpreter lock prevents two threads from making progress at the same time. Jython and IronPython do not suffer from this problem.