Comparison of type systems

Programming language static / dynamic strong / weak safety nominative / structural
Ada static strong safe nominative
Assembly language none strong unsafe structural
APL dynamic weak safe nominative
BASIC static weak safe nominative
C static weak unsafe nominative
C++ static strong unsafe nominative
C#[1] static strong both nominative
Cayenne dependent strong safe structural
Clipper dynamic weak safe duck
D static strong both[2] nominative
Delphi static strong safe nominative
E dynamic strong safe nominative + duck
Eiffel static strong safe nominative
Erlang dynamic strong safe nominative
F# static strong safe nominative
Fortran static strong safe nominative
Go static strong safe structural
Groovy dynamic strong safe duck
Haskell static strong safe nominative + structural
Io dynamic strong safe duck
Java static strong safe nominative
JavaScript dynamic weak safe duck
Julia dynamic + static strong both? A usable subset is safe.[3] See manual[4]
Lisp dynamic strong safe structural
Lua[5] dynamic weak safe structural
ML static strong safe structural
Objective-C[6] static+dynamic strong unsafe nominative
Pascal static strong safe nominative
Perl 1–5 dynamic weak safe nominative
Perl 6[7] hybrid hybrid safe duck
PHP dynamic weak safe ?
Pike static+dynamic strong safe structural
Python dynamic strong safe duck
Ruby dynamic strong safe duck
Scala[8] static strong safe nominative + structural
Scheme dynamic strong safe nominative
Smalltalk dynamic strong safe duck
Swift static strong safe nominative
Visual Basic hybrid hybrid safe nominative
Windows PowerShell hybrid hybrid safe duck
xHarbour dynamic weak safe duck


  1. The C basis is unchanged. 3.0 has hybrid typing with Anonymous Types. Can be both unsafe and safe with use of 'unsafe' functions and code blocks.
  2. D's philosophy is: safe by default with unsafe "backdoors". D also supports @safe functions that provably can't corrupt memory at the cost of disabling some of the unsafe language constructs.
  3. "RFC / Discussion: Security and Julia". Julia code can do anything C code can (e.g. you can work with raw unchecked pointers if you want to), so it is equivalent to C code in terms of security. i.e. you should not run untrusted Julia code, unless you use OS-level sandboxing.
  5. Variables can change type with the use of metatables.
  6. Applies to the Objective-C extension only.
  7. Not yet released.
  8. Scala supports structural types through runtime reflection on the JVM
This article is issued from Wikipedia - version of the 11/9/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.