Weekend work. The main points:

* Type::getCardinality() returns the cardinality for for all types.
  Theories give a cardinality in the their kinds file.  For
  cardinalities that depend on a type argument, a "cardinality
  computer" function is named in the kinds file, which takes a
  TypeNode and returns its cardinality.

* There's a bitmap for the set of "active theories" in the
  TheoryEngine.  Theories become "active" when a term that is owned by
  them, or whose type is owned by them, is pre-registered (run CVC4
  with --verbose to see theory activation).  Non-active theories don't
  get any calls for check() or propagate() or anything, and if we're
  running in single-theory mode, the shared term manager doesn't have
  to get involved.  This is really important for get() performance
  (which can only skimp on walking the entire sub-DAG only if the
  theory doesn't require it AND the shared term manager doesn't
  require it).

* TheoryEngine now does not call presolve(), registerTerm(),
  notifyRestart(), etc., on a Theory if that theory doesn't declare
  that property in its kinds file.  To avoid coding errors,
  mktheorytraits greps the theory header and gives warnings if:
  + the theory appears to declare one of the functions (check,
    propagate, etc.) that isn't listed among its kinds file properties
    (but probably should be)
  + the theory appears NOT to declare one of the functions listed in
    its kinds file properties

* some bounded token stream work

1 files changed, 65 insertions, 0 deletions

diff --git a/src/util/language.cpp b/src/util/language.cpp
new file mode 100644
index 000000000..da54a4783
--- /dev/null
+++ b/src/util/language.cpp
@@ -0,0 +1,65 @@
+/*********************                                                        */
+/*! \file language.cpp
+ ** \verbatim
+ ** Original author: mdeters
+ ** Major contributors: none
+ ** Minor contributors (to current version): none
+ ** This file is part of the CVC4 prototype.
+ ** Copyright (c) 2009, 2010, 2011  The Analysis of Computer Systems Group (ACSys)
+ ** Courant Institute of Mathematical Sciences
+ ** New York University
+ ** See the file COPYING in the top-level source directory for licensing
+ ** information.\endverbatim
+ **
+ ** \brief Definition of input and output languages
+ **
+ ** Definition of input and output languages.
+ **/
+
+#include "util/language.h"
+
+namespace CVC4 {
+namespace language {
+
+InputLanguage toInputLanguage(OutputLanguage language) {
+  switch(language) {
+  case output::LANG_SMTLIB:
+  case output::LANG_SMTLIB_V2:
+  case output::LANG_CVC4:
+    // these entries directly correspond (by design)
+    return InputLanguage(int(language));
+
+  default: {
+    std::stringstream ss;
+    ss << "Cannot map output language `" << language
+       << "' to an input language.";
+    throw CVC4::Exception(ss.str());
+  }
+  }/* switch(language) */
+}/* toInputLanguage() */
+
+OutputLanguage toOutputLanguage(InputLanguage language) {
+  switch(language) {
+  case input::LANG_SMTLIB:
+  case input::LANG_SMTLIB_V2:
+  case input::LANG_CVC4:
+    // these entries directly correspond (by design)
+    return OutputLanguage(int(language));
+
+  default:
+    // Revert to the default (AST) language.
+    //
+    // We used to throw an exception here, but that's not quite right.
+    // We often call this while constructing exceptions, for one, and
+    // it's better to output SOMETHING related to the original
+    // exception rather than mask it with another exception.  Also,
+    // the input language isn't always defined---e.g. during the
+    // initial phase of the main CVC4 driver while it determines which
+    // language is appropriate, and during unit tests.  Also, when
+    // users are writing their own code against the library.
+    return output::LANG_AST;
+  }/* switch(language) */
+}/* toOutputLanguage() */
+
+}/* CVC4::language namespace */
+}/* CVC4 namespace */