Move ExprManager::isNAryKind to NodeManager. (#6107)

This also renames metakind::getLowerBoundForKind and
metakind::getUpperBoundForKind for consistency.

Note that the NodeManager class needs to be reordered to comply to our
style guidelines. This PR does not reorder but introduces a public block
at the top (where the rest of the public interface of the class should
go eventually).

6 files changed, 36 insertions, 18 deletions

diff --git a/src/expr/expr_manager_template.cpp b/src/expr/expr_manager_template.cpp
index c4a8871fe..414d8a611 100644
--- a/src/expr/expr_manager_template.cpp
+++ b/src/expr/expr_manager_template.cpp
@@ -812,11 +812,11 @@ Expr ExprManager::mkChain(Kind kind, const std::vector<Expr>& children)
 }
 
 unsigned ExprManager::minArity(Kind kind) {
-  return metakind::getLowerBoundForKind(kind);
+  return metakind::getMinArityForKind(kind);
 }
 
 unsigned ExprManager::maxArity(Kind kind) {
-  return metakind::getUpperBoundForKind(kind);
+  return metakind::getMaxArityForKind(kind);
 }
 
 bool ExprManager::isNAryKind(Kind fun)
diff --git a/src/expr/metakind_template.cpp b/src/expr/metakind_template.cpp
index 96e06156d..6e76c0da3 100644
--- a/src/expr/metakind_template.cpp
+++ b/src/expr/metakind_template.cpp
@@ -147,7 +147,8 @@ ${metakind_constDeleters}
 // re-enable the strict-aliasing warning
 # pragma GCC diagnostic warning "-Wstrict-aliasing"
 
-unsigned getLowerBoundForKind(::CVC4::Kind k) {
+uint32_t getMinArityForKind(::CVC4::Kind k)
+{
   static const unsigned lbs[] = {
     0, /* NULL_EXPR */
 ${metakind_lbchildren}
@@ -158,7 +159,8 @@ ${metakind_lbchildren}
   return lbs[k];
 }
 
-unsigned getUpperBoundForKind(::CVC4::Kind k) {
+uint32_t getMaxArityForKind(::CVC4::Kind k)
+{
   static const unsigned ubs[] = {
     0, /* NULL_EXPR */
 ${metakind_ubchildren}
@@ -168,8 +170,7 @@ ${metakind_ubchildren}
 
   return ubs[k];
 }
-
-}/* CVC4::metakind namespace */
+}  // namespace metakind
 
 /**
  * Map a kind of the operator to the kind of the enclosing expression. For
diff --git a/src/expr/metakind_template.h b/src/expr/metakind_template.h
index 4e47d4230..42b7da248 100644
--- a/src/expr/metakind_template.h
+++ b/src/expr/metakind_template.h
@@ -187,8 +187,10 @@ struct NodeValueConstPrinter {
  */
 void deleteNodeValueConstant(::CVC4::expr::NodeValue* nv);
 
-unsigned getLowerBoundForKind(::CVC4::Kind k);
-unsigned getUpperBoundForKind(::CVC4::Kind k);
+/** Return the minimum arity of the given kind. */
+uint32_t getMinArityForKind(::CVC4::Kind k);
+/** Return the maximum arity of the given kind. */
+uint32_t getMaxArityForKind(::CVC4::Kind k);
 
 }/* CVC4::kind::metakind namespace */
 
diff --git a/src/expr/node_builder.h b/src/expr/node_builder.h
index 2f4640668..91b378c5f 100644
--- a/src/expr/node_builder.h
+++ b/src/expr/node_builder.h
@@ -957,15 +957,15 @@ expr::NodeValue* NodeBuilder<nchild_thresh>::constructNV() {
   // check that there are the right # of children for this kind
   Assert(getMetaKind() != kind::metakind::CONSTANT)
       << "Cannot make Nodes with NodeBuilder that have CONSTANT-kinded kinds";
-  Assert(getNumChildren() >= kind::metakind::getLowerBoundForKind(getKind()))
+  Assert(getNumChildren() >= kind::metakind::getMinArityForKind(getKind()))
       << "Nodes with kind " << getKind() << " must have at least "
-      << kind::metakind::getLowerBoundForKind(getKind())
+      << kind::metakind::getMinArityForKind(getKind())
       << " children (the one under "
          "construction has "
       << getNumChildren() << ")";
-  Assert(getNumChildren() <= kind::metakind::getUpperBoundForKind(getKind()))
+  Assert(getNumChildren() <= kind::metakind::getMaxArityForKind(getKind()))
       << "Nodes with kind " << getKind() << " must have at most "
-      << kind::metakind::getUpperBoundForKind(getKind())
+      << kind::metakind::getMaxArityForKind(getKind())
       << " children (the one under "
          "construction has "
       << getNumChildren() << ")";
@@ -1132,15 +1132,15 @@ expr::NodeValue* NodeBuilder<nchild_thresh>::constructNV() const {
   // check that there are the right # of children for this kind
   Assert(getMetaKind() != kind::metakind::CONSTANT)
       << "Cannot make Nodes with NodeBuilder that have CONSTANT-kinded kinds";
-  Assert(getNumChildren() >= kind::metakind::getLowerBoundForKind(getKind()))
+  Assert(getNumChildren() >= kind::metakind::getMinArityForKind(getKind()))
       << "Nodes with kind " << getKind() << " must have at least "
-      << kind::metakind::getLowerBoundForKind(getKind())
+      << kind::metakind::getMinArityForKind(getKind())
       << " children (the one under "
          "construction has "
       << getNumChildren() << ")";
-  Assert(getNumChildren() <= kind::metakind::getUpperBoundForKind(getKind()))
+  Assert(getNumChildren() <= kind::metakind::getMaxArityForKind(getKind()))
       << "Nodes with kind " << getKind() << " must have at most "
-      << kind::metakind::getUpperBoundForKind(getKind())
+      << kind::metakind::getMaxArityForKind(getKind())
       << " children (the one under "
          "construction has "
       << getNumChildren() << ")";
diff --git a/src/expr/node_manager.cpp b/src/expr/node_manager.cpp
index 5eb01ecbb..12fc99eaa 100644
--- a/src/expr/node_manager.cpp
+++ b/src/expr/node_manager.cpp
@@ -27,6 +27,7 @@
 #include "expr/bound_var_manager.h"
 #include "expr/dtype.h"
 #include "expr/dtype_cons.h"
+#include "expr/metakind.h"
 #include "expr/node_manager_attributes.h"
 #include "expr/skolem_manager.h"
 #include "expr/type_checker.h"
@@ -108,6 +109,11 @@ NodeManager::NodeManager(ExprManager* exprManager)
   init();
 }
 
+bool NodeManager::isNAryKind(Kind k)
+{
+  return kind::metakind::getMaxArityForKind(k) == expr::NodeValue::MAX_CHILDREN;
+}
+
 TypeNode NodeManager::booleanType()
 {
   return mkTypeConst<TypeConstant>(BOOLEAN_TYPE);
@@ -965,7 +971,7 @@ Node NodeManager::mkAssociative(Kind kind, const std::vector<Node>& children)
 {
   AlwaysAssert(kind::isAssociative(kind)) << "Illegal kind in mkAssociative";
 
-  const unsigned int max = kind::metakind::getUpperBoundForKind(kind);
+  const unsigned int max = kind::metakind::getMaxArityForKind(kind);
   size_t numChildren = children.size();
 
   /* If the number of children is within bounds, then there's nothing to do. */
@@ -973,7 +979,7 @@ Node NodeManager::mkAssociative(Kind kind, const std::vector<Node>& children)
   {
     return mkNode(kind, children);
   }
-  const unsigned int min = kind::metakind::getLowerBoundForKind(kind);
+  const unsigned int min = kind::metakind::getMinArityForKind(kind);
 
   std::vector<Node>::const_iterator it = children.begin();
   std::vector<Node>::const_iterator end = children.end();
diff --git a/src/expr/node_manager.h b/src/expr/node_manager.h
index 7eba1b2ea..fc58410d1 100644
--- a/src/expr/node_manager.h
+++ b/src/expr/node_manager.h
@@ -98,6 +98,15 @@ class NodeManager
   friend class NodeBuilder;
   friend class NodeManagerScope;
 
+ public:
+  /**
+   * Return true if given kind is n-ary. The test is based on n-ary kinds
+   * having their maximal arity as the maximal possible number of children
+   * of a node.
+   */
+  static bool isNAryKind(Kind k);
+
+ private:
   /** Predicate for use with STL algorithms */
   struct NodeValueReferenceCountNonZero {
     bool operator()(expr::NodeValue* nv) { return nv->d_rc > 0; }