Convert symbol table from Expr-level to Term-level (#5355)

This task is left over from parser migration.

This PR also drops support for a case of symbol overloading, in particular symbols (constructors, selectors) for parametric datatypes cannot be overloaded. One regression is disabled as a result.

2 files changed, 188 insertions, 175 deletions

diff --git a/src/expr/symbol_table.cpp b/src/expr/symbol_table.cpp
index 42c9e10d3..888434665 100644
--- a/src/expr/symbol_table.cpp
+++ b/src/expr/symbol_table.cpp
@@ -23,12 +23,11 @@
 #include <unordered_map>
 #include <utility>
 
+#include "api/cvc4cpp.h"
 #include "context/cdhashmap.h"
 #include "context/cdhashset.h"
 #include "context/context.h"
 #include "expr/dtype.h"
-#include "expr/expr.h"
-#include "expr/expr_manager_scope.h"
 #include "expr/type.h"
 
 namespace CVC4 {
@@ -95,32 +94,34 @@ using ::std::vector;
 class OverloadedTypeTrie {
  public:
   OverloadedTypeTrie(Context* c, bool allowFunVariants = false)
-      : d_overloaded_symbols(new (true) CDHashSet<Expr, ExprHashFunction>(c)),
+      : d_overloaded_symbols(
+            new (true) CDHashSet<api::Term, api::TermHashFunction>(c)),
         d_allowFunctionVariants(allowFunVariants)
   {
   }
   ~OverloadedTypeTrie() { d_overloaded_symbols->deleteSelf(); }
 
   /** is this function overloaded? */
-  bool isOverloadedFunction(Expr fun) const;
+  bool isOverloadedFunction(api::Term fun) const;
 
   /** Get overloaded constant for type.
    * If possible, it returns a defined symbol with name
    * that has type t. Otherwise returns null expression.
    */
-  Expr getOverloadedConstantForType(const std::string& name, Type t) const;
+  api::Term getOverloadedConstantForType(const std::string& name,
+                                         api::Sort t) const;
 
   /**
    * If possible, returns a defined function for a name
    * and a vector of expected argument types. Otherwise returns
    * null expression.
    */
-  Expr getOverloadedFunctionForTypes(const std::string& name,
-                                     const std::vector<Type>& argTypes) const;
+  api::Term getOverloadedFunctionForTypes(
+      const std::string& name, const std::vector<api::Sort>& argTypes) const;
   /** called when obj is bound to name, and prev_bound_obj was already bound to
    * name Returns false if the binding is invalid.
    */
-  bool bind(const string& name, Expr prev_bound_obj, Expr obj);
+  bool bind(const string& name, api::Term prev_bound_obj, api::Term obj);
 
  private:
   /** Marks expression obj with name as overloaded.
@@ -138,9 +139,9 @@ class OverloadedTypeTrie {
    * These are put in the same place in the trie but do not have identical type,
    * hence we return false.
    */
-  bool markOverloaded(const string& name, Expr obj);
+  bool markOverloaded(const string& name, api::Term obj);
   /** the null expression */
-  Expr d_nullExpr;
+  api::Term d_nullTerm;
   // The (context-independent) trie storing that maps expected argument
   // vectors to symbols. All expressions stored in d_symbols are only
   // interpreted as active if they also appear in the context-dependent
@@ -148,15 +149,15 @@ class OverloadedTypeTrie {
   class TypeArgTrie {
    public:
     // children of this node
-    std::map<Type, TypeArgTrie> d_children;
+    std::map<api::Sort, TypeArgTrie> d_children;
     // symbols at this node
-    std::map<Type, Expr> d_symbols;
+    std::map<api::Sort, api::Term> d_symbols;
   };
   /** for each string with operator overloading, this stores the data structure
    * above. */
   std::unordered_map<std::string, TypeArgTrie> d_overload_type_arg_trie;
   /** The set of overloaded symbols. */
-  CDHashSet<Expr, ExprHashFunction>* d_overloaded_symbols;
+  CDHashSet<api::Term, api::TermHashFunction>* d_overloaded_symbols;
   /** allow function variants
    * This is true if we allow overloading (non-constant) functions that expect
    * the same argument types.
@@ -168,76 +169,64 @@ class OverloadedTypeTrie {
   * if reqUnique=true.
   * Otherwise, it returns the null expression.
   */
-  Expr getOverloadedFunctionAt(const TypeArgTrie* tat, bool reqUnique=true) const;
+  api::Term getOverloadedFunctionAt(const TypeArgTrie* tat,
+                                    bool reqUnique = true) const;
 };
 
-bool OverloadedTypeTrie::isOverloadedFunction(Expr fun) const {
+bool OverloadedTypeTrie::isOverloadedFunction(api::Term fun) const
+{
   return d_overloaded_symbols->find(fun) != d_overloaded_symbols->end();
 }
 
-Expr OverloadedTypeTrie::getOverloadedConstantForType(const std::string& name,
-                                                      Type t) const {
+api::Term OverloadedTypeTrie::getOverloadedConstantForType(
+    const std::string& name, api::Sort t) const
+{
   std::unordered_map<std::string, TypeArgTrie>::const_iterator it =
       d_overload_type_arg_trie.find(name);
   if (it != d_overload_type_arg_trie.end()) {
-    std::map<Type, Expr>::const_iterator its = it->second.d_symbols.find(t);
+    std::map<api::Sort, api::Term>::const_iterator its =
+        it->second.d_symbols.find(t);
     if (its != it->second.d_symbols.end()) {
-      Expr expr = its->second;
+      api::Term expr = its->second;
       // must be an active symbol
       if (isOverloadedFunction(expr)) {
         return expr;
       }
     }
   }
-  return d_nullExpr;
+  return d_nullTerm;
 }
 
-Expr OverloadedTypeTrie::getOverloadedFunctionForTypes(
-    const std::string& name, const std::vector<Type>& argTypes) const {
+api::Term OverloadedTypeTrie::getOverloadedFunctionForTypes(
+    const std::string& name, const std::vector<api::Sort>& argTypes) const
+{
   std::unordered_map<std::string, TypeArgTrie>::const_iterator it =
       d_overload_type_arg_trie.find(name);
   if (it != d_overload_type_arg_trie.end()) {
     const TypeArgTrie* tat = &it->second;
     for (unsigned i = 0; i < argTypes.size(); i++) {
-      std::map<Type, TypeArgTrie>::const_iterator itc =
+      std::map<api::Sort, TypeArgTrie>::const_iterator itc =
           tat->d_children.find(argTypes[i]);
       if (itc != tat->d_children.end()) {
         tat = &itc->second;
       } else {
         Trace("parser-overloading")
             << "Could not find overloaded function " << name << std::endl;
-        // it may be a parametric datatype
-        TypeNode tna = TypeNode::fromType(argTypes[i]);
-        if (tna.isParametricDatatype())
-        {
-          Trace("parser-overloading")
-              << "Parametric overloaded datatype selector " << name << " "
-              << tna << std::endl;
-          const DType& dt = TypeNode::fromType(argTypes[i]).getDType();
-          // tng is the "generalized" version of the instantiated parametric
-          // type tna
-          Type tng = dt.getTypeNode().toType();
-          itc = tat->d_children.find(tng);
-          if (itc != tat->d_children.end())
-          {
-            tat = &itc->second;
-          }
-        }
-        if (tat == nullptr)
-        {
+
           // no functions match
-          return d_nullExpr;
-        }
+        return d_nullTerm;
       }
     }
     // we ensure that there is *only* one active symbol at this node
     return getOverloadedFunctionAt(tat);
   }
-  return d_nullExpr;
+  return d_nullTerm;
 }
 
-bool OverloadedTypeTrie::bind(const string& name, Expr prev_bound_obj,
-                              Expr obj) {
+bool OverloadedTypeTrie::bind(const string& name,
+                              api::Term prev_bound_obj,
+                              api::Term obj)
+{
   bool retprev = true;
   if (!isOverloadedFunction(prev_bound_obj)) {
     // mark previous as overloaded
@@ -248,25 +237,33 @@ bool OverloadedTypeTrie::bind(const string& name, Expr prev_bound_obj,
   return retprev && retobj;
 }
 
-bool OverloadedTypeTrie::markOverloaded(const string& name, Expr obj) {
+bool OverloadedTypeTrie::markOverloaded(const string& name, api::Term obj)
+{
   Trace("parser-overloading") << "Overloaded function : " << name;
-  Trace("parser-overloading") << " with type " << obj.getType() << std::endl;
+  Trace("parser-overloading") << " with type " << obj.getSort() << std::endl;
   // get the argument types
-  Type t = obj.getType();
-  Type rangeType = t;
-  std::vector<Type> argTypes;
-  if (t.isFunction()) {
-    argTypes = static_cast<FunctionType>(t).getArgTypes();
-    rangeType = static_cast<FunctionType>(t).getRangeType();
-  } else if (t.isConstructor()) {
-    argTypes = static_cast<ConstructorType>(t).getArgTypes();
-    rangeType = static_cast<ConstructorType>(t).getRangeType();
-  } else if (t.isTester()) {
-    argTypes.push_back(static_cast<TesterType>(t).getDomain());
-    rangeType = static_cast<TesterType>(t).getRangeType();
-  } else if (t.isSelector()) {
-    argTypes.push_back(static_cast<SelectorType>(t).getDomain());
-    rangeType = static_cast<SelectorType>(t).getRangeType();
+  api::Sort t = obj.getSort();
+  api::Sort rangeType = t;
+  std::vector<api::Sort> argTypes;
+  if (t.isFunction())
+  {
+    argTypes = t.getFunctionDomainSorts();
+    rangeType = t.getFunctionCodomainSort();
+  }
+  else if (t.isConstructor())
+  {
+    argTypes = t.getConstructorDomainSorts();
+    rangeType = t.getConstructorCodomainSort();
+  }
+  else if (t.isTester())
+  {
+    argTypes.push_back(t.getTesterDomainSort());
+    rangeType = t.getTesterCodomainSort();
+  }
+  else if (t.isSelector())
+  {
+    argTypes.push_back(t.getSelectorDomainSort());
+    rangeType = t.getSelectorCodomainSort();
   }
   // add to the trie
   TypeArgTrie* tat = &d_overload_type_arg_trie[name];
@@ -278,10 +275,11 @@ bool OverloadedTypeTrie::markOverloaded(const string& name, Expr obj) {
   if (d_allowFunctionVariants || argTypes.empty())
   {
     // they are allowed, check for redefinition
-    std::map<Type, Expr>::iterator it = tat->d_symbols.find(rangeType);
+    std::map<api::Sort, api::Term>::iterator it =
+        tat->d_symbols.find(rangeType);
     if (it != tat->d_symbols.end())
     {
-      Expr prev_obj = it->second;
+      api::Term prev_obj = it->second;
       // if there is already an active function with the same name and expects
       // the same argument types and has the same return type, we reject the 
       // re-declaration here.
@@ -294,7 +292,7 @@ bool OverloadedTypeTrie::markOverloaded(const string& name, Expr obj) {
   else
   {
     // they are not allowed, we cannot have any function defined here.
-    Expr existingFun = getOverloadedFunctionAt(tat, false);
+    api::Term existingFun = getOverloadedFunctionAt(tat, false);
     if (!existingFun.isNull())
     {
       return false;
@@ -307,15 +305,16 @@ bool OverloadedTypeTrie::markOverloaded(const string& name, Expr obj) {
   return true;
 }
 
-Expr OverloadedTypeTrie::getOverloadedFunctionAt(
+api::Term OverloadedTypeTrie::getOverloadedFunctionAt(
     const OverloadedTypeTrie::TypeArgTrie* tat, bool reqUnique) const
 {
-  Expr retExpr;
-  for (std::map<Type, Expr>::const_iterator its = tat->d_symbols.begin();
+  api::Term retExpr;
+  for (std::map<api::Sort, api::Term>::const_iterator its =
+           tat->d_symbols.begin();
        its != tat->d_symbols.end();
        ++its)
   {
-    Expr expr = its->second;
+    api::Term expr = its->second;
     if (isOverloadedFunction(expr))
     {
       if (retExpr.isNull())
@@ -332,7 +331,7 @@ Expr OverloadedTypeTrie::getOverloadedFunctionAt(
       else
       {
         // multiple functions match
-        return d_nullExpr;
+        return d_nullTerm;
       }
     }
   }
@@ -343,7 +342,7 @@ class SymbolTable::Implementation {
  public:
   Implementation()
       : d_context(),
-        d_exprMap(new (true) CDHashMap<string, Expr>(&d_context)),
+        d_exprMap(new (true) CDHashMap<string, api::Term>(&d_context)),
         d_typeMap(new (true) TypeMap(&d_context))
   {
     d_overload_trie = new OverloadedTypeTrie(&d_context);
@@ -355,15 +354,18 @@ class SymbolTable::Implementation {
     delete d_overload_trie;
   }
 
-  bool bind(const string& name, Expr obj, bool levelZero, bool doOverload);
-  void bindType(const string& name, Type t, bool levelZero = false);
-  void bindType(const string& name, const vector<Type>& params, Type t,
+  bool bind(const string& name, api::Term obj, bool levelZero, bool doOverload);
+  void bindType(const string& name, api::Sort t, bool levelZero = false);
+  void bindType(const string& name,
+                const vector<api::Sort>& params,
+                api::Sort t,
                 bool levelZero = false);
   bool isBound(const string& name) const;
   bool isBoundType(const string& name) const;
-  Expr lookup(const string& name) const;
-  Type lookupType(const string& name) const;
-  Type lookupType(const string& name, const vector<Type>& params) const;
+  api::Term lookup(const string& name) const;
+  api::Sort lookupType(const string& name) const;
+  api::Sort lookupType(const string& name,
+                       const vector<api::Sort>& params) const;
   size_t lookupArity(const string& name);
   void popScope();
   void pushScope();
@@ -371,29 +373,30 @@ class SymbolTable::Implementation {
   void reset();
   //------------------------ operator overloading
   /** implementation of function from header */
-  bool isOverloadedFunction(Expr fun) const;
+  bool isOverloadedFunction(api::Term fun) const;
 
   /** implementation of function from header */
-  Expr getOverloadedConstantForType(const std::string& name, Type t) const;
+  api::Term getOverloadedConstantForType(const std::string& name,
+                                         api::Sort t) const;
 
   /** implementation of function from header */
-  Expr getOverloadedFunctionForTypes(const std::string& name,
-                                     const std::vector<Type>& argTypes) const;
+  api::Term getOverloadedFunctionForTypes(
+      const std::string& name, const std::vector<api::Sort>& argTypes) const;
   //------------------------ end operator overloading
  private:
   /** The context manager for the scope maps. */
   Context d_context;
 
   /** A map for expressions. */
-  CDHashMap<string, Expr>* d_exprMap;
+  CDHashMap<string, api::Term>* d_exprMap;
 
   /** A map for types. */
-  using TypeMap = CDHashMap<string, std::pair<vector<Type>, Type>>;
+  using TypeMap = CDHashMap<string, std::pair<vector<api::Sort>, api::Sort>>;
   TypeMap* d_typeMap;
 
   //------------------------ operator overloading
   // the null expression
-  Expr d_nullExpr;
+  api::Term d_nullTerm;
   // overloaded type trie, stores all information regarding overloading
   OverloadedTypeTrie* d_overload_trie;
   /** bind with overloading
@@ -401,14 +404,16 @@ class SymbolTable::Implementation {
    * allowed. If a symbol is previously bound to that name, it marks both as
    * overloaded. Returns false if the binding was invalid.
    */
-  bool bindWithOverloading(const string& name, Expr obj);
+  bool bindWithOverloading(const string& name, api::Term obj);
   //------------------------ end operator overloading
 }; /* SymbolTable::Implementation */
 
-bool SymbolTable::Implementation::bind(const string& name, Expr obj,
-                                       bool levelZero, bool doOverload) {
-  PrettyCheckArgument(!obj.isNull(), obj, "cannot bind to a null Expr");
-  ExprManagerScope ems(obj);
+bool SymbolTable::Implementation::bind(const string& name,
+                                       api::Term obj,
+                                       bool levelZero,
+                                       bool doOverload)
+{
+  PrettyCheckArgument(!obj.isNull(), obj, "cannot bind to a null api::Term");
   if (doOverload) {
     if (!bindWithOverloading(name, obj)) {
       return false;
@@ -426,33 +431,40 @@ bool SymbolTable::Implementation::isBound(const string& name) const {
   return d_exprMap->find(name) != d_exprMap->end();
 }
 
-Expr SymbolTable::Implementation::lookup(const string& name) const {
+api::Term SymbolTable::Implementation::lookup(const string& name) const
+{
   Assert(isBound(name));
-  Expr expr = (*d_exprMap->find(name)).second;
+  api::Term expr = (*d_exprMap->find(name)).second;
   if (isOverloadedFunction(expr)) {
-    return d_nullExpr;
+    return d_nullTerm;
   } else {
     return expr;
   }
 }
 
-void SymbolTable::Implementation::bindType(const string& name, Type t,
-                                           bool levelZero) {
+void SymbolTable::Implementation::bindType(const string& name,
+                                           api::Sort t,
+                                           bool levelZero)
+{
   if (levelZero) {
-    d_typeMap->insertAtContextLevelZero(name, make_pair(vector<Type>(), t));
+    d_typeMap->insertAtContextLevelZero(name,
+                                        make_pair(vector<api::Sort>(), t));
   } else {
-    d_typeMap->insert(name, make_pair(vector<Type>(), t));
+    d_typeMap->insert(name, make_pair(vector<api::Sort>(), t));
   }
 }
 
 void SymbolTable::Implementation::bindType(const string& name,
-                                           const vector<Type>& params, Type t,
-                                           bool levelZero) {
+                                           const vector<api::Sort>& params,
+                                           api::Sort t,
+                                           bool levelZero)
+{
   if (Debug.isOn("sort")) {
     Debug("sort") << "bindType(" << name << ", [";
     if (params.size() > 0) {
-      copy(params.begin(), params.end() - 1,
-           ostream_iterator<Type>(Debug("sort"), ", "));
+      copy(params.begin(),
+           params.end() - 1,
+           ostream_iterator<api::Sort>(Debug("sort"), ", "));
       Debug("sort") << params.back();
     }
     Debug("sort") << "], " << t << ")" << endl;
@@ -468,8 +480,9 @@ bool SymbolTable::Implementation::isBoundType(const string& name) const {
   return d_typeMap->find(name) != d_typeMap->end();
 }
 
-Type SymbolTable::Implementation::lookupType(const string& name) const {
-  pair<vector<Type>, Type> p = (*d_typeMap->find(name)).second;
+api::Sort SymbolTable::Implementation::lookupType(const string& name) const
+{
+  pair<vector<api::Sort>, api::Sort> p = (*d_typeMap->find(name)).second;
   PrettyCheckArgument(p.first.size() == 0, name,
                       "type constructor arity is wrong: "
                       "`%s' requires %u parameters but was provided 0",
@@ -477,64 +490,52 @@ Type SymbolTable::Implementation::lookupType(const string& name) const {
   return p.second;
 }
 
-Type SymbolTable::Implementation::lookupType(const string& name,
-                                             const vector<Type>& params) const {
-  pair<vector<Type>, Type> p = (*d_typeMap->find(name)).second;
+api::Sort SymbolTable::Implementation::lookupType(
+    const string& name, const vector<api::Sort>& params) const
+{
+  std::pair<std::vector<api::Sort>, api::Sort> p =
+      (*d_typeMap->find(name)).second;
   PrettyCheckArgument(p.first.size() == params.size(), params,
                       "type constructor arity is wrong: "
                       "`%s' requires %u parameters but was provided %u",
                       name.c_str(), p.first.size(), params.size());
   if (p.first.size() == 0) {
-    PrettyCheckArgument(p.second.isSort(), name.c_str());
+    PrettyCheckArgument(p.second.isUninterpretedSort(), name.c_str());
     return p.second;
   }
   if (p.second.isSortConstructor()) {
     if (Debug.isOn("sort")) {
       Debug("sort") << "instantiating using a sort constructor" << endl;
       Debug("sort") << "have formals [";
-      copy(p.first.begin(), p.first.end() - 1,
-           ostream_iterator<Type>(Debug("sort"), ", "));
+      copy(p.first.begin(),
+           p.first.end() - 1,
+           ostream_iterator<api::Sort>(Debug("sort"), ", "));
       Debug("sort") << p.first.back() << "]" << endl << "parameters   [";
-      copy(params.begin(), params.end() - 1,
-           ostream_iterator<Type>(Debug("sort"), ", "));
+      copy(params.begin(),
+           params.end() - 1,
+           ostream_iterator<api::Sort>(Debug("sort"), ", "));
       Debug("sort") << params.back() << "]" << endl
                     << "type ctor    " << name << endl
                     << "type is      " << p.second << endl;
     }
 
-    Type instantiation = SortConstructorType(p.second).instantiate(params);
+    api::Sort instantiation = p.second.instantiate(params);
 
     Debug("sort") << "instance is  " << instantiation << endl;
 
     return instantiation;
   } else if (p.second.isDatatype()) {
-    PrettyCheckArgument(DatatypeType(p.second).isParametric(), name,
-                        "expected parametric datatype");
-    return DatatypeType(p.second).instantiate(params);
-  } else {
-    if (Debug.isOn("sort")) {
-      Debug("sort") << "instantiating using a sort substitution" << endl;
-      Debug("sort") << "have formals [";
-      copy(p.first.begin(), p.first.end() - 1,
-           ostream_iterator<Type>(Debug("sort"), ", "));
-      Debug("sort") << p.first.back() << "]" << endl << "parameters   [";
-      copy(params.begin(), params.end() - 1,
-           ostream_iterator<Type>(Debug("sort"), ", "));
-      Debug("sort") << params.back() << "]" << endl
-                    << "type ctor    " << name << endl
-                    << "type is      " << p.second << endl;
-    }
-
-    Type instantiation = p.second.substitute(p.first, params);
-
-    Debug("sort") << "instance is  " << instantiation << endl;
-
-    return instantiation;
+    PrettyCheckArgument(
+        p.second.isParametricDatatype(), name, "expected parametric datatype");
+    return p.second.instantiate(params);
   }
+  // failed to instantiate
+  Unhandled() << "Could not instantiate sort";
+  return p.second;
 }
 
 size_t SymbolTable::Implementation::lookupArity(const string& name) {
-  pair<vector<Type>, Type> p = (*d_typeMap->find(name)).second;
+  pair<vector<api::Sort>, api::Sort> p = (*d_typeMap->find(name)).second;
   return p.first.size();
 }
 
@@ -556,25 +557,29 @@ void SymbolTable::Implementation::reset() {
   new (this) SymbolTable::Implementation();
 }
 
-bool SymbolTable::Implementation::isOverloadedFunction(Expr fun) const {
+bool SymbolTable::Implementation::isOverloadedFunction(api::Term fun) const
+{
   return d_overload_trie->isOverloadedFunction(fun);
 }
 
-Expr SymbolTable::Implementation::getOverloadedConstantForType(
-    const std::string& name, Type t) const {
+api::Term SymbolTable::Implementation::getOverloadedConstantForType(
+    const std::string& name, api::Sort t) const
+{
   return d_overload_trie->getOverloadedConstantForType(name, t);
 }
 
-Expr SymbolTable::Implementation::getOverloadedFunctionForTypes(
-    const std::string& name, const std::vector<Type>& argTypes) const {
+api::Term SymbolTable::Implementation::getOverloadedFunctionForTypes(
+    const std::string& name, const std::vector<api::Sort>& argTypes) const
+{
   return d_overload_trie->getOverloadedFunctionForTypes(name, argTypes);
 }
 
 bool SymbolTable::Implementation::bindWithOverloading(const string& name,
-                                                      Expr obj) {
-  CDHashMap<string, Expr>::const_iterator it = d_exprMap->find(name);
+                                                      api::Term obj)
+{
+  CDHashMap<string, api::Term>::const_iterator it = d_exprMap->find(name);
   if (it != d_exprMap->end()) {
-    const Expr& prev_bound_obj = (*it).second;
+    const api::Term& prev_bound_obj = (*it).second;
     if (prev_bound_obj != obj) {
       return d_overload_trie->bind(name, prev_bound_obj, obj);
     }
@@ -582,40 +587,44 @@ bool SymbolTable::Implementation::bindWithOverloading(const string& name,
   return true;
 }
 
-bool SymbolTable::isOverloadedFunction(Expr fun) const {
+bool SymbolTable::isOverloadedFunction(api::Term fun) const
+{
   return d_implementation->isOverloadedFunction(fun);
 }
 
-Expr SymbolTable::getOverloadedConstantForType(const std::string& name,
-                                               Type t) const {
+api::Term SymbolTable::getOverloadedConstantForType(const std::string& name,
+                                                    api::Sort t) const
+{
   return d_implementation->getOverloadedConstantForType(name, t);
 }
 
-Expr SymbolTable::getOverloadedFunctionForTypes(
-    const std::string& name, const std::vector<Type>& argTypes) const {
+api::Term SymbolTable::getOverloadedFunctionForTypes(
+    const std::string& name, const std::vector<api::Sort>& argTypes) const
+{
   return d_implementation->getOverloadedFunctionForTypes(name, argTypes);
 }
 
-SymbolTable::SymbolTable()
-    : d_implementation(new SymbolTable::Implementation()) {}
+SymbolTable::SymbolTable() : d_implementation(new SymbolTable::Implementation())
+{
+}
 
 SymbolTable::~SymbolTable() {}
 bool SymbolTable::bind(const string& name,
-                       Expr obj,
+                       api::Term obj,
                        bool levelZero,
                        bool doOverload)
 {
   return d_implementation->bind(name, obj, levelZero, doOverload);
 }
 
-void SymbolTable::bindType(const string& name, Type t, bool levelZero)
+void SymbolTable::bindType(const string& name, api::Sort t, bool levelZero)
 {
   d_implementation->bindType(name, t, levelZero);
 }
 
 void SymbolTable::bindType(const string& name,
-                           const vector<Type>& params,
-                           Type t,
+                           const vector<api::Sort>& params,
+                           api::Sort t,
                            bool levelZero)
 {
   d_implementation->bindType(name, params, t, levelZero);
@@ -629,17 +638,17 @@ bool SymbolTable::isBoundType(const string& name) const
 {
   return d_implementation->isBoundType(name);
 }
-Expr SymbolTable::lookup(const string& name) const
+api::Term SymbolTable::lookup(const string& name) const
 {
   return d_implementation->lookup(name);
 }
-Type SymbolTable::lookupType(const string& name) const
+api::Sort SymbolTable::lookupType(const string& name) const
 {
   return d_implementation->lookupType(name);
 }
 
-Type SymbolTable::lookupType(const string& name,
-                             const vector<Type>& params) const
+api::Sort SymbolTable::lookupType(const string& name,
+                                  const vector<api::Sort>& params) const
 {
   return d_implementation->lookupType(name, params);
 }
diff --git a/src/expr/symbol_table.h b/src/expr/symbol_table.h
index fb6457f2e..35bed1dbf 100644
--- a/src/expr/symbol_table.h
+++ b/src/expr/symbol_table.h
@@ -29,6 +29,12 @@
 
 namespace CVC4 {
 
+namespace api {
+class Solver;
+class Sort;
+class Term;
+}  // namespace api
+
 class CVC4_PUBLIC ScopeException : public Exception {};
 
 /**
@@ -65,7 +71,7 @@ class CVC4_PUBLIC SymbolTable {
    * Returns false if the binding was invalid.
    */
   bool bind(const std::string& name,
-            Expr obj,
+            api::Term obj,
             bool levelZero = false,
             bool doOverload = false);
 
@@ -80,7 +86,7 @@ class CVC4_PUBLIC SymbolTable {
    * @param t the type to bind to <code>name</code>
    * @param levelZero set if the binding must be done at level 0
    */
-  void bindType(const std::string& name, Type t, bool levelZero = false);
+  void bindType(const std::string& name, api::Sort t, bool levelZero = false);
 
   /**
    * Bind a type to a name in the current scope.  If <code>name</code>
@@ -96,8 +102,8 @@ class CVC4_PUBLIC SymbolTable {
    * locally within the current scope)
    */
   void bindType(const std::string& name,
-                const std::vector<Type>& params,
-                Type t,
+                const std::vector<api::Sort>& params,
+                api::Sort t,
                 bool levelZero = false);
 
   /**
@@ -125,7 +131,7 @@ class CVC4_PUBLIC SymbolTable {
    * It returns the null expression if there is not a unique expression bound to
    * <code>name</code> in the current scope (i.e. if there is not exactly one).
    */
-  Expr lookup(const std::string& name) const;
+  api::Term lookup(const std::string& name) const;
 
   /**
    * Lookup a bound type.
@@ -133,7 +139,7 @@ class CVC4_PUBLIC SymbolTable {
    * @param name the type identifier to lookup
    * @returns the type bound to <code>name</code> in the current scope.
    */
-  Type lookupType(const std::string& name) const;
+  api::Sort lookupType(const std::string& name) const;
 
   /**
    * Lookup a bound parameterized type.
@@ -143,8 +149,8 @@ class CVC4_PUBLIC SymbolTable {
    * @returns the type bound to <code>name(<i>params</i>)</code> in
    * the current scope.
    */
-  Type lookupType(const std::string& name,
-                  const std::vector<Type>& params) const;
+  api::Sort lookupType(const std::string& name,
+                       const std::vector<api::Sort>& params) const;
 
   /**
    * Lookup the arity of a bound parameterized type.
@@ -170,13 +176,14 @@ class CVC4_PUBLIC SymbolTable {
 
   //------------------------ operator overloading
   /** is this function overloaded? */
-  bool isOverloadedFunction(Expr fun) const;
+  bool isOverloadedFunction(api::Term fun) const;
 
   /** Get overloaded constant for type.
    * If possible, it returns the defined symbol with name
    * that has type t. Otherwise returns null expression.
   */
-  Expr getOverloadedConstantForType(const std::string& name, Type t) const;
+  api::Term getOverloadedConstantForType(const std::string& name,
+                                         api::Sort t) const;
 
   /**
    * If possible, returns the unique defined function for a name
@@ -189,15 +196,12 @@ class CVC4_PUBLIC SymbolTable {
    * no functions with name and expected argTypes, or alternatively there is
    * more than one function with name and expected argTypes.
    */
-  Expr getOverloadedFunctionForTypes(const std::string& name,
-                                     const std::vector< Type >& argTypes) const;
+  api::Term getOverloadedFunctionForTypes(
+      const std::string& name, const std::vector<api::Sort>& argTypes) const;
   //------------------------ end operator overloading
 
  private:
-  // Copying and assignment have not yet been implemented.
-  SymbolTable(const SymbolTable&);
-  SymbolTable& operator=(SymbolTable&);
-
+  /** The implementation of the symbol table */
   class Implementation;
   std::unique_ptr<Implementation> d_implementation;
 }; /* class SymbolTable */