From 12a8a7f9a90e45e8313f26af527a52e6dda943d3 Mon Sep 17 00:00:00 2001
From: "Christopher L. Conway" <christopherleeconway@gmail.com>
Date: Tue, 13 Apr 2010 22:50:07 +0000
Subject: Merging from branches/decl-scopes (r401:411)

---
 src/expr/declaration_scope.h | 132 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 132 insertions(+)
 create mode 100644 src/expr/declaration_scope.h

(limited to 'src/expr/declaration_scope.h')

diff --git a/src/expr/declaration_scope.h b/src/expr/declaration_scope.h
new file mode 100644
index 000000000..e08c25173
--- /dev/null
+++ b/src/expr/declaration_scope.h
@@ -0,0 +1,132 @@
+/*********************                                                        */
+/** context.h
+ ** Original author: cconway
+ ** This file is part of the CVC4 prototype.
+ ** Copyright (c) 2009, 2010  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.
+ **
+ ** Convenience class for scoping variable and type declarations.
+ **/
+
+#ifndef DECLARATION_SCOPE_H_
+#define DECLARATION_SCOPE_H_
+
+#include "expr.h"
+
+#include <ext/hash_map>
+
+namespace CVC4 {
+
+class Type;
+
+namespace context {
+
+class Context;
+
+template <class Key, class Data, class HashFcn>
+class CDMap;
+
+} //namespace context
+
+/** A basic hash function for std::string
+ * TODO: Does this belong somewhere else (like util/)?
+ */
+struct StringHashFunction {
+  size_t operator()(const std::string& str) const {
+    return __gnu_cxx::hash<const char*>()(str.c_str());
+  }
+};
+
+class CVC4_PUBLIC ScopeException : public Exception {
+};
+
+/**
+ * A convenience class for handling scoped declarations. Implements the usual
+ * nested scoping rules for declarations, with separate bindings for expressions
+ * and types.
+ */
+class CVC4_PUBLIC DeclarationScope {
+  /** The context manager for the scope maps. */
+  context::Context *d_context;
+
+  /** A map for expressions. */
+  context::CDMap<std::string,Expr,StringHashFunction> *d_exprMap;
+
+  /** A map for types. */
+  context::CDMap<std::string,Type*,StringHashFunction> *d_typeMap;
+
+public:
+  /** Create a declaration scope. */
+  DeclarationScope();
+
+  /** Destroy a declaration scope. */
+  ~DeclarationScope();
+
+  /** Bind an expression to a name in the current scope level.
+   * If <code>name</code> is already bound in the current level, then the
+   * binding is replaced. If <code>name</code> is bound in a previous
+   * level, then the binding is "covered" by this one until the current
+   * scope is popped.
+   *
+   * @param name an identifier
+   * @param obj the expression to bind to <code>name</code>
+   */
+  void bind(const std::string& name, const Expr& obj) throw ();
+
+  /** Bind a type to a name in the current scope.
+   * If <code>name</code> is already bound to a type in the current level,
+   * then the binding is replaced. If <code>name</code> is bound in a
+   * previous level, then the binding is "covered" by this one until the
+   * current scope is popped.
+   *
+   * @param name an identifier
+   * @param t the type to bind to <code>name</code>
+   */
+  void bindType(const std::string& name, Type* t) throw ();
+
+  /** Check whether a name is bound to an expression.
+   *
+   * @param name the identifier to check.
+   * @returns true iff name is bound in the current scope.
+   */
+  bool isBound(const std::string& name) const throw ();
+
+  /** Check whether a name is bound to a type.
+   *
+   * @param name the identifier to check.
+   * @returns true iff name is bound to a type in the current scope.
+   */
+  bool isBoundType(const std::string& name) const throw ();
+
+  /** Lookup a bound expression.
+   *
+   * @param name the identifier to lookup
+   * @returns the expression bound to <code>name</code> in the current scope.
+   */
+  Expr lookup(const std::string& name) const throw ();
+
+  /** Lookup a bound type.
+   *
+   * @param name the identifier to lookup
+   * @returns the type bound to <code>name</code> in the current scope.
+   */
+  Type* lookupType(const std::string& name) const throw ();
+
+  /** Pop a scope level. Deletes all bindings since the last call to
+   * <code>pushScope</code>. Calls to <code>pushScope</code> and
+   * <code>popScope</code> must be "properly nested." I.e., a call to
+   * <code>popScope</code> is only legal if the number of prior calls to
+   * <code>pushScope</code> on this <code>DeclarationScope</code> is strictly
+   * greater than then number of prior calls to <code>popScope</code>. */
+  void popScope() throw (ScopeException);
+
+  /** Push a scope level. */
+  void pushScope() throw ();
+};
+
+} // namespace CVC4
+
+#endif /* DECLARATION_SCOPE_H_ */
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