/*********************                                                        */
/*! \file parser.h
 ** \verbatim
 ** Original author: cconway
 ** Major contributors: mdeters
 ** Minor contributors (to current version): dejan, ajreynol
 ** 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 A collection of state for use by parser implementations.
 **
 ** A collection of state for use by parser implementations.
 **/

#include "cvc4parser_public.h"

#ifndef __CVC4__PARSER__PARSER_STATE_H
#define __CVC4__PARSER__PARSER_STATE_H

#include <string>
#include <set>
#include <list>

#include "parser/input.h"
#include "parser/parser_exception.h"
#include "expr/expr.h"
#include "expr/declaration_scope.h"
#include "expr/kind.h"
#include "expr/expr_stream.h"

namespace CVC4 {

// Forward declarations
class BooleanType;
class ExprManager;
class Command;
class FunctionType;
class Type;

namespace parser {

class Input;

/** Types of check for the symols */
enum DeclarationCheck {
  /** Enforce that the symbol has been declared */
  CHECK_DECLARED,
  /** Enforce that the symbol has not been declared */
  CHECK_UNDECLARED,
  /** Don't check anything */
  CHECK_NONE
};

/**
 * Returns a string representation of the given object (for
 * debugging).
 */
inline std::ostream& operator<<(std::ostream& out, DeclarationCheck check) {
  switch(check) {
  case CHECK_NONE:
    return out << "CHECK_NONE";
  case CHECK_DECLARED:
    return out << "CHECK_DECLARED";
  case CHECK_UNDECLARED:
    return out << "CHECK_UNDECLARED";
  default:
    return out << "DeclarationCheck!UNKNOWN";
  }
}

/**
 * Types of symbols. Used to define namespaces.
 */
enum SymbolType {
  /** Variables */
  SYM_VARIABLE,
  /** Sorts */
  SYM_SORT
};

/**
 * Returns a string representation of the given object (for
 * debugging).
 */
inline std::ostream& operator<<(std::ostream& out, SymbolType type) {
  switch(type) {
  case SYM_VARIABLE:
    return out << "SYM_VARIABLE";
  case SYM_SORT:
    return out << "SYM_SORT";
  default:
    return out << "SymbolType!UNKNOWN";
  }
}

/**
 * This class encapsulates all of the state of a parser, including the
 * name of the file, line number and column information, and in-scope
 * declarations.
 */
class CVC4_PUBLIC Parser {
  friend class ParserBuilder;

  /** The expression manager */
  ExprManager *d_exprManager;

  /** The input that we're parsing. */
  Input *d_input;

  /**
   * The declaration scope that is "owned" by this parser.  May or
   * may not be the current declaration scope in use.
   */
  DeclarationScope d_declScopeAllocated;

  /**
   * This current symbol table used by this parser.  Initially points
   * to d_declScopeAllocated, but can be changed (making this parser
   * delegate its definitions and lookups to another parser).
   * See useDeclarationsFrom().
   */
  DeclarationScope* d_declScope;

  /** How many anonymous functions we've created. */
  size_t d_anonymousFunctionCount;

  /** Are we done */
  bool d_done;

  /** Are semantic checks enabled during parsing? */
  bool d_checksEnabled;

  /** Are we parsing in strict mode? */
  bool d_strictMode;

  /** Are we only parsing? */
  bool d_parseOnly;

  /** The set of operators available in the current logic. */
  std::set<Kind> d_logicOperators;

  /**
   * The current set of unresolved types.  We can get by with this NOT
   * being on the scope, because we can only have one DATATYPE
   * definition going on at one time.  This is a bit hackish; we
   * depend on mkMutualDatatypeTypes() to check everything and clear
   * this out.
   */
  std::set<Type> d_unresolved;

  /**
   * "Preemption commands": extra commands implied by subterms that
   * should be issued before the currently-being-parsed command is
   * issued.  Used to support SMT-LIBv2 ":named" attribute on terms.
   */
  std::list<Command*> d_commandQueue;

  /** Lookup a symbol in the given namespace. */
  Expr getSymbol(const std::string& var_name, SymbolType type);

protected:
  /**
   * Create a parser state.
   *
   * @attention The parser takes "ownership" of the given
   * input and will delete it on destruction.
   *
   * @param exprManager the expression manager to use when creating expressions
   * @param input the parser input
   * @param strictMode whether to incorporate strict(er) compliance checks
   * @param parseOnly whether we are parsing only (and therefore certain checks
   * need not be performed, like those about unimplemented features, @see
   * unimplementedFeature())
   */
  Parser(ExprManager* exprManager, Input* input, bool strictMode = false, bool parseOnly = false);

public:

  virtual ~Parser() {
    delete d_input;
  }

  /** Get the associated <code>ExprManager</code>. */
  inline ExprManager* getExprManager() const {
    return d_exprManager;
  }

  /** Get the associated input. */
  inline Input* getInput() const {
    return d_input;
  }

  /** Deletes and replaces the current parser input. */
  void setInput(Input* input)  {
    delete d_input;
    d_input = input;
    d_input->setParser(*this);
    d_done = false;
  }

  /**
   * Check if we are done -- either the end of input has been reached, or some
   * error has been encountered.
   * @return true if parser is done
   */
  inline bool done() const {
    return d_done;
  }

  /** Sets the done flag */
  inline void setDone(bool done = true) {
    d_done = done;
  }

  /** Enable semantic checks during parsing. */
  void enableChecks() { d_checksEnabled = true; }

  /** Disable semantic checks during parsing. Disabling checks may lead to crashes on bad inputs. */
  void disableChecks() { d_checksEnabled = false; }

  /** Enable strict parsing, according to the language standards. */
  void enableStrictMode() { d_strictMode = true; }

  /** Disable strict parsing. Allows certain syntactic infelicities to
      pass without comment. */
  void disableStrictMode() { d_strictMode = false; }

  bool strictModeEnabled() { return d_strictMode; }

  /**
   * Returns a variable, given a name.
   *
   * @param name the name of the variable
   * @return the variable expression
   */
  Expr getVariable(const std::string& name);

  /**
   * Returns a function, given a name.
   *
   * @param name the name of the variable
   * @return the variable expression
   */
  Expr getFunction(const std::string& name);

  /**
   * Returns a sort, given a name.
   * @param sort_name the name to look up
   */
  Type getSort(const std::string& sort_name);

  /**
   * Returns a (parameterized) sort, given a name and args.
   */
  Type getSort(const std::string& sort_name,
               const std::vector<Type>& params);

  /**
   * Returns arity of a (parameterized) sort, given a name and args.
   */
  size_t getArity(const std::string& sort_name);

  /**
   * Checks if a symbol has been declared.
   * @param name the symbol name
   * @param type the symbol type
   * @return true iff the symbol has been declared with the given type
   */
  bool isDeclared(const std::string& name, SymbolType type = SYM_VARIABLE);

  /**
   * Checks if the declaration policy we want to enforce holds
   * for the given symbol.
   * @param name the symbol to check
   * @param check the kind of check to perform
   * @param type the type of the symbol
   * @throws ParserException if checks are enabled and the check fails
   */
  void checkDeclaration(const std::string& name, DeclarationCheck check,
                        SymbolType type = SYM_VARIABLE) throw(ParserException);

  /**
   * Checks whether the given name is bound to a function.
   * @param name the name to check
   * @throws ParserException if checks are enabled and name is not
   * bound to a function
   */
  void checkFunctionLike(const std::string& name) throw(ParserException);

  /**
   * Check that <code>kind</code> can accept <code>numArgs</code> arguments.
   * @param kind the built-in operator to check
   * @param numArgs the number of actual arguments
   * @throws ParserException if checks are enabled and the operator
   * <code>kind</code> cannot be applied to <code>numArgs</code>
   * arguments.
   */
  void checkArity(Kind kind, unsigned numArgs) throw(ParserException);

  /**
   * Check that <code>kind</code> is a legal operator in the current
   * logic and that it can accept <code>numArgs</code> arguments.
   *
   * @param kind the built-in operator to check
   * @param numArgs the number of actual arguments
   * @throws ParserException if the parser mode is strict and the
   * operator <code>kind</code> has not been enabled
   */
  void checkOperator(Kind kind, unsigned numArgs) throw(ParserException);

  /**
   * Returns the type for the variable with the given name.
   *
   * @param var_name the symbol to lookup
   * @param type the (namespace) type of the symbol
   */
  Type getType(const std::string& var_name, SymbolType type = SYM_VARIABLE);

  /** Create a new CVC4 variable expression of the given type. */
  Expr mkVar(const std::string& name, const Type& type);

  /**
   * Create a set of new CVC4 variable expressions of the given type.
   */
  std::vector<Expr>
  mkVars(const std::vector<std::string> names, const Type& type);

  /** Create a new CVC4 function expression of the given type. */
  Expr mkFunction(const std::string& name, const Type& type);

  /**
   * Create a new CVC4 function expression of the given type,
   * appending a unique index to its name.  (That's the ONLY
   * difference between mkAnonymousFunction() and mkFunction()).
   */
  Expr mkAnonymousFunction(const std::string& prefix, const Type& type);

  /** Create a new variable definition (e.g., from a let binding). */
  void defineVar(const std::string& name, const Expr& val);

  /** Create a new function definition (e.g., from a define-fun). */
  void defineFunction(const std::string& name, const Expr& val);

  /** Create a new type definition. */
  void defineType(const std::string& name, const Type& type);

  /** Create a new (parameterized) type definition. */
  void defineType(const std::string& name,
                  const std::vector<Type>& params, const Type& type);

  /** Create a new type definition (e.g., from an SMT-LIBv2 define-sort). */
  void defineParameterizedType(const std::string& name,
                               const std::vector<Type>& params,
                               const Type& type);

  /**
   * Creates a new sort with the given name.
   */
  SortType mkSort(const std::string& name);

  /**
   * Creates a new sort constructor with the given name and arity.
   */
  SortConstructorType mkSortConstructor(const std::string& name, size_t arity);

  /**
   * Creates a new "unresolved type," used only during parsing.
   */
  SortType mkUnresolvedType(const std::string& name);

  /**
   * Creates a new unresolved (parameterized) type constructor of the given
   * arity.
   */
  SortConstructorType mkUnresolvedTypeConstructor(const std::string& name, 
                                                  size_t arity);
  /**
   * Creates a new unresolved (parameterized) type constructor given the type
   * parameters.
   */
  SortConstructorType mkUnresolvedTypeConstructor(const std::string& name, 
                                                  const std::vector<Type>& params);

  /**
   * Returns true IFF name is an unresolved type.
   */
  bool isUnresolvedType(const std::string& name);

  /**
   * Create sorts of mutually-recursive datatypes.
   */
  std::vector<DatatypeType>
  mkMutualDatatypeTypes(const std::vector<Datatype>& datatypes);

  /**
   * Add an operator to the current legal set.
   *
   * @param kind the built-in operator to add
   */
  void addOperator(Kind kind);

  /**
   * Preempt the next returned command with other ones; used to
   * support the :named attribute in SMT-LIBv2, which implicitly
   * inserts a new command before the current one.
   */
  void preemptCommand(Command* cmd);

  /** Is the symbol bound to a boolean variable? */
  bool isBoolean(const std::string& name);

  /** Is the symbol bound to a function (or function-like thing)? */
  bool isFunctionLike(const std::string& name);

  /** Is the symbol bound to a defined function? */
  bool isDefinedFunction(const std::string& name);

  /** Is the Expr a defined function? */
  bool isDefinedFunction(Expr func);

  /** Is the symbol bound to a predicate? */
  bool isPredicate(const std::string& name);

  /** Parse and return the next command. */
  Command* nextCommand() throw(ParserException);

  /** Parse and return the next expression. */
  Expr nextExpression() throw(ParserException);

  /** Raise a parse error with the given message. */
  inline void parseError(const std::string& msg) throw(ParserException) {
    d_input->parseError(msg);
  }

  /**
   * If we are parsing only, don't raise an exception; if we are not,
   * raise a parse error with the given message.  There is no actual
   * parse error, everything is as expected, but we cannot create the
   * Expr, Type, or other requested thing yet due to internal
   * limitations.  Even though it's not a parse error, we throw a
   * parse error so that the input line and column information is
   * available.
   *
   * Think quantifiers.  We don't have a TheoryQuantifiers yet, so we
   * have no kind::FORALL or kind::EXISTS.  But we might want to
   * support parsing quantifiers (just not doing anything with them).
   * So this mechanism gives you a way to do it with --parse-only.
   */
  inline void unimplementedFeature(const std::string& msg) throw(ParserException) {
    if(!d_parseOnly) {
      parseError("Unimplemented feature: " + msg);
    }
  }

  inline void pushScope() { d_declScope->pushScope(); }
  inline void popScope() { d_declScope->popScope(); }

  /**
   * Set the current symbol table used by this parser.
   * From now on, this parser will perform its definitions and
   * lookups in the declaration scope of the "parser" argument
   * (but doesn't re-delegate if the other parser's declaration scope
   * changes later).  A NULL argument restores this parser's
   * "primordial" declaration scope assigned at its creation.  Calling
   * p->useDeclarationsFrom(p) is a no-op.
   *
   * This feature is useful when e.g. reading out-of-band expression data:
   * 1. Parsing --replay log files produced with --replay-log.
   * 2. Perhaps a multi-query benchmark file is being single-stepped
   *    with intervening queries on stdin that must reference
   *
   * However, the feature must be used carefully.  Pushes and pops
   * should be performed with the correct current declaration scope.
   * Care must be taken to match up declaration scopes, of course;
   * If variables in the deferred-to parser go out of scope, the
   * secondary parser will give errors that they are undeclared.
   * Also, an outer-scope variable shadowed by an inner-scope one of
   * the same name may be temporarily inaccessible.
   *
   * In short, caveat emptor.
   */
  inline void useDeclarationsFrom(Parser* parser) {
    if(parser == NULL) {
      d_declScope = &d_declScopeAllocated;
    } else {
      d_declScope = parser->d_declScope;
    }
  }

  /**
   * Gets the current declaration level.
   */
  inline size_t getDeclarationLevel() const throw() {
    return d_declScope->getLevel();
  }

  /**
   * An expression stream interface for a parser.  This stream simply
   * pulls expressions from the given Parser object.
   *
   * Here, the ExprStream base class allows a Parser (from the parser
   * library) and core components of CVC4 (in the core library) to
   * communicate without polluting the public interface or having them
   * reach into private (undocumented) interfaces.
   */
  class ExprStream : public CVC4::ExprStream {
    Parser* d_parser;
  public:
    ExprStream(Parser* parser) : d_parser(parser) {}
    ~ExprStream() { delete d_parser; }
    Expr nextExpr() { return d_parser->nextExpression(); }
  };/* class Parser::ExprStream */
};/* class Parser */

}/* CVC4::parser namespace */
}/* CVC4 namespace */

#endif /* __CVC4__PARSER__PARSER_STATE_H */