src/util/sexpr.h

   1 /*********************                                                        */
   2 /*! \file sexpr.h
   3  ** \verbatim
   4  ** Top contributors (to current version):
   5  **   Tim King, Morgan Deters, Christopher L. Conway
   6  ** This file is part of the CVC4 project.
   7  ** Copyright (c) 2009-2016 by the authors listed in the file AUTHORS
   8  ** in the top-level source directory) and their institutional affiliations.
   9  ** All rights reserved.  See the file COPYING in the top-level source
  10  ** directory for licensing information.\endverbatim
  11  **
  12  ** \brief Simple representation of S-expressions
  13  **
  14  ** Simple representation of S-expressions.
  15  ** These are used when a simple, and obvious interface for basic
  16  ** expressions is appropraite.
  17  **
  18  ** These are quite ineffecient.
  19  ** These are totally disconnected from any ExprManager.
  20  ** These keep unique copies of all of their children.
  21  ** These are VERY overly verbose and keep much more data than is needed.
  22  **/
  23
  24 #include "cvc4_public.h"
  25
  26 #ifndef __CVC4__SEXPR_H
  27 #define __CVC4__SEXPR_H
  28
  29 #include <iomanip>
  30 #include <iosfwd>
  31 #include <string>
  32 #include <vector>
  33
  34 #include "base/exception.h"
  35 #include "options/language.h"
  36 #include "util/integer.h"
  37 #include "util/rational.h"
  38
  39 namespace CVC4 {
  40
  41 class CVC4_PUBLIC SExprKeyword {
  42   std::string d_str;
  43 public:
  44   SExprKeyword(const std::string& s) : d_str(s) {}
  45   const std::string& getString() const { return d_str; }
  46 };/* class SExpr::Keyword */
  47
  48 /**
  49  * A simple S-expression. An S-expression is either an atom with a
  50  * string value, or a list of other S-expressions.
  51  */
  52 class CVC4_PUBLIC SExpr {
  53 public:
  54
  55   typedef SExprKeyword Keyword;
  56
  57   SExpr();
  58   SExpr(const SExpr&);
  59   SExpr& operator=(const SExpr& other);
  60   ~SExpr();
  61
  62   SExpr(const CVC4::Integer& value);
  63
  64   SExpr(int value);
  65   SExpr(long int value);
  66   SExpr(unsigned int value);
  67   SExpr(unsigned long int value);
  68
  69   SExpr(const CVC4::Rational& value);
  70
  71   SExpr(const std::string& value);
  72
  73   /**
  74    * This constructs a string expression from a const char* value.
  75    * This cannot be removed in order to support SExpr("foo").
  76    * Given the other constructors this SExpr("foo") converts to bool.
  77    * instead of SExpr(string("foo")).
  78    */
  79   SExpr(const char* value);
  80
  81   /**
  82    * This adds a convenience wrapper to SExpr to cast from bools.
  83    * This is internally handled as the strings "true" and "false"
  84    */
  85   SExpr(bool value);
  86   SExpr(const Keyword& value);
  87   SExpr(const std::vector<SExpr>& children);
  88
  89   /** Is this S-expression an atom? */
  90   bool isAtom() const;
  91
  92   /** Is this S-expression an integer? */
  93   bool isInteger() const;
  94
  95   /** Is this S-expression a rational? */
  96   bool isRational() const;
  97
  98   /** Is this S-expression a string? */
  99   bool isString() const;
 100
 101   /** Is this S-expression a keyword? */
 102   bool isKeyword() const;
 103
 104   /**
 105    * This wraps the toStream() printer.
 106    * NOTE: toString() and getValue() may differ on Keywords based on
 107    * the current language set in expr.
 108    */
 109   std::string toString() const;
 110
 111   /**
 112    * Get the string value of this S-expression. This will cause an
 113    * error if this S-expression is not an atom.
 114    */
 115   std::string getValue() const;
 116
 117   /**
 118    * Get the integer value of this S-expression. This will cause an
 119    * error if this S-expression is not an integer.
 120    */
 121   const CVC4::Integer& getIntegerValue() const;
 122
 123   /**
 124    * Get the rational value of this S-expression. This will cause an
 125    * error if this S-expression is not a rational.
 126    */
 127   const CVC4::Rational& getRationalValue() const;
 128
 129   /**
 130    * Get the children of this S-expression. This will cause an error
 131    * if this S-expression is not a list.
 132    */
 133   const std::vector<SExpr>& getChildren() const;
 134
 135   /** Is this S-expression equal to another? */
 136   bool operator==(const SExpr& s) const;
 137
 138   /** Is this S-expression different from another? */
 139   bool operator!=(const SExpr& s) const;
 140
 141
 142   /**
 143    * This returns the best match in the following order:
 144    * match atom with
 145    *  "true", "false" -> SExpr(value)
 146    * | is and integer -> as integer
 147    * | is a rational -> as rational
 148    * | _ -> SExpr()
 149    */
 150   static SExpr parseAtom(const std::string& atom);
 151
 152   /**
 153    * Parses a list of atoms.
 154    */
 155   static SExpr parseListOfAtoms(const std::vector<std::string>& atoms);
 156
 157   /**
 158    * Parses a list of list of atoms.
 159    */
 160   static SExpr parseListOfListOfAtoms(const std::vector< std::vector<std::string> >& atoms_lists);
 161
 162
 163   /**
 164    * Outputs the SExpr onto the ostream out. This version reads defaults to the
 165    * OutputLanguage, language::SetLanguage::getLanguage(out). The indent level is
 166    * set to 2 if PrettySExprs::getPrettySExprs() is on and is 0 otherwise.
 167    */
 168   static void toStream(std::ostream& out, const SExpr& sexpr) throw();
 169
 170   /**
 171    * Outputs the SExpr onto the ostream out. This version sets the indent level
 172    * to 2 if PrettySExprs::getPrettySExprs() is on.
 173    */
 174   static void toStream(std::ostream& out, const SExpr& sexpr, OutputLanguage language) throw();
 175
 176   /**
 177    * Outputs the SExpr onto the ostream out.
 178    * If the languageQuotesKeywords(language), then a top level keyword, " X",
 179    * that needs quoting according to the SMT2 language standard is printed with
 180    * quotes, "| X|".
 181    * Otherwise this prints using toStreamRec().
 182    *
 183    * TIM: Keywords that are children are not currently quoted. This seems
 184    * incorrect but I am just reproduicing the old behavior even if it does not make
 185    * sense.
 186    */
 187   static void toStream(std::ostream& out, const SExpr& sexpr, OutputLanguage language, int indent) throw();
 188
 189 private:
 190
 191   /**
 192    * Simple printer for SExpr to an ostream.
 193    * The current implementation is language independent.
 194    */
 195   static void toStreamRec(std::ostream& out, const SExpr& sexpr, OutputLanguage language, int indent) throw();
 196
 197
 198   /** Returns true if this language quotes Keywords when printing. */
 199   static bool languageQuotesKeywords(OutputLanguage language);
 200
 201   enum SExprTypes {
 202     SEXPR_STRING,
 203     SEXPR_KEYWORD,
 204     SEXPR_INTEGER,
 205     SEXPR_RATIONAL,
 206     SEXPR_NOT_ATOM
 207   } d_sexprType;
 208
 209   /** The value of an atomic integer-valued S-expression. */
 210   CVC4::Integer d_integerValue;
 211
 212   /** The value of an atomic rational-valued S-expression. */
 213   CVC4::Rational d_rationalValue;
 214
 215   /** The value of an atomic S-expression. */
 216   std::string d_stringValue;
 217
 218   typedef std::vector<SExpr> SExprVector;
 219
 220   /**
 221    * The children of a list S-expression.
 222    * Whenever the SExpr isAtom() holds, this points at NULL.
 223    *
 224    * This should be a pointer in case the implementation of vector<SExpr> ever
 225    * directly contained or allocated an SExpr. If this happened this would trigger,
 226    * either the size being infinite or SExpr() being an infinite loop.
 227    */
 228   SExprVector* d_children;
 229 };/* class SExpr */
 230
 231 /** Prints an SExpr. */
 232 std::ostream& operator<<(std::ostream& out, const SExpr& sexpr) CVC4_PUBLIC;
 233
 234 /**
 235  * IOStream manipulator to pretty-print SExprs.
 236  */
 237 class CVC4_PUBLIC PrettySExprs {
 238   /**
 239    * The allocated index in ios_base for our setting.
 240    */
 241   static const int s_iosIndex;
 242
 243   /**
 244    * When this manipulator is used, the setting is stored here.
 245    */
 246   bool d_prettySExprs;
 247
 248 public:
 249   /**
 250    * Construct a PrettySExprs with the given setting.
 251    */
 252   PrettySExprs(bool prettySExprs) : d_prettySExprs(prettySExprs) {}
 253
 254   inline void applyPrettySExprs(std::ostream& out) {
 255     out.iword(s_iosIndex) = d_prettySExprs;
 256   }
 257
 258   static inline bool getPrettySExprs(std::ostream& out) {
 259     return out.iword(s_iosIndex);
 260   }
 261
 262   static inline void setPrettySExprs(std::ostream& out, bool prettySExprs) {
 263     out.iword(s_iosIndex) = prettySExprs;
 264   }
 265
 266   /**
 267    * Set the pretty-sexprs state on the output stream for the current
 268    * stack scope.  This makes sure the old state is reset on the
 269    * stream after normal OR exceptional exit from the scope, using the
 270    * RAII C++ idiom.
 271    */
 272   class Scope {
 273     std::ostream& d_out;
 274     bool d_oldPrettySExprs;
 275
 276   public:
 277
 278     inline Scope(std::ostream& out, bool prettySExprs) :
 279       d_out(out),
 280       d_oldPrettySExprs(PrettySExprs::getPrettySExprs(out)) {
 281       PrettySExprs::setPrettySExprs(out, prettySExprs);
 282     }
 283
 284     inline ~Scope() {
 285       PrettySExprs::setPrettySExprs(d_out, d_oldPrettySExprs);
 286     }
 287
 288   };/* class PrettySExprs::Scope */
 289
 290 };/* class PrettySExprs */
 291
 292 /**
 293  * Sets the default pretty-sexprs setting for an ostream.  Use like this:
 294  *
 295  *   // let out be an ostream, s an SExpr
 296  *   out << PrettySExprs(true) << s << endl;
 297  *
 298  * The setting stays permanently (until set again) with the stream.
 299  */
 300 std::ostream& operator<<(std::ostream& out, PrettySExprs ps);
 301
 302
 303 }/* CVC4 namespace */
 304
 305 #endif /* __CVC4__SEXPR_H */