include/minizinc/eval_par.hh

/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */

/*
 *  Main authors:
 *     Guido Tack <guido.tack@monash.edu>
 */

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#pragma once

#include <minizinc/astexception.hh>
#include <minizinc/iter.hh>
#include <minizinc/model.hh>
#include <minizinc/prettyprinter.hh>

namespace MiniZinc {

/// Evaluate par int expression \a e
IntVal eval_int(EnvI& env, Expression* e);
/// Evaluate par bool expression \a e
bool eval_bool(EnvI& env, Expression* e);
/// Evaluate par float expression \a e
FloatVal eval_float(EnvI& env, Expression* e);
/// Evaluate an array expression \a e into an array literal
ArrayLit* eval_array_lit(EnvI& env, Expression* e);
/// Evaluate an access to array \a with indices \a idx and return whether
/// access succeeded in \a success
Expression* eval_arrayaccess(EnvI& env, ArrayLit* a, const std::vector<IntVal>& idx, bool& success);
/// Evaluate an array access \a e and return whether access succeeded in \a success
Expression* eval_arrayaccess(EnvI& env, ArrayAccess* e, bool& success);
/// Evaluate a set expression \a e into a set literal
SetLit* eval_set_lit(EnvI& env, Expression* e);
/// Evaluate a par integer set \a e
IntSetVal* eval_intset(EnvI& env, Expression* e);
/// Evaluate a par bool set \a e
IntSetVal* eval_boolset(EnvI& env, Expression* e);
/// Evaluate a par float set \a e
FloatSetVal* eval_floatset(EnvI& env, Expression* e);
/// Evaluate a par string \a e
std::string eval_string(EnvI& env, Expression* e);
/// Evaluate a par expression \a e and return it wrapped in a literal
Expression* eval_par(EnvI& env, Expression* e);
/// Check if variable declaration \a vd satisfies the domain and index set constraints
void check_par_declaration(EnvI& env, VarDecl* vd);

/// Representation for bounds of an integer expression
struct IntBounds {
  /// Lower bound
  IntVal l;
  /// Upper bound
  IntVal u;
  /// Whether the bounds are valid
  bool valid;
  /// Constructor
  IntBounds(IntVal l0, IntVal u0, bool valid0) : l(l0), u(u0), valid(valid0) {}
};

/// Compute bounds of an integer expression
IntBounds compute_int_bounds(EnvI& env, Expression* e);

/// Representation for bounds of a float expression
struct FloatBounds {
  /// Lower bound
  FloatVal l;
  /// Upper bound
  FloatVal u;
  /// Whether the bounds are valid
  bool valid;
  /// Constructor
  FloatBounds(FloatVal l0, FloatVal u0, bool valid0) : l(l0), u(u0), valid(valid0) {}
};

/// Compute bounds of an integer expression
FloatBounds compute_float_bounds(EnvI& env, Expression* e);

/**
 * \brief Compute bounds of a set of int expression
 *
 * Returns NULL if bounds cannot be determined
 */
IntSetVal* compute_intset_bounds(EnvI& env, Expression* e);

class EvalBase {
public:
  /// Evaluate bool expression that may contain variables
  static bool evalBoolCV(EnvI& env, Expression* e);
  /// Flatten expression that may contain variables
  static KeepAlive flattenCV(EnvI& env, Expression* e);
};

template <class Eval>
void eval_comp_array(EnvI& env, Eval& eval, Comprehension* e, int gen, int id, KeepAlive in,
                     std::vector<typename Eval::ArrayVal>& a);

template <class Eval>
void eval_comp_set(EnvI& env, Eval& eval, Comprehension* e, int gen, int id, KeepAlive in,
                   std::vector<typename Eval::ArrayVal>& a);

template <class Eval>
void eval_comp_set(EnvI& env, Eval& eval, Comprehension* e, int gen, int id, IntVal i, KeepAlive in,
                   std::vector<typename Eval::ArrayVal>& a) {
  {
    GCLock lock;
    GC::mark();
    e->decl(gen, id)->trail();
    e->decl(gen, id)->e(IntLit::a(i));
  }
  CallStackItem csi(env, e->decl(gen, id)->id(), i);
  if (id == e->numberOfDecls(gen) - 1) {
    bool where = true;
    if (e->where(gen) != nullptr && !e->where(gen)->type().isvar()) {
      where = eval.evalBoolCV(env, e->where(gen));
    }
    if (where) {
      if (gen == e->numberOfGenerators() - 1) {
        a.push_back(eval.e(env, e->e()));
      } else {
        if (e->in(gen + 1) == nullptr) {
          eval_comp_array<Eval>(env, eval, e, gen + 1, 0, 0, e->in(gen + 1), a);
        } else {
          KeepAlive nextin;
          Expression* gen_in = e->in(gen + 1);
          if (gen_in->type().isvar() || gen_in->type().cv()) {
            gen_in = eval.flattenCV(env, e->in(gen + 1))();
          }
          if (gen_in->type().dim() == 0) {
            GCLock lock;
            nextin = new SetLit(Location(), eval_intset(env, gen_in));
          } else {
            GCLock lock;
            nextin = eval_array_lit(env, gen_in);
          }
          if (e->in(gen + 1)->type().dim() == 0) {
            eval_comp_set<Eval>(env, eval, e, gen + 1, 0, nextin, a);
          } else {
            eval_comp_array<Eval>(env, eval, e, gen + 1, 0, nextin, a);
          }
        }
      }
    }
  } else {
    eval_comp_set<Eval>(env, eval, e, gen, id + 1, in, a);
  }
  GC::untrail();
  e->decl(gen, id)->flat(nullptr);
}

template <class Eval>
void eval_comp_array(EnvI& env, Eval& eval, Comprehension* e, int gen, int id, IntVal i,
                     KeepAlive in, std::vector<typename Eval::ArrayVal>& a) {
  GC::mark();
  e->decl(gen, id)->trail();
  CallStackItem csi(env, e->decl(gen, id)->id(), i);
  if (in() == nullptr) {
    // this is an assignment generator
    Expression* asn;
    if (e->where(gen)->type().isvar() || e->where(gen)->type().cv()) {
      asn = eval.flattenCV(env, e->where(gen))();
    } else {
      asn = eval_par(env, e->where(gen));
    }
    e->decl(gen, id)->e(asn);
    e->rehash();
  } else {
    auto* al = in()->cast<ArrayLit>();
    e->decl(gen, id)->e((*al)[static_cast<int>(i.toInt())]);
    e->rehash();
  }
  if (id == e->numberOfDecls(gen) - 1) {
    bool where = true;
    if (e->in(gen) != nullptr && e->where(gen) != nullptr && !e->where(gen)->type().isvar()) {
      where = eval.evalBoolCV(env, e->where(gen));
    }
    if (where) {
      if (gen == e->numberOfGenerators() - 1) {
        a.push_back(eval.e(env, e->e()));
      } else {
        if (e->in(gen + 1) == nullptr) {
          eval_comp_array<Eval>(env, eval, e, gen + 1, 0, 0, e->in(gen + 1), a);
        } else {
          KeepAlive nextin;
          Expression* gen_in = e->in(gen + 1);
          if (gen_in->type().isvar() || gen_in->type().cv()) {
            gen_in = eval.flattenCV(env, e->in(gen + 1))();
          }
          if (gen_in->type().dim() == 0) {
            GCLock lock;
            nextin = new SetLit(Location(), eval_intset(env, gen_in));
          } else {
            GCLock lock;
            nextin = eval_array_lit(env, gen_in);
          }
          if (gen_in->type().dim() == 0) {
            eval_comp_set<Eval>(env, eval, e, gen + 1, 0, nextin, a);
          } else {
            eval_comp_array<Eval>(env, eval, e, gen + 1, 0, nextin, a);
          }
        }
      }
    }
  } else {
    eval_comp_array<Eval>(env, eval, e, gen, id + 1, in, a);
  }
  GC::untrail();
  e->decl(gen, id)->flat(nullptr);
}

/**
 * \brief Evaluate comprehension expression
 *
 * Calls \a eval.e for every element of the comprehension \a e,
 * where \a gen is the current generator, \a id is the current identifier
 * in that generator, \a in is the expression of that generator, and
 * \a a is the array in which to place the result.
 */
template <class Eval>
void eval_comp_set(EnvI& env, Eval& eval, Comprehension* e, int gen, int id, KeepAlive in,
                   std::vector<typename Eval::ArrayVal>& a) {
  IntSetVal* isv = eval_intset(env, in());
  if (isv->card().isPlusInfinity()) {
    throw EvalError(env, in()->loc(), "comprehension iterates over an infinite set");
  }
  IntSetRanges rsi(isv);
  Ranges::ToValues<IntSetRanges> rsv(rsi);
  for (; rsv(); ++rsv) {
    eval_comp_set<Eval>(env, eval, e, gen, id, rsv.val(), in, a);
  }
}

/**
 * \brief Evaluate comprehension expression
 *
 * Calls \a eval.e for every element of the comprehension \a e,
 * where \a gen is the current generator, \a id is the current identifier
 * in that generator, \a in is the expression of that generator, and
 * \a a is the array in which to place the result.
 */
template <class Eval>
void eval_comp_array(EnvI& env, Eval& eval, Comprehension* e, int gen, int id, KeepAlive in,
                     std::vector<typename Eval::ArrayVal>& a) {
  auto* al = in()->cast<ArrayLit>();
  for (unsigned int i = 0; i < al->size(); i++) {
    eval_comp_array<Eval>(env, eval, e, gen, id, i, in, a);
  }
}

/**
 * \brief Evaluate comprehension expression
 *
 * Calls \a eval.e for every element of the comprehension \a e and
 * returns a vector with all the evaluated results.
 */
template <class Eval>
std::vector<typename Eval::ArrayVal> eval_comp(EnvI& env, Eval& eval, Comprehension* e) {
  std::vector<typename Eval::ArrayVal> a;
  if (e->in(0) == nullptr) {
    eval_comp_array<Eval>(env, eval, e, 0, 0, 0, e->in(0), a);
  } else {
    KeepAlive in;
    {
      GCLock lock;
      if (e->in(0)->type().dim() == 0) {
        if (e->in(0)->type().isvar()) {
          in = new SetLit(Location(), compute_intset_bounds(env, e->in(0)));
        } else {
          in = new SetLit(Location(), eval_intset(env, e->in(0)));
        }
      } else {
        if (e->in(0)->type().isvar() || e->in(0)->type().cv()) {
          in = eval_array_lit(env, eval.flattenCV(env, e->in(0))());
        } else {
          in = eval_array_lit(env, e->in(0));
        }
      }
    }
    if (e->in(0)->type().dim() == 0) {
      eval_comp_set<Eval>(env, eval, e, 0, 0, in, a);
    } else {
      eval_comp_array<Eval>(env, eval, e, 0, 0, in, a);
    }
  }
  return a;
}

/**
 * \brief Evaluate comprehension expression
 *
 * Calls \a Eval::e for every element of the comprehension \a e and
 * returns a vector with all the evaluated results.
 */
template <class Eval>
std::vector<typename Eval::ArrayVal> eval_comp(EnvI& env, Comprehension* e) {
  Eval eval;
  return eval_comp(env, eval, e);
}

Expression* follow_id(Expression* e);
Expression* follow_id_to_decl(Expression* e);
Expression* follow_id_to_value(Expression* e);

}  // namespace MiniZinc