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80664353b2
* examples/c++/glr/ast.hh, examples/c++/glr/c++-types.yy: here. * examples/c++/glr/local.mk: Fix distribution of ast.hh.
128 lines
2.3 KiB
C++
128 lines
2.3 KiB
C++
/*
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Copyright (C) 2020 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <iostream>
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#if __cplusplus < 201103L
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# define nullptr 0
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#endif
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class Node
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{
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public:
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Node ()
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: parents_ (0)
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{}
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virtual ~Node ();
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void free ()
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{
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parents_ -= 1;
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/* Free only if 0 (last parent) or -1 (no parents). */
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if (parents_ <= 0)
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delete this;
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}
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virtual std::ostream& print (std::ostream& o) const = 0;
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protected:
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friend class Nterm;
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friend class Term;
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int parents_;
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};
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Node::~Node ()
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{}
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static std::ostream&
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operator<< (std::ostream& o, const Node &node)
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{
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return node.print (o);
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}
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class Nterm : public Node
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{
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public:
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Nterm (char const *form,
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Node *child0 = nullptr, Node *child1 = nullptr, Node *child2 = nullptr)
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: form_ (form)
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{
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children_[0] = child0;
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if (child0)
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child0->parents_ += 1;
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children_[1] = child1;
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if (child1)
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child1->parents_ += 1;
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children_[2] = child2;
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if (child2)
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child2->parents_ += 1;
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}
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~Nterm ();
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std::ostream& print (std::ostream& o) const
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{
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o << form_;
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if (children_[0])
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{
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o << '(' << *children_[0];
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if (children_[1])
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o << ", " << *children_[1];
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if (children_[2])
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o << ", " << *children_[2];
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o << ')';
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}
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return o;
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}
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private:
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char const *form_;
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Node *children_[3];
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};
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Nterm::~Nterm ()
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{
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for (int i = 0; i < 3; ++i)
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if (children_[i])
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children_[i]->free ();
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}
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class Term : public Node
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{
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public:
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Term (const std::string &text)
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: text_ (text)
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{}
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~Term();
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std::ostream& print (std::ostream& o) const
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{
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o << text_;
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return o;
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}
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private:
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std::string text_;
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};
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Term::~Term ()
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{
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}
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