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/*

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 * (c) 2003 Mario de Sousa

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 *

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 * Offered to the public under the terms of the GNU General Public License

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 * as published by the Free Software Foundation; either version 2 of the

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 * License, or (at your option) any later version.

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 *

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 * This program is distributed in the hope that it will be useful, but

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 * WITHOUT ANY WARRANTY; without even the implied warranty of

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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General

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 * Public License for more details.

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 *

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 * This code is made available on the understanding that it will not be

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 * used in safety-critical situations without a full and competent review.

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 */

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/*

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 * An IEC 61131-3 IL and ST compiler.

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 *

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 * Based on the

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 * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)

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 *

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 */

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/*

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 * A generic symbol table.

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 *

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 * This is used to create symbol tables such as a list of

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 * variables currently in scope, a list of previously defined

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 * functions, etc...

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 */

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#ifndef _SYMTABLE_HH

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#define _SYMTABLE_HH

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#include "../absyntax/absyntax.hh"

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#include <map>

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#include <string>

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template<typename value_type, value_type null_value> class symtable_c {

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  /* Case insensitive string compare copied from

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   * "The C++ Programming Language" - 3rd Edition

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   * by Bjarne Stroustrup, ISBN 0201889544.

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   */

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  class nocase_c {

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    public:

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      bool operator() (const std::string& x, const std::string& y) const {

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        std::string::const_iterator ix = x.begin();

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        std::string::const_iterator iy = y.begin();

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        for(; (ix != x.end()) && (iy != y.end()) && (toupper(*ix) == toupper(*iy)); ++ix, ++iy);

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        if (ix == x.end()) return (iy != y.end());

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        if (iy == y.end()) return false;

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        return (toupper(*ix) < toupper(*iy));

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      };

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  };

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  public:

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    typedef value_type value_t;

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  private:

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    /* Comparison between identifiers must ignore case, therefore the use of nocase_c */

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    typedef std::map<std::string, value_t, nocase_c> base_t;

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    base_t _base;

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  public:

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  typedef typename base_t::iterator iterator;

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  typedef typename base_t::const_iterator const_iterator;

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  typedef typename base_t::reverse_iterator reverse_iterator;

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  typedef typename base_t::const_reverse_iterator const_reverse_iterator;

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  private:

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      /* pointer to symbol table of the next inner scope */

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    symtable_c *inner_scope;

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    void reset(void); /* clear all entries... */

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  public:

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    symtable_c(void);

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    void push(void); /* create new inner scope */

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    int  pop(void);  /* clear most inner scope */

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    void set(const char *identifier_str, value_t value);

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    void set(const symbol_c *symbol, value_t value);

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    void insert(const char *identifier_str, value_t value);

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    void insert(const symbol_c *symbol, value_t value);

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    /* Search for an entry. Will return end_value() if not found */

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    value_t end_value(void) {return null_value;}

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    value_t find_value(const char *identifier_str);

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    value_t find_value(const symbol_c *symbol);

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    iterator find(const char *identifier_str) {return _base.find(identifier_str);}

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  /* iterators pointing to beg/end of map... */

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    iterator begin() 			{return _base.begin();}

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    const_iterator begin() const	{return _base.begin();}

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    iterator end()			{return _base.end();}

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    const_iterator end() const 		{return _base.end();}

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    reverse_iterator rbegin()		{return _base.rbegin();}

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    const_reverse_iterator rbegin() const {return _base.rbegin();}

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    reverse_iterator rend() 		{return _base.rend();}

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    const_reverse_iterator rend() const	{return _base.rend();}

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    /* debuging function... */

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    void print(void);

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};

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/* Templates must include the source into the code! */

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#include "symtable.cc"

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#endif /*  _SYMTABLE_HH */