Props.hh

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/*
 
Cadabra: a field-theory motivated computer algebra system.
Copyright (C) 2001-2014  Kasper Peeters <kasper.peeters@phi-sci.com>
 
This program is free software: you can redistribute it and/or
modify it under the terms of the GNU General Public License as
    published by the Free Software Foundation, either version 3 of the
License, or (at your option) any later version.
 
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
*/
 
// Classes handling storage of property information. Actual property
// implementations are in the properties directory in separate files.
 
#pragma once
 
#include <map>
#include <list>
#include <type_traits>
#include "Storage.hh"
 
namespace cadabra {
 
    class Properties;
    class Kernel;
    class Accent;
    class LaTeXForm;
    class Ex_comparator;
    
    class pattern {
        public:
            pattern();
            pattern(const Ex&);
 
            
            bool match(const Properties&, const Ex::iterator&, bool ignore_parent_rel=false, bool ignore_properties=false) const;
            bool children_wildcard() const;
 
            bool match_ext(const Properties&, const Ex::iterator&, Ex_comparator& comp, bool ignore_parent_rel=false, bool ignore_properties=false) const;
 
            Ex obj;
        };
 
 
    class keyval_t {
        public:
            typedef std::pair<std::string, Ex> kvpair_t;
            typedef std::list<kvpair_t>        kvlist_t;
 
            typedef kvlist_t::const_iterator const_iterator;
            typedef kvlist_t::iterator       iterator;
            typedef kvpair_t value_type;
 
            const_iterator find(const std::string&) const;
            iterator       find(const std::string&);
            const_iterator begin() const;
            const_iterator end() const;
            void           push_back(const kvpair_t&);
            void           erase(iterator);
 
        private:
            kvlist_t keyvals;
        };
 
    // default implementation returns true for any pattern.
 
 
    class property {
        public:
            property(bool hidden=false);
            virtual ~property() {};
 
            // Parse the argument tree into key-value pairs. Returns false on error.
            bool                parse_to_keyvals(const Ex&, keyval_t&);
 
            // Use the pre-parsed arguments in key/value form to set parameters.
            // Parses universal arguments by default. Will be called once for
            // every property; assigning a non-list property to multiple patterns
            // still calls this only once.
            // FIXME: failure to call
            // into superclass may lead to problems for labelled properties.
            virtual bool        parse(Kernel&, keyval_t& keyvals);
 
            // New entry point, which also passes the Ex of the pattern, so that
            // the property itself can inject other properties automatically (e.g.
            // declare an InverseMetric if a Metric is declared).
            virtual bool        parse(Kernel&, std::shared_ptr<Ex>, keyval_t& keyvals);
 
            // Check whether the property can be associated with the pattern.
            // Throw an error if validation fails. Needs access to all other
            // declared properties so that it can understand what the pattern
            // means (which objects are indices etc.).
            //
            // This is currently also the point where properties are allowed
            // to insert other, related properties (see e.g. `Indices`), and form
            // that reason the Kernel parameter is not const. FIXME: split and
            // then make Kernel const again).
            virtual void        validate(Kernel&, std::shared_ptr<Ex>) const;
 
            //      virtual void        display(std::ostream&) const;
 
            virtual void        latex(std::ostream&) const;
 
            virtual std::string name() const=0;
            virtual std::string unnamed_argument() const;
 
            // To compare properties we sometimes need to compare their variables, not only
            // their type. The following function needs to be overridden in all properties
            // for which comparison by type is not sufficient to establish equality.
            //
            //   id_match:    only one of these properties can be registered, but their data is not the same
            //   exact_match: these properties are exactly identical
            enum match_t { no_match, id_match, exact_match };
            virtual match_t equals(const property *) const;
 
            void hidden(bool h);
            bool hidden(void) const;
 
        private:
            bool                parse_one_argument(Ex::iterator arg, keyval_t& keyvals);
            bool hidden_;
        };
 
    class labelled_property : virtual public property {
        public:
            virtual bool parse(Kernel&, std::shared_ptr<Ex>, keyval_t&) override;
            std::string label;
        };
 
 
    class list_property : public property {
        public:
        };
 
 
    template<class T>
    class Inherit : virtual public property {
        public:
            virtual ~Inherit() {};
            virtual std::string name() const
                {
//              T tmp;
                // T can be abstract, so we cannot instantiate. Maybe use typeid,
                // but then we need to be careful about name mangling.
                return std::string("Inherit");
                };
        };
 
 
    class PropertyInherit : virtual public property {
        public:
            virtual std::string name() const
                {
                return std::string("PropertyInherit");
                };
        };
 
 
    class Properties {
        public:
            // Registering property types.
            class registered_property_map_t {
                public:
                    ~registered_property_map_t();
 
                    typedef std::map<std::string, property* (*)()> internal_property_map_t;
                    typedef internal_property_map_t::iterator iterator;
 
                    internal_property_map_t store;
                };
 
 
            void                          register_property(property* (*)(), const std::string& name);
            registered_property_map_t     registered_properties;
            typedef std::pair<pattern *, const property *>  pat_prop_pair_t;
 
            typedef std::multimap<nset_t::iterator, pat_prop_pair_t, nset_it_less>  property_map_t;
            typedef std::multimap<const property *, pattern *>                      pattern_map_t;
 
            std::string master_insert(Ex proptree, const property *thepropbase);
 
            void        clear();
 
            property_map_t  props;  // pattern -> property
            pattern_map_t   pats;   // property -> pattern; for list properties, patterns are stored here in order
 
            template<class T> const T*  get(Ex::iterator, bool ignore_parent_rel=false) const;
            template<class T> const T*  get(Ex::iterator, int& serialnum, bool doserial=true, bool ignore_parent_rel=false) const;
            template<class T> const T*  get(Ex::iterator, const std::string& label) const;
            template<class T> const T*  get(Ex::iterator, int& serialnum, const std::string& label, bool doserial=true) const;
            template<class T> const T*  get(Ex::iterator, Ex::iterator, bool ignore_parent_rel=false) const;
            template<class T> const T*  get(Ex::iterator, Ex::iterator, int&, int&, bool ignore_parent_rel=false) const;
 
            template<class T>
            std::pair<const T*, const pattern *> get_with_pattern(Ex::iterator, int& serialnum,
                                                                                    const std::string& label,
                                                                                    bool doserial=true, bool ignore_parent_rel=false) const;
 
            template<class T>
            std::pair<const T*, const pattern *> get_with_pattern_ext(Ex::iterator, Ex_comparator&, int& serialnum,
                                                                                    const std::string& label,
                                                                                    bool doserial=true, bool ignore_parent_rel=false) const;
 
            // Get the outermost node which has the given property attached, i.e. go down through
            // all (if any) nodes which have just inherited the property.
            template<class T> Ex::iterator head(Ex::iterator, bool ignore_parent_rel=false) const;
 
            // Inverse search: given a property type, get a pattern which has this property.
            // When given an iterator, it starts to search in the property
            // map from this particular point. Note: this searches on property type, not exact property.
            //      template<class T>
            //      property_map_t::iterator      get_pattern(property_map_t::iterator=props.begin());
 
            // Equivalent search: given a node, get a pattern of equivalents.
            //      property_map_t::iterator      get_equivalent(Ex::iterator,
            //                                                                    property_map_t::iterator=props.begin());
 
        private:
            // Insert a property. Do not use this directly, use the public
            // interface `master_insert` instead.
            void insert_prop(const Ex&, const property *);
            void insert_list_prop(const std::vector<Ex>&, const list_property *);
            bool check_label(const property *, const std::string&) const;
            bool check_label(const labelled_property *, const std::string&) const;          
            // Search through pointers
            bool has(const property *, Ex::iterator);
            // Find serial number of a pattern in a given list property
            int  serial_number(const property *, const pattern *) const;
            Ex_comparator *create_comparator() const;
            void           destroy_comparator(Ex_comparator *) const;           
        };
 
    template<class T>
    const T* Properties::get(Ex::iterator it, bool ignore_parent_rel) const
        {
        int tmp;
        return get<T>(it, tmp, false, ignore_parent_rel);
        }
 
    template<class T>
    const T* Properties::get(Ex::iterator it, int& serialnum, bool doserial, bool ignore_parent_rel) const
        {
        auto ret = get_with_pattern<T>(it, serialnum, "", doserial, ignore_parent_rel);
        return ret.first;
        }
 
    template<class T>
    std::pair<const T*, const pattern *> Properties::get_with_pattern(Ex::iterator it, int& serialnum, const std::string& label,
                                                                                            bool doserial, bool ignore_parent_rel) const
        {
        Ex_comparator *compptr = create_comparator();
        // FIXME: catch and rethrow all exceptions so we do not leak memory
        auto ret = get_with_pattern_ext<T>(it, *compptr, serialnum, label, doserial, ignore_parent_rel);
        destroy_comparator(compptr);
        return ret;
        }
 
    template<class T>
    std::pair<const T*, const pattern *> Properties::get_with_pattern_ext(Ex::iterator it, Ex_comparator& comp,
                                                                                                 int& serialnum, const std::string& label,
                                                                                                 bool doserial, bool ignore_parent_rel) const
        {
        std::pair<const T*, const pattern *> ret;
        ret.first=0;
        ret.second=0;
        bool inherits=false;
 
        //std::cerr << *it->name_only() << std::endl;
        //  std::cerr << props.size() << std::endl;
        std::pair<property_map_t::const_iterator, property_map_t::const_iterator> pit=props.equal_range(it->name_only());
 
        // First look for properties of the node itself. Go through the loop twice:
        // once looking for patterns which do not have wildcards, and then looking
        // for wildcard patterns.
        bool wildcards=false;
 
        // For some properties, we cannot lookup properties lower down the
        // tree, because it would lead to an endless recursion (and it would
        // not make sense anyway). At the moment, this is only for Accent.
        bool ignore_properties=false;
        if(std::is_same<T, Accent>::value)
            ignore_properties=true;
        
        for(;;) {
            property_map_t::const_iterator walk=pit.first;
            while(walk!=pit.second) {
                if(wildcards==(*walk).second.first->children_wildcard()) {
                    // First check property type; a dynamic cast is much faster than a pattern match.
                    ret.first=dynamic_cast<const T *>((*walk).second.second);
                    if(ret.first) {
                        if((*walk).second.first->match_ext(*this, it, comp, ignore_parent_rel, ignore_properties)) {
                            ret.second=(*walk).second.first;
                            if(!check_label(ret.first, label)) 
                                ret.first=0;
                            else {
                                if(doserial) 
                                    serialnum=serial_number( (*walk).second.second, (*walk).second.first );
                                break;
                                }
                            }
                        }
                    ret.first=0;
                    if(dynamic_cast<const PropertyInherit *>((*walk).second.second))
                        inherits=true;
                    else if(dynamic_cast<const Inherit<T> *>((*walk).second.second))
                        inherits=true;
                    }
                ++walk;
                }
            if(!wildcards && !ret.first) {
                //          std::cerr << "not yet found, switching to wildcards" << std::endl;
                wildcards=true;
                }
            else break;
            }
 
        // Do not walk down the tree if the property cannot be passed up the tree.
        // FIXME: see issue/259.
        if(std::is_same<T, LaTeXForm>::value)
            inherits=false;
        
        // If no property was found, figure out whether a property is inherited from a child node.
        if(!ret.first && inherits) {
            //      std::cout << "no match but perhaps inheritance?" << std::endl;
            Ex::sibling_iterator sib=it.begin();
            while(sib!=it.end()) {
                std::pair<const T*, const pattern *> tmp=get_with_pattern<T>((Ex::iterator)(sib), serialnum, label, doserial);
                if(tmp.first) {
                    ret=tmp;
                    break;
                    }
                ++sib;
                }
            }
 
        //  std::cout << ret << std::endl;
        return ret;
        }
 
    template<class T>
    const T* Properties::get(Ex::iterator it, const std::string& label) const
        {
        int tmp;
        return get<T>(it, tmp, label, false);
        }
 
    template<class T>
    const T* Properties::get(Ex::iterator it, int& serialnum, const std::string& label, bool doserial) const
        {
        auto ret=get_with_pattern<T>(it, serialnum, label, doserial, false);
        return ret.first;
        }
 
    template<class T>
    const T* Properties::get(Ex::iterator it1, Ex::iterator it2, bool ignore_parent_rel) const
        {
        int tmp1, tmp2;
        return get<T>(it1,it2,tmp1,tmp2, ignore_parent_rel);
        }
 
    template<class T>
    const T* Properties::get(Ex::iterator it1, Ex::iterator it2, int& serialnum1, int& serialnum2, bool ignore_parent_rel) const
        {
        const T* ret1=0;
        const T* ret2=0;
        bool found=false;
 
        bool inherits1=false, inherits2=false;
        std::pair<property_map_t::const_iterator, property_map_t::const_iterator> pit1=props.equal_range(it1->name_only());
        std::pair<property_map_t::const_iterator, property_map_t::const_iterator> pit2=props.equal_range(it2->name_only());
 
        property_map_t::const_iterator walk1=pit1.first;
        while(walk1!=pit1.second) {
            if((*walk1).second.first->match(*this, it1, ignore_parent_rel)) { // match for object 1 found
                ret1=dynamic_cast<const T *>((*walk1).second.second);
                if(ret1) { // property of the right type found for object 1
                    property_map_t::const_iterator walk2=pit2.first;
                    while(walk2!=pit2.second) {
                        if((*walk2).second.first->match(*this, it2, ignore_parent_rel)) { // match for object 2 found
                            ret2=dynamic_cast<const T *>((*walk2).second.second);
                            if(ret2) { // property of the right type found for object 2
                                if(ret1==ret2 && walk1!=walk2) { // accept if properties are the same and patterns are not
                                    serialnum1=serial_number( (*walk1).second.second, (*walk1).second.first );
                                    serialnum2=serial_number( (*walk2).second.second, (*walk2).second.first );
                                    found=true;
                                    goto done;
                                    }
                                }
                            }
                        if(dynamic_cast<const PropertyInherit *>((*walk2).second.second))
                            inherits2=true;
                        ++walk2;
                        }
                    }
                if(dynamic_cast<const PropertyInherit *>((*walk1).second.second))
                    inherits1=true;
                }
            ++walk1;
            }
 
        // If no property was found, figure out whether a property is inherited from a child node.
        if(!found && (inherits1 || inherits2)) {
            Ex::sibling_iterator sib1, sib2;
            if(inherits1) sib1=it1.begin();
            else          sib1=it1;
            bool keepgoing1=true;
            do {    // 1
                bool keepgoing2=true;
                if(inherits2) sib2=it2.begin();
                else          sib2=it2;
                do { // 2
                    const T* tmp=get<T>((Ex::iterator)(sib1), (Ex::iterator)(sib2), serialnum1, serialnum2, ignore_parent_rel);
                    if(tmp) {
                        ret1=tmp;
                        found=true;
                        goto done;
                        }
                    if(!inherits2 || ++sib2==it2.end())
                        keepgoing2=false;
                    }
                while(keepgoing2);
                if(!inherits1 || ++sib1==it1.end())
                    keepgoing1=false;
                }
            while(keepgoing1);
            }
 
done:
        if(!found) ret1=0;
        return ret1;
        }
 
    template<class T>
    Ex::iterator Properties::head(Ex::iterator it, bool ignore_parent_rel) const
        {
        Ex::iterator dn=it;
        for(;;) {
            if(get<PropertyInherit>(dn, ignore_parent_rel)) {
                dn=dn.begin();
                }
            else {
                assert(get<T>(dn));
                break;
                }
            }
        return dn;
        }
 
    }