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kpeter (Peter Kovacs)
kpeter@inf.elte.hu
Improvements in named-param.dox (ticket #147)
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1 file changed with 11 insertions and 11 deletions:
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Ignore white space 12 line context
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/* -*- C++ -*-
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/* -*- mode: C++; indent-tabs-mode: nil; -*-
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 *
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 * This file is a part of LEMON, a generic C++ optimization library
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 * This file is a part of LEMON, a generic C++ optimization library.
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 *
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 * Copyright (C) 2003-2008
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 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
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 * (Egervary Research Group on Combinatorial Optimization, EGRES).
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 *
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 * Permission to use, modify and distribute this software is granted
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@@ -22,35 +22,35 @@
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\section named-func-param Named Function Parameters
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Several modern languages provide a convenient way to refer the
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function parameters by name also when you call the function. It is
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especially comfortable in case of a function having tons of parameters
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with natural default values. Sadly, C++ lack this amenity. 
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with natural default values. Sadly, C++ lack this amenity.
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However, with a crafty trick and with some little
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inconvenience, it is possible to emulate is.
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The example below shows how to do it.
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\code
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class namedFn 
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class namedFn
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{
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  int _id;
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  double _val;
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  int _dim;
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  public:
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  namedFn() : _id(0), _val(1), _dim(2) {}
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  namedFn& id(int p)     { _id  = p ; return *this; }
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  namedFn& val(double p) { _val = p ; return *this; }
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  namedFn& dim(int p)    { _dim = p ; return *this; }
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  run() {
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  std::cout << "Here comes the function itself\n" <<
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            << "With parameters "
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            << _id << ", " << _val << ", " << _dim << std::endl; 
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    std::cout << "Here comes the function itself\n" <<
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              << "With parameters "
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              << _id << ", " << _val << ", " << _dim << std::endl;
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  }
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};
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\endcode
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Then you can use it like this.
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@@ -73,13 +73,13 @@
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<b>Therefore, by convention, <tt>.run()</tt> must be used
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explicitly to execute a function having named parameters
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everywhere in LEMON.</b>
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\section named-templ-func-param Named Function Template Parameters
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A named parameter can also be a template functions. The usage is
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A named parameter can also be a template function. The usage is
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exactly the same, but the implementation behind is a kind of black
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magic and they are the dirtiest part of the LEMON code.
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You will probably never need to know how it works, but if you really
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committed, have a look at \ref lemon/graph_to_eps.h for an example.
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@@ -100,20 +100,20 @@
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was instantiated by using a traits class as a template parameter, and
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the class contains named parameters, we do not have to instantiate again
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the class with new traits class, but instead adaptor classes can
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be used as shown in the following example.
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\code
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Dijkstra<>::SetPredNodeMap<NullMap<Node,Node> >::Create
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Dijkstra<>::SetPredMap<NullMap<Node,Arc> >::Create
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\endcode
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It can also be used in conjunction with other named template
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parameters in arbitrary order.
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\code
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Dijkstra<>::SetDistMap<MyMap>::SetPredMap<NullMap<Node,Edge> >::Create
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Dijkstra<>::SetDistMap<MyMap>::SetPredMap<NullMap<Node,Arc> >::Create
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\endcode
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The result will be an instantiated Dijkstra class, in which the
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DistMap and the PredMap is modified.
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*/
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