LUMIERA.clone/src/gui/interact/gen-node-location-query.hpp
Ichthyostega c39442a287 LocationQuery: recast syntax for inline structure definitions
this fixes a silly mistake:
obviously we want named sub-nodes, aka. "Attributes",
but we used the anonymous sub-nodes instead, aka. "Children"

Incidentally, this renders the definitions also way more readable;
in fact the strange post-fix naming notation of the original version
was a clear indication of using the system backwards....
2017-10-28 00:17:56 +02:00

198 lines
7.9 KiB
C++

/*
GEN-NODE-LOCATION-QUERY.hpp - pose UI-coordinate location queries against a GenNode structure
Copyright (C) Lumiera.org
2017, Hermann Vosseler <Ichthyostega@web.de>
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 2 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, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/** @file gen-node-location-query.hpp
** Implementation of the gui::interact::LocationQuery interface to work on a GenNode tree.
** The interface allows to pose queries against a concrete structure to verify and reshape some
** [UI Coordinate specification](\ref UICoord); basically it offers methods to navigate within a
** tree-like structure. While in the actual implementation, such a query interface would be backed
** by navigating real UI structures, the implementation given here instead uses a generic tree structure
** given as `Record<GenNode>`.
**
** # Representing UI structure as GenNode tree
**
** While basically the interface LocationQuery abstracts and reduces the structure of an UI into
** just some hierarchically arranged and nested IDs, we should note some specific twists how a GenNode
** tree is used here to represent the structure elements as defined through [UI coordinates](\ref UICoord):
** - we use the special _type_ attribute to represent the _perspective_ within each window;
** deliberately, we'll use this twisted structure here to highlight the fact that the
** backing structure need not be homogeneous; rather, it may require explicit branching
** - we use the _attributes_ within the GenNode "object" representation, since these are _named_
** nested elements, and the whole notion of an UI coordinate path is based on named child components
** - relying upon the [object builder notation](\ref Record::Mutator), it is possible to define a whole
** structure as nested inline tree; named nested elements can be added with the `set(key, val)`
** builder function, and for each nested scope, we start a new nested builder with `MakeRec()`.
** - since GenNodeLocationQuery is conceived for writing test and verification code, there is a
** special convention to set the `currentWindow` to be the last one in list -- in a real UI
** this would not of course not be a configurable property of the LocationQuery, and rather
** just reflect the transient window state and return the currently activated window
**
** @todo WIP 10/2017 started in the effort of shaping the LoactionQuery interface, and used
** to support writing unit tests, to verify the UiCoordResolver. It remains to be seen
** if this implementation can be used beyond this limited purpose
**
** @see UICoordResolver_test
** @see ui-coord-resolver.hpp
** @see navigator.hpp
*/
#ifndef GUI_INTERACT_GEN_NODE_LOCATION_QUERY_H
#define GUI_INTERACT_GEN_NODE_LOCATION_QUERY_H
#include "lib/error.hpp"
//#include "lib/symbol.hpp"
#include "gui/interact/ui-coord-resolver.hpp"
#include "lib/diff/gen-node.hpp"
#include "lib/format-string.hpp"
#include "lib/itertools.hpp"
#include "lib/util.hpp"
//#include <boost/noncopyable.hpp>
//#include <string>
//#include <vector>
#include <utility>
//#include <memory>
namespace gui {
namespace interact {
namespace error = lumiera::error;
// using std::unique_ptr;
// using std::string;
// using lib::Literal;
// using lib::Symbol;
using lib::diff::Rec;
using util::_Fmt;
// using util::unConst;
// using util::isnil;
// using util::min;
/**
* Test/Diagnostics: implementation of the LocationQuery-API
* based on a abstract topological structure given as Record<GenNode> ("GenNode tree").
* @remark intended for verifying path resolution and navigation through unit tests
* @todo initial draft as of 10/2017
*/
class GenNodeLocationQuery
: public LocationQuery
{
Rec tree_;
public:
template<class REC>
GenNodeLocationQuery(REC&& backingStructure)
: tree_(std::forward<REC>(backingStructure))
{ }
/* === LocationQuery interface === */
/** resolve Anchor against GenNode tree */
virtual Literal
determineAnchor (UICoord const& path)
{
if (isnil(tree_) or not path.isPresent(UIC_WINDOW))
return Symbol::BOTTOM;
if (UIC_FIRST_WINDOW == path.getWindow())
return getFirstWindow();
if (UIC_CURRENT_WINDOW == path.getWindow())
return getCurrentWindow();
if (not tree_.hasAttribute(string{path.getWindow()})) /////////////////////////////////////TICKET #1113 : unnecessary repackaging of a Literal into string when GenNode ID is based on Literal
return Symbol::BOTTOM;
return path.getWindow();
}
/** evaluate to what extent a UIcoord spec matches the structure given as GenNode tree */
virtual size_t
determineCoverage (UICoord const& path)
{
size_t depth = 0;
drillDown (tree_, path, path.size(), depth);
return depth;
}
/** get the sequence of child IDs at a designated position in the backing GenNode tree */
virtual ChildIter
getChildren (UICoord const& path, size_t pos)
{
size_t depth = 0;
Rec const& node = drillDown (tree_, path, pos, depth);
if (pos != depth-1)
throw error::State(_Fmt{"unable to drill down to depth %d: "
"element %s at pos %d in path %s is in "
"contradiction to actual UI structure"}
% pos
% (depth<path.size()? path[depth] : Symbol::BOTTOM)
% depth
% path
);
return childSequence(node);
}
private:
Literal
getFirstWindow()
{
return Symbol{*tree_.keys()}; //////////////////////////////////////////////TICKET #1113 : warning use of Symbol table becomes obsolete when EntryID relies on Literal
}
Literal
getCurrentWindow()
{
return Symbol{lib::pull_last (tree_.keys())}; //////////////////////////////////////////////TICKET #1113 : warning use of Symbol table becomes obsolete when EntryID relies on Literal
}
static ChildIter
childSequence (Rec const& node)
{
auto internedString = [](string const& id) -> Literal
{
return Symbol{id};
};
///////////////////////////////////////////////////////////////TICKET #1113 : could just use lib::wrapIter when GenNode exposes Literal as ID
return lib::transform (node.keys(), internedString);
}
static Rec const&
drillDown (Rec const& tree, UICoord const& path, size_t maxDepth, size_t& depth)
{
if (depth<maxDepth and path.isPresent(depth))
{
const char* pathElm = path[depth];
if (tree.hasAttribute(pathElm))
return drillDown (tree.get(pathElm).data.get<Rec>(), path, maxDepth, ++depth);
}
return tree;
}
};
}}// namespace gui::interact
#endif /*GUI_INTERACT_GEN_NODE_LOCATION_QUERY_H*/