*** wxParserDemo - STX Expression Parser Demo Application ***

Author: Timo Bingmann (Mail: tb a-with-circle idlebox dot net)
Date: 2007-07-17

--- Summary ---

This directory contains a wxWidgets demo application. It is a user-friendly
graphical user interface to demonstrate the STX Expression Parser's functions.

The demo allows the user to enter an expression string and press "Evaluate" to
run the parser over it. If the expression could be parsed and evaluated
correctly, the result's value and type are displayed. Otherwise an error
message is shown. The demo also has a data input grid to specify variables,
which can be used in the expression.

The demo program uses the cross-platform wxWidgets toolkit and can be compiled
on Linux, Windows and MacOSX.

--- Website / License ---

The current demo source and some compiled binaries can be downloaded from
http://idlebox.net/2007/stx-exparser/

Some binary executables for Linux and Windows can be downloaded from
http://idlebox.net/2007/stx-exparser/demo.htt

The demo's source code is released under the GNU General Public License v2
(GPL) which can be found in the file COPYING.

--- Short Usage Walk-Through ---

The demo application has one large expression input field in the upper half of
the dialog. The given expression can be parsed and evaluated by pressing
"Evaluate". These results are printed in the "Result" tag, which automatically
gets activated.

The "Result" tab is separated into two parts: the upper group box contains the
resulting parse tree converted back to a string; or the syntax error if the
expression is invalid. The re-stringified expression usually contains more
brackets than your input expression. It is generated by the toString() function
of stx::ParseNode or stx::ParseTree.

The lower part of the "Result" tab shows the evaluation result, if it could be
computed. Both type and value of the resulting AnyScalar are displayed. If the
tree could not be evaluated, e.g. if an undefined variable was used, then the
exception message is shown.

The "XML Tree" tab contains Boost.Spirit's debug XML output. It shows in detail
which Spirit rules are used to compose the parse tree.

The demo applications allows input expressions to use variable names. The
(non-standard) variables set before evaluating a parse tree are shown in the
grid input on the "Variables" tab. They can be set by entering data into the
grid. Lines with empty names are ignored.

For screenshots on how to use the demo, please see the screenshot directory. Or
visit http://idlebox.net/2007/stx-exparser/demo.htt