February 12, 2008 at 10:33 PM
Couple of weeks ago, I needed to parse a set of XML files. As always, my first thought was to search the web for free XML parsers. But then I remembered that I found a solution in the past: Xerces XML parser. Even though, xerces was originally written in Java, there is an excellent port to c/c++. Xerces was developed by Apachi Software Foundation, and it supports wide range of compilers. To use it with Visual Studio 2005 C++ compiler, following steps are required:
- Download compiler in binary form from here;
- Unpack into any folder; This step will create subfolders include and lib;
- Add path include and lib folders to VC++ directories;
- To statically link to a project, link with xerces-c_static_2.lib or (xerces-c_static_2D.lib for debug version);
- Set to ignore libcmt.lib
Steps 4 and 5 are shown in the screen shot below:
May 31, 2007 at 6:59 PM
Authentication and authorization as fundamental part of a web application was tremendously simplified with arrival of .NET 2.0. Basic authentication and authorization can be performed using different DBMS systems. There are numerous examples implementing authentication using Access database. One such example can be found in the article ASP.NET 2.0 Authentication using Access Database. In this article the example implements bare minimum to achieve desired goal, namely authentication and authorization using access database. However, authentication and authorization is only first part of the user management system. Second fundamental part of user management is allowing users to create an account at will. In such instances, users can sign up and become members of the community without administrator intervention. Furthermore, the user should be able to provide contact information (email) so that he/she can be contacted if necessary. Contact information must be verified. This article focuses on very simple ways to achieve such goal.
May 31, 2007 at 5:05 PM
Couple of days ago, I worked on an MFC application that required special functionallity of F1 key. At first, I thought that all I need is to override application's PreTranslateMessage function and trap the F1 key. However, I was wrong. Every time I pressed F1 key, the application performed custom function, but also popped message box saying that help file could not be located. My first thought was that MFC/Windows is placing a windows hook to trap such functionality and that the workaround might not be very elegant. Fortunatly that was not the case. After some investigation, I noticed the following code:
In other words, main application is getting notification to handle help request and is passing it to default MFC implementation. Once the ON_COMMAND line is commented out, such hadling is disabled.
May 8, 2007 at 5:43 PM
The compiler design is a well researched area of computer science. Typically, compiler designers use a parser generator framework like YACC or PCCTS to construct lexer, scanner, parser, and abstract syntax tree. With the arrival of expression templates and template meta-programming, it is possible to construct a parser by simply using the template meta-programming technique. The Spirit library is object-oriented recursive-decent parser implemented in C++ using expression templates and meta-programming. In Spirit the parser is constructed during the compile time using a combination of primitive parsers and fusing them through template meta-programming. TinyPascal is a practical application of Spirit framework.
March 25, 2007 at 5:31 PM
According to one of expression templates inventors, Todd Veldhuizen, expression templates are “new C++ technique for passing expressions as functions arguments” . The purpose of expression template is to inline expressions during compilation, which produces faster and arguably more readable code. Most of expression template articles focus on numeric array classes and operations on those using expression template techniques. For instance, expression templates could be utilized for matrix multiplication without using temporaries. For such article and code examples, please refer to articles referenced under  and .
As probably suspected, this article will not focus on expression templates as applied on numeric array classes. In this article, the focus will be on parsing and language recognition using expression template techniques. Furthermore the article will focus on Spirit library , a parser framework implemented completely using expression templates and template meta-programming. At this point the reader is encouraged to refer to introductory part of Spirit documentation as found here http://www.boost.org/libs/spirit/doc/introduction.html.
In addition it is important to note that this article will not focus on all parts of Spirit framework. This article is rather attempt to explain fundamentals behind expression templates as applied in Spirit framework.