This is the third in a series about the new features in the recently released alpha version of Tcl 8.7. This post deals with the enhancements in Tcl 8.7 related to arrays.(read more ...)
This is the second in a series of posts about the new features in the recently released alpha version of Tcl 8.7. This post deals with the enhancements to list processing.(read more ...)
The long-awaited alpha release of Tcl 8.7 calls for a series of posts summarizing the enhancements in this release. The first in this series is about the new
-command option to the regsub command. I have wished for this feature many times and now thanks to DKF it is now available in Tcl.
Windows can send notifications to applications advising them of changes in device configuration. The most common manifestation of this is file managers popping up a window showing the contents of a USB pen drive when it is plugged in and automatically closing it when the drive is ejected. This post describes how to hook into these notifications within a Tcl application.(read more ...)
The latest post in our series on promises introduced the
await commands. That post focused on how these commands further simplify asynchronous programming with promises. This post takes a different angle on their utility - how they can be used to speed up sequential code with minimal effort.
This blog post is adapted from my book The Tcl Programming Language.
What is metaprogramming? Roughly speaking, metaprogramming involves writing a program that in turn writes a program to do the desired task. In some cases metaprogramming makes for simpler or more succinct code while in others it optimizes performance by generating specialized code at runtime. Tcl lends itself naturally to this style of programming. This article illustrates one such use.(read more)
Having gone through several introductory posts covering background material such as CSP's, contexts, key containers and methods of key generation, we are now ready to delve into the actual cryptographic operations that use symmetric algorithms in detail.(read more)
In a prior post, I described the use of Windows CryptoAPI to compute message digests and message authentication codes which ensure integrity of messages. We now move on to the use of symmetric algorithms in cryptography, which can be used for both message confidentiality and integrity. Asymmetric algorithms will be covered in future posts. Refer to the introductory post in this series for the difference between the two.(read more)
In my prior post, I introduced several abstractions — Cryptographic Service Providers, cryptographic contexts and key containers — that are part of Windows CryptoAPI and promised to look at cryptographic keys next.
Well, I changed my mind, figuring it might be better to first talk about simpler operations that do not require the use of keys at all. This post thus describes the generation of hashes, message digests and message integrity codes using Windows CryptoAPI and TWAPI.(read more)
This is the second in a series of posts on the use of cryptography on Windows. The previous blog post introduced the basic concepts related to cryptography. Here we delve into how those concepts are implemented in Windows at a system or architectural level and of course, how one accesses them from Tcl. This will lay the ground for discussing the actual cryptographic operations in future posts.(read more)