- Elegant code is not only correct but visibly, transparently correct. It does not merely communicate an algorithm to a computer, but also conveys insight and assurance to the mind of a human that reads it.
- Emacs Lisp libraries are discoverable but not transparent. Which means it is easy to modify a certain part but difficult to comprehend whole system. Linux kernel on the otherhand is very transparent but not easily discoverable since it is easy to understand its organization but hard to modify a certain piece of the code.
- “Discoverability is about reducing barriers to entry; transparency is about reducing the cost of living in the code”.
- fetchmail -v outputs detailed protocol exhanges (IMAP, SMTP, or POP3). And thus makes this discoverable.
- GCC is transparent.
- GCC is organized as a sequence of processing stages knit together by a driver program. The stages are: preprocessor, parser, code generator, assembler, and linker.
- The first three stages are all textual and thus easy to debug.
- Transparency in UI code is when the UI does not hide too much from the user. For example, kmail shows the SMTP transactions in its status bar. Thus, can easily be debugged if there are problems or failures. It is not loud thus does not bother simple users.
- Terminfo uses the file system itself as a simple hierarchical database. This is a superb bit of constructive laziness, obeying the Rule of Economy and the Rule of Transparency. It means that all the ordinary tools for navigating, examining and modifying the file system can be used to navigate, examine, and modify the terminfo database;
- If you want transparent code, the most effective route is simply not to layer too much abstraction over what you are manipulating with the code.
- Static depth of a procedural-call hierarchy should really not be more than four i.e. to accomplish a certain procedure if the function you call is more than four deep, might need to re-think the design.
- If there is a single global structure that reflects system state, make sure it is easily explorable.
- For the reasons stated above, client authentication is rarely used with TLS. A common technique is to use TLS to authenticate the server to the client and to establish a private channel, and for the client to authenticate to the server using some other means - for example, a username and password using HTTP basic or digest authentication.
- Some programs such as sng take a non-transparent format png and
convert it back and forth to a transparent one. This is very
important in debugging.
- With sng, for example, you can convert png to text, run some scripts through it to add annotations and then convert it back.
- If the binary object is dynamically generated or very large, then it may not be practical or possible to capture all the state with a textualizer. In that case, the equivalent task is to write a browser. This is used for visualizing databases.
- Unix programmers learn a tendency to scrap and rebuild rather than patching grubby code.
- One very important practice is an application of the Rule of Clarity: choosing simple algorithms. In Chapter 1 we quoted Ken Thompson: When in doubt, use brute force.
- It is also important to include hacker guides. Helpful docs on helping discoverablity of the code.