I'm certainly novice in C, but as I was reading, I wondered about this
{"get",getCommand,2,"r",0,NULL,1,1,1,0,0},
"The fourth field, set to "r", is specifying that the
command is read only and doesn’t modify any keys’ value
or state. There are a whole bunch of one letter flags
that you can specify in this string that are explained
in detail in the nearby block comment. The field
following this string should always be set to zero, and
will be computed later. It’s simply a bitmask
representation of the information implied by the string."
Why would you opt for this, when you could specify some constants and bitwise or them together? Isn't that a more common thing to do, than to calculate a bitwise flags at run time?
I'm sure there's a good reason, but this style seems strange to me.
Maybe redis makes use of the string later? but I can't help but feel it should build the string based on the flags, rather than build the flags based on the string.
In defence of the technique, the command table is quite succinct and arguably more readable at a glance than if there were a bunch of constants |ed together. I have no idea whether this was the original motivation though.
ACTUALLY! It reminds me of a technique Bisqwit used when he made his emulator. He used strings to define the behavior of certain instructions, the strings were actually interpreted at compile time. Though I think this is a C++ specific trick.
I'm sure there's a good reason, but this style seems strange to me.
Maybe redis makes use of the string later? but I can't help but feel it should build the string based on the flags, rather than build the flags based on the string.