Not sure if this is what antirez had in mind, but when I'm working on stuff, I whiteboard (if I'm at home--and who isn't these days) or write in a notebook.
First thing I figure out is how I want to interact with a thing. Whether that's a program or a class or a function. How do I want to call it? What parameters do I want to pass? What do I want it to return? How do I want to use what it returns? So, basically, write the interface first.
If I'm building something with multiple parts rather than a single class or function, I'll map out how these things all work together. A loose graph of interactions. Invoke A and have it return X; invoke B and pass X to it and it returns Y; etc.
Then I'll consider failure modes and think about what should happen if something doesn't work out quite right. Is it possible to route failures to a centralized cluster of error handlers so I don't have to implement error handling at every level?
Finally, I'll think about whether I can map behaviors to defined data structures instead of controlling flow with if/else patterns.
Once I have all that written down or mapped out, then I'll start implementing from the outside in. Stub the object, methods and return dummy data structures that fit until I have a complete system that's interacting the way I want. Then I go in and implement the actual functionality I need.
The last part--implementing functionality--often implies modifications to my initial thought process. But it's easier to understand what those changes affect if you've already mapped your design. So you might think B can produce Y with I parameter. Maybe it turns out you can't. So now you need to add a new param. Where is that going to come from? Well, you don't have to invent that out of nowhere because you've already mapped out what is happening. You know that you need to either add another node to the call graph or change the return value somewhere else.
By the end of the process, you have a working program, and you've also done a lot of your documentation work as well.
Again, I have no idea if this is what anyone else is talking about here. But this is how I personally work. It annoys the hell out of some people. But it works for me and helps me create sane software with interfaces people can remember over time.
First thing I figure out is how I want to interact with a thing. Whether that's a program or a class or a function. How do I want to call it? What parameters do I want to pass? What do I want it to return? How do I want to use what it returns? So, basically, write the interface first.
If I'm building something with multiple parts rather than a single class or function, I'll map out how these things all work together. A loose graph of interactions. Invoke A and have it return X; invoke B and pass X to it and it returns Y; etc.
Then I'll consider failure modes and think about what should happen if something doesn't work out quite right. Is it possible to route failures to a centralized cluster of error handlers so I don't have to implement error handling at every level?
Finally, I'll think about whether I can map behaviors to defined data structures instead of controlling flow with if/else patterns.
Once I have all that written down or mapped out, then I'll start implementing from the outside in. Stub the object, methods and return dummy data structures that fit until I have a complete system that's interacting the way I want. Then I go in and implement the actual functionality I need.
The last part--implementing functionality--often implies modifications to my initial thought process. But it's easier to understand what those changes affect if you've already mapped your design. So you might think B can produce Y with I parameter. Maybe it turns out you can't. So now you need to add a new param. Where is that going to come from? Well, you don't have to invent that out of nowhere because you've already mapped out what is happening. You know that you need to either add another node to the call graph or change the return value somewhere else.
By the end of the process, you have a working program, and you've also done a lot of your documentation work as well.
Again, I have no idea if this is what anyone else is talking about here. But this is how I personally work. It annoys the hell out of some people. But it works for me and helps me create sane software with interfaces people can remember over time.