I see what you're saying, but I'm still not understanding how it becomes a generalizable rule for real-world code without adding a lot of exceptions to the rule, or doing something over-engineered like parsing into an increasingly specific number of customized structs/objects in different branches of the code.
Just to be clear, I actually really like the idea of parsing the input into a structure. I do the same thing in a lot of my code. I just don't see how it removes the need to also perform validation in many (maybe most) cases as soon as one gets beyond contrived examples.
The empty array example seems to be a can of worms. Maybe it's specific to the kinds of software that I've written, but in most of the cases I can think of, I wouldn't know if it was OK for a particular array within a structure to be empty until after the code had made some other determinations and branched based on them. And yet, like the example, once it got to the real handling for that case, it would be a problem if the array were empty. So the image in my mind is many layers of parsing that are much more complicated and confusing to read than validating the length of the array.
I still think it's a great idea for a lot of things, just that the "parse, don't validate" name seems really misleading. I might go with something like "parse first, validate where necessary".
Just to be clear, I actually really like the idea of parsing the input into a structure. I do the same thing in a lot of my code. I just don't see how it removes the need to also perform validation in many (maybe most) cases as soon as one gets beyond contrived examples.
The empty array example seems to be a can of worms. Maybe it's specific to the kinds of software that I've written, but in most of the cases I can think of, I wouldn't know if it was OK for a particular array within a structure to be empty until after the code had made some other determinations and branched based on them. And yet, like the example, once it got to the real handling for that case, it would be a problem if the array were empty. So the image in my mind is many layers of parsing that are much more complicated and confusing to read than validating the length of the array.
I still think it's a great idea for a lot of things, just that the "parse, don't validate" name seems really misleading. I might go with something like "parse first, validate where necessary".