Record access value by name

[cd155]

We can access the value in a record by a name. Is the record fundamental the same as the dictionary/hash table? They all access values by name.

[JacquesCarette]

Records can be statically checked (at compile time) to have the right fields. Dictionaries/hash table are dynamic structures that must do this checking at run-time, and this check can fail.

They are only similar at a quite shallow level.

[cd155]

Thanks for explaining it in detail.

This promotes me think about why functions are accessed by both name and distance. I feel almost all programming languages, we call the function by its name and give arguments. Those arguments will be accessed by distance, like the first argument, the second... I just wonder why the function will be used in this way. Does it become a common practice?

[JacquesCarette]

Because we (humans) can do 1-2-3 very easily, but 6-7-8 is already hard, 11-12-13 is awful. (I mean those numbers as positions.) Just because computers can do positional trivially doesn't me we can. Furthermore, having 7 arguments (say) that all are int but all mean something different is a recipe for subtle bugs, as it is too trivial to permute things.

We, humans, work much better with signals of intent, which are easiest done via words, in this case, field names in records.

[cd155]

Should the function don't use positional access at all? Arguments could access by name, right?

[JacquesCarette]

By-name-only would be awkward for 1-argument functions. By position is ok for 1-3 arguments of different types.