[loup-vaillant]

> The concept of instancing is inappropriate to most situations.

At the application level, maybe. At the library level, this can easily kill reuse. See Lex/Yacc. They used to assume a program would only have one parser. Then some naive developer tried to parse both JSON and Lua tables in the same program. Oops.

Another example: standard libraries (including home grown ones). They instantiate everywhere: arrays, hash tables, file descriptors…

[jstimpfle]

Sure, there are exceptions. The other side goes the same way: If it's not a static resource, don't make it a global...

> arrays, hash tables, file descriptors

Most arrays / hashtables in my own use are actually static resources as well...

File descriptors, same thing. They are (or correspond to) a process-wide resource managed by the OS. Most maintainable way is to manage them in a global pool.

[loup-vaillant]

I feel we are not talking about the same thing.

There's no question you instantiate a substantial number of arrays and hash tables in your program. Maybe most of them are global variables, but you still spawn several instances of arrays and hash tables. You do not have a single giant array and a single giant hash table, you have several of them.

Same thing with parsers. Lex/Yacc used to allow only one parser of any kind in the whole program. But if you want to parse 2 languages, you need 2 parsers. Of course, you'd need only one parser per language, and perhaps those two parsers parser's state will be stored in global/static variables. You still instantiated 2 parsers.

At least that's how I understand "instantiation".