Re: priority of execution

[Ray Andrews <rayandrews@xxxxxxxxxxx>]

On 2022-10-25 09:08, Peter Stephenson wrote:
> The different categories known to whence, from looking at the source,
> are aliases, reserved words, shell functions, builtins, and binaries
> in the file system (in the case of whence, those found via $PATH).
In that order?
> Autoloadable functions are a special category of function

But whence reports them specially:

$ whence -v zmv
zmv is an autoload shell function

... I'm just trying to extract as much information as whence can supply.

> --- the
> difference only comes into play once the shell has decided it's
> looking for a shell function, so it's hidden from top-level
> execution.
So when it comes to precedence would a 'normal' function and an 
autoload, if they shared the ... Ah! the can't share the same name 
because if you define a function with the same name as an autoload the 
former is ... how to say it ... overruled.  So that's no issue. But 
whence will report the difference very politely.
> The same goes for shell scripts as a special category of
> binaries found in the file system.  The shell sees the script is
> a binary in the path and tries to execute it just like anything
> else marked as executable.  Typically the OS knows how to deal
> specially with scripts, though the shell has this knowledge as
> a fallback.

So it would be first found, first executed?  Or will there be precedence 
rules?

> > $ whence -av declare
> > declare is a reserved word
> > declare is a shell builtin
> That second case is rather special; you wouldn't encounter it very
> often.  But people moan horribly if we break their special cases.

Too heavy for me, that's stuff than only happens in the engine room.

But I'd still say that this should be the output:

$ whence -v declare

declare is a shell builtin

... it might be naive but that's what would seem to be the ... hmmm ... 
if 'reserved word' really does have precedence then maybe that's what's 
got to show, and the fact that I want to see 'shell builtin' is too bad 
for me.  It's intuitive that whence is looking for commands of some 
sort, but maybe strictness is more important.  Nothing is simple.