[TUHS] [TULSA] Re: python

Alejandro Colomar alx.manpages at gmail.com
Fri Aug 4 03:29:00 AEST 2023

On 2023-08-03 18:57, Phil Budne wrote:
> On the subject of "no printf", there is not one, not two, but THREE
> ways to format strings, easily compounded with print:
> 	print("%s %s" % ("hello", "world"))
> 	print("{1} {two}".format("hello", two="world"))
> 	print(f"{greeting} {populace}")
> I'm pretty sure the last method (which initially made me vomit, due to
> violating my hardwired ideas about complicating the lexer, as if it
> can even be thought of as a separate layer), BUT I Seem To Recall that
> it allows a class to implement a formatting method, which may (or may
> not) work for complex numbers.

Actually, there's no need to move away from printf(3) for customization.
glibc provides register_printf_specifier(3), register_printf_modifier(3),
and register_printf_modifier(3), with which you can register %S for
printing your very nice struct.  You can even register modifiers, such as
%vS for printing your structure in a different manner.

Of course, those APIs are not portable, but that's a matter of porting
them; you don't need to invent a completely new formatted print variant
just to do that.

How does one even specify the equivalent of "%+'0#8.5f" in the new {}

Of course, there may be reasons to move away from printf(3): C++ seems
to have a faster thing with std:format (or so they claim; I didn't try
it).  But if speed is not a problem, I'd keep the good ol' syntax that
everybody knows.  No need to make everybody learn a "cool" new print
function, that probably won't be as tunable as printf(3) is.

Another thing is type safety.  printf(3) is actually type-safe.  At least
as long as you use powerful compilers that can diagnose misuses of
printf-like APIs.  GCC provides [[gnu::format()]] for a reason.  And if
you customize printf with your own formats, Clang has tools for checking
those too.

> Type "hinting" has been mentioned: again, it's almost like a whole new
> version of the language.  You need to pick a type checker, and likely
> turn up the knobs to achieve any actual safety, and then deal with the
> fact that not all packages supply hints out of the box.  It kind of
> offers the desert-topping/floor-wax dichotomy: You can easily/quickly
> write small programs with dynamic typing for quick one-offs, AND write
> better armored code for libraries & production code.
> On tabs vs spaces: Python3 forbids mixing them.  Again, fascist, but
> "it's for your own good".
> So yes, Python sucks, but I continue using it, and unlike sendmail
> (which I continue to run, as I have a 200+ line .mc file it would take
> me at LEAST a week to replicate the effects of in another MTA), I
> don't tell people Python is unsuitable at any speed.
> I'd probably happily write Go or Rust, given a situation (existing
> project/program) where its use was inevitable, and I DO have a program
> I think is a good candidate for rewriting in Go, but on the whole,
> it's a useful tool for many kinds of programmers, and in many
> situations, which I think is somewhat remarkable.

I'll go a little step further, and claim that newlines being significant
is another bad decission.  It's one of the things I dislike from
languages, including sh(1).  My scripts end up having a lot of escaped
newlines, because I find the pipe to be more readable and pleasant as

foo \
| bar

rather than

foo |

While I can forgive that in the shell, because interactive mode is as
important as scripts, I can't do the same with Go.  Go is a programming
language, and having newlines be significant is nonsense.  Saving from
typing ;s is a similar excuse that the one python used for saving typing
{}s.  And the consequence is that due to that fascist rule of go, I
can't put the opening brace of a function declaration in a new line; it
must be sticked to the same line as the function declarator.

I never enjoyed Go, and that was the main reason.  In any case, I never
found a need for it.  Most (all?) of what I do can be done with sh(1)
or C.


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