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Re: Resources to learn common lisp?

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On 2026-08-14 17:15, David Brown wrote:
>> [...]
> 
> While I think it is reasonable to learn the ideas of regular 
> expressions, and a little of the simplest and most common types, I don't 
> think it is practical for anyone to learn to "master" regexs. 

Mastering them comes from alone once you make an informed start
(and not pause in stasis).

(To me it appears like mathematics in real life; the majority of
folks in my country regularly says things like "it's confusing",
"it's complicated", "we don't expect that understand that (as I
don't)", "it's normal that one cannot understand that", "math is
just difficult", and so on. Children get systematically repelled
to listening and learning maths, they quit at the first obstacle
they encounter. - I'm recognizing the same discussion mechanics
in our IT domain with Regexps. - Here in this thread that they'd
"attract mistakes".)

As with many things we start with "the simplest and most common
types" (as you formulated it). But there's no reason to stop if
you want to get more productive.

(Reminds me how some folks using the Vi editor; and completely
missing the power it evolves when getting past 'i' and 'Esc'.
If you are modest and feel comfortable with that it's okay, as
it's okay if you use only primitive elements of Regexps. But if
you use it for editing power you should continue learn not only
the concept but also the non-trivialities, and you'll observe
that your skill will not get twice as fast but magnitudes. That
is not much different from other areas; including Regexps.)

> For one thing, there are a dozen different variations.

This is true; certainly for different applications. But so what?
Are you saying that you have no problems switching to other tools
but the differences between the advanced regexp implementations
is an issue? If that is so for you, fair enough.

(BTW, for me it's at most only half a dozen that I occasionally
use.)

But at least we have a couple _common classes_ to distinguish.
POSIX standardized BRE and ERE or the pleasing PCRE (from Perl),
are the historically widely spread ones.

I observe that especially the basics (that you focused on above)
are widely the same. The details and differences come when you get
into it; in one tool the + meta-symbol isn't supported at all, in
another it needs an escape \+ . - Yes, that's what mastering may
mean, to know that. But you can also just try, in case you didn't
want to read the manual first. - Myself, in case of doubt, I just
try it, and I test my regexps, as I test my other program code.

> And while a lot of 
> people find them useful on occasion, few need them regularly enough to 
> be confident in writing them (or reading them, which can often be harder).

Well, I cannot speak for "lot of people"; I can speak for myself,
friends with IT (or CS) background, and the people from the areas
I worked in during the past decades. - Where Regexps were sensible
to use those people just used them.

I mentioned in my previous post already that they may be "appearing
cryptic to the uninitiated". So I'd like to emphasize again that at
least some engagement is necessary to learn them. Otherwise you're
completely lost of course.

(Imagining a similar uninformed approach to some uninitiated "C"
programmers; and things like *p--, or C's declaration syntax.
"Here are a set of symbols, now go compose your C-programs!".
The Regexps are compared to the C-language like a piece of cake!)

At some (early point) of learning writing them is okay but reading
third-party Regexps may be a problem; in complex cases. - That is
correct. But no one prevents you from *commenting* complex Regexps
where they appear (as you should comment complex code). In case of
undocumented code decomposition helps; this method is as well not
restricted to Regexps. And some tools that support Regexps allow
composing them (like a BNF specification; very readable, been there
done that).

(If I imagine the bulk of code I'd have to write to replace a Regexp
I'm shuddering, and I'm pity for those who have been repelled from
learning them by the spread commonplace myths and FUD.)

> 
> Fortunately, there is no good reason for mastering them unless you 
> really do have a lot of use of them. 

It's a personal choice whether you want to master them or just know
the concepts deeply enough to judge its application value. (Or if
you decide to abstain in advance, because they "attract mistakes"
or are "too difficult", or there are "too many subtle differences"
to even start using them.)

Yes. If you have no reason to use them you not only have no need to
master them but also not use them in the first place. - It's just a
pity if one cannot recognize where their applications would benefit.

> There are countless online 
> "generator" sites for them, as well as for testing them or interpreting 
> existing ones (when you are faced with the "fun" of debugging someone 
> else's regex).

Well, this I consider a counterproductive statement, but certainly
in the company of other "don't learn them" statements quoted above.

In this vein let me add to let an AI formulate (and analyze) your
Regexps. </sarcasm>

> 
> Like most things, they can be a useful tool, but some people get overly 
> smart about them and produce monstrosities that no one understands and 
> are impossible to debug or maintain.  Keep them reasonable, and they are 
> fine.

I've seen monstrosities of Regexps as I've seen monstrosities of "C"
(or other) code. The problem there were always the programmers, not
"C", not Regexps.

What are the alternatives to Regexps (or Regexp-monstrosities)?

If you can answer that question the "problems" vanish into thin air.

Janis

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Re: Resources to learn common lisp? Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-07-31 07:17 +0800
  Re: Resources to learn common lisp? Anton Antimo <anton@safunu.org> - 2026-07-31 12:21 -0300
    Re: Resources to learn common lisp? Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-01 01:48 +0800
      Re: Resources to learn common lisp? Anton Antimo <anton@safunu.org> - 2026-08-05 13:13 -0300
        Re: Resources to learn common lisp? Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-08-05 21:48 +0000
          Re: Resources to learn common lisp? David Brown <david.brown@hesbynett.no> - 2026-08-06 09:05 +0200
          Manipulating C code at the AST level, in C (was: Re: Resources to learn common lisp?) Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-09 05:33 +0800
            Re: Manipulating C code at the AST level, in C Paul Rubin <no.email@nospam.invalid> - 2026-08-10 01:11 -0700
              Re: Manipulating C code at the AST level, in C "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-08-10 13:10 -0700
            Re: Manipulating C code at the AST level, in C Anton Antimo <anton@safunu.org> - 2026-08-10 17:41 -0300
              Re: Manipulating C code at the AST level, in C Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-08-10 23:53 +0000
                Re: Manipulating C code at the AST level, in C scott@slp53.sl.home (Scott Lurndal) - 2026-08-11 14:29 +0000
                kqueues and port_create() (was: Re: Manipulating C code at the AST level, in C) Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-12 07:51 +0800
                Re: kqueues and port_create() Paul Rubin <no.email@nospam.invalid> - 2026-08-11 20:59 -0700
                Re: kqueues and port_create() Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-12 13:07 +0800
                Re: kqueues and port_create() Alan Bawden <alan@csail.mit.edu> - 2026-08-12 03:23 -0400
                Re: kqueues and port_create() Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-08-12 07:50 +0000
                Re: kqueues and port_create() Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-13 11:33 +0800
                Re: kqueues and port_create() Paul Rubin <no.email@nospam.invalid> - 2026-08-12 02:22 -0700
                Re: kqueues and port_create() Alan Bawden <alan@csail.mit.edu> - 2026-08-12 20:55 -0400
                Re: kqueues and port_create() Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-13 11:37 +0800
                Re: kqueues and port_create() "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-08-12 12:59 -0700
                Re: Manipulating C code at the AST level, in C Nuno Silva <nunojsilva@invalid.invalid> - 2026-08-14 12:26 +0100
              D.N.S. in Common Lisp (was: Re: Manipulating C code at the AST level, in C) Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-12 07:59 +0800
                Re: D.N.S. in Common Lisp Anton Antimo <anton@safunu.org> - 2026-08-12 09:01 -0300
        Re: Resources to learn common lisp? Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-12 13:18 +0800
          Re: Resources to learn common lisp? bixbox <noreply@example.invalid> - 2026-08-12 10:16 +0200
            Re: Resources to learn common lisp? Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-08-13 02:18 +0000
              Re: Resources to learn common lisp? Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-08-13 04:56 +0200
                Re: Resources to learn common lisp? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-08-12 21:13 -0700
                Re: Resources to learn common lisp? Anton Antimo <anton@safunu.org> - 2026-08-13 12:25 -0300
                Re: Resources to learn common lisp? Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-08-13 19:01 +0200
                Re: Resources to learn common lisp? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-08-13 14:50 -0700
                Re: Resources to learn common lisp? Anton Antimo <anton@safunu.org> - 2026-08-14 08:27 -0300
                Re: Resources to learn common lisp? Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-08-15 03:18 +0000
                Re: Resources to learn common lisp? Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-08-14 02:47 +0000
                Re: Resources to learn common lisp? cross@spitfire.i.gajendra.net (Dan Cross) - 2026-08-14 12:20 +0000
                Re: Resources to learn common lisp? Anton Antimo <anton@safunu.org> - 2026-08-16 15:37 -0300
                Re: Resources to learn common lisp? cross@spitfire.i.gajendra.net (Dan Cross) - 2026-08-14 12:17 +0000
                Re: Resources to learn common lisp? Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-08-14 16:31 +0200
              Re: Resources to learn common lisp? Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-13 11:29 +0800
              Re: Resources to learn common lisp? Michael S <already5chosen@yahoo.com> - 2026-08-14 15:30 +0300
                Re: Resources to learn common lisp? Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-08-14 16:45 +0200
                Re: Resources to learn common lisp? David Brown <david.brown@hesbynett.no> - 2026-08-14 17:15 +0200
                Re: Resources to learn common lisp? Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-08-14 19:51 +0200
                Re: Resources to learn common lisp? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-08-14 12:05 -0700
    Re: Resources to learn common lisp? Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-07-31 22:46 +0000
      Re: Resources to learn common lisp? Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-01 07:38 +0800
        Re: Resources to learn common lisp? steve g <Sgonedes1977@gmail.com> - 2026-08-04 22:26 -0400
          Making a C compiler in Rust (was: Re: Resources to learn common lisp?) Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-21 13:06 +0800
            Re: Making a C compiler in Rust (was: Re: Resources to learn common lisp?) "Kerr-Mudd, John" <admin@127.0.0.1> - 2026-08-21 11:34 +0100
            Re: Making a C compiler in Rust Paul Rubin <no.email@nospam.invalid> - 2026-08-21 15:03 -0700
      Re: Resources to learn common lisp? tfb <tfb@work.it.out> - 2026-08-01 09:08 +0000
        Re: Resources to learn common lisp? Paul <nospam@needed.invalid> - 2026-08-01 07:49 -0400
          Re: Resources to learn common lisp? Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-08-01 23:37 +0000
            Re: Resources to learn common lisp? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-08-01 16:54 -0700
          Re: Resources to learn common lisp? tfb <tfb@work.it.out> - 2026-08-02 07:39 +0000
        Re: Resources to learn common lisp? steve g <Sgonedes1977@gmail.com> - 2026-08-04 22:39 -0400
    Re: Resources to learn common lisp? steve g <Sgonedes1977@gmail.com> - 2026-07-31 23:59 -0400
      Re: Resources to learn common lisp? Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-01 16:12 +0800
        Re: Resources to learn common lisp? steve g <Sgonedes1977@gmail.com> - 2026-08-04 22:50 -0400
          Re: Resources to learn common lisp? Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-05 19:02 +0800
            Re: Resources to learn common lisp? steve g <Sgonedes1977@gmail.com> - 2026-08-06 19:36 -0400
              Re: Resources to learn common lisp? Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-08-09 02:11 +0800
                Re: Resources to learn common lisp? steve g <Sgonedes1977@gmail.com> - 2026-08-09 18:49 -0400
                Re: Resources to learn common lisp? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-08-10 13:08 -0700

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