Re^7: AI in the workplace (... in the Monastery)

(a longer meditation)

Many search engines nowadays come up with an AI generated preface summing up the results before showing the hits.

Of course we are not a search engine nor a code writing service, but a community tool helping others becoming better programmers.

I initially said it's a horrible idea, bc the way harangzsolt is proposing would lead to too many problems, (apart from implementation problems)

But let's try:

So I took the liberty to feed a current question into Duck.AI using ChatGPT 4o

> Why is "any" slow in this case?

Answer:

It reads interesting - like always with AI - but requires deeper analysis for disguised non-sense. (Disclaimer: I didn't)

Definitely nothing an amateur could handle. But an expert can draw inspiration from this.

For instance I was intrigued by the idea of $1 being slow because it can't optimize numification.(point 2)

So I asked for clarification, guessing this being about dual-values.

> why is numification of read-only slower

Answer:

## 🧩 Understanding Numification of Read-Only Variables in Perl

Numification refers to the process of converting a string or other data type into a numeric value in Perl. When dealing with read-only variables like `$1` and `$2`, which are special variables that hold the results of a regex match, the performance implications of numification can be significant. Here’s why:

### 🔍 Key Reasons for Slower Numification of Read-Only Variables

#### 1. *Repeated Conversion Overhead*

When you use `$1` and `$2` directly in comparisons, Perl must convert these values to numeric form each time they are accessed. This involves:

**Checking the Type**: Perl first checks the type of the variable to determine if it needs to be converted.
**Performing the Conversion**: If the variable is not already in numeric form, Perl performs the conversion, which adds overhead.

This repeated checking and conversion can slow down performance, especially in tight loops where comparisons are made frequently.

#### 2. *Lack of Caching*

Unlike lexically scoped variables (like `$c` and `$r` in your "ugly_cr" method), which can be assigned once and accessed multiple times without further conversion, read-only variables do not benefit from caching. Each access to `$1` and `$2` results in a fresh conversion, leading to inefficiencies.

#### 3. *Context Sensitivity*

Perl is context-sensitive, meaning that the same variable can behave differently depending on how it is used (numeric vs. string context). When using `$1` and `$2`, Perl must always be aware of the context in which they are being used, adding additional overhead to the process.

### 🧠 Conclusion

In summary, the numification of read-only variables like `$1` and `$2` is slower due to:

The *repeated overhead* of type checking and conversion.
The *lack of caching* benefits that come with assigning values to lexicals.
The *context sensitivity* of Perl, which requires additional processing.

By assigning these values to lexicals, you can avoid the repeated numification, leading to improved performance in your code. This is why methods that use lexicals tend to perform better in scenarios involving frequent comparisons.

Again interesting, but I'm not convinced. The claim (Point 2) that "read-only variables do not benefit from caching" can't be reproduced. Because $1 is indeed also a dual-value.

:~$ perl -MDevel::Peek -E'"42"=~/(\d+)/; say $1; Dump $1; $a=$1+1; Dum
+p $1'
42
SV = PVMG(0x5d60b28468a0) at 0x5d60b2868a50
  REFCNT = 1
  FLAGS = (GMG,SMG,POK,pPOK)
  IV = 0
  NV = 0
  PV = 0x5d60b283f5f0 "42"\0
  CUR = 2
  LEN = 16
  MAGIC = 0x5d60b286f0e0
    MG_VIRTUAL = &PL_vtbl_sv
    MG_TYPE = PERL_MAGIC_sv(\0)
    MG_OBJ = 0x5d60b2868a38
    MG_LEN = 1
SV = PVMG(0x5d60b28468a0) at 0x5d60b2868a50
  REFCNT = 1
  FLAGS = (GMG,SMG,IOK,POK,pIOK,pPOK)
  IV = 42                                             #<--- Caching
  NV = 0
  PV = 0x5d60b283f5f0 "42"\0
  CUR = 2
  LEN = 16
  MAGIC = 0x5d60b286f0e0
    MG_VIRTUAL = &PL_vtbl_sv
    MG_TYPE = PERL_MAGIC_sv(\0)
    MG_OBJ = 0x5d60b2868a38
    MG_LEN = 1
:~$
[download]

Probably another caching mechanism is meant??? Nope ChatGPT confirms that dual-values are meant:

MY CONCLUSION (so far):

LLM output can inspire good ideas in our context but require an expert to deal with. The wordy answers are often full of hidden pitfalls and contrary to a human being the LLM doesn't even try to cross-check what it (hear-)says.

Is there is a meaningful way to integrate an LLM into our question/answer process?
I don't know. But using normal questions as prompts is obviously a horrible idea.
But can we stop amateurs posting AI generated texts here, in order to pose as an expert?
Hardly. This is most likely already happening, at least with AnoMonk posts.
Will we be forced to increasingly deal with AI here?
Very likely, at least in requiring us to increase the quality standards of answers or demanding POCs.

Cheers Rolf
_{(addicted to the Perl Programming Language :)

see Wikisyntax for the Monastery}

IN HINDSIGHT

This should probably better be a meditation in it's own thread.

Disclaimer

This test is far from methodical. I ran this conversation with Duck.AI after the original question already got many answers. Hence the replies might have already been training and influencing the LLM.

Comment on Re^7: AI in the workplace (... in the Monastery) Select or Download Code

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Re^8: AI in the workplace (... in the Monastery) by ikegami (Patriarch) on Jul 28, 2025 at 18:30 UTC
The performance drop in "ugly" compared to "ugly_cr" can be attributed to the fact that `$1` and `$2` are read-only and are re-evaluated each time they are used in a comparison. This means that every time you check `$1` or `$2`, Perl has to numify them again, which adds overhead. In contrast, "ugly_cr" assigns these values to lexicals, which are faster to access. Perl does have to numify them again, but not for the reason given. `no warnings qw( void ); use Devel::Peek qw( Dump ); "a" =~ /(.)/s or die; 0+$1; # Fetch and numify Dump($1); my $x = $1; # Fetch Dump($1);` [download] `... FLAGS = (GMG,SMG,POK,pIOK,pNOK,pPOK) ... FLAGS = (GMG,SMG,POK,pPOK) ...` [download] As you can see, `$1` gets numified. But every time you read from it, it gets repopulated since it's a magic variable. This wipes the previous values. In the context of analyzing the AI's answer, it's worth noting that I missed the repeated numification in my answer. I stopped too soon. The "any_cr" method is slower than "any" because of the additional overhead of assigning values to lexicals before performing the checks. That can't be true since `ugly_cr` is way faster than `ugly`. The actual culprit is the overhead from the addition of capturing. In the context of analyzing the AI's answer, it's worth noting the response is self-contradicting. According to the AI, assigning to the lexicals makes the cr version faster by only doing numification once, but it makes the cr version slower because of the addition of an assignment.	[reply] [d/l] [select]
Re^9: AI in the workplace (... in the Monastery) by LanX (Saint) on Jul 28, 2025 at 20:20 UTC
In the example I've shown, the IV slot is set after the first numification. In fact it doesn't look to me like repeated numification (or magic fetching) was happening. `:~$ perl -MDevel::Peek -E'"42"=~/(\d+)/; say $1; Dump $1; $a=$1+1; Dum +p $1; say $1; Dump $1' 2>&1 \|grep IV IV = 0 IV = 42 IV = 42 :~$` [download] Edit hm ... probably the IV values don't matter if the appropriate `I` flags aren't set. `~$ perl -MDevel::Peek -E'"42"=~/(\d+)/; say $1; Dump $1; $a=$1+1; Dump + $1; say $1; Dump $1' 2>&1 \|grep FLAGS FLAGS = (GMG,SMG,POK,pPOK) FLAGS = (GMG,SMG,IOK,POK,pIOK,pPOK) FLAGS = (GMG,SMG,POK,pPOK)` [download] Cheers Rolf _{(addicted to the Perl Programming Language :) see Wikisyntax for the Monastery}	[reply] [d/l] [select]
Re^10: AI in the workplace (... in the Monastery) by ikegami (Patriarch) on Jul 28, 2025 at 20:25 UTC
Correct, you should be looking at the flags.	[reply]

MY CONCLUSION (so far):

IN HINDSIGHT

Disclaimer

Edit