Re: [bug-gawk] GAWK feature suggestions

[address@hidden]

Hi David,

Thanks for your reply. I started using awk with an SCO Xenix setup in 1988. 
We’re neither of us getting any younger ☺

By “multi-dimensional array”, I meant the gawk extension, using the 
array[i][j], notation, without the need for SUBSEP. This makes managing 
multi-dimensional arrays easier, but my main point was to have the ability to 
return arrays from a function. For me, in general this seems cleaner and more 
intuitive.

This is of course a personal preference, but in my opinion the array isn’t a 
parameter, it’s the result, so it shouldn’t have to be included in the 
parameters passed into the function.

As a simple example, let’s suppose I want to write a function that returns the 
quotient and remainder for Euclidean division :

This
function euclid(n, d,       ret) {
    ret[“q”] = int(n, d)
    ret[“r”] = n % d
    return ret
}
and
arr = euclid(1023, 17)

seems better than
function euclid(n, d, ret) {
    ret[“q”] = int(n, d)
    ret[“r”] = n % d
}
and
euclid(1023, 17, arr)


Any thoughts on my other suggestions ?

Kind regards,
Chris



From: david kerns [mailto:address@hidden]
Sent: 28 August 2019 14:57
To: Newell, Christopher (IE Dundrum)
Cc: address@hidden; address@hidden
Subject: Re: [bug-gawk] GAWK feature suggestions


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I've been using awk since ~ 1986 (RIP AT&T Bell Labs) .. but I too love the 
gawk extensions...
However, multi-dimensional arrays is NOT one of them. And while you can't 
return an array from a function, you can pass one in and re-initialize it.

$ cat md
func mf(a,i) {
  for (i in a) delete a[i];
  a[1,1] = 2;
  a[1,2] = 3;
  a[2,2] = 4;
}
BEGIN {
  b[1] = primer;
  mf(b);
  for (i in b) {
     n = split(i, idx, SUBSEP);
     if (n == 2) {
       printf("1: %d 2: %d -> %d\n", idx[1], idx[2], b[idx[1],idx[2]]);
     } else {
       print "unexpected index", i;
     }
  }
}
$ awk -version
awk version 20070501
$ awk -f md
1: 1 2: 1 -> 2
1: 1 2: 2 -> 3
1: 2 2: 2 -> 4
$ gawk --version | head -2
GNU Awk 4.2.0, API: 2.0
Copyright (C) 1989, 1991-2017 Free Software Foundation.
$ gawk -f md
1: 1 2: 1 -> 2
1: 1 2: 2 -> 3
1: 2 2: 2 -> 4

On Wed, Aug 28, 2019 at 6:29 AM address@hidden<mailto:address@hidden> 
<address@hidden<mailto:address@hidden>> wrote:
Hi,

I've been using awk and now gawk on and off for a number of years, since the 
late 1980s to be exact, usually for one-liners or small scripts.

Gawk is a major step up from awk, in particular multi-dimensional arrays and 
the SYMTAB array which I'm using extensively. The new namespace feature is a 
god-send too as I'm working with multiple library files and avoiding name 
clashes was getting quite complex. I'm now working on developing a fairly major 
project (several thousand lines of code so far), and in the course of working 
on this I've come across a few features that I would find really useful, which 
I'd like to suggest for future consideration.

So, in no particular order :

-        Possibility to return an array from a function. This has probably 
already been requested, it would avoid the need for a number of public arrays.

-        Nested functions. Not particularly important, but useful to hide 
helper functions from public view

-        Block comments. Probably already suggested.

-        And most useful for me when testing function libraries: ignore all 
rules if a file is called via @include (or maybe a @ignore-rules directive, as 
there may be rare cases where you want to include rules in an @include file). 
This would allow to combine test code and functions in a single file.

Thanks to all who've contributed to this project over the years, keep up the 
good work.

Kind regards,
Chris Newell

Chris Newell
Application Support Engineer
BAE Systems Applied Intelligence
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