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From: Bart <bc@freeuk.com>
Newsgroups: comp.lang.c
Subject: Re: Command line globber/tokenizer library for C?
Date: Thu, 12 Sep 2024 14:44:03 +0100
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On 12/09/2024 13:20, Janis Papanagnou wrote:
> On 12.09.2024 13:29, Bart wrote:
>> On 12/09/2024 03:22, Bonita Montero wrote:
>>> Am 11.09.2024 um 22:19 schrieb Bart:
>>>
>>>> C++ is a simpler language? You're having a laugh!
>>>
>>> The solutions are simpler because you've a fifth of the code as in C.
>>>
>>> In this case, it actually needed somewhat more code, even if the line
>> count was half.
>>
>> But your solutions are always incomprehensible because they strive for
>> the most advanced features possible.
> 
> I don't know of the other poster's solutions. But a quick browse seems
> to show nothing incomprehensible or anything that should be difficult
> to understand. (YMMV; especially if you're not familiar with C++ then
> I'm sure the code may look like noise to you.)
> 
> In the given context of C and C++ I've always perceived the features
> of C++ to add to comprehensibility of source code where the respective
> C code required writing clumsy code and needed (unnecessary) syntactic
> ballast to implement similar functions and program constructs.
> 
> Your undifferentiated complaint sounds more like someone not willing
> to understand the other concepts or have a reluctance or laziness to
> make yourself familiar with them.

I'm saying it's not necessary to use such advanced features to do some 
trivial parsing.

I've given a C solution below. (To test outside of Windows, remove 
windows.h and set cmdline to any string containing a test input or use a 
local function to get the program's command line as one string.)

It uses no special features. Anybody can understand such code. Anybody 
can port it to another language far more easily than the C++. (Actually 
I wrote it first in my language then ported it to C. I only needed to do 
1- to 0-based conversion.)

There are two things missing compared with the C++ (other than it uses 
UTF8 strings):

* Individual parameters are capped in length (to 1023 chars here). This 
can be solved by determining only the span of the item then working from 
that.

* Handling an unknown number of parameters is not automatic:

For the latter, the example uses a fixed array size. For a dynamic array 
size, call 'strtoargs' with a count of 0 to first determine the number 
of args, then allocate an array and call again to populate it.


-------------------------------------------
#include <windows.h>
#include <stdio.h>
#include <string.h>

int strtoargs(char* cmd, char** dest, int count) {
     enum {ilen=1024};
     char item[ilen];
     int n=0, length, c;
     char *p=cmd, *q, *end=&item[ilen-1];

     while (c=*p++) {
         if (c==' ' || c=='\t')
             continue;
         else if (c=='"') {
             length=0;
             q=item;

             while (c=*p++, c!='"') {
                 if (c==0) {
                     --p;
                     break;
                 } else {
                     if (q<end) *q++ = c;
                 }
             }
             goto store;
         } else {
             length=0;
             q=item;
             --p;

             while (c=*p++, c!=' ' && c!='\t') {
                 if (c==0) {
                     --p;
                     break;
                 } else {
                     if (q<end) *q++ = c;
                 }
             }

store:      *q=0;
             ++n;
             if (n<=count) dest[n-1]=strdup(item);
         }
     }
     return n;
}

int main(void) {
     char* cmdline;
     enum {cap=30};
     char* args[cap];
     int n;

     cmdline = GetCommandLineA();

     n=strtoargs(cmdline, args, cap);

     for (int i=0; i<n; ++i) {
         if (i<cap)
             printf("%d %s\n", i, args[i]);
         else
             printf("%d <overflow>\n", i);
     }
}
-------------------------------------------