Preferred coding style?

makyo · 03-26-2010, 04:06 PM

Hi, gnashley.

Quote:

Originally Posted by gnashley

makyo, what do you use for formatting shell scripts?

I use shtidy, a perl script, that a colleague wrote ... cheers, makyo

Code:

NAME
            shtidy - Re-format Bourne-shell family scripts.

VERSION
            1.0

USAGE
            shtidy [-h] files

REQUIRED ARGUMENTS
            None.

OPTIONS
            -h      Display this help message.

DESCRIPTION
            The shtidy program re-formats a shell script written in the
            Bourne shell dialect.  It does not process csh-family
            scripts.

            The reformatting is quite simple.  Loops and conditionals are
            aligned so that an attractive, yet-space-conserving result is
            obtained.

DIAGNOSTICS
            A warning issued for HERE documents which are in an indented
            section.  The closing string (typically "EOF") will need to
            be out-dented manually.

ta0kira · 03-26-2010, 04:20 PM

Quote:

Originally Posted by MrCode

Ack, I've seen über-concatenated code like that before — although it might have just been to obfuscate it to discourage copying...?

Sometimes combining lines like this makes it more obvious that the two loops are nearly identical, e.g. iteration over a matrix. If we're talking about the sematics and not just the formatting of otherwise-equivalent code, concatenating operations can make a huge difference in speed for e.g. sorting algorithms.

One thing I find useful is formatting that makes scanning for sections easier. Not just annotations, but indentations and particular styles of formatting nested statements so you (I) can quickly find a part based on the "at a glance" appearance of something rather than having to read every comment.

I dislike indenting nested blocks quite a bit because eventually you run out of "rightness" on your screen. On the other hand, I indent nested blocks in scripting because there isn't much nesting and often no delimiters (bash, R, and MATLAB mostly.) For things like C, C++, and Java, I start most procedure lines one tab in and indent the {} by one space per nesting. I have a pretty good eye for how far in a {} is by glancing. Having a definite margin for procedural code makes it easy to find the beginning and end of classes and functions, and if I need to throw in debugging code I don't indent it so I can find it easily later, and so I can grep a source tree to make sure I don't miss any of it.
Kevin Barry

devnull10 · 03-27-2010, 04:12 AM

It depends what I'm doing... If I'm throwing something together quickly for myself then I'll generally do it a bit hacked and whatever I feel like. If I'm doing something for work etc then I'll tend to make it a bit easier to read! I usually always have the first opening brace on the same line as the function.
If declaring more than one temporary variable of the same type I'll usually keep them on the same line however it again depends on how it's being used.

Code:

#include<stdio.h>

int main(int argc, char ** argv) {
  int a, b=0;

  for (a=0;a<100;a++) {
    b+=2;
  }

  printf("This is a simple example - %i, %i\n",a,b);

  return 0;
}

gnashley · 03-27-2010, 12:29 PM

makyo, can you post a copy of shtidy? I don't seem to find it anywhere.

smeezekitty · 03-27-2010, 01:32 PM

Quote:

Originally Posted by devnull10

It depends what I'm doing... If I'm throwing something together quickly for myself then I'll generally do it a bit hacked and whatever I feel like. If I'm doing something for work etc then I'll tend to make it a bit easier to read! I usually always have the first opening brace on the same line as the function.
If declaring more than one temporary variable of the same type I'll usually keep them on the same line however it again depends on how it's being used.

Code:

#include<stdio.h>

int main(int argc, char ** argv) {
  int a, b=0;

  for (a=0;a<100;a++) {
    b+=2;
  }

  printf("This is a simple example - %i, %i\n",a,b);

  return 0;
}

ACK!
Two many blank lines makes the program too spread out to read.

MTK358 · 03-27-2010, 01:41 PM

@smeezekitty

Code:

#include <stdio.h>
#include <stdlib.h>
short filelength(char *f){
    FILE *t = fopen(f, "rb");
    fseek(t, 0, SEEK_END);
    int x = ftell(t);
    fclose(t);
    return x;
}

int main(int argc, char *argv[0xFF])
{
    int f=0,z=0,r=0,p=0,e=0;
    if(argc != 3){printf("Usage: %s <input file> <output file>", argv[0]); return -1;}
    FILE *in = fopen(argv[1], "rb");
    FILE *out_ = fopen(argv[2], "wb");
    if(in == NULL){printf("ERROR: *** CANNOT OPEN FILE: %s", argv[1]); return -1;}
    if(out_ == NULL){printf("ERROR: *** CANNOT OPEN FILE: %s", argv[2]); return -1;}
    char *ind = (char *)malloc(f=  filelength(argv[1]) + 1);
    char *out = (char *)malloc(f+= filelength(argv[2]) + 1);
    z = filelength(argv[1]);
    if(ind == NULL || out == NULL){
        printf("ERROR: *** CANNOT ALLOCATE MEMORY ***: %d KB", f/1024);
        return -1;
    }
    p=0;
    while(!feof(in)){fread(&ind[p++], 1, 1, in);}
    fclose(in);
    p=0;
    for(r=0;r<z;r++){
        if(ind[r] == ind[r+1] || (unsigned char)ind[r] == (unsigned char)0xEA){
        e=0;
        while(ind[r+e] == ind[r]){e++; if(e > 126){break;}}
        //printf("Found run at offset (%d-%d): %d [%d]\n", r, r+e, e, ind[r]);
        out[p] = 0xEA;
        out[p+1] = e;
        out[p+2] = ind[r];
        r+=(e-1);
        p+=3;
        } else {
            out[p] = ind[r];
            p++;
        }
    }
        fwrite(out, 1, p, out_);
return 0;

}

No offence, but do you think this looks good?

For me, at least, it's almost illegible.

smeezekitty · 03-27-2010, 01:50 PM

Quote:

Originally Posted by MTK358

@smeezekitty

Code:

#include <stdio.h>
#include <stdlib.h>
short filelength(char *f){
    FILE *t = fopen(f, "rb");
    fseek(t, 0, SEEK_END);
    int x = ftell(t);
    fclose(t);
    return x;
}

int main(int argc, char *argv[0xFF])
{
    int f=0,z=0,r=0,p=0,e=0;
    if(argc != 3){printf("Usage: %s <input file> <output file>", argv[0]); return -1;}
    FILE *in = fopen(argv[1], "rb");
    FILE *out_ = fopen(argv[2], "wb");
    if(in == NULL){printf("ERROR: *** CANNOT OPEN FILE: %s", argv[1]); return -1;}
    if(out_ == NULL){printf("ERROR: *** CANNOT OPEN FILE: %s", argv[2]); return -1;}
    char *ind = (char *)malloc(f=  filelength(argv[1]) + 1);
    char *out = (char *)malloc(f+= filelength(argv[2]) + 1);
    z = filelength(argv[1]);
    if(ind == NULL || out == NULL){
        printf("ERROR: *** CANNOT ALLOCATE MEMORY ***: %d KB", f/1024);
        return -1;
    }
    p=0;
    while(!feof(in)){fread(&ind[p++], 1, 1, in);}
    fclose(in);
    p=0;
    for(r=0;r<z;r++){
        if(ind[r] == ind[r+1] || (unsigned char)ind[r] == (unsigned char)0xEA){
        e=0;
        while(ind[r+e] == ind[r]){e++; if(e > 126){break;}}
        //printf("Found run at offset (%d-%d): %d [%d]\n", r, r+e, e, ind[r]);
        out[p] = 0xEA;
        out[p+1] = e;
        out[p+2] = ind[r];
        r+=(e-1);
        p+=3;
        } else {
            out[p] = ind[r];
            p++;
        }
    }
        fwrite(out, 1, p, out_);
return 0;

}

No offence, but do you think this looks good?

For me, at least, it's almost illegible.

Perfectly readable...

MrCode · 03-27-2010, 01:51 PM

Quote:

Two many blank lines makes the program too spread out to read.

I agree that too many blank lines can be distracting, but they can be a good tool for organizing your code.

For example (C++ here):

Code:

#include <stdio.h>
#include <stdlib.h>

int numA = 2,
    numB = 3,
    numC = 4;
                          //<-- blank space to separate variable types
float numAf = 0.0f,
      numBf = 1.25f,
      numCf = 3.1415926f;

int main()
{
    float numArray1 = new float [numA];
    float numArray2 = new float [numB];
    float numArray3 = new float [numC];

    numArray1[0] = numAf;
    numArray1[1] = numBf;
                          //<-- blank space to separate assignment operations to different variables
    numArray2[0] = numAf;
    numArray2[1] = numBf;
    numArray2[2] = numCf;

    numArray3[0] = numAf;
    numArray3[1] = numBf;
    numArray3[2] = numCf;
    numArray3[3] = sin(numCf / 2);
                                 //<-- blank space to separate assignment from procedure
    for(int i = 0; i < 1; i++)
        printf("%i",numArray1[i]);

    for(int i = 0; i < 2; i++)
        printf("%i",numArray2[i]);

    for(int i = 0; i < 3; i++)
        printf("%i",numArray3[i]);

    delete[] numArray1;
    delete[] numArray2;
    delete[] numArray3;

    return 0;
}

The same program, without spacing:

Code:

#include <stdio.h>
#include <stdlib.h>

int numA = 2,
    numB = 3,
    numC = 4;
float numAf = 0.0f,
      numBf = 1.25f,
      numCf = 3.1415926f;

int main()
{
    float numArray1 = new float [numA];
    float numArray2 = new float [numB];
    float numArray3 = new float [numC];
    numArray1[0] = numAf;
    numArray1[1] = numBf;
    numArray2[0] = numAf;
    numArray2[1] = numBf;
    numArray2[2] = numCf;
    numArray3[0] = numAf;
    numArray3[1] = numBf;
    numArray3[2] = numCf;
    numArray3[3] = sin(numCf / 2);
    for(int i = 0; i < 1; i++)
        printf("%i",numArray1[i]);
    for(int i = 0; i < 2; i++)
        printf("%i",numArray2[i]);
    for(int i = 0; i < 3; i++)
        printf("%i",numArray3[i]);
    delete[] numArray1;
    delete[] numArray2;
    delete[] numArray3;
    return 0;
}

MTK358 · 03-27-2010, 01:51 PM

Quote:

Originally Posted by smeezekitty

Perfectly readable...

I am in total disbelief...

MTK358 · 03-27-2010, 01:53 PM

@MrCode

I do think that using blank lines to separate blocks of code that do a certain small task together is a good practice.

devnull10 · 03-27-2010, 01:56 PM

Quote:

Originally Posted by MTK358

@MrCode

I do think that using blank lines to separate blocks of code that do a certain small task together is a good practice.

Which is what I do. I wouldn't have a blank line after every statement however if the statement was logically separate from the previous then I generally would.

makyo · 03-27-2010, 02:34 PM

Hi, gnashley.

Quote:

Originally Posted by gnashley

makyo, can you post a copy of shtidy? I don't seem to find it anywhere.

Yes ... cheers, makyo