Fabric calculator - a better way to do it?

[ailie]

This is a script I wrote to calculate how much fabric I need when making various quilt blocks. At the moment it's run from the command line, but I'd like to eventually get it so it can be run from a web page. That's where I really started to get frustrated. Alternately, a GUI might be sort of neat.

Anyway, I would be interested in receiving feedback on the script as it stands now. I have a vague feeling that perhaps there are better, cleaner ways to do much of what I've got, and I'd like to learn them.

#!/usr/bin/perl -w
use strict;

# How many fabrics are you using?

my $j;
my $number_of_fabrics;
print "How many fabrics are you using? \n";
chomp($number_of_fabrics = <STDIN>);
for ($j = 1; $j <= $number_of_fabrics; $j++) {

# How wide is the fabric you are using?

   my %fabric_width;
   my $fab_width;
   print "How wide is fabric $j? \n";
   chomp($fab_width = <STDIN>);
   $fabric_width{$j} = $fab_width - 2;
   print "To be safe, we'll use a width of $fabric_width{$j} for fabri
+c $j. \n";

# How many different shapes is a block made of?

   my $number_of_shapes;
   print "How many different shapes of fabric $j is a block made of? \
+n";
   chomp($number_of_shapes = <STDIN>);

# What are the dimensions of the shapes?

   my $i;
   my %width;
   my %height;
   my %shape;
   my $piece;
   for ($i = 1; $i <= $number_of_shapes; $i++) {
      my $shape_width;
      print "What is the width of shape $i? \n";
      chomp($shape_width = <STDIN>);
      $width{$i} = $shape_width;
      my $shape_height;
      print "What is the height of shape $i? \n";
      chomp($shape_height = <STDIN>);
      $height{$i} = $shape_height;
      $shape{$i} = $shape_width . "x" . $shape_height;
      }
   print "Shape dimensions: \n";
   foreach $i (keys (%shape)) {
      print "The dimensions of shape $i are $shape{$i}\n";
      }

# For each shape, how many can be made per yard of fabric?

   my $number_per_fabric_width_strip;
   my $strips_per_yard;
   my $number_per_yard;
   my $number_of_pieces;
   my %pieces;
   my $number_of_strips;
   my $strip_yardage;
   my $remainder;
   my $fabric_yardage;
   my $number_of_blocks;
   my $total_pieces;
   foreach $i (keys (%height)) {
      $number_per_fabric_width_strip = $fabric_width{$j} / ($height{$i
+});
      $number_per_fabric_width_strip = int $number_per_fabric_width_st
+rip;
      print "You can get $number_per_fabric_width_strip piece(s) of sh
+ape $i per
      $width{$i}\" strip of fabric $j.\n";
      $strips_per_yard = 36 / ($width{$i});
      $strips_per_yard = int $strips_per_yard;
      print "You can get $strips_per_yard $width{$i}\" strips per yard
+. \n";
      $number_per_yard = $number_per_fabric_width_strip * $strips_per_
+yard;
      print "You can get $number_per_yard of shape $i per yard of
      $fabric_width{$j}\" of fabric $j. \n";
      print "How many of shape $i do you need per block? \n";
      chomp($number_of_pieces = <STDIN>);
      $pieces{$i} = "$number_of_pieces";
      print "You need $number_of_pieces per block. \n";
      print "How many blocks are you making? \n";
      chomp($number_of_blocks = <STDIN>);
      print "You are making $number_of_blocks blocks. \n";
      $total_pieces = $number_of_pieces * $number_of_blocks;
      print "You need $total_pieces of shape $i. \n";
      if ($total_pieces <= $number_per_fabric_width_strip) {
         print "You will need one $width{$i}\" strip of fabric $j. \n"
+;
         }
      else {
         $number_of_strips = $total_pieces / $number_per_fabric_width_
+strip;
         $number_of_strips = int $number_of_strips;
         $remainder = $total_pieces % $number_per_fabric_width_strip;
         $strip_yardage= $number_of_strips * $width{$i};
         if ($remainder == 0) {
            print "You will need exactly $strip_yardage\". \n";
            }
         else {
            $fabric_yardage = $strip_yardage + $width{$i};
        print "You will need $fabric_yardage\" of fabric $j. The last 
+$width{$i}\" strip will have only $remainder pieces cut from it. \n";
        }
         }
      } 
   }

Thanks for any advice.

[jynx]

A few suggestions,

Most of these are rather cosmetic, but they should help readability.

Considering how many times you read from STDIN you may want to farm that part out to a subroutine. It would remove clutter from the rest of the code and should be a bit more maintainable later.

For structures like %width an array seems to make more sense than a hash. It works either way, but it's probably a good idea to try and use more appropriate tools when possible.

Also you can reduce the number of variables you have to keep track of by using a hash for multiple things. For example, your $number_of_* variables in the last section could probably be written as (using a subroutine for getting STDIN):

my %number;
$number{blocks} = get_input("How many blocks are you making?");
$number{strips} = int( $total_pieces / $number_per_fabric_width_strip)
+;
etc...

jynx

[crazyinsomniac]

This is me just being a monkey and testing the script out:

F:\dev>perl fabric.pl
How many fabrics are you using?
2
How wide is fabric 1?
1
To be safe, we'll use a width of -1 for fabric 1.
How many different shapes of fabric 1 is a block made of?
1
What is the width of shape 1?
1
What is the height of shape 1?
2
Shape dimensions:
The dimensions of shape 1 are 1x2
You can get 0 piece(s) of shape 1 per
      1" strip of fabric 1.
You can get 36 1" strips per yard.
You can get 0 of shape 1 per yard of
      -1" of fabric 1.
How many of shape 1 do you need per block?
23
You need 23 per block.
How many blocks are you making?
2
You are making 2 blocks.
You need 46 of shape 1.
Illegal division by zero at fabric.pl line 88, <STDIN> line 7.

F:\dev>

I'll update this node after I've messed with the code.

My monkeying around immediately proves insightful into how you can improve this (at least it appears so to me).

A good strategy might be to turn this into a module, and then, write "interfaces" for it, like commandline, CGI, GUI. All I have to say at this point is, not bad quiltmaker (some of your math may be funny, but useful to real people and immensly perlmonkish -- no prog/perl bg, good practices at the beginning). I see sanity checks, units of measurement conversions, price estimation.... ;D

update:

#!/usr/bin/perl -w
use strict;

# How many fabrics are you using?

my $number_of_fabrics;

print "How many fabrics are you using? \n";

chomp($number_of_fabrics = <STDIN>);

$number_of_fabrics =~ s/\D//; # only allow number input

## $number_of_fabrics ||= 3;  # assume default quietly

unless($number_of_fabrics and $number_of_fabrics >=3 )
{
    warn "Ahem!!! You must enter a NUMBER >= 3, but that's ok, default
+ is 3";
    $number_of_fabrics = 3;
}
#... more to come ... ;D

 
___crazyinsomniac_______________________________________
Disclaimer: Don't blame. It came from inside the void
perl -e "$q=$_;map({chr unpack qq;H*;,$_}split(q;;,q*H*));print;$q/$q;"

[ailie]

Wow. It never even occurred to me to put in widths like that, since quilting fabric is almost always 45" wide, sometimes 60" wide - certainly not 1" wide. Of course, now I'm going "D'oh!"

The math is inelegant, but that's a basic fact of calculating fabric yardages for quilts. Simple math, but annoying.

I like the module idea. Of course, I have no idea how to go about such a thing, but learning is really the whole point.

Price estimation is simple:
print "No, you may not buy more fabric. \n";