Manage a pie shop!

Question

Summary

Code golf is good. Pie is good. When you put the two together, only good stuff can happen.

Specifications

In this challenge you will manage a pie shop. The user will be able to input five different commands: list, count, buy, sell, and exit. Here are the specifications for each:

• list

  • Print a list of all the pies owned, and how many. Separate with | and pad with a space on either side. |s must be aligned. Pie amount may be negative (that means you owe pie to someone :(). For example:

    | apple     | 500 |
    | blueberry | 2   |
    | cherry    | -30 |
    

• count [type]

  • Print how many {{type}} pies there are. Print "There is no {{type}} pie!" if there is none. {{type}} will always match the regex \w+ (i.e, it will always be a single word). For example, if I had the amount of pies shown in the above example list, then

    > count apple
    500
    > count peach
    There is no peach pie!
    

• buy [n] [type]

  • Add {{n}} to the count of {{type}} pie, and print it. Create {{type}} pie if it does not exist. {{n}} will always match the regex [0-9]+ (i.e, it will always be a number). Here's another example (with the same pie inventory as the previous examples):

    > count blueberry
    2
    > buy 8 blueberry
    10
    

• sell [n] [type]

  • Subtract {{n}} from the count of {{type}} pie, and print it. Create {{type}} pie if it does not exist. Pie can be negative (oh no, that would mean you owe someone pie!).

    > sell 15 blueberry
    -5
    > buy 5 blueberry
    0
    

• exit

  • Print "The pie store has closed!" and exit the program.

    > exit
    The pie store has closed!
    

Further clarifications

• If a non-existing function is called (the first word), then print "That's not a valid command."
• If an existing function is called with invalid arguments (the words after the first word), how your program behaves doesn't matter. "Invalid arguments" includes too many arguments, too little arguments, {{n}} not being a number, etc.
• Pie is good.
• Your input must be distinguished from your output. If you are running the program on the command line/terminal/shell/other text-based thing, you must prefix input with "> ​" (a "greater than" sign and a space) or some other shell input prefix thing.
• Pie is good.

• If all of these clarifications are not good enough, here's some sample output:

  > list
  > buy 10 apple
  10
  > sell 10 blueberry
  -10
  > list
  | apple     | 10  |
  | blueberry | -10 |
  > count apple
  10
  > count peach
  There is no peach pie!
  > exit
  The pie store has closed!
  

• If you buy/sell pie and the net count becomes 0, you can either keep it in the list or not, and you can either return 0 or There is no {{type}} pie! when you count it.

• This is code-golf; shortest code wins.
• Did I mention that pie is good?

Answer 1

Ruby, 335 330

h=Hash.new 0
loop{$><<"> "
puts case gets when/^list/
h.map{|x|?|+" %%%ds |"%h.flatten.map{|e|e.to_s.size}.max*2%x}when/^count (.*)/
h[$1]!=0?h[$1]:"There is no #{$1} pie!"when/^buy#{m=" (.*)"*2}/
h[$2]+=$1.to_i when/^sell#{m}/
h[$2]-=$1.to_i when/^exit/
puts"The pie store has closed!"
break else"That's not a valid command."end}

Some tricks here:

?|+" %%%ds |"%[*h].flatten.map{|e|e.to_s.size}.max*2%x

Doorknob's idea to use a formatter is taken a step further here, literally. First, the longest string in the hash among all keys and values is formatted using " %%%ds |" to produce a string like " %6s |". Yep, no shrinkwrapping each column separately. There was never the requirement to. One size fits all. Then this string is duplicated and used as a formatting string for the two-element array containing the current row. Finally, the + near the start gets its word and prepends a single leading pipe. Oh, and puts has a nice handling of arrays.

Ruby has interpolation in regex literals. It's a tight save, but it does save a little.

Ruby requires semicolons after the when expression, but not before the keyword. This leads to a weird rendering artifact when the semicolon is replaced with a newline.

And, of course, perlism known as magic globals and automatic matching of regex literals against them.

Also, most statements including case are expressions.

Answer 2

Ruby, 427 384 characters

alias x puts
p={}
loop{
print'> '
case(u=gets.chop.split)[0]when'exit'
x'The pie store has closed!'
exit
when'list'
p.each{|k,v|printf"| %-#{p.keys.map(&:size).max}s | %-#{p.map{|e,a|a.to_s.size}.max}s |\n",k,v}
when'count'
x p[t=u[1]]||"There is no #{t} pie!"
when/sell|buy/
m=(u[0]<?s?1:-1)*u[1].to_i
if p[t=u[2]]
x p[t]+=m
else
x p[t]=m
end
else x"That's not a valid command."
end}

Thanks to Jan Dvorak of huge improvement from 427 to 384 (!)

Answer 3

Python Pie-thon 437

I'm sure there is some slack on the second last line, but the requirement to align the bars for both the pie type and number is a doozy.

p,C,l={},"count",len
while 1:
 a=raw_input("> ").split();c=a.pop(0)
 if"exit"==c:print"The pie store has closed!";break
 if"sell"==c:a[0]=int(a[0])*-1
 if c in[C,"buy","sell"]:
  y=a[-1]
  if c!=C:p[y]=p.get(y,0)+int(a[0])
  print p.get(y,"There is no %s pie!"%y)
 elif"list"==c:
  for i in p:print"| %s | %s |"%(i.ljust(l(max(p.keys(),l))),str(p[i]).rjust(max([l(str(x)) for x in p.values()])))
 else:print"That's not a valid command."

As per Igby Largeman's comment the rules are unclear around what to do if there was a pie of a specific type, but there are 0 now. So I've interpreted it in my favour.

Sample output:

> buy 10 apple
10
> sell 1 blueberry
-1
> buy 1 keylime
1
> sell 3 apple
7
> buy 5 blueberry
4
> list
| keylime   | 1 |
| apple     | 7 |
| blueberry | 4 |
> sell 1 keylime
0
> count keylime
0

Answer 4

C# - 571 568 559

Bringing up the rear as usual with the hopelessly verbose C#.

using C=System.Console;class Z{static void Main(){var P=new 
System.Collections.Generic.Dictionary<string,int>();int i=0,n;a:C.Write
("> ");var I=C.ReadLine().Split(' ');var c=I[0];object s=c=="exit"?
"The pie store has closed!":"That's not a valid command.";if(c==
"count")try{s=P[c=I[1]];}catch{s="There is no "+c+" pie!";}if(c==
"buy"||c=="sell"){n=int.Parse(I[1]);n=c=="sell"?-n:n;try{n+=P[c=
I[2]];}catch{}s=P[c]=n;i=(n=c.Length)>i?n:i;}if(c=="list")foreach(
var p in P.Keys)C.Write("| {0,"+-i+"} | {1,11} |\n",p,P[p]);else C.
WriteLine(s);if(c!="exit")goto a;}}

I took some liberty with the rule about list output. To save some characters I hardcoded the width of the count column to the maximum width of an integer value. (The rules didn't say extra spaces weren't allowed.)

Formatted:

using C = System.Console;
class Z
{
    static void Main()
    {
        var P = new System.Collections.Generic.Dictionary<string, int>();
        int i = 0, n;
    a:
        C.Write("> ");
        var I = C.ReadLine().Split(' ');
        var c = I[0];
        object s = c == "exit" ? "The pie store has closed!" 
                               : "That's not a valid command.";

        // allow Dictionary to throw exceptions; cheaper than using ContainsKey()
        if (c == "count")
            try { s = P[c = I[1]]; }
            catch { s = "There is no " + c + " pie!"; }

        if (c == "buy" || c == "sell")
        {
            n = int.Parse(I[1]);
            n = c == "sell" ? -n : n;

            try { n += P[c = I[2]]; }
            catch { }

            s = P[c] = n;
            i = (n = c.Length) > i ? n : i;
        }

        if (c == "list")
            foreach (var p in P.Keys) 
                C.Write("| {0," + -i + "} | {1,11} |\n", p, P[p]);
        else
            C.WriteLine(s);

        if (c != "exit") goto a; // goto is cheaper than a loop
    }
}

Answer 5

Python 3, 310

p={}
c=G=p.get
while c:
 l=("exit list buy count sell "+input("> ")).split();c=l.index(l[5]);*_,n=l
 if~-c%2*c:p[n]=(3-c)*int(l[6])+G(n,0)
 print(["The pie store has closed!","\n".join("| %*s | %9s |"%(max(map(len,p)),k,p[k])for k in p),G(n),G(n,"There is no %s pie!"%n),G(n),"That's not a valid command."][c])

Answer 6

Java - 772 751 739 713 666 619

I know it's not winning the contest, but just for fun!

import java.util.*;class a{static<T>void p(T p){System.out.print(p);}public static
 void main(String[]s){z:for(Map<String,Long>m=new HashMap();;){p("> ");s=new
 Scanner(System.in).nextLine().split(" ");switch(s[0]){case"list":for(Map.Entry 
e:m.entrySet())System.out.printf("|%12s|%6s|\n",e.getKey(),e.getValue());break;
case"count":p(m.get(s[1])!=null?m.get(s[1]):"There is no "+s[1]+" pie!\n");break;
case"buy":case"sell":long r=(s[0].length()==3?1:-1)*new Long(s[1])+(m.get(s[2])!=null?
m.get(s[2]):0);p(r+"\n");m.put(s[2],r);break;case"exit":p("The pie store has
 closed!");break z;default:p("That's not a valid command.\n");}}}}

With line breaks and tabs:

import java.util.*;

class a{

    static<T>void p(T p){
        System.out.print(p);
    }

    public static void main(String[]s){
        z:for(Map<String,Long>m=new HashMap();;){
            p("\n> ");
            s=new Scanner(System.in).nextLine().split(" ");
            switch(s[0]){
            case"list":
                for(Map.Entry e:m.entrySet())
                    System.out.printf("|%12s|%6s|\n",e.getKey(),e.getValue());
                break;
            case"count":
                p(m.get(s[1])!=null?m.get(s[1]):"There is no "+s[1]+" pie!");
                break;
            case"buy":
            case"sell":
                long r=(s[0].length()==3?1:-1)*new Long(s[1])+(m.get(s[2])!=null?m.get(s[2]):0);
                p(r);
                m.put(s[2],r);
                break;
            case"exit":
                p("The pie store has closed!");
                break z;
            default:
                p("That's not a valid command.");
            }
        }
    }

}