Welcome to the first (?) Sunday Perl Challenge Trip! The challenge will last one week and then points will be calculated. I dont hope someone is mad enough to accept the challange, but I think is more fun this way, instead of posting my code alone. But who knows..

Assignement

We need to implement nested autocompletion while reading user input: the command A lead to options 1 2 3 and command B to 4 5 etc..

Simple? No: a dread :) Let specify it better. Given the following data:

# dummy items to play with
my @animals = (qw( cow camel dog cat  ));
my @foods   = (qw( fish pasture meat  ));
my @places  = (qw( wood sea    desert ));

# commands 
my $commands = {
    select => {
        completion_list => \@animals,
        commands => {
                        give => {
                                    completion_list => \@foods,
                        },
                        take_to => {
                                    completion_list => \@places,
                        },
        },
    },
    kill  => {
        completion_list => \@animals,
    }
};
[download]

the first choices are only select and kill and if you choose select (entering it or using selTAB to autocomplete it) then autocomplete should permit only one item from @animals Once you entered (directly or autocompleting it) an animal then only the two commands give and take_to should be available. And so on.

I used hardcoded keywords commands and completion_list to drive my solution: feel free to use them or not or to change them.

An example session:

Press TAB for autocompletion or available options

autocompletion nested>("kill", "select")                              
+ # 'TAB' on empty input shows available commands
autocompletion nested>select c("camel", "cat", "cow")                 
+ # 'cTAB' shows animals but not 'dog'
autocompletion nested>select ca("camel", "cat")                       
+ # 'caTAB' shows two animals starting with 'ca'
autocompletion nested>select camel ("give", "take_to")                
+ # I press 'mTAB' thae autocomplete in 'camel' 
                                                                      
+ #    'TAB' again for next level commands: give and take_to
autocompletion nested>select camel take_to ("desert", "sea", "wood")  
+ # 'tTAB' and 'TAB' again
autocompletion nested>select camel take_to desert                     
+ # 'desTAB' leads to 'desert'
                                                                      
+ # ENTER 1
autocompletion nested>                                                
+ # ENTER 2 exits the user input cycle
CHOOSEN: select camel take_to desert                                  
+ # finally we print the resulting path
[download]

Points

• +50 points to get the job done. Runnable code.
• +Reputation of the node when the challenge close
• -5 for reading Hint1 (declare it in the answer):
  <Reveal this spoiler or all spoilers in this node or all in this thread>
• -10 for reading Hint2 (declare it in the answer):
  <Reveal this spoiler>
• -20 for reading my solution (declare it in the answer: it includes Hint1 and Hint2) and use it as starting point :)

Extra points

• +40 points for not using Term::ReadLine family modules :)
• +20 points for a correct use of BACKSPACE to have editable lines: you change your mind and you go back through the line
• +10 points if you are able to avoid the double ENTER I need to end the line building when we reached the end of the datastructure
• +100 points if you publish it as CPAN module in this week
• my ethernal gratidute if I understand your code :)

My solution

My code is ugly enough, but it works. It is full of comments to help you understing what's going on. Some unused code is commented to show possible improvemnts. It has some debug options: 0 (default), 1, 2 that ruins a bit the output but are useful to see the flow.

Avoid to comment my code before the challange ends. Here we are:

Have fun!

L*