For Max

animals.sh

#!/bin/bash

yesno() {
  while true ; do
    echo "--> $1"
    read
    case "$REPLY" in
      y*) return 0 ;;
      n*) return 1 ;;
      *) echo "Please answer y or n" ;;
    esac
  done
}

ANIMALS=db.animals

touch $ANIMALS

ix=0

echo "Think of an animal, I'll try to guess it"

while true ; do
  last=$ix
  read ix yes no question <<<"$(grep -E "^$ix" $ANIMALS)"
  if [ "$question" ] ; then
    if yesno "$question"; then ix=$yes ; else ix=$no ; fi
    ix=$(echo "$ix" | cut -d~ -f2)
  elif [ "$yes" ] ; then
    yes=$(echo "$yes" | cut -d~ -f2)
    if yesno "Is it a $yes?" ; then
      echo "I win! Hurrah!"
      exit
    else
      echo "You win! What was it you were thinking of?"
      read thing
      read kix kyes kno kquestion <<<"$(grep -E " y~$thing " $ANIMALS)"
      if [ "$kix" ] ; then
        echo "That's odd - I see $thing already in my database under these different questions and answers:"
        while [[ kix -ne 0 ]] ; do
          ix=$kix
          read kix kyes kno kquestion <<<"$(grep -E "~$kix " $ANIMALS)"
          echo -n " * $kquestion -> "
          if [[ "y~$ix" == "$kyes" ]] ; then echo YES ; else echo NO ; fi
          kix=$( echo $kix | cut -d~ -f 2 )
        done | tac
        exit
      fi
      echo "Great! Please give me a yes/no question I can ask you next time to distinguish a $yes from a $thing"
      while true ; do
        read question
        if yesno "Thanks! Now: if you're thinking of a $yes, would you answer yes or no to $question?" ; then
          qyes=true
        else
          qyes=false
        fi
        if yesno "And to check: if you're thinking of a $thing, would you answer yes or no to $question?" ; then
          qthing=true
        else
          qthing=false
        fi
        if [[ "$qyes" != "$qthing" ]] ; then
          break
        fi
        echo "Oh... Can you type a question where the answer is different for $yes and $thing?"
      done
      echo "Nice! I'll add that to my database!"
      ll=$(wc -l < $ANIMALS)
      sed -i "s/^$ix .*/$ix y~$(( ll + 1 )) n~$(( ll + 2 )) $question/" $ANIMALS
      if $qyes ; then
        echo "$(( ll + 1 )) y~$yes n~" >> $ANIMALS
        echo "$(( ll + 2 )) y~$thing n~" >> $ANIMALS
      else
        echo "$(( ll + 1 )) y~$thing n~" >> $ANIMALS
        echo "$(( ll + 2 )) y~$yes n~" >> $ANIMALS
      fi
      exit
    fi  
  else
    echo "Actually... I don't know any animals yet. What were you thinking of?"
    read
    echo "Cool! I'll add that to my database."
    echo "0 y~$REPLY" >> $ANIMALS
    exit
  fi
done

tim@omoensis:$ cat db.animals
0 y1 n2 does it have stripes?
1 y12 n13 Is it in the weasel family?
2 y3 n4 Is it extinct?
3 yGorgonposid
4 y5 n6 does it look like a mini bear
5 y9 n10 does it have a prehensile tail.
6 y7 n8 Does it have a white tipped tail and is it red
7 yFox n
8 ymink n
9 ybinturong n
10 ywolverine n
12 ybadger n
13 ytiger n