Primitive implementation of Conway's Game of Life in Bash

gameoflife.sh

#!/bin/bash
#
# Problematic life by Simonas@irc.data.lt
# Studying of bash performance
# v0.2.0

term_width=$(($(tput cols) ))
term_height=$(($(tput lines) * 2 - 2))
full_square='█'
upper_square='▀'
lower_square='▄'
empty_square='░'
game_seed=10
generation='0.01'
log_file=debug.log

debug_call() {
  ts=$(date "+%s %N")
  echo "$ts $@" >> $log_file 2> /dev/null
  eval $@
}

declare -A matrix
declare -A matrix_next

for ((i=0; i < term_height; i++)) do
  for ((j=0; j < term_width; j++)) do
    if [ $(($RANDOM%$game_seed)) -gt 0 ];
    then matrix[$i,$j]=0
    else matrix[$i,$j]=1
    fi
  done
done

# main loop

clear
while true; do
  for ((i=0; i < term_height; i+=2)) do
    line=$(($i/2))
    row=''
    for ((j=0; j < term_width; j++)) do
      if [ ${matrix[$i,$j]} -eq 1 ] && [ ${matrix[$(($i+1)),$j]} -eq 1 ] ;
      then row+="${full_square}"
      elif [ ${matrix[$i,$j]} -eq 1 ] && [ ${matrix[$(($i+1)),$j]} -eq 0 ] ;
      then row+="${upper_square}"
      elif [ ${matrix[$i,$j]} -eq 0 ] && [ ${matrix[$(($i+1)),$j]} -eq 1 ] ;
      then row+="${lower_square}"
      else row+="${empty_square}"
      fi
    done
    echo -en "\033[${line};0f$row"
  done

  # calculate conway's loop into $matrix_next
  for ((i=0; i < term_height; i++)) do
    for ((j=0; j < term_width; j++)) do
      sum_neighbours=$(("
          ${matrix[$(($i-1)),$(($j-1))]:-0} + ${matrix[$i,$(($j-1))]:-0} +
          ${matrix[$(($i+1)),$((j-1))]:-0} + ${matrix[$(($i-1)),$j]:-0} +
          ${matrix[$(($i+1)),$j]:-0} + ${matrix[$(($i-1)),$(($j+1))]:-0} +
          ${matrix[$i,$(($j+1))]:-0} + ${matrix[$(($i+1)),$(($j+1))]:-0} "))
            if [ ${matrix[$i,$j]} -eq 1 ];
            then
                if [ $sum_neighbours -lt 2 ] || [ $sum_neighbours -gt 3 ];
                then matrix_next[$i,$j]=0
                else matrix_next[$i,$j]=1
                fi
            elif [ ${matrix[$i,$j]} -eq 0 ];
            then
                if [ $sum_neighbours -eq 3 ];
                then matrix_next[$i,$j]=1
                else matrix_next[$i,$j]=0
                fi
            fi
        done
    done
    # copy next matrix into main
    for ((i=0; i < term_height; i++)) do
      for ((j=0; j < term_width; j++)) do
        matrix[$i,$j]=${matrix_next[$i,$j]}
      done
    done
    sleep $generation
done