main.rb

#!/usr/bin/env ruby

# Take a file path from a cmd line argument
if ARGV.length != 1
    puts "Please provide the path to brainfuck program"
    exit
end
bf_filename = ARGV[0]
unless File.exist?(bf_filename)
    puts "File %s doesnt exist" % [bf_filename]
    exit
end

# Open the file
FILE = File.read(bf_filename)
size = FILE.size

# bf_chars = ['>','<','+','-','.',',','[',']']
bf_pointer = 0
bf_tape = [0]

# print "Brainfuck characters: ", bf_chars
# puts
# puts
# puts "File content: ", FILE

# test = $stdin.gets.chomp
# puts "test: !%s! " % test[-1]


puts
i = 0
while i < FILE.size do
    case FILE[i]
    when '>'
        bf_pointer+=1
        if bf_pointer >= bf_tape.size-1 
            bf_tape << 0
        end
        puts FILE[i],'{incrementing pointer ptr=%d}'% bf_pointer
    i+=1
    when '<'
        bf_pointer-=1
        puts FILE[i],'{decrementing pointer ptr=%d}'% bf_pointer

        if bf_pointer < 0 
            puts "ERROR: Using negative tape pointer."
            exit 1
        end
    i+=1
    when '+'
        bf_tape[bf_pointer]+=1
        puts FILE[i],'{incrementing contents cont=%d ptr=%d}' % [ bf_tape[bf_pointer], bf_pointer ]
    i+=1
    when '-'
        bf_tape[bf_pointer]-=1
        puts FILE[i],'{decrementing contents cont=%d ptr=%d}' % [ bf_tape[bf_pointer], bf_pointer ]
    i+=1
    when '.'
        print bf_tape[bf_pointer].chr
        puts FILE[i],'{printing %s }' % bf_tape[bf_pointer].chr
    i+=1
    when ','
        ch = $stdin.gets.chomp
        unless ch.length == 0
            bf_tape[bf_pointer] = ch[-1].ord
        end
        puts FILE[i],'{saving user input character %s}' % ch[-1]
    i+=1
    when '['
        puts FILE[i],'{handling [ }'

        nested_cnt=0
        if bf_tape[bf_pointer] == 0
            puts "SKIPPING THE BRACKET"
            # set pointer to the maching closing bracket
            while true do
                i+=1
                if FILE[i] == ']' && nested_cnt == 0
                    break
                end

                if FILE[i] == '['
                    nested_cnt+=1
                puts "nested_cnt: " + nested_cnt.to_s

                end
                if nested_cnt >0 && FILE[i] == ']'
                    nested_cnt-=1
                puts "nested_cnt: " + nested_cnt.to_s

                end
            end

        else
            puts "ENTERING THE LOOP"
        end
    i+=1
    when ']'
        puts FILE[i],'{handling ] }'
        
        nested_cnt=0
        while true do
            i-=1
            
            if FILE[i] == '[' && nested_cnt==0
                break
            end

            if FILE[i] == ']'
                nested_cnt+=1
            end
            if nested_cnt >0 && FILE[i] == '['
                nested_cnt-=1
            end
            puts "nested_cnt: " + nested_cnt.to_s
        end
        
    else
        print FILE[i]
    i+=1
    end


puts "index: "+i.to_s
puts "pointer: "+bf_pointer.to_s
print "tape: ", bf_tape, "\ntape size: ", bf_tape.size
puts
puts

sleep 1
end




# def FILE.remove_nonbf_chars
#     puts "HELLO from inside method"
#     puts FILE
# end

# FILE.remove_nonbf_chars
# puts "File content: ", FILE.remove_nonbf_chars