inital commit

example.jl

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+include("simulator.jl")
+
+input_file = "example_input_1.txt"
+program_file = "example_program_1.txt"
+
+input = load_input(input_file)
+program, init_state, halt_state = load_program(program_file)
+
+tape_left, tape_right = set_up(input)

example_input_1.txt

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+01100101

example_program_1.txt

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+// Binary numbers divisible by 3
+
+// Input: a binary number n
+// Output: accepts if n mod 3 == 0
+// Example: accepts 110 (=6)
+
+// ------- States -----------|
+// q0 - mod3 == 0            |
+// q1 - mod3 == 1            |
+// q2 - mod3 == 2            |
+// qHalt - halting state     |
+// --------------------------|
+
+init: q0
+halt: qHalt
+
+q0,0,q0,0,>
+
+q0,1,q1,1,>
+
+q1,0,q2,0,>
+
+q1,1,q0,1,>
+
+q2,0,q1,0,>
+
+q2,1,q2,1,>
+
+q0,_,qHalt,_,-

simulator.jl

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+using DataStructures
+using DelimitedFiles
+
+# Read Input / Change value of current input (or do nothing), Move L or R or do nothing
+# e.g. 1/0, L = if current cell value is 1, change it to 0, then move left
+# e.g. 0/1, . = if current cell value is 0, change it to 1, then don't move
+
+"""
+    load_input(file_name)
+
+Takes a text file containing a continuous string of `n` integers (no spaces) and returns an `n`-element
+array, where each element is an integer. The array is ordered as the input string.
+
+Input
+- `file_name`::string : path of text file containing an input string of `n` integers (no spaces)
+
+Output
+- ::`n`-element Array{Char, 1} : output array of integers, ordered as the input string
+"""
+function load_input(file_name)
+    file = readdlm(file_name, String)
+    return collect(file[])
+end
+
+"""
+    load_program(file_name)
+
+Takes a text file containing a Turing program. Please see docs for how to write such a program.
+
+Input
+"""
+function load_program(file_name)
+    program_file = readdlm("example_program_1.txt")
+    rows, cols = size(program_file)
+    program = Dict{Any,Any}()
+    init_state = []
+    halt_state = []
+    for i = 1:rows
+        if program_file[i,1] == "//"
+            continue
+        else
+            if program_file[i,1] == "init:"
+                push!(init_state, program_file[i,2])
+            elseif program_file[i,1] == "halt:"
+                push!(halt_state, program_file[i,2])
+            else
+                card = split(program_file[i,1], r",")
+                state_read = (String(card[1]),String(card[2]))
+                instruction = (String(card[3]),String(card[4]),String(card[5]))
+                program[state_read] = instruction
+            end
+        end
+    end
+    return program, init_state[], halt_state[]
+end
+
+"""
+    set_up(input)
+
+Performs initial set-up for the simulation of single tape. The `length(input)` must be equal of greater
+than 1. The input will be placed on tape to the right of the head.
+
+Input
+- `input`::`n`-element Array{Char, 1} : initial data to insert to the right of the head
+
+Output
+- `tape_left`::Deque{Int} : initial values for the stack to the left of the head
+- `tape_right`::Deque{Int} : initial values for the stack to the right of the head
+"""
+function set_up(input)
+    # set up two stacks to simulate a single tape
+    tape_left = Deque{Int}() # simulates tape lying to the left of the head
+    tape_right = Deque{Int}() # simulates tape lying to the right of the head
+
+    for i = 1:length(input)
+        push!(tape_right, parse(Int, input[i]))
+    end
+
+    return tape_left, tape_right
+end