Intcode assembler: start expression evaluation

lib/intcode/assembler.ex

@@ -1,28 +1,31 @@
 defmodule Assembler do
   @asm """
-    in #30
-    clt 30 #8 #31
-    jnz 31 #lessThan
-    ceq 30 #8 #31
-    jnz 31 #equal
-    out #1001
+    in res
+    clt $res 8 cmpRes
+    jnz $cmpRes lessThan
+    ceq $res 8 cmpRes
+    jnz $cmpRes equal
+    out 1001
     hlt
 
   lessThan:
-    out #999
+    out 999
     hlt
 
   equal:
-    out #1000
+    out 1000
     hlt
+
+  res: 0
+  cmpRes: 0
   """
   def test do
     @asm
     |> IO.inspect()
-    |> assemble(32)
+    |> assemble()
   end
 
-  def assemble(asm, pad_length \\ 0) do
+  def assemble(asm) do
     {memory, labels} =
       asm
       |> String.split("\n")
@@ -44,34 +47,81 @@ defmodule Assembler do
               Map.put(labels, String.slice(line, 0..-2), length(memory))
             }
 
+          Regex.match?(~r/^\w+: \d+$/, line) ->
+            [name, value] = String.split(line, ": ")
+            value = String.to_integer(value)
+
+            {
+              [value | memory],
+              Map.put(labels, name, length(memory))
+            }
+
           true ->
             IO.inspect("Ignoring line: #{line}")
         end
       end)
 
-    memory =
-      Enum.map(memory, fn
-        {:label, name} -> Map.fetch!(labels, name)
-        it -> it
-      end)
+    # IO.inspect(labels)
 
-    memory =
-      if pad_length > length(memory) do
-        repeat(0, pad_length - length(memory)) ++ memory
-      else
-        memory
-      end
-
-    IO.inspect(labels)
-    Enum.reverse(memory)
+    memory
+    |> Enum.reverse()
+    |> Enum.with_index()
+    |> Enum.map(fn
+      {{:label, name}, index} -> get_label(name, index, labels)
+      {it, _} -> it
+    end)
   end
 
-  def repeat(_, 0), do: []
-  def repeat(n, count), do: [n | repeat(n, count - 1)]
+  @doc """
+  Get the address of a label.
 
+  `_self` is a special label that resolves to the address of where it's being inserted into the program.
+
+  ## Examples
+    iex> Assembler.get_label("test", 1, %{"test" => 14})
+    14
+    iex> Assembler.get_label("_self", 1, %{})
+    1
+  """
+  def get_label(name, index, labels)
+
+  def get_label("_self", index, _) do
+    index
+  end
+
+  def get_label(name, _, labels) do
+    Map.fetch!(labels, name)
+  end
+
+  @doc """
+  Raises the base to to the given power.
+
+  ## Examples
+    iex> Assembler.pow(10, 3)
+    1000
+    iex> Assembler.pow(5, 4)
+    625
+  """
   def pow(base, 1), do: base
   def pow(base, exp), do: base * pow(base, exp - 1)
 
+  @doc """
+  Parses assembly instruction parameter values and modes.
+
+  ## Examples
+    iex> Assembler.parse_params("1 2 3", [:read, :read, :read])
+    {[1, 2, 3], 11100}
+    iex> Assembler.parse_params("1 2 3", [:read, :read, :write])
+    {[1, 2, 3], 1100}
+    iex> Assembler.parse_params("1 2 $3", [:read, :read, :write])
+    {[1, 2, 3], 1100}
+    iex> Assembler.parse_params("$1 2 3", [:read, :read, :write])
+    {[1, 2, 3], 1000}
+    iex> Assembler.parse_params("$label 2 3", [:read, :read, :write])
+    {[{:label, "label"}, 2, 3], 1000}
+    iex> Assembler.parse_params("1 label 3", [:read, :read, :write])
+    {[1, {:label, "label"}, 3], 1100}
+  """
   def parse_params(params, param_types) do
     params
     |> String.split(" ")
@@ -79,74 +129,156 @@ defmodule Assembler do
     |> Enum.with_index()
     |> Enum.map_reduce(0, fn {{param, type}, index}, modes ->
       val =
-        case Regex.run(~r/^#?(\d+)$/, param) do
+        case Regex.run(~r/^\$?(\d+)$/, param) do
           [_, digits] ->
             String.to_integer(digits)
 
           _ ->
-            [_, name] = Regex.run(~r/^#(\w+)$/, param)
+            [_, name] = Regex.run(~r/^\$?(\w+)$/, param)
             {:label, name}
         end
 
       modes =
-        if type == :read && String.starts_with?(param, "#") do
-          modes + pow(10, index + 2)
-        else
-          modes
+        case type do
+          :read ->
+            if String.starts_with?(param, "$") do
+              modes
+            else
+              modes + pow(10, index + 2)
+            end
+
+          _ ->
+            modes
         end
 
       {val, modes}
     end)
   end
 
+  @doc """
+  Assembles the given instruction and adds it to the memory (in reverse order).
+  """
   def assemble_instruction(insn, memory \\ [])
 
+  @doc """
+  Assemble add instruction.
+
+  ## Examples
+    iex> Assembler.assemble_instruction("add 1 2 3")
+    [3, 2, 1, 1101]
+  """
   def assemble_instruction("add " <> params, memory) do
     {[a, b, dest], modes} = parse_params(params, [:read, :read, :write])
 
     [dest, b, a, 1 + modes | memory]
   end
 
+  @doc """
+  Assemble multiply instruction.
+
+  ## Examples
+    iex> Assembler.assemble_instruction("mul 1 2 3")
+    [3, 2, 1, 1102]
+  """
   def assemble_instruction("mul " <> params, memory) do
     {[a, b, dest], modes} = parse_params(params, [:read, :read, :write])
 
     [dest, b, a, 2 + modes | memory]
   end
 
+  @doc """
+  Assemble halt instruction.
+
+  ## Examples
+    iex> Assembler.assemble_instruction("hlt")
+    [99]
+  """
   def assemble_instruction("hlt", memory) do
     [99 | memory]
   end
 
+  @doc """
+  Assemble input instruction.
+
+  ## Examples
+    iex> Assembler.assemble_instruction("in 7")
+    [7, 3]
+  """
   def assemble_instruction("in " <> params, memory) do
     {[dest], modes} = parse_params(params, [:write])
 
     [dest, 3 + modes | memory]
   end
 
+  @doc """
+  Assemble input instruction.
+
+  ## Examples
+    iex> Assembler.assemble_instruction("out 7")
+    [7, 104]
+    iex> Assembler.assemble_instruction("out $7")
+    [7, 4]
+  """
   def assemble_instruction("out " <> params, memory) do
     {[val], modes} = parse_params(params, [:read])
 
     [val, 4 + modes | memory]
   end
 
+  @doc """
+  Assemble jump-if-non-zero instruction.
+
+  ## Examples
+    iex> Assembler.assemble_instruction("jnz 1 2")
+    [2, 1, 105]
+    iex> Assembler.assemble_instruction("jnz $var 2")
+    [2, {:label, "var"}, 5]
+  """
   def assemble_instruction("jnz " <> params, memory) do
     {[target, dest], modes} = parse_params(params, [:read, :read])
 
     [dest, target, 5 + modes | memory]
   end
 
+  @doc """
+  Assemble jump-if-zero instruction.
+
+  ## Examples
+    iex> Assembler.assemble_instruction("jez 1 2")
+    [2, 1, 106]
+    iex> Assembler.assemble_instruction("jez $var 2")
+    [2, {:label, "var"}, 6]
+  """
   def assemble_instruction("jez " <> params, memory) do
     {[target, dest], modes} = parse_params(params, [:read, :read])
 
     [dest, target, 6 + modes | memory]
   end
 
+  @doc """
+  Assemble compare-less-than instruction.
+
+  ## Examples
+    iex> Assembler.assemble_instruction("clt 1 2 3")
+    [3, 2, 1, 1107]
+    iex> Assembler.assemble_instruction("clt $1 $2 3")
+    [3, 2, 1, 7]
+  """
   def assemble_instruction("clt " <> params, memory) do
     {[a, b, dest], modes} = parse_params(params, [:read, :read, :write])
 
     [dest, b, a, 7 + modes | memory]
   end
 
+  @doc """
+  Assemble compare-equal instruction.
+
+  ## Examples
+    iex> Assembler.assemble_instruction("ceq 1 2 3")
+    [3, 2, 1, 1108]
+    iex> Assembler.assemble_instruction("ceq $1 $2 3")
+    [3, 2, 1, 8]
+  """
   def assemble_instruction("ceq " <> params, memory) do
     {[a, b, dest], modes} = parse_params(params, [:read, :read, :write])
 

lib/intcode/expression_evaluator.ex

@@ -0,0 +1,93 @@
+defmodule ExpressionEvaluator do
+  def eval(expr, vars) do
+    expr
+    |> String.to_charlist()
+    |> tokenize()
+    |> run(vars)
+
+    # |> parse()
+
+    # |> run(vars)
+  end
+
+  @digits ?0..?9
+  @alpha ?a..?z
+  @operators [?+, ?-, ?*]
+
+  def do_tokenize([first | _] = str) when first in @digits do
+    {digits, rest} = Enum.split_while(str, &(&1 in @digits))
+    num = digits |> to_string() |> String.to_integer()
+    {{:number, num}, rest}
+  end
+
+  def do_tokenize([?( | rest]) do
+    {:lparen, rest}
+  end
+
+  def do_tokenize([?) | rest]) do
+    {:rparen, rest}
+  end
+
+  def do_tokenize([op | rest]) when op in @operators do
+    atom = [op] |> to_string() |> String.to_atom()
+    {{:operator, atom}, rest}
+  end
+
+  def do_tokenize([first | _] = str) when first in @alpha do
+    {var, rest} = Enum.split_while(str, &(&1 in @alpha))
+    {{:variable, var}, rest}
+  end
+
+  def tokenize([]), do: []
+
+  def tokenize(str) do
+    {token, rest} =
+      str
+      |> Enum.drop_while(&(&1 == ?\s))
+      |> do_tokenize()
+
+    [token | tokenize(rest)]
+  end
+
+  # def to_rpn([{:number, _} = num | rest]) do
+  #  [num | to_rpn(rest)]
+  # end
+  #
+  # def to_rpn([{:operator, _} = op | rest]) do
+  #  [op | to_rpn(rest)]
+  # end
+  #
+  # def to_rpn
+
+  # def parse(tokens) do
+  #  {expr, rest} = do_parse(tokens)
+  #  [expr | 
+  # end
+
+  def run([:lparen | _] = tokens, vars) do
+    paren_tokens =
+      tokens
+      |> Enum.drop(1)
+      |> Enum.reduce_while({1, []}, fn token, {count, paren_tokens} ->
+        count =
+          case token do
+            :lparen -> count + 1
+            :rparen -> count - 1
+            _ -> count
+          end
+
+        if count == 0 do
+          {:halt, Enum.reverse(paren_tokens)}
+        else
+          {:cont, {count, [token | paren_tokens]}}
+        end
+      end)
+
+    # paren_expr = run(paren_tokens) 
+    rest_tokens = Enum.drop(tokens, length(paren_tokens))
+
+    paren_res = run(paren_tokens, vars)
+
+    run([{:number, paren_res} | rest_tokens])
+  end
+end

test/intcode/assembler_test.exs

@@ -0,0 +1,79 @@
+defmodule AssemblerTest do
+  use ExUnit.Case
+  doctest Assembler
+
+  test "assembles empty program" do
+    assert Assembler.assemble("") == []
+  end
+
+  test "assembles simple program" do
+    program = """
+      add 1 2 10
+      mul 2 3 11
+      add $10 $11 12
+      hlt
+    """
+
+    assert Assembler.assemble(program) == [
+             1101,
+             1,
+             2,
+             10,
+             1102,
+             2,
+             3,
+             11,
+             1,
+             10,
+             11,
+             12,
+             99
+           ]
+  end
+
+  test "assembles simple program with a label" do
+    program = """
+      add 1 2 10
+      jnz $10 nonZero
+    nonZero:
+      hlt
+    """
+
+    assert Assembler.assemble(program) == [
+             1101,
+             1,
+             2,
+             10,
+             1005,
+             10,
+             7,
+             99
+           ]
+  end
+
+  test "assembles a simple program with a data label" do
+    program = """
+      add 1 2 var
+      out $var
+    var: 0
+    """
+
+    assert Assembler.assemble(program) == [
+             1101,
+             1,
+             2,
+             6,
+             4,
+             6,
+             0
+           ]
+  end
+
+  test "assembles a program with a _self label" do
+    program = """
+      add 1 2 _self
+    """
+
+    assert Assembler.assemble(program) == [1101, 1, 2, 3]
+  end
+end