From 36ea4a177d8a2f34a7b7ec07a580eeb5305b37ef Mon Sep 17 00:00:00 2001
From: Shadowfacts <me@shadowfacts.net>
Date: Fri, 6 Dec 2019 10:32:41 -0500
Subject: [PATCH] Intcode assembler: add data labels

---
 lib/intcode/assembler.ex | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/lib/intcode/assembler.ex b/lib/intcode/assembler.ex
index b01e3cc..6468e78 100644
--- a/lib/intcode/assembler.ex
+++ b/lib/intcode/assembler.ex
@@ -1,9 +1,9 @@
 defmodule Assembler do
   @asm """
-    in #30
-    clt 30 #8 #31
+    in #res
+    clt res #8 #31
     jnz 31 #lessThan
-    ceq 30 #8 #31
+    ceq res #8 #31
     jnz 31 #equal
     out #1001
     hlt
@@ -15,14 +15,16 @@ defmodule Assembler do
   equal:
     out #1000
     hlt
+
+  res: 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")
@@ -44,6 +46,15 @@ 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
@@ -55,13 +66,6 @@ defmodule Assembler do
         it -> it
       end)
 
-    memory =
-      if pad_length > length(memory) do
-        repeat(0, pad_length - length(memory)) ++ memory
-      else
-        memory
-      end
-
     IO.inspect(labels)
     Enum.reverse(memory)
   end
@@ -84,7 +88,7 @@ defmodule Assembler do
             String.to_integer(digits)
 
           _ ->
-            [_, name] = Regex.run(~r/^#(\w+)$/, param)
+            [_, name] = Regex.run(~r/^#?(\w+)$/, param)
             {:label, name}
         end