From b933c30beaca2fc3517fd8c86316b0ddb0563956 Mon Sep 17 00:00:00 2001
From: Shadowfacts <me@shadowfacts.net>
Date: Fri, 6 Dec 2019 10:49:25 -0500
Subject: [PATCH] Intcode assembler: make immediate mode the default

---
 lib/intcode/assembler.ex | 35 +++++++++++++++++++++--------------
 1 file changed, 21 insertions(+), 14 deletions(-)

diff --git a/lib/intcode/assembler.ex b/lib/intcode/assembler.ex
index 6468e78..0c1ba2d 100644
--- a/lib/intcode/assembler.ex
+++ b/lib/intcode/assembler.ex
@@ -1,22 +1,23 @@
 defmodule Assembler do
   @asm """
-    in #res
-    clt res #8 #31
-    jnz 31 #lessThan
-    ceq res #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
@@ -83,20 +84,26 @@ 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}