From 3dce44334d4d6d1d00e4875c4cbec07ad56fac39 Mon Sep 17 00:00:00 2001
From: Nick Krichevsky <nick@ollien.com>
Date: Thu, 5 Dec 2019 01:56:18 -0500
Subject: [PATCH] Give position mode constants proper names, minor day 5
 cleanup

---
 day5/py/main.py | 33 +++++++++++++++++++--------------
 1 file changed, 19 insertions(+), 14 deletions(-)

diff --git a/day5/py/main.py b/day5/py/main.py
index a00dda8..df1c873 100644
--- a/day5/py/main.py
+++ b/day5/py/main.py
@@ -1,5 +1,5 @@
 import sys
-from typing import List, Tuple, Optional
+from typing import Iterable, List, Tuple, Optional
 
 
 # Halt indicates that the assembled program should terminate
@@ -7,6 +7,7 @@ class Halt(Exception):
     pass
 
 
+# Operation represents an operation that the intcode computer should do
 class Operation:
     OPCODE_TERMINATE = 99
     OPCODE_ADD = 1
@@ -17,19 +18,19 @@ class Operation:
     OPCODE_JUMP_IF_FALSE = 6
     OPCODE_LESS_THAN = 7
     OPCODE_EQUALS = 8
-    MODE_PARAMETER = 0
+    MODE_POSITION = 0
     MODE_IMMEDIATE = 1
-    OPCODE__ALLS = (OPCODE_TERMINATE, OPCODE_ADD, OPCODE_MULTIPLY, OPCODE_INPUT, OPCODE_OUTPUT,
-                    OPCODE_JUMP_IF_TRUE, OPCODE_JUMP_IF_FALSE, OPCODE_LESS_THAN, OPCODE_EQUALS)
+    ALL_OPCODES = (OPCODE_TERMINATE, OPCODE_ADD, OPCODE_MULTIPLY, OPCODE_INPUT, OPCODE_OUTPUT,
+                   OPCODE_JUMP_IF_TRUE, OPCODE_JUMP_IF_FALSE, OPCODE_LESS_THAN, OPCODE_EQUALS)
 
     def __init__(self, instruction: int):
         # The opcode is the first two digits of the number, the rest are parameter modes
         self.opcode: int = instruction % 100
-        if self.opcode not in Operation.OPCODE__ALLS:
+        if self.opcode not in Operation.ALL_OPCODES:
             raise ValueError(f"Bad opcode: {self.opcode}")
-        self.modes: Tuple[int] = self._extract_parameter_modes(instruction//100)
+        self.modes: Tuple[int, ...] = self._extract_parameter_modes(instruction//100)
 
-    def _extract_parameter_modes(self, raw_modes) -> Tuple[int]:
+    def _extract_parameter_modes(self, raw_modes) -> Tuple[int, ...]:
         PARAMETER_COUNTS = {
             Operation.OPCODE_TERMINATE: 0,
             Operation.OPCODE_ADD: 3,
@@ -41,11 +42,12 @@ class Operation:
             Operation.OPCODE_LESS_THAN: 3,
             Operation.OPCODE_EQUALS: 3,
         }
+        # Opcodes that write to memory as their last parameter
         MEMORY_OPCODES = (Operation.OPCODE_ADD, Operation.OPCODE_MULTIPLY, Operation.OPCODE_INPUT,
                           Operation.OPCODE_LESS_THAN, Operation.OPCODE_EQUALS)
 
         num_parameters = PARAMETER_COUNTS[self.opcode]
-        modes = [Operation.MODE_PARAMETER for i in range(num_parameters)]
+        modes = [Operation.MODE_POSITION for i in range(num_parameters)]
         mode_str = str(raw_modes)
         # Iterate over the modes digits backwards, assigning them to the parameter list until we exhaust the modes
         # The rest must be leading zeroes
@@ -53,7 +55,8 @@ class Operation:
             modes[mode_index] = int(digit)
 
         # The last argument (the address parameter) must always be in immediate mode
-
+        # The problem statement is misleading in this regard. You do NOT want to get an address to store the value
+        # at from another address.
         if self.opcode in MEMORY_OPCODES:
             modes[-1] = Operation.MODE_IMMEDIATE
 
@@ -61,7 +64,7 @@ class Operation:
 
     # Run the given operation, starting at the given instruction pointer
     # Returns the address that the instruction pointer should become
-    def run(self, memory: List[int], instruction_pointer: int, program_input=None) -> int:
+    def run(self, memory: List[int], instruction_pointer: int, program_input: Optional[int] = None) -> int:
         OPERATION_FUNCS = {
             # nop for terminate
             Operation.OPCODE_TERMINATE: Operation.terminate,
@@ -80,7 +83,7 @@ class Operation:
             # Add 1 to move past the opcode itself
             pointer = instruction_pointer + i + 1
             arg = memory[pointer]
-            if mode == Operation.MODE_PARAMETER:
+            if mode == Operation.MODE_POSITION:
                 arg = memory[arg]
             elif mode != Operation.MODE_IMMEDIATE:
                 raise ValueError(f"Invalid parameter mode {mode}")
@@ -88,10 +91,10 @@ class Operation:
             args.append(arg)
 
         func = OPERATION_FUNCS[self.opcode]
-        if program_input is not None:
-            jump_addr = func(memory, program_input, *args)
-        else:
+        if program_input is None:
             jump_addr = func(memory, *args)
+        else:
+            jump_addr = func(memory, program_input, *args)
 
         if jump_addr is not None:
             return jump_addr
@@ -169,5 +172,7 @@ if __name__ == "__main__":
     with open(sys.argv[1]) as f:
         inputs = [int(item) for item in f.read().rstrip().split(",")]
 
+    print("PART 1")
     part1(inputs)
+    print("PART 2")
     part2(inputs)