From 8332da3dddbe564c5cdf56a5b5081e8a21b48760 Mon Sep 17 00:00:00 2001
From: Michael Kohn <mike@mikekohn.net>
Date: Thu, 17 Oct 2024 20:14:28 -0500
Subject: [PATCH] Separating out Operator from eval_expression.

---
 common/Operator.cpp | 124 ++++++++++++++++++++++++++++++++++++++++++++
 common/Operator.h   |  70 +++++++++++++++++++++++++
 2 files changed, 194 insertions(+)
 create mode 100644 common/Operator.cpp
 create mode 100644 common/Operator.h

diff --git a/common/Operator.cpp b/common/Operator.cpp
new file mode 100644
index 00000000..394c6d8c
--- /dev/null
+++ b/common/Operator.cpp
@@ -0,0 +1,124 @@
+/**
+ *  naken_asm assembler.
+ *  Author: Michael Kohn
+ *   Email: mike@mikekohn.net
+ *     Web: https://www.mikekohn.net/
+ * License: GPLv3
+ *
+ * Copyright 2010-2024 by Michael Kohn
+ *
+ */
+
+#include "Operator.h"
+
+bool Operator::is_math_operator(const char *token)
+{
+  if (token[1] != 0) { return false; }
+
+  switch (token[0])
+  {
+    case '*':
+    case '/':
+    case '%':
+    case '+':
+    case '-':
+    case '&':
+    case '^':
+    case '|':
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool Operator::set_operator(const char *token)
+{
+  // Single character token.
+  if (token[1] == 0)
+  {
+    switch (token[0])
+    {
+      case '~':
+        precedence = PREC_NOT;
+        operation  = OPER_NOT;
+        break;
+      case '*':
+        precedence = PREC_MUL;
+        operation  = OPER_MUL;
+        break;
+      case '/':
+        precedence = PREC_MUL;
+        operation = OPER_DIV;
+        break;
+      case '%':
+        precedence = PREC_MUL;
+        operation = OPER_MOD;
+        break;
+      case '+':
+        precedence = PREC_ADD;
+        operation = OPER_PLUS;
+        break;
+      case '-':
+        precedence = PREC_ADD;
+        operation = OPER_MINUS;
+        break;
+      case '&':
+        precedence = PREC_AND;
+        operation = OPER_AND;
+        break;
+      case '^':
+        precedence = PREC_XOR;
+        operation = OPER_XOR;
+        break;
+      case '|':
+        precedence = PREC_OR;
+        operation = OPER_OR;
+        break;
+      default:
+        return false;
+    }
+
+    return true;
+  }
+
+  // If token is more than 2 characters, return false.
+  if (token[2] != 0) { return false; }
+
+  if (token[0] == '<' && token[1] == '<')
+  {
+    precedence = PREC_SHIFT;
+    operation = OPER_LEFT_SHIFT;
+    return true;
+  }
+    else
+  if (token[0] == '>' && token[1] == '>')
+  {
+    precedence = PREC_SHIFT;
+    operation = OPER_RIGHT_SHIFT;
+    return true;
+  }
+
+  return false;
+}
+
+const char *Operator::to_string()
+{
+  const char *s[] =
+  {
+    "",   // OPER_UNSET:
+    "~",  // OPER_NOT:
+    "*",  // OPER_MUL:
+    "/",  // OPER_DIV:
+    "%",  // OPER_MOD:
+    "+",  // OPER_PLUS:
+    "-",  // OPER_MINUS:
+    "<<", // OPER_LEFT_SHIFT:
+    ">>", // OPER_RIGHT_SHIFT:
+    "&",  // OPER_AND:
+    "^",  // OPER_XOR:
+    "|"   // OPER_OR::
+  };
+
+  return s[operation];
+}
+
diff --git a/common/Operator.h b/common/Operator.h
new file mode 100644
index 00000000..5b9bc6d4
--- /dev/null
+++ b/common/Operator.h
@@ -0,0 +1,70 @@
+/**
+ *  naken_asm assembler.
+ *  Author: Michael Kohn
+ *   Email: mike@mikekohn.net
+ *     Web: https://www.mikekohn.net/
+ * License: GPLv3
+ *
+ * Copyright 2010-2024 by Michael Kohn
+ *
+ */
+
+#ifndef NAKEN_ASM_OPERATOR_H
+#define NAKEN_ASM_OPERATOR_H
+
+class Operator
+{
+public:
+  Operator() :
+    operation  (OPER_UNSET),
+    precedence (PREC_UNSET)
+  {
+  }
+
+  bool is_unset() { return operation == OPER_UNSET; }
+  bool is_set()   { return operation != OPER_UNSET; }
+
+  void reset()
+  {
+    operation  = OPER_UNSET;
+    precedence = PREC_UNSET;
+  }
+
+  bool is_math_operator(const char *token);
+  bool set_operator(const char *token);
+  const char *to_string();
+
+  enum
+  {
+    PREC_NOT,
+    PREC_MUL,
+    PREC_ADD,
+    PREC_SHIFT,
+    PREC_AND,
+    PREC_XOR,
+    PREC_OR,
+    PREC_UNSET
+  };
+
+  enum
+  {
+    OPER_UNSET,
+    OPER_NOT,
+    OPER_MUL,
+    OPER_DIV,
+    OPER_MOD,
+    OPER_PLUS,
+    OPER_MINUS,
+    OPER_LEFT_SHIFT,
+    OPER_RIGHT_SHIFT,
+    OPER_AND,
+    OPER_XOR,
+    OPER_OR
+  };
+
+  int operation;
+  int precedence;
+};
+
+#endif
+