Wrote a new lexer API in C++

Essentially a refactor of the C formed lexer into C++ style.  I can
already see some benefits from doing this, in particular speed of
prototyping.

asm/lexer.hpp

@@ -0,0 +1,96 @@
+/* Copyright (C) 2024 Aryadev Chavali
+
+ * You may distribute and modify this code under the terms of the
+ * GPLv2 license.  You should have received a copy of the GPLv2
+ * license with this file.  If not, please write to:
+ * aryadev@aryadevchavali.com.
+
+ * Created: 2024-04-14
+ * Author: Aryadev Chavali
+ * Description: Lexer for assembly language
+ */
+
+#ifndef LEXER_HPP
+#define LEXER_HPP
+
+#include <ostream>
+#include <string>
+#include <tuple>
+#include <vector>
+
+enum token_type_t
+{
+  PP_CONST,     // %const(<symbol>)...
+  PP_USE,       // %use <string>
+  PP_END,       // %end
+  PP_REFERENCE, // $<symbol>
+  GLOBAL,
+  STAR,
+  LITERAL_NUMBER,
+  LITERAL_CHAR,
+  LITERAL_STRING,
+  NOOP,
+  HALT,
+  PUSH,
+  POP,
+  PUSH_REG,
+  MOV,
+  DUP,
+  MALLOC,
+  MALLOC_STACK,
+  MSET,
+  MSET_STACK,
+  MGET,
+  MGET_STACK,
+  MDELETE,
+  MSIZE,
+  NOT,
+  OR,
+  AND,
+  XOR,
+  EQ,
+  LT,
+  LTE,
+  GT,
+  GTE,
+  PLUS,
+  SUB,
+  MULT,
+  PRINT,
+  JUMP_ABS,
+  JUMP_STACK,
+  JUMP_IF,
+  CALL,
+  CALL_STACK,
+  RET,
+  SYMBOL,
+};
+
+const char *token_type_as_cstr(token_type_t type);
+
+struct token_t
+{
+  token_type_t type;
+  size_t column, line;
+  std::string content;
+
+  token_t();
+  token_t(token_type_t, std::string, size_t col = 0, size_t line = 0);
+};
+
+std::ostream &operator<<(std::ostream &, token_t &);
+
+enum lerr_t
+{
+  OK = 0,
+  INVALID_CHAR_LITERAL,
+  INVALID_CHAR_LITERAL_ESCAPE_SEQUENCE,
+  INVALID_STRING_LITERAL,
+  INVALID_NUMBER_LITERAL,
+  INVALID_PREPROCESSOR_DIRECTIVE,
+};
+const char *lerr_as_cstr(lerr_t);
+
+lerr_t tokenise_string(std::string_view, std::vector<token_t> &);
+
+#endif