Officially The Messiest Code Ever

messiestever.cpp

#include <map>
#include <list>
#include <string>
#include <iostream>

using namespace std;

enum struct token_type {
	ID, // identifier
	HEX, // hexidecimal integer
	DEC, // decimal integer
	OCT, // octal integer
	BIN, // binary integer
	COMMA, // comma
	DOT, // full stop/dot/period
	COLON, // colon
	SEMI, // semi-colon
	STRING, // double-quote delimited string
	NL, // newline
};

struct token {
	token_type type;
	string value;
	token(token_type type, string value) : type(type), value(value) {}
};

enum struct instr_type {
	SET,
	ADD, SUB,
	MUL, MLI,
	DIV, DVI,
	MOD, MDI,
	AND, BOR, XOR,
	SHR, ASR, SHL,
	IFB, IFC,
	IFE, IFN,
	IFG, IFA,
	IFL, IFU,
};

enum struct value_type {
	REG, // register - 00-07 REGISTER, 1B SP, 1C PC, 1D EX
	LIT, // literal - 1F NEXT WORD and 20-3F LITERAL VALUE.
	STK, // stack - 18 PUSH/POP, 19 PEEK, 1A PICK
	RVL, // register value - 08-0F [REGISTER] if value is 0, 10-17 [REGISTER + NEXT WORD] otherwise
	NVL, // next value - 1E [NEXT WORD]
};

struct value {
	value_type type;
	int value;
};

struct instruction {
	instr_type type;
	list<value> values;
};

list<token>
tokenise(string::iterator begin, string::iterator end)
{
	list<token> tokens;

	string::iterator iter = begin;
	while (iter != end) {
		cout << *iter;
		if (*iter == ',') {
			tokens.emplace_back(token_type::COMMA, ",");
			++iter;
		}
		else if (*iter == '.') {
			tokens.emplace_back(token_type::DOT, ".");
			++iter;
		}
		else if (*iter == '\n') {
			tokens.emplace_back(token_type::NL, "\n");
			++iter;
		}
		else if (*iter == ':') {
			tokens.emplace_back(token_type::COLON, ":");
			++iter;
		}
		else if (*iter == ';') {
			tokens.emplace_back(token_type::SEMI, ";");
			++iter;
		}
		else if (*iter == '"') {
			string str = "";
			++iter;
			while (iter != end && *iter != '"') {
				str.push_back(*iter);
				++iter;
			}

			// Skip final quotation mark
			if (iter != end) ++iter;

			tokens.emplace_back(token_type::STRING, str);
			continue;
	        }
		else if (*iter == ' ') {
			++iter;
		}
		else if (*iter == '0') {
			cout << *iter << "advancing next character" << endl;
			++iter;
			cout << *iter << "advanced to next character" << endl;
			if (iter == end || *iter == ' ') {
				cout << *iter << "end or space" << endl;
				tokens.emplace_back(token_type::DEC, "0");
			}
			else if (*iter == 'o' || *iter >= '0' && *iter <= '7') {
				// octal
				string tok;
			
				// skip the octal designator
				if (*iter == 'o') ++iter;

				while (iter != end && *iter != ' ') {
					tok.push_back(*iter);
					++iter;
				}
				tokens.emplace_back(token_type::OCT, tok);
			}
			else if (*iter == 'x') {
				// hexidecimal
				string tok;

				// skip the hex designator
				++iter;

				while (iter != end && *iter != ' ') {
					tok.push_back(*iter);
					++iter;
				}
				tokens.emplace_back(token_type::HEX, tok);
			}
			else if (*iter == 'b') {
				// binary
				string tok;

				// skip the binary designator
				++iter;

				while (iter != end && *iter != ' ') {
					tok.push_back(*iter);
					++iter;
				}
				tokens.emplace_back(token_type::BIN, tok);
			}
			continue;
		}
		else {
			// ident | decimal
			if (*iter >= '0' && *iter <= '9') {
				// decimal
				string tok;

				while (iter != end && *iter != ' ') {
					tok.push_back(*iter);
					++iter;
				}
				tokens.emplace_back(token_type::DEC, tok);
			}
			else if (*iter == '_' ||
				 *iter >= 'A' && *iter <= 'Z' ||
				 *iter >= 'a' && *iter <= 'z') {
				// identifier
				string tok;

				while (iter != end &&
				       (*iter == '_' ||
					*iter >= 'A' && *iter <= 'Z' ||
					*iter >= 'a' && *iter <= 'z')) {
					tok.push_back(*iter);
					++iter;
				}
				tokens.emplace_back(token_type::ID, tok);
			}
		}
	} // end while-loop

	return tokens;
} // end function

int main()
{
	// string str = "0123 \"0b123\" 0x123";
	string str = "set pc, 0x123";

	map<token_type, string> tt_index;
	
	tt_index[token_type::ID] = "identifier";
	tt_index[token_type::HEX] = "hexidecimal integer";
	tt_index[token_type::DEC] = "decimal integer";
	tt_index[token_type::OCT] = "octal integer";
	tt_index[token_type::BIN] = "binary integer";
	tt_index[token_type::COMMA] = "comma";
	tt_index[token_type::DOT] = "full stop/dot/period";
	tt_index[token_type::COLON] = "colon";
	tt_index[token_type::SEMI] = "semi-colon";
	tt_index[token_type::STRING] = "double-quote delimited string";
	tt_index[token_type::NL] = "newline";

	list<token> tokens = tokenise(begin(str), end(str));

	cout << endl << endl << "==PRINTING NEXT TOKEN==" << endl;

	for (token& tok : tokens) {
		cout << "[" << tt_index[tok.type] << ":" << tok.value << ']' << endl;
	}

	return 0;

}

There's a 120-line function.