Assembler (#6)

Co-authored-by: Andre Wagner <WagnerAndre@JohnDeere.com>
Reviewed-on: https://192.168.5.48/andre/tyche/pulls/6

src/assembler/lexer.hh

@@ -0,0 +1,45 @@
+#ifndef TYCHE_LEXER_HH
+#define TYCHE_LEXER_HH
+
+#include <string>
+#include <utility>
+#include <variant>
+
+namespace tyche::as {
+
+enum class TokenType {
+    BOF, Directive, Instruction, Integer, Float, String, Enter, Colon, EOF_
+};
+
+using TokenValue = std::variant<std::monostate, int, float, std::string>;
+
+struct Token {
+    TokenType   type;
+    TokenValue  token = std::monostate();
+    size_t      line = 0;
+    size_t      column = 0;
+
+    friend bool operator==(Token const& lhs, Token const& rhs) { return std::tie(lhs.type, lhs.token) == std::tie(rhs.type, rhs.token); }
+};
+
+std::string token_type_name(TokenType type);
+
+class Lexer {
+public:
+    explicit Lexer(std::string source) : source_(std::move(source)) { reset(); }
+
+    void reset();
+    [[nodiscard]] Token peek() const;
+    [[nodiscard]] Token ingest();
+
+private:
+    const std::string source_;
+    size_t pos_ = 0;
+    Token current_token_ { TokenType::BOF };
+
+    void ingest_next_token();
+};
+
+} // tyche
+
+#endif //TYCHE_LEXER_HH