feat(furc): implement lexer

furc/src/main.cpp

@@ -1,7 +1,18 @@
+#include "furc/front/lexer.hpp"
+
 #include <iostream>
 
 int main(void) {
-    std::cout << "Farewell, stasiu!\n";
-
-    return 0;
+    furc::lexer lexer = { "<AK>", "func main(argc: u64) -> s32 { return '\\\\'; }" };
+    while (true) {
+        furc::token token = lexer.next_token();
+        std::cout << token.loc.filepath << ':' << token.loc.row + 1 << ':' << token.loc.col + 1 << ": " << token
+                  << '\n';
+        switch (token.type) {
+        case furc::token::UnexpectedCharacter:
+        case furc::token::UnexpectedEOF: return 1;
+        case furc::token::EndOfFile: return 0;
+        default: break;
+        }
+    }
 }