Added the beginning of the language

src/lang.h

@@ -11,4 +11,50 @@
 
 namespace fs = std::filesystem;
 
+enum class TokenType {
+  LEFT_PAREN,
+  RIGHT_PAREN,
+  COLONCOLON,
+  STRING,
+  INTRINSIC,
+  CONSTANT
+};
+enum class Intrinsic { LET, UNLET, ENTER, EXIT, SHOW, HIDE };
+enum class Constant { Character, Location, Image };
+
+struct Token {
+  TokenType type;
+  std::string value;
+};
+
+struct IntrinsicToken : Token {
+  Intrinsic intrinsic;
+};
+
+struct ConstantToken : Token {
+  Constant constant;
+};
+
+struct StringToken : Token {
+  std::string string;
+};
+
+std::map<std::string, Token> tokens = {
+    {"(", Token{TokenType::LEFT_PAREN, "("}},
+    {")", Token{TokenType::RIGHT_PAREN, ")"}},
+    {"::", Token{TokenType::COLONCOLON, "::"}},
+    {"let", IntrinsicToken{TokenType::INTRINSIC, "let", Intrinsic::LET}},
+    {"unlet", IntrinsicToken{TokenType::INTRINSIC, "unlet", Intrinsic::UNLET}},
+    {"enter", IntrinsicToken{TokenType::INTRINSIC, "enter", Intrinsic::ENTER}},
+    {"exit", IntrinsicToken{TokenType::INTRINSIC, "exit", Intrinsic::EXIT}},
+    {"show", IntrinsicToken{TokenType::INTRINSIC, "show", Intrinsic::SHOW}},
+    {"hide", IntrinsicToken{TokenType::INTRINSIC, "hide", Intrinsic::HIDE}},
+    {"Character",
+     ConstantToken{TokenType::CONSTANT, "Character", Constant::Character}},
+    {"Location",
+     ConstantToken{TokenType::CONSTANT, "Location", Constant::Location}},
+    {"Image", ConstantToken{TokenType::CONSTANT, "Image", Constant::Image}},
+};
+
 int read_file(std::deque<std::string> args);
+int parse_line(std::istream stream);