feat(lexer): Finish lexer parse and add tests

src/frontend/types.rs

@@ -0,0 +1,41 @@
+use strum::EnumString;
+
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Token {
+    pub value: TokenValue,
+    pub span: Span,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Span {
+    pub line: usize,
+    pub column: usize,
+    pub length: usize,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum TokenValue {
+    IntLit(i64), // TODO: more literal types
+    Ident(String),
+    TypeIdent(TypeIdent),
+    
+    Plus, Minus, Star, Slash, Percent,
+    Equal, DoubleEqual, NotEqual, Less, LessEqual, Greater, GreaterEqual,
+
+    LParen, RParen,
+    LBrace, RBrace,
+    Comma, Semicolon,
+
+    If, Else, While, Return, Break, Continue,
+
+    Eof,
+    Unrecognized(char),
+}
+#[derive(Debug, Clone, PartialEq, Eq, EnumString)]
+pub enum TypeIdent {
+    #[strum(serialize = "int")]
+    Int,
+    #[strum(serialize = "void")]
+    Void,
+}