some things

src/lib.rs

@@ -0,0 +1,82 @@
+use logos::Logos;
+
+mod lexer {
+    use logos::Logos;
+
+    #[derive(Logos, Clone, Eq, PartialEq, Hash)]
+    pub enum Token<'a> {
+        #[token("λ")]
+        Lambda,
+
+        #[token(".")]
+        Dot,
+
+        #[token(":=")]
+        Binding,
+
+        #[token("(")]
+        ParenO,
+
+        #[token(")")]
+        ParenC,
+
+        #[regex("[a-zA-Z]+")]
+        Ident(&'a str),
+
+        #[error]
+        #[regex(r"[ \t\r\n]+", logos::skip)]
+        Error,
+    }
+}
+
+mod parser {
+    use crate::lexer::Token;
+    use chumsky::prelude::*;
+
+    enum Expr {
+        Name(String),
+        Application {
+            function: Box<Expr>,
+            argument: Box<Expr>,
+        },
+        Abstraction {
+            args: Vec<String>,
+            body: Expr,
+        },
+    }
+
+    fn expr_parser<'a>() -> impl Parser<Token<'a>, Spanned<Expr>, Error = Simple<Token<'a>>> + Clone
+    {
+        recursive(|expr| {
+            let variable = filter_map(|span, token| match token {
+                Token::Ident(name) => Ok(Expr::Name(name.to_string())),
+                _ => Err(Simple::expected_input_found(span, [], Some(token))),
+            })
+            .labelled("variable");
+
+            let abstraction = just(Token::Lambda)
+                .ignore_then(variable)
+                .then(Token::Dot)
+                .then(expr.clone());
+
+            let application = just(expr).then(expr.clone());
+
+            let atom = variable
+                .or(expr.delimited_by(Token::ParenO, Token::ParenC))
+                .or(abstraction)
+                .or(application);
+
+            let binding = just(variable)
+                .then_ignore(Token::Binding)
+                .then(expr.clone());
+
+            let statement = just(expr.clone()).or(binding);
+
+            todo!()
+        })
+    }
+}
+
+pub fn run(input: &str) {
+    let mut lex = lexer::Token::lexer(input);
+}

src/main.rs

@@ -1,3 +1,3 @@
 fn main() {
-    println!("Hello, world!");
+    lambda_calculus::run("hello");
 }