rust/syntax: explicit binds for lambda types

rust/crates/yanais-syntax/src/expr.rs

@@ -29,13 +29,17 @@ impl Parse for Lambda {
 
 #[derive(Clone, Debug)]
 pub enum Expr {
+    Infer,
+
     Literal(Literal),
 
     Use(SelIdent),
 
     Lambda(Lambda),
-    TyLambda(Lambda),
-    TyLambdaLin(Lambda),
+    TyLambda {
+        binds: Box<Expr>,
+        lam: Lambda,
+    },
     Apply(Box<Expr>, Vec<(EvEqSourceSpan, Expr)>),
 
     Record(Record<Expr>),
@@ -64,10 +68,16 @@ fn parse_minexpr(env: &mut ParseEnv<'_>) -> Result<Expr> {
             }
         }
 
+        Tok::Kw(Kw::Infer) => Ok(Expr::Infer),
         Tok::Kw(Kw::Literal(lit)) => Ok(Expr::Literal(lit)),
         Tok::Kw(Kw::Lambda) => Lambda::parse(env).map(Expr::Lambda),
-        Tok::Kw(Kw::TyLambda) => Lambda::parse(env).map(Expr::TyLambda),
-        Tok::Kw(Kw::TyLambdaLin) => Lambda::parse(env).map(Expr::TyLambdaLin),
+        Tok::Kw(Kw::TyLambda) => {
+            env.lxr.expect(Tok::LParen, Ectx::Parentheses)?;
+            let binds = Box::new(Expr::parse(env)?);
+            env.lxr.expect(Tok::RParen, Ectx::Parentheses)?;
+            let lam = Lambda::parse(env)?;
+            Ok(Expr::TyLambda { binds, lam })
+        },
 
         Tok::LParen => {
             let inner = Expr::parse(env)?;

rust/crates/yanais-syntax/src/kw.rs

@@ -14,7 +14,7 @@ pub enum Kw {
     Let,
     Lambda,
     TyLambda,
-    TyLambdaLin,
+    Infer,
 }
 
 impl MaybeParse for (EvEqSourceSpan, Literal) {
@@ -51,7 +51,7 @@ impl core::str::FromStr for Kw {
         Ok(match s {
             "λ" => Kw::Lambda,
             "Λ" => Kw::TyLambda,
-            "Λlin" => Kw::TyLambdaLin,
+            "infer" => Kw::Infer,
             "let" => Kw::Let,
             _ => return Err(()),
         })