Make it parse let-expressions

tools/lsp/pascaligo/grammar.js

@@ -181,11 +181,11 @@ module.exports = grammar({
           ':',
           field("type", $._type_expr),
           'is',
-          field("body", $._let_expr),
+          field("body", $.let_expr),
         ),
       ),
 
-    _let_expr: $ =>
+    let_expr: $ =>
       choice(
         seq(
           field("locals", $.block),

tools/lsp/squirrel/src/AST/Parser.hs

@@ -27,8 +27,8 @@ declaration :: Parser (Declaration Range)
 declaration =
   stubbed "declaration" do
     field "declaration" do
-      (b, info) <- range binding
-      return (ValueDecl info b)
+        (b, info) <- range binding
+        return (ValueDecl info b)
 
 par x = do
   consume "("
@@ -63,12 +63,38 @@ binding = do
         field "type" type_
     consume "is"
     exp <- stubbed "body" do
-      field "expr" expr
+      field "body" letExpr
     return (Function info (recur == Just "recursive") name params ty exp)
 
 expr :: Parser (Expr Range)
-expr = do
-  fallback "expr"
+expr = select
+  [ Ident <$> getRange <*> name
+  -- , ident
+  -- , constant
+  ]
+  where
+  -- $.case_expr,
+  -- $.cond_expr,
+  -- $.disj_expr,
+  -- $.fun_expr,
+
+letExpr = do
+  subtree "let_expr" do
+    r <- getRange
+    decls <- optional do
+      field "locals" do
+        subtree "block" do
+          many "decl" do
+            field "statement" do
+              declaration
+    body <- field "body" do
+      -- gets pfGrove >>= traceShowM
+      stubbed "expr" do
+        expr
+
+    return case decls of
+      Just them -> Let r them body
+      Nothing   -> body
 
 paramDecl :: Parser (VarDecl Range)
 paramDecl = do

tools/lsp/squirrel/src/AST/Types.hs

@@ -34,6 +34,8 @@ instance Stubbed (Declaration info) where stub = WrongDecl
 data Binding info
   = Irrefutable  info (Pattern info) (Expr info)
   | Function     info Bool (Name info) [VarDecl info] (Type info) (Expr info)
+  | Var          info (Name info) (Type info) (Expr info)
+  | Const        info (Name info) (Type info) (Expr info)
   | WrongBinding      Error
   deriving (Show) via PP (Binding info)
 
@@ -71,7 +73,7 @@ data Expr info
   = Let       info [Declaration info] (Expr info)
   | Apply     info (Expr info) [Expr info]
   | Constant  info (Constant info)
-  | Ident     info (QualifiedName info)
+  | Ident     info (Name info)
   | WrongExpr      Error
   deriving (Show) via PP (Expr info)
 
@@ -151,6 +153,16 @@ instance Pretty (Binding i) where
         )
         2
         (pp body)
+    Var   _ name ty value ->
+      hang
+        ("var" <+> pp name <+> ":" <+> pp ty <+> ":=")
+        2
+        (pp value)
+    Const _ name ty body ->
+      hang
+        ("var" <+> pp name <+> ":" <+> pp ty <+> "=")
+        2
+        (pp body)
     WrongBinding err ->
       pp err
 
@@ -187,8 +199,8 @@ instance Pretty (Type i) where
 
 instance Pretty (Expr i) where
   pp = \case
-    Let       _ decls body -> hang "let" 2 (vcat $ map pp decls)
-                           <> hang "in"  2 (pp body)
+    Let       _ decls body -> hang "block {" 2 (vcat $ map pp decls)
+                           $$ hang "} with"  2 (pp body)
     Apply     _ f xs       -> pp f <> tuple xs
     Constant  _ constant   -> pp constant
     Ident     _ qname      -> pp qname