support functions in let

grammar.js

@@ -38,7 +38,7 @@ module.exports = grammar({
 
     param_block : $ => seq(
       '(',
-      field('param', repeat($.identifier)),
+      field('param', repeat1($.identifier)),
       ':',
       field('type', $.expr),
       ')'
@@ -71,6 +71,7 @@ module.exports = grammar({
     binding : $ => seq(
       '(',
       $.identifier,
+      repeat($.param_block),
       ':=',
       $.expr,
       ')',

src/grammar.json

@@ -92,7 +92,7 @@
           "type": "FIELD",
           "name": "param",
           "content": {
-            "type": "REPEAT",
+            "type": "REPEAT1",
             "content": {
               "type": "SYMBOL",
               "name": "identifier"
@@ -254,6 +254,13 @@
           "type": "SYMBOL",
           "name": "identifier"
         },
+        {
+          "type": "REPEAT",
+          "content": {
+            "type": "SYMBOL",
+            "name": "param_block"
+          }
+        },
         {
           "type": "STRING",
           "value": ":="

src/node-types.json

@@ -91,6 +91,10 @@
         {
           "type": "identifier",
           "named": true
+        },
+        {
+          "type": "param_block",
+          "named": true
         }
       ]
     }
@@ -215,7 +219,7 @@
     "fields": {
       "param": {
         "multiple": true,
-        "required": false,
+        "required": true,
         "types": [
           {
             "type": "identifier",

test/corpus/let.txt

@@ -4,6 +4,7 @@ Let
 
 foo := let (x := a)
            (y := x)
+           (f (x : A) := x)
        in
            x
        end;
@@ -30,6 +31,20 @@ foo := let (x := a)
                 (app
                   (term
                     (identifier))))))
+          (binding
+            (identifier)
+            (param_block
+              (identifier)
+              (expr
+                (app_term
+                  (app
+                    (term
+                      (identifier))))))
+            (expr
+              (app_term
+                (app
+                  (term
+                    (identifier))))))
           (expr
             (app_term
               (app