From 96d070c3700692858035f3524cc0ad944cef2594 Mon Sep 17 00:00:00 2001
From: Matthew Toohey <contact@mtoohey.com>
Date: Sun, 21 Jan 2024 20:56:11 -0500
Subject: [PATCH] fix handling of trailing lambdas in matchexpr

---
 src/scanner.c          | 18 ++++++++++-
 test/corpus/corpus.txt | 70 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 87 insertions(+), 1 deletion(-)

diff --git a/src/scanner.c b/src/scanner.c
index d7ec06d..31658c4 100644
--- a/src/scanner.c
+++ b/src/scanner.c
@@ -1,5 +1,4 @@
 #include <assert.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <tree_sitter/parser.h>
@@ -14,6 +13,7 @@ enum TokenType {
 
 struct scanner {
   int close_braces_to_insert;
+  bool insert_open_brace;
   int semis_to_insert;
   bool no_final_semi_insert;
   bool eof_semi_inserted;
@@ -25,6 +25,7 @@ struct scanner {
 
 void scanner_reset(struct scanner *scanner) {
   scanner->close_braces_to_insert = 0;
+  scanner->insert_open_brace = false;
   scanner->semis_to_insert = 0;
   scanner->no_final_semi_insert = false;
   scanner->eof_semi_inserted = false;
@@ -191,6 +192,12 @@ bool tree_sitter_koka_external_scanner_scan(void *payload, TSLexer *lexer,
     lexer->result_symbol = Semi;
     return true;
   }
+  if (scanner->insert_open_brace) {
+    scanner->insert_open_brace = false;
+    if (valid_symbols[OpenBrace])
+      lexer->result_symbol = OpenBrace;
+    return true;
+  }
 
   lexer->mark_end(lexer);
 
@@ -302,6 +309,15 @@ bool tree_sitter_koka_external_scanner_scan(void *payload, TSLexer *lexer,
         scanner->no_final_semi_insert = true;
       }
       lexer->result_symbol = Semi;
+
+      prev_indent_length =
+          scanner->stack_len != 0 ? scanner->stack[scanner->stack_len - 1] : 0;
+      if (prev_indent_length < indent_length) {
+        scanner->insert_open_brace = true;
+        scanner_push_indent(scanner, indent_length);
+        scanner->no_final_semi_insert = true;
+      }
+
       return true;
     }
   }
diff --git a/test/corpus/corpus.txt b/test/corpus/corpus.txt
index f9e49fc..b4b7ab7 100644
--- a/test/corpus/corpus.txt
+++ b/test/corpus/corpus.txt
@@ -3074,3 +3074,73 @@ fun foo()
                                           (atom
                                             (literal
                                               (int))))))))))))))))))))))))
+
+=========================
+block argument with mask
+=========================
+
+fun foo() {
+  match mask<bar>
+      baz
+    Quux -> 32
+
+---
+
+(program
+  (moduledecl)
+  (modulebody
+    (topdecl
+      (puredecl
+        (funid
+          (identifier
+            (varid
+              (id))))
+        (funbody
+          (bodyexpr
+            (blockexpr
+              (expr
+                (block
+                  (statements
+                    (statement
+                      (basicexpr
+                        (matchexpr
+                          (expr
+                            (basicexpr
+                              (opexpr
+                                (prefixexpr
+                                  (appexpr
+                                    (appexpr
+                                      (atom
+                                        (mask
+                                          (tbasic
+                                            (typeapp
+                                              (typecon
+                                                (varid
+                                                  (id))))))))
+                                    (block
+                                      (statements
+                                        (statement
+                                          (basicexpr
+                                            (opexpr
+                                              (prefixexpr
+                                                (appexpr
+                                                  (atom
+                                                    (qidentifier
+                                                      (identifier
+                                                        (varid
+                                                          (id)))))))))))))))))
+                          (matchrules
+                            (matchrule
+                              (patterns
+                                (pattern
+                                  (qconstructor
+                                    (conid))))
+                              (blockexpr
+                                (expr
+                                  (basicexpr
+                                    (opexpr
+                                      (prefixexpr
+                                        (appexpr
+                                          (atom
+                                            (literal
+                                              (int))))))))))))))))))))))))