From 8858161484c1903bfd2de2f21a765738ff2d7fd3 Mon Sep 17 00:00:00 2001
From: jclc <jclc@protonmail.com>
Date: Wed, 4 Apr 2018 05:11:59 +0300
Subject: [PATCH 1/4] skip UTF-8 BOM

---
 src/vm/wren_compiler.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/vm/wren_compiler.c b/src/vm/wren_compiler.c
index 66af1432..c7f0de37 100644
--- a/src/vm/wren_compiler.c
+++ b/src/vm/wren_compiler.c
@@ -3416,20 +3416,27 @@ void definition(Compiler* compiler)
 ObjFn* wrenCompile(WrenVM* vm, ObjModule* module, const char* source,
                    bool isExpression, bool printErrors)
 {
+  // Skip potential UTF-8 BOM
+  size_t sourceOffset = 0;
+  if (source[0] == (char) 0xef && source[1] == (char) 0xbb && source[2] == (char) 0xbf)
+  {
+    sourceOffset = 3;
+  }
+
   Parser parser;
   parser.vm = vm;
   parser.module = module;
-  parser.source = source;
+  parser.source = source + sourceOffset;
 
-  parser.tokenStart = source;
-  parser.currentChar = source;
+  parser.tokenStart = source + sourceOffset;
+  parser.currentChar = source + sourceOffset;
   parser.currentLine = 1;
   parser.numParens = 0;
 
   // Zero-init the current token. This will get copied to previous when
   // advance() is called below.
   parser.current.type = TOKEN_ERROR;
-  parser.current.start = source;
+  parser.current.start = source + sourceOffset;
   parser.current.length = 0;
   parser.current.line = 0;
   parser.current.value = UNDEFINED_VAL;
@@ -3439,6 +3446,7 @@ ObjFn* wrenCompile(WrenVM* vm, ObjModule* module, const char* source,
   parser.printErrors = printErrors;
   parser.hasError = false;
 
+
   // Read the first token.
   nextToken(&parser);
 

From fe2ca0e89a87a7e0ef1787cf5c963677924c2b75 Mon Sep 17 00:00:00 2001
From: jclc <jclc@protonmail.com>
Date: Wed, 4 Apr 2018 05:14:05 +0300
Subject: [PATCH 2/4] remove extra line

---
 src/vm/wren_compiler.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/vm/wren_compiler.c b/src/vm/wren_compiler.c
index c7f0de37..3937d1d2 100644
--- a/src/vm/wren_compiler.c
+++ b/src/vm/wren_compiler.c
@@ -3446,12 +3446,11 @@ ObjFn* wrenCompile(WrenVM* vm, ObjModule* module, const char* source,
   parser.printErrors = printErrors;
   parser.hasError = false;
 
-
   // Read the first token.
   nextToken(&parser);
 
   int numExistingVariables = module->variables.count;
-  
+
   Compiler compiler;
   initCompiler(&compiler, &parser, NULL, true);
   ignoreNewlines(&compiler);

From 4034a6d65a99b2daf85655a6d344f0ec243d1063 Mon Sep 17 00:00:00 2001
From: jclc <jclc@protonmail.com>
Date: Sat, 7 Apr 2018 06:04:32 +0300
Subject: [PATCH 3/4] crunched BOM skipping

---
 src/vm/wren_compiler.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/src/vm/wren_compiler.c b/src/vm/wren_compiler.c
index 3937d1d2..75d0136e 100644
--- a/src/vm/wren_compiler.c
+++ b/src/vm/wren_compiler.c
@@ -3417,26 +3417,25 @@ ObjFn* wrenCompile(WrenVM* vm, ObjModule* module, const char* source,
                    bool isExpression, bool printErrors)
 {
   // Skip potential UTF-8 BOM
-  size_t sourceOffset = 0;
-  if (source[0] == (char) 0xef && source[1] == (char) 0xbb && source[2] == (char) 0xbf)
+  if (strncmp(source, "\xEF\xBB\xBF", 3) == 0)
   {
-    sourceOffset = 3;
+    source += 3;
   }
 
   Parser parser;
   parser.vm = vm;
   parser.module = module;
-  parser.source = source + sourceOffset;
+  parser.source = source;
 
-  parser.tokenStart = source + sourceOffset;
-  parser.currentChar = source + sourceOffset;
+  parser.tokenStart = source;
+  parser.currentChar = source;
   parser.currentLine = 1;
   parser.numParens = 0;
 
   // Zero-init the current token. This will get copied to previous when
   // advance() is called below.
   parser.current.type = TOKEN_ERROR;
-  parser.current.start = source + sourceOffset;
+  parser.current.start = source;
   parser.current.length = 0;
   parser.current.line = 0;
   parser.current.value = UNDEFINED_VAL;

From e66115c9fc086d3dafdbf20141999e707a7667df Mon Sep 17 00:00:00 2001
From: jclc <jclc@protonmail.com>
Date: Tue, 10 Apr 2018 18:53:56 +0300
Subject: [PATCH 4/4] add regression test for #520

---
 test/regression/520.wren | 2 ++
 1 file changed, 2 insertions(+)
 create mode 100644 test/regression/520.wren

diff --git a/test/regression/520.wren b/test/regression/520.wren
new file mode 100644
index 00000000..6eddf921
--- /dev/null
+++ b/test/regression/520.wren
@@ -0,0 +1,2 @@
+// This file should have a UTF-8 byte order mark
+System.print("ok") // expect: ok