From d070b1cd8d6f0044602e2d7b0e37b27284eda318 Mon Sep 17 00:00:00 2001
From: Patrice Chalin <pchalin@gmail.com>
Date: Fri, 4 Mar 2022 09:08:10 -0500
Subject: [PATCH] Fix for C# identifiers with leading underscores

---
 lexers/embedded/csharp.xml                 |  2 +-
 lexers/testdata/csharp/csharp_var.actual   |  1 +
 lexers/testdata/csharp/csharp_var.expected | 11 +++++++++++
 3 files changed, 13 insertions(+), 1 deletion(-)
 create mode 100644 lexers/testdata/csharp/csharp_var.actual
 create mode 100644 lexers/testdata/csharp/csharp_var.expected

diff --git a/lexers/embedded/csharp.xml b/lexers/embedded/csharp.xml
index e194d48aa..8c2ff450f 100644
--- a/lexers/embedded/csharp.xml
+++ b/lexers/embedded/csharp.xml
@@ -49,7 +49,7 @@
       <rule pattern="&#39;\\.&#39;|&#39;[^\\]&#39;">
         <token type="LiteralStringChar"/>
       </rule>
-      <rule pattern="0[xX][0-9a-fA-F]+[Ll]?|[0-9_](\.[0-9]*)?([eE][+-]?[0-9]+)?[flFLdD]?">
+      <rule pattern="0[xX][0-9a-fA-F]+[Ll]?|\d[_\d]*(\.\d*)?([eE][+-]?\d+)?[flFLdD]?">
         <token type="LiteralNumber"/>
       </rule>
       <rule pattern="#[ \t]*(if|endif|else|elif|define|undef|line|error|warning|region|endregion|pragma|nullable)\b[^\n\r]+">
diff --git a/lexers/testdata/csharp/csharp_var.actual b/lexers/testdata/csharp/csharp_var.actual
new file mode 100644
index 000000000..689097567
--- /dev/null
+++ b/lexers/testdata/csharp/csharp_var.actual
@@ -0,0 +1 @@
+var _abc = 123;
diff --git a/lexers/testdata/csharp/csharp_var.expected b/lexers/testdata/csharp/csharp_var.expected
new file mode 100644
index 000000000..42c361da6
--- /dev/null
+++ b/lexers/testdata/csharp/csharp_var.expected
@@ -0,0 +1,11 @@
+[
+  {"type":"KeywordType","value":"var"},
+  {"type":"Text","value":" "},
+  {"type":"Name","value":"_abc"},
+  {"type":"Text","value":" "},
+  {"type":"Punctuation","value":"="},
+  {"type":"Text","value":" "},
+  {"type":"LiteralNumber","value":"123"},
+  {"type":"Punctuation","value":";"},
+  {"type":"Text","value":"\n"}
+]