1 file changed, 4 insertions, 2 deletions
diff --git a/custom/extensions/syntax-highlight.lua b/custom/extensions/syntax-highlight.lua
index 282b0cf..7414b63 100644
--- a/custom/extensions/syntax-highlight.lua
+++ b/custom/extensions/syntax-highlight.lua
@@ -153,9 +153,11 @@ local function load_scintillua()
 end
 
 -- The first line goes along to detect(), so a script with no extension is
--- still known by its shebang.
+-- still known by its shebang. detect() matches an extension by its case, so
+-- a name in capitals such as MAIN.C is tried again in lower case.
 local function lexer_for(name, text)
-	local lang = scintillua.detect(name, string.match(text, "^[^\n]*"))
+	local first = string.match(text, "^[^\n]*")
+	local lang = scintillua.detect(name, first) or scintillua.detect(string.lower(name), first)
 	return lang and scintillua.load(lang)
 end