Merge pull request #228 from teo-tsirpanis/fix-no-header

Fix compile errors in fsyacc's output if there is no header in the input file.

Author: nojaf

src/FsYacc.Core/fsyaccdriver.fs

@@ -120,11 +120,12 @@ type Writer(outputFileName, outputFileInterface) =
     member x.WriteUInt16(i: int) = fprintf os "%dus;" i
 
     member x.WriteCode(code, pos) =
-        x.WriteLine "# %d \"%s\"" pos.pos_lnum pos.pos_fname
-        x.WriteLine "%s" code
-        let codeLines = code.Replace("\r", "").Split([| '\n' |]).Length
-        outputLineCount <- outputLineCount + codeLines
-        x.WriteLine "# %d \"%s\"" outputLineCount outputFileName
+        if code <> "" then
+            x.WriteLine "# %d \"%s\"" pos.pos_lnum pos.pos_fname
+            x.WriteLine "%s" code
+            let codeLines = code.Replace("\r", "").Split([| '\n' |]).Length
+            outputLineCount <- outputLineCount + codeLines
+            x.WriteLine "# %d \"%s\"" outputLineCount outputFileName
 
     member x.OutputLineCount = outputLineCount
 

tests/LexAndYaccMiniProject/Parser.fsy

@@ -1,9 +1,4 @@
-%{
-
-
-%}
-
-// The start token becomes a parser function in the compiled code:
+// The start token becomes a parser function in the compiled code:
 %start start
 
 // Regular tokens