allow keyword Append to be used as a variable. bnc#745930

statements like
  Dim AppEnd As Integer
will generate compiler errors because Append is a special symbol/keyword in libreoffice basic. This restriction though is too strict because 'Append' is only such a keyword when used within the 'Open' statement ( where it refers to one of the possible values for a paramater ).

basic/source/comp/io.cxx

@@ -178,6 +178,7 @@ void SbiParser::Input()
 
 void SbiParser::Open()
 {
+    bInStatement = true;
     SbiExpression aFileName( this );
     SbiToken eTok;
     TestToken( FOR );
@@ -273,6 +274,7 @@ void SbiParser::Open()
     aGen.Gen( _OPEN, nMode, nFlags );
     delete pLen;
     delete pChan;
+    bInStatement = false;
 }
 
 // NAME file AS file

basic/source/comp/scanner.cxx

@@ -53,9 +53,10 @@ SbiScanner::SbiScanner( const ::rtl::OUString& rBuf, StarBASIC* p ) : aBuf( rBuf
     bSymbol  =
     bCompatible =
     bVBASupportOn =
-    bPrevLineExtentsComment = sal_False;
+    bInStatement =
+    bPrevLineExtentsComment = false;
     bHash    =
-    bErrors  = sal_True;
+    bErrors  = true;
 }
 
 SbiScanner::~SbiScanner()

basic/source/comp/token.cxx

@@ -401,6 +401,15 @@ special:
         return eCurTok = SYMBOL;
     else if( tp->t == TEXT )
         return eCurTok = SYMBOL;
+    // maybe we can expand this for other statements that have parameters
+    // that are keywords ( and those keywords are only used within such
+    // statements )
+    // what's happening here is that if we come across 'append' ( and we are
+    // not in the middle of parsing a special statement ( like 'Open')
+    // we just treat keyword 'append' as a normal 'SYMBOL'.
+    // Also we accept Dim APPEND
+    else if ( ( !bInStatement || eCurTok == DIM ) && tp->t == APPEND )
+        return eCurTok = SYMBOL;
 
     // #i92642: Special LINE token handling -> SbiParser::Line()
 

basic/source/inc/scanner.hxx

@@ -73,6 +73,7 @@ protected:
     bool   bVBASupportOn;               // sal_True: OPTION VBASupport 1 otherwise default False
     bool   bPrevLineExtentsComment;     // sal_True: Previous line is comment and ends on "... _"
 
+    bool   bInStatement;
     void   GenError( SbError );
 public:
     SbiScanner( const ::rtl::OUString&, StarBASIC* = NULL );