++new:

  * Added the basic structure to the Sweet parser in sch_part.cpp.
  * Got inheritence working off of the 'extends' keyword and PART::inherit()
  * Tossed the units support out of sweet.keywords, since we agreed to go dimensionless.
++richio:
  * Added the problemInputLine support to PARSE_ERROR, so UI can show the
    offending line of bytes.  Yes bytes, not even guaranteed to be characters.

CHANGELOG.txt

@@ -4,6 +4,17 @@ KiCad ChangeLog 2010
 Please add newer entries at the top, list the date and your name with
 email address.
 
+2011-Jan-1 UPDATE Dick Hollenbeck <dick@softplc.com>
+================================================================================
+++new:
+  * Added the basic structure to the Sweet parser in sch_part.cpp.
+  * Got inheritence working off of the 'extends' keyword and PART::inherit()
+  * Tossed the units support out of sweet.keywords, since we agreed to go dimensionless.
+++richio:
+  * Added the problemInputLine support to PARSE_ERROR, so UI can show the
+    offending line of bytes.  Yes bytes, not even guaranteed to be characters.
+
+
 2010-dec-31 UPDATE Wayne Stambaugh <stambaughw@verizon.net>
 ================================================================================
 ++all

common/dsnlexer.cpp

@@ -231,7 +231,7 @@ wxString DSNLEXER::GetTokenString( int aTok )
 {
     wxString    ret;
 
-    ret << wxT("'") << wxConvertMB2WX( GetTokenText(aTok) ) << wxT("'");
+    ret << wxT("'") << wxString::FromUTF8( GetTokenText(aTok) ) << wxT("'");
 
     return ret;
 }
@@ -249,24 +249,11 @@ bool DSNLEXER::IsSymbol( int aTok )
 }
 
 
-void DSNLEXER::ThrowIOError( wxString aText, int charOffset ) throw( IO_ERROR )
-{
-    // @todo convert this to THROW_PARSE_ERROR()
-
-    // append to aText, do not overwrite
-    aText << wxT(" ") << _("in") << wxT(" \"") << CurSource()
-          << wxT("\" ") << _("on line") << wxT(" ") << reader->LineNumber()
-          << wxT(" ") << _("at offset") << wxT(" ") << charOffset;
-
-    THROW_IO_ERROR( aText );
-}
-
-
 void DSNLEXER::Expecting( int aTok ) throw( IO_ERROR )
 {
     wxString    errText( _("Expecting") );
     errText << wxT(" ") << GetTokenString( aTok );
-    ThrowIOError( errText, CurOffset() );
+    THROW_PARSE_ERROR( errText, CurSource(), CurLine(), CurLineNumber(), CurOffset() );
 }
 
 
@@ -274,7 +261,7 @@ void DSNLEXER::Expecting( const wxString& text ) throw( IO_ERROR )
 {
     wxString    errText( _("Expecting") );
     errText << wxT(" '") << text << wxT("'");
-    ThrowIOError( errText, CurOffset() );
+    THROW_PARSE_ERROR( errText, CurSource(), CurLine(), CurLineNumber(), CurOffset() );
 }
 
 
@@ -282,15 +269,22 @@ void DSNLEXER::Unexpected( int aTok ) throw( IO_ERROR )
 {
     wxString    errText( _("Unexpected") );
     errText << wxT(" ") << GetTokenString( aTok );
-    ThrowIOError( errText, CurOffset() );
+    THROW_PARSE_ERROR( errText, CurSource(), CurLine(), CurLineNumber(), CurOffset() );
 }
 
+void DSNLEXER::Duplicate( int aTok ) throw( IO_ERROR )
+{
+    wxString    errText;
+
+    errText.Printf( _("%s is a duplicate"), GetTokenString( aTok ).GetData() );
+    THROW_PARSE_ERROR( errText, CurSource(), CurLine(), CurLineNumber(), CurOffset() );
+}
 
 void DSNLEXER::Unexpected( const wxString& text ) throw( IO_ERROR )
 {
     wxString    errText( _("Unexpected") );
     errText << wxT(" '") << text << wxT("'");
-    ThrowIOError( errText, CurOffset() );
+    THROW_PARSE_ERROR( errText, CurSource(), CurLine(), CurLineNumber(), CurOffset() );
 }
 
 
@@ -408,7 +402,7 @@ L_read:
             case '"':
                 break;
             default:
-                ThrowIOError( errtxt, CurOffset() );
+                THROW_PARSE_ERROR( errtxt, CurSource(), CurLine(), CurLineNumber(), CurOffset() );
             }
 
             curText = cc;
@@ -417,7 +411,7 @@ L_read:
 
             if( head<limit && *head!=')' && *head!='(' && !isSpace(*head) )
             {
-                ThrowIOError( errtxt, CurOffset() );
+                THROW_PARSE_ERROR( errtxt, CurSource(), CurLine(), CurLineNumber(), CurOffset() );
             }
 
             curTok = DSN_QUOTE_DEF;
@@ -514,7 +508,7 @@ L_read:
             }
 
             wxString errtxt(_("Un-terminated delimited string") );
-            ThrowIOError( errtxt, CurOffset() );
+            THROW_PARSE_ERROR( errtxt, CurSource(), CurLine(), CurLineNumber(), CurOffset() );
 
 #else   // old code, did not understand nested quotes
             ++cur;  // skip over the leading delimiter: ",', or $
@@ -527,7 +521,7 @@ L_read:
             if( head >= limit )
             {
                 wxString errtxt(_("Un-terminated delimited string") );
-                ThrowIOError( errtxt, CurOffset() );
+                THROW_PARSE_ERROR( errtxt, CurSource(), CurLine(), CurLineNumber(), CurOffset() );
             }
 
             curText.clear();

include/dsnlexer.h

@@ -330,13 +330,6 @@ public:
      */
     static bool IsSymbol( int aTok );
 
-    /**
-     * Function ThrowIOError
-     * encapsulates the formatting of an error message which contains the exact
-     * location within the input file of something the caller is rejecting.
-     */
-    void ThrowIOError( wxString aText, int charOffset ) throw( IO_ERROR );
-
     /**
      * Function Expecting
      * throws an IO_ERROR exception with an input file specific error message.
@@ -363,6 +356,16 @@ public:
      */
     void Unexpected( int aTok ) throw( IO_ERROR );
 
+    /**
+     * Function Duplicate
+     * throws an IO_ERROR exception with a message saying specifically that aTok
+     * is a duplicate of one already seen in current context.
+     * @param aTok is the token/keyword type which was not expected at the
+     *         current input location.
+     * @throw IO_ERROR with the location within the input file of the problem.
+     */
+    void Duplicate( int aTok ) throw( IO_ERROR );
+
     /**
      * Function Unexpected
      * throws an IO_ERROR exception with an input file specific error message.
@@ -411,6 +414,16 @@ public:
         return curText.c_str();
     }
 
+    /**
+     * Function FromUTF8
+     * returns the current token text as a wxString, assuming that the input
+     * byte stream is UTF8 encoded.
+     */
+    wxString FromUTF8()
+    {
+        return wxString::FromUTF8( curText.c_str() );
+    }
+
     /**
      * Function CurLineNumber
      * returns the current line number within my LINE_READER
@@ -420,6 +433,16 @@ public:
         return reader->LineNumber();
     }
 
+    /**
+     * Function CurLine
+     * returns the current line of text, from which the CurText() would return
+     * its token.
+     */
+    const char* CurLine()
+    {
+        return (const char*)(*reader);
+    }
+
     /**
      * Function CurFilename
      * returns the current LINE_READER source.
@@ -433,7 +456,7 @@ public:
 
     /**
      * Function CurOffset
-     * returns the char offset within the current line, using a 1 based index.
+     * returns the byte offset within the current line, using a 1 based index.
      * @return int - a one based index into the current line.
      */
     int CurOffset()

include/richio.h

@@ -46,8 +46,8 @@
  */
 
 
-#define IO_FORMAT       _( "IO_ERROR: '%s'\n from %s : %s" )
-#define PARSE_FORMAT    _( "PARSE_ERROR: '%s' in input/source '%s', line %d, offset %d\n from %s : %s" )
+#define IO_FORMAT       _( "IO_ERROR: %s\n from %s : %s" )
+#define PARSE_FORMAT    _( "PARSE_ERROR: %s in input/source \"%s\", line %d, offset %d\n from %s : %s" )
 
 // references:
 // http://stackoverflow.com/questions/2670816/how-can-i-use-the-compile-time-constant-line-in-a-string
@@ -123,12 +123,11 @@ struct IO_ERROR // : std::exception
 };
 
 
-#define THROW_PARSE_ERROR( msg, input, line, offset )   throw PARSE_ERROR( __FILE__, __LOC__, msg, input, line, offset )
-
 /**
  * Class PARSE_ERROR
- * contains a filename or source description, a line number, a character offset,
- * and an error message.
+ * contains a filename or source description, a problem input line, a line number,
+ * a byte offset, and an error message which contains the the caller's report and his
+ * call site information: CPP source file, function, and line number.
  * @author Dick Hollenbeck
  */
 struct PARSE_ERROR : public IO_ERROR
@@ -138,24 +137,36 @@ struct PARSE_ERROR : public IO_ERROR
     int         lineNumber;     ///< at which line number, 1 based index.
     int         byteIndex;      ///< at which character position within the line, 1 based index
 
+    /// problem line of input [say, from a LINE_READER].
+    /// this is brought up in original byte format rather than wxString form, incase
+    /// there was a problem with the encoding, in which case converting to wxString is
+    /// not reliable in this context.
+    std::string inputLine;
+
+    /**
+     * Constructor
+     * which is normally called via the macro THROW_PARSE_ERROR so that
+     * __FILE__ and __LOC__ can be captured from the call site.
+     */
     PARSE_ERROR( const char* aThrowersFile, const char* aThrowersLoc,
                  const wxString& aMsg, const wxString& aSource,
+                 const char* aInputLine,
                  int aLineNumber, int aByteIndex ) :
         IO_ERROR()
     {
-        init( aThrowersFile, aThrowersLoc, aMsg, aSource, aLineNumber, aByteIndex );
+        init( aThrowersFile, aThrowersLoc, aMsg, aSource, aInputLine, aLineNumber, aByteIndex );
     }
 
     void init( const char* aThrowersFile, const char* aThrowersLoc,
                const wxString& aMsg, const wxString& aSource,
+               const char* aInputLine,
                int aLineNumber, int aByteIndex )
     {
-        // save line and offset in binary for Sweet text editor, which will catch exceptions
+        // save inpuLine, lineNumber, and offset for UI (.e.g. Sweet text editor)
+        inputLine  = aInputLine;
         lineNumber = aLineNumber;
         byteIndex  = aByteIndex;
 
-        // #define PARSE_FORMAT    _( "PARSE_ERROR: %s in source %s, line %d, offset %d\nfrom cpp:%s func:%s" )
-
         errorText.Printf( PARSE_FORMAT, aMsg.GetData(), aSource.GetData(),
             aLineNumber, aByteIndex,
             wxString::FromUTF8( aThrowersFile ).GetData(),
@@ -165,6 +176,11 @@ struct PARSE_ERROR : public IO_ERROR
     ~PARSE_ERROR() throw ( /*none*/ ){}
 };
 
+
+#define THROW_PARSE_ERROR( aMsg, aSource, aInputLine, aLineNumber, aByteIndex )  \
+        throw PARSE_ERROR( __FILE__, __LOC__, aMsg, aSource, aInputLine, aLineNumber, aByteIndex )
+
+
 /** @} exception_types */
 
 

new/make-dir-lib-source-test-data.sh

@@ -16,8 +16,7 @@ for C in ${CATEGORIES}; do
 
     for P in ${PARTS};  do
         for R in ${REVS}; do
-            echo "#$R: (part $C/$P)" > $BASEDIR/$C/$P.part.$R
+            (part $C/$P/$R extends $P/$R (value 22)(footprint SM0805)) > $BASEDIR/$C/$P.part.$R
         done
     done
 done
-

new/sch_lib_table.cpp

@@ -413,6 +413,12 @@ int main( int argc, char** argv )
 
         lib_table.Test();
     }
+    catch( PARSE_ERROR& ioe )   // most derived class first
+    {
+        printf( "%s\n", (const char*) ioe.errorText.ToUTF8() );
+        printf( "%s", ioe.inputLine.c_str() );      // rare not to have \n at end
+        printf( "%*s^\n", ioe.byteIndex-1, " " );
+    }
     catch( IO_ERROR& ioe )
     {
         printf( "%s\n", (const char*) ioe.errorText.ToUTF8() );

new/sch_lpid.cpp

@@ -187,6 +187,7 @@ LPID::LPID( const STRING& aLPID ) throw( PARSE_ERROR )
         THROW_PARSE_ERROR(
                 _( "Illegal character found in LPID string" ),
                 wxConvertMB2WX( aLPID.c_str() ),
+                aLPID.c_str(),
                 0,
                 offset
                 );

new/sch_lpid.h

@@ -59,7 +59,7 @@ class LPID  // aka GUID
 {
 public:
 
-    LPID();
+    LPID() {}
 
     /**
      * Constructor LPID

new/sch_part.cpp

@@ -21,22 +21,259 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  */
 
+#include <wx/wx.h>          // _()
 
 #include <sch_part.h>
 #include <sweet_lexer.h>
-#include <wx/wx.h>          // _()
-
+#include <sch_lpid.h>
+#include <sch_lib_table.h>
 
 using namespace SCH;
 
 
-void PART::Parse( SWEET_LEXER* aLexer, LIB_TABLE* aTable ) throw( PARSE_ERROR )
+//-----<temporary home for PART sub objects, move after stable>------------------
+
+
+
+//-----</temporary home for PART sub objects, move after stable>-----------------
+
+
+/**
+ * Class PART_PARSER
+ * is a localized/hidden PART Parser.  You get here through the public interface
+ * PART::Parse().  Advantages of private class declaration in this situation:
+ * 1) keeps all the recursive parsing helper functions out of the main public PART
+*     header file and so should speed up compilation.
+ * 2) Allows use of cost-less Java like inline functions, since nobody knows about
+ *    them but this source file.  Most are only used once and called from one place.
+ * <p>
+ * All the functions in this class throw PARSE_ERROR.  If SWEET_LEXER throws, it
+ * may be an IO_ERROR, propogated from here also.  The throws() statements are left off
+ * to keep the noise level down.
+ */
+class PART_PARSER
+{
+    SWEET_LEXER*    in;
+    LIB_TABLE*      libs;
+    int             contains;
+
+public:
+    PART_PARSER( PART* aPart, SWEET_LEXER* aLexer, LIB_TABLE* aTable ) :
+        in( aLexer ),
+        libs( aTable ),
+        contains( 0 )
+    {
+        parsePart( aPart );
+    }
+
+    /// @param me = ja mir, the object getting stuffed, from its perspective
+    void parsePart( PART* me )
+    {
+        PART_T tok;
+
+        if( (tok = in->NextTok()) == T_LEFT )
+            tok = in->NextTok();
+
+        // a token "( part .." i.e. class PART
+        // Be flexible regarding the starting point of the stream.
+        // Caller may not have read the first two tokens out of the
+        // stream: T_LEFT and T_part, so ignore them if seen here.
+        // The 1st two tokens T_LEFT and T_part are then optional in the grammar.
+        if( tok == T_part )
+        {
+            in->NeedSYMBOLorNUMBER(); // read in part NAME_HINT, and toss
+            tok = in->NextTok();
+        }
+
+        // extends must be _first_ thing, if it is present at all, after NAME_HINT
+        if( tok == T_extends )
+        {
+            PART*   base;
+            int     offset;
+
+            if( contains & PB(EXTENDS) )
+                in->Duplicate( tok );
+            in->NeedSYMBOLorNUMBER();
+            me->setExtends( new LPID() );
+            offset = me->extends->Parse( in->CurText() );
+            if( offset > -1 )   // -1 is success
+                THROW_PARSE_ERROR( _("invalid extends LPID"),
+                    in->CurSource(),
+                    in->CurLine(),
+                    in->CurLineNumber(),
+                    in->CurOffset() + offset );
+            // we could be going in circles here, recursively, @todo add a max counter or stack chain
+            base = libs->LookupPart( *me->extends, me->Owner() );
+            me->inherit( *base );
+            contains |= PB(EXTENDS);
+            tok = in->NextTok();
+        }
+
+        for(  ; tok!=T_RIGHT && tok!=T_EOF;  tok = in->NextTok() )
+        {
+            if( tok == T_LEFT )
+                tok = in->NextTok();
+
+            switch( tok )
+            {
+            default:
+                // describe what we expect at this level
+                in->Expecting( wxT(
+                    "anchor|value|footprint|model|keywords|alternates\n"
+                    "|property\n"
+                    "  |property_del\n"
+                    "|pin\n"
+                    "  |pin_merge|pin_swap|pin_renum|pin_rename|route_pin_swap\n"
+                    "|polyline|line|rectangle|circle|arc|bezier|text"
+                    )
+                 );
+                break;
+
+            case T_anchor:
+                if( contains & PB(ANCHOR) )
+                    in->Duplicate( tok );
+                contains |= PB(ANCHOR);
+                break;
+
+        /*
+            case T_value:
+                if( contains & PB(VALUE) )
+                    in->Duplicate( tok );
+                contains |= PB(VALUE);
+                in->NeedSYMBOLorNUMBER();
+                // me->value = in->CurText();
+                in->NeedRIGHT();
+                break;
+
+            case T_footprint:
+                break;
+
+            case T_model:
+                break;
+
+            case T_keywords:
+                break;
+
+            case T_alternates:
+                break;
+
+            case T_property:
+                break;
+
+            case T_property_del:
+                break;
+
+            case T_pin:
+                break;
+
+            case T_pin_merge:
+                break;
+
+            case T_pin_swap:
+                break;
+
+            case T_pin_renum:
+                break;
+
+            case T_pin_rename:
+                break;
+
+            case T_route_pin_swap:
+                break;
+
+            case T_polyline:
+                break;
+
+            case T_line:
+                break;
+
+            case T_rectangle:
+                break;
+
+            case T_circle:
+                break;
+
+            case T_arc:
+                break;
+
+            case T_bezier:
+                break;
+
+            case T_text:
+                break;
+        */
+
+            // Not sure about reference in a PART, comes in at COMPONENT object.
+            // It is maybe just a hint here or a prefix.
+            case T_reference:
+                if( contains & PB(REFERENCE) )
+                    in->Duplicate( tok );
+                contains |= PB(REFERENCE);
+                break;
+            }
+        }
+    }
+
+
+    void parseAt( PART* me )
+    {
+    }
+};
+
+
+PART::PART( LIB* aOwner, const STRING& aPartName, const STRING& aRevision ) :
+    owner( aOwner ),
+    contains( 0 ),
+    partName( aPartName ),
+    revision( aRevision ),
+    extends( 0 )
+{}
+
+
+PART::~PART()
+{
+    delete extends;
+}
+
+
+void PART::setExtends( LPID* aLPID )
 {
-    // Wayne's world, if he still wants it.
+    delete extends;
+    extends = aLPID;
+}
+
+
+void PART::inherit( const PART& other )
+{
+    contains = other.contains;
+
+    setExtends( other.extends ? new LPID( *other.extends ) : 0 );
 
+    body     = other.body;
 }
 
 
+PART& PART::operator=( const PART& other )
+{
+    owner    = other.owner;
+    partName = other.partName;
+    revision = other.revision;
+
+    // maintain inherit() as a partial assignment operator.
+    inherit( other );
+
+    return *this;
+}
+
+
+void PART::Parse( SWEET_LEXER* aLexer, LIB_TABLE* aTable ) throw( IO_ERROR )
+{
+    PART_PARSER( this, aLexer, aTable );
+}
+
+
+
+
 #if 0 && defined(DEBUG)
 
 int main( int argc, char** argv )

new/sch_part.h

@@ -28,9 +28,13 @@
 #include <sch_lib.h>
 
 class SWEET_LEXER;
+class PART_PARSER;
+
 
 namespace SCH {
 
+class LPID;
+
 /**
  * Enum PartBit
  * is a set of bit positions that can be used to create flag bits within
@@ -39,9 +43,16 @@ namespace SCH {
  */
 enum PartBit
 {
+    BODY,       ///< body has been read in.
     PARSED,     ///< have parsed this part already, otherwise 'body' text must be parsed
     EXTENDS,    ///< saw and "extends" keyword, inheriting from another PART
-
+    VALUE,
+    ANCHOR,
+    REFERENCE,
+    FOOTPRINT,
+    DATASHEET,
+    MODEL,
+    KEYWORDS,
 };
 
 /// Function PB
@@ -63,34 +74,40 @@ static inline const int PB( PartBit oneBitOnly )
  */
 class PART
 {
-    /// LIB class has great license to modify what's in here, nobody else does.
-    /// Modification is done through the LIB so it can track the state of the
-    /// PART and take action as needed.  Actually most of the modification will
-    /// be done by PARTS_LIST, a class derived from LIB.
-    friend class LIB;
-
-    /// a private constructor, only a LIB can instantiate a PART.
-    PART( LIB* aOwner, const STRING& aPartName, const STRING& aRevision ) :
-        owner( aOwner ),
-        contains( 0 ),
-        partName( aPartName ),
-        revision( aRevision )
-    {}
+    friend class LIB;           // is the owner of all PARTS, afterall
+    friend class ::PART_PARSER;
 
 protected:      // not likely to have C++ descendants, but protected none-the-less.
 
+    /// a protected constructor, only a LIB can instantiate a PART.
+    PART( LIB* aOwner, const STRING& aPartName, const STRING& aRevision );
+
+    /**
+     * Function inherit
+     * is a specialized assignment function that copies a specific subset, enough
+     * to fulfill the requirements of the Sweet s-expression language.
+     */
+    void inherit( const PART& aBasePart );
+
+
+    //PART( LIB* aOwner );
+
     LIB*        owner;      ///< which LIB am I a part of (pun if you want)
     int         contains;   ///< has bits from Enum PartParts
 
-    STRING      extends;    ///< LPID of base part
-
     STRING      partName;   ///< example "passives/R", immutable.
     STRING      revision;   // @todo need a single search key, this won't do.
 
+    LPID*       extends;    ///< of base part, NULL if none, otherwise I own it.
+
+    /// encapsulate the old version deletion, take ownership of @a aLPID
+    void setExtends( LPID* aLPID );
+
     /// s-expression text for the part, initially empty, and read in as this part
     /// actually becomes cached in RAM.
     STRING      body;
 
+
     // 3 separate lists for speed:
 
     /// A property list.
@@ -105,16 +122,13 @@ protected:      // not likely to have C++ descendants, but protected none-the-le
     /// Alternate body forms.
     //ALTERNATES  alternates;
 
-    // lots of other stuff, like the mandatory properties.
+    // lots of other stuff, like the mandatory properties, but no units, since we went with dimensionless
 
 public:
 
-    /**
-     * Function Inherit
-     * is a specialized assignment function that copies a specific subset, enough
-     * to fulfill the requirements of the Sweet s-expression language.
-     */
-    void Inherit( const PART& aBasePart );
+    ~PART();
+
+    PART& operator=( const PART& other );
 
     /**
      * Function Owner
@@ -122,6 +136,7 @@ public:
      */
     LIB* Owner()  { return owner; }
 
+
     /**
      * Function Parse
      * translates a Sweet string into a binary form that is represented
@@ -133,7 +148,7 @@ public:
      * @param aLibTable is the LIB_TABLE view that is in effect for inheritance,
      *  and comes from the big containing SCHEMATIC object.
      */
-    void Parse( SWEET_LEXER* aLexer, LIB_TABLE* aTable ) throw( PARSE_ERROR );
+    void Parse( SWEET_LEXER* aLexer, LIB_TABLE* aTable ) throw( IO_ERROR );
 
 /*
     void SetBody( const STR_UTF& aSExpression )

new/sweet.keywords

@@ -25,6 +25,7 @@ keywords
 length
 line
 line_width
+model
 name
 none
 number
@@ -38,6 +39,7 @@ pin_del
 pin_merge
 pin_rename
 pin_renum
+pin_swap
 polyline
 pos
 power_in
@@ -58,5 +60,6 @@ tristate
 unconnected
 units
 unspecified
+value
 visible
 xy

pcbnew/specctra_export.cpp

@@ -111,7 +111,7 @@ void WinEDA_PcbFrame::ExportToSpecctra( wxCommandEvent& event )
         // if an exception is thrown by FromBOARD or ExportPCB(), then
         // ~SPECCTRA_DB() will close the file.
     }
-    catch( IO_ERROR ioe )
+    catch( IO_ERROR& ioe )
     {
         ok = false;
 

pcbnew/specctra_import.cpp

@@ -96,7 +96,7 @@ void WinEDA_PcbFrame::ImportSpecctraSession( wxCommandEvent& event )
         db.LoadSESSION( fullFileName );
         db.FromSESSION( GetBoard() );
     }
-    catch( IO_ERROR ioe )
+    catch( IO_ERROR& ioe )
     {
         SetLocaleTo_Default( );    // revert to the current locale