protected override bool ScanFraction()
{
StreamPointer savPosition = streamInPtr; // Position of '.'
do
{
NextCh();
} while (Char.IsDigit(ch));
bool result = (streamInPtr.Position > savPosition.Position + 1); // a fraction
if (result)
{
if (ch == 'i')
{
symbol.TerminalId = ImagLiteral;
NextCh();
}
else
{
symbol.TerminalId = RealLiteral;
}
}
else
{
InitCh(savPosition);
}
return(result);
}
private void InitCh(StreamPointer c)
{
streamInPtr = c;
GetStreamInChar(streamInPtr.Position, out ch);
if (streamInPtr.Position <= 0)
prevCh = ' ';
else
GetStreamInChar(streamInPtr.Position - 1, out prevCh);
endText = (streamInPtr.Position > streamInLen - 1);
if (endText) ch = '\x0';
}
protected override void ScanIdOrTerminalOrCommentStart()
{
TerminalDescr tRec;
bool firstLow = Char.IsLower(ch);
StreamPointer iPtr = streamInPtr;
StreamPointer tPtr = iPtr;
int aLen = (ch.IsIdStartChar()) ? 1 : 0; // length of longest Identifier sofar
int tLen = 0; // length of longest Terminal sofar
int fCnt = 0; // count of calls to FindCharAndSubtree
bool isDot = (ch == '.'); // remains valid only if symbol length is 1
terminalTable.FindCharInSubtreeReset();
while (fCnt++ >= 0 && terminalTable.FindCharInSubtree(ch, out tRec))
{
if (tRec != null)
{
symbol.TerminalId = tRec.IVal;
symbol.Payload = tRec.Payload; // not used
symbol.Class = tRec.Class;
tLen = fCnt;
tPtr = streamInPtr; // next char to be processed
if (symbol.TerminalId == CommentStart || symbol.TerminalId == CommentSingle)
{
return;
}
if (terminalTable.AtLeaf)
{
break; // terminal cannot be extended
}
}
NextCh();
if (aLen == fCnt && (Char.IsLetterOrDigit(ch) || ch == '_'))
{
aLen++;
iPtr = streamInPtr;
}
} // fCnt++ by last (i.e. failing) Call
/*
* At this point: (in the Prolog case, read 'Identifier and Atom made up
* from specials' for 'Identifier'):
* - tLen has length of BaseTrie terminal (if any, 0 otherwise);
* - aLen has length of Identifier (if any, 0 otherwise);
* - fCnt is the number of characters inspected (for Id AND terminal)
* - The character pointer is on the last character inspected (for both)
* Iff aLen = fCnt then the entire sequence read sofar is an Identifier.
* Now try extending the Identifier, only meaningful if iLen = fCnt.
* Do not do this for an Atom made up from specials if a Terminal was recognized !!
*/
if (aLen == fCnt)
{
while (true)
{
NextCh();
if (Char.IsLetterOrDigit(ch) || ch == '_')
{
aLen++;
iPtr = streamInPtr;
}
else
{
break;
}
}
}
if (aLen > tLen) // tLen = 0 iff Terminal == Undefined
{
symbol.TerminalId = Identifier;
symbol.Class = SymbolClass.Id;
InitCh(iPtr);
}
else if (symbol.TerminalId == Undefined)
{
InitCh(iPtr);
}
else // we have a terminal != Identifier
{
if (aLen == tLen)
{
symbol.Class = SymbolClass.Id;
}
InitCh(tPtr);
}
NextCh();
}
protected override void ScanIdOrTerminalOrCommentStart()
{
TerminalDescr tRec;
bool special = ch.IsSpecialAtomChar();
bool firstLow = Char.IsLower(ch);
StreamPointer iPtr = streamInPtr;
StreamPointer tPtr = iPtr;
int aLen = (ch.IsIdStartChar() || special) ? 1 : 0; // length of longest Atom sofar
int tLen = 0; // length of longest Terminal sofar
int fCnt = 0; // count of calls to FindCharAndSubtree
bool isDot = (ch == '.'); // remains valid only if symbol length is 1
terminalTable.FindCharInSubtreeReset();
while (fCnt++ >= 0 && terminalTable.FindCharInSubtree(ch, out tRec))
{
if (tRec != null)
{
symbol.TerminalId = tRec.IVal;
symbol.Payload = tRec.Payload;
symbol.Class = tRec.Class;
tLen = fCnt;
tPtr = streamInPtr; // next char to be processed
if (symbol.TerminalId == CommentStart || symbol.TerminalId == CommentSingle)
{
return;
}
if (terminalTable.AtLeaf)
{
break; // terminal cannot be extended
}
}
NextCh();
if (aLen == fCnt &&
(special && ch.IsSpecialAtomChar() ||
!special && ch.IsIdAtomContinueChar(extraUnquotedAtomChar)
)
)
{
aLen++;
iPtr = streamInPtr;
}
} // fCnt++ by last (i.e. failing) Call
// At this point: (in the Prolog case, read 'Identifier and Atom made up
// from specials' for 'Identifier'):
// - tLen has length of BaseTrie terminal (if any, 0 otherwise);
// - aLen has length of Identifier (if any, 0 otherwise);
// - fCnt is the number of characters inspected (for Id AND terminal)
// - The character pointer is on the last character inspected (for both)
// Iff aLen = fCnt then the entire sequence read sofar is an Identifier.
// Now try extending the Identifier, only meaningful if iLen = fCnt.
// Do not do this for an Atom made up from specials if a Terminal was recognized !!
if (aLen == fCnt)
{
while (true)
{
NextCh();
if (special ? ch.IsSpecialAtomChar() : ch.IsIdAtomContinueChar(extraUnquotedAtomChar))
{
aLen++;
iPtr = streamInPtr;
}
else
{
break;
}
}
}
if (aLen > tLen) // tLen = 0 iff Terminal == Undefined
{
if (firstLow || special)
{
symbol.TerminalId = Atom;
}
else
{
symbol.TerminalId = Identifier;
}
symbol.Class = SymbolClass.Id;
InitCh(iPtr);
}
else if (symbol.TerminalId == Undefined)
{
InitCh(iPtr);
}
else // we have a terminal != Identifier
{
if (aLen == tLen)
{
symbol.Class = SymbolClass.Id;
}
InitCh(tPtr);
}
NextCh();
// a bit hacky: find erroneous conditional define symbols
// such as e.g. !ifxxx (space omitted between !if and xxx)
if (symbol.Class == SymbolClass.Meta)
{
int pos = streamInPtr.Position;
while (ch.IsIdAtomContinueChar(extraUnquotedAtomChar))
{
NextCh();
}
if (pos != streamInPtr.Position)
{
symbol.TerminalId = Undefined;
}
}
// Dot-patch: a '.' is a Dot only if it is followed by layout,
// otherwise it is an atom (or an operator if defined as such)
if (isDot && aLen == 1 && (ch == '\0' || ch == '%' || Char.IsWhiteSpace(ch)))
{
symbol.TerminalId = Dot;
}
}
