/// <summary>
/// Adds a BibTeX entry at the last in the document.
/// </summary>
/// <param name="bibTexEntry">BibTeX entry to be added to the Bibtex document.</param>
public void Add(BibTeXEntry bibTexEntry)
{
this._allBibTexEntries.Add(bibTexEntry);
}
/// <summary>
/// Inserts a BibTeX entry after the given index in the document.
/// </summary>
/// <param name="index">Zero based index at which item should be inserted.</param>
/// <param name="bibTexEntry">Item to be inserted.</param>
public void Insert(int index, BibTeXEntry bibTexEntry)
{
this._allBibTexEntries.Insert(index, bibTexEntry);
}
public BibTeXEntry GetBibTeXEntry(ICollection <BibTeXToken> tokens)
{
//TODO: Need to reduce complexity of this function
//
// Algorithm to implement the logic for the parsing a set of tokens
//
// * Algorithm to parse a set of tokens
// * 1. check for minimum no of tokens.
// Minimum tokens:
// @ proceedings { DBLP:conf/vldb/2005 , }
// * 2. Retrieve name and key from the list. Check for sync characters like '{' before and after ',' key.
// * 3. Build all properties. Check for sync character also. Like '=', ','
//
// The function follows DFA (Deterministic Finite State Automate):
// It reads one value at a time and moves to expected state. In the new state if the current
// symbol is not expected then it throws error.
List <BibTeXToken> allTokens = new List <BibTeXToken>(tokens);
BibTeXEntry bibtex = new BibTeXEntry();
#region Check for empty values, Minimum size
// Check for length here... must be at least 4
// Must be atleast 4 tokens. For Example: @ typeName { }
if (allTokens.Count < 4)
{
throw new BibTeXParserException(Properties.Resources.BIBTEXPARSER_NOT_WELL_FORMED,
allTokens[0].LineNumber, allTokens[0].ColumnNumber, allTokens[0].Value);
}
#endregion
#region Retrieve Name and Key. Check for sync tokens also
// First token must be '@'
if (!AreEqual(allTokens[0].Value, BibTeXHelper.BT_ENTRY_AT))
{
throw new BibTeXParserException("'@' expected",
allTokens[0].LineNumber, allTokens[0].ColumnNumber, allTokens[0].Value);
}
// Check for valid entry name
if (!BibTeXHelper.IsValidEntyName(allTokens[1].Value))
{
throw new BibTeXParserException("Invalid entry name",
allTokens[1].LineNumber, allTokens[1].ColumnNumber, allTokens[1].Value);
}
bibtex.Name = allTokens[1].Value;
// third token must be start of the entry '{'
if (!AreEqual(allTokens[2].Value, BibTeXHelper.BT_ENTRY_LEFT_BRACE) &&
!AreEqual(allTokens[2].Value, BibTeXHelper.BT_ENTRY_LEFT_PARENTHESIS))
{
throw new BibTeXParserException("'{' or '(' expected",
allTokens[2].LineNumber, allTokens[2].ColumnNumber, allTokens[2].Value);
}
// Check for valid key
if (!BibTeXHelper.IsValidKey(allTokens[3].Value))
{
throw new BibTeXParserException("Invalid key",
allTokens[3].LineNumber, allTokens[3].ColumnNumber, allTokens[3].Value);
}
bibtex.Key = allTokens[3].Value;
// Last token must be '}' : TODO: Do this check at last.
//if (!this.AreEqual(allTokens[allTokens.Count - 1].Value, BibTeXHelper.BT_ENTRY_RIGHT_BRACE))
//{
// throw new BibTeXParserException("'}' expected", allTokens[allTokens.Count - 1].LineNumber,
// allTokens[allTokens.Count - 1].ColumnNumber, allTokens[allTokens.Count - 1].Value);
//}
#endregion
#region Check whether any key-value pair is present?
if (allTokens.Count == 4)
{
if (AreEqual(allTokens[2].Value, BibTeXHelper.BT_ENTRY_LEFT_PARENTHESIS))
{
throw new BibTeXParserException("')' expected",
allTokens[3].LineNumber, allTokens[3].ColumnNumber + allTokens[3].Value.Length, String.Empty);
}
else
{
throw new BibTeXParserException("'}' expected",
allTokens[3].LineNumber, allTokens[3].ColumnNumber + allTokens[3].Value.Length, String.Empty);
}
}
#endregion
#region Process Properties. Operating liner way (one symbol at a time) allows easy error populating.
List <BibTeXToken> .Enumerator enumerator = allTokens.GetEnumerator();
// skip first four entries which are already processed (Name and Key).
int i;
for (i = 0; i < 4; i++)
{
enumerator.MoveNext();
}
i--;
EntryStates nextExpectedSymbol = EntryStates.CommaSign;
//ValueEncapsulator encapsulator = ValueEncapsulator.None;
ComplexValueStates nextTokenComplexVlaue = ComplexValueStates.Exited;
string key = string.Empty;
string value = string.Empty;
bool skipMoveNext = false;
System.Text.RegularExpressions.Regex nonAlphaNumericPattern =
new System.Text.RegularExpressions.Regex("[^a-zA-Z0-9]");
// Format of a particular key-value pair
// , title = { value }
while (true)
{
if (!skipMoveNext)
{
enumerator.MoveNext();
// break; // should not be called in any case,
// as exiting from the loop is handled in following 'if'
i++;
}
else
{
skipMoveNext = false;
}
// Following 'if' ensures that the loop will break, before enumerator.MoveNext() returns false
if (i == allTokens.Count - 1)
{
if ((AreEqual(enumerator.Current.Value, BibTeXHelper.BT_ENTRY_RIGHT_BRACE) &&
AreEqual(allTokens[2].Value, BibTeXHelper.BT_ENTRY_LEFT_BRACE)
)
||
(AreEqual(enumerator.Current.Value, BibTeXHelper.BT_ENTRY_RIGHT_PARENTHESIS)) &&
AreEqual(allTokens[2].Value, BibTeXHelper.BT_ENTRY_LEFT_PARENTHESIS)
)
{
// probably the last element so exist from the loop
// but before exiting, is there any pending complexValue creation running ?
if (nextTokenComplexVlaue == ComplexValueStates.ConcatenationOrComma && !String.IsNullOrEmpty(key))
{
bibtex.Properties[key] = value;
nextExpectedSymbol = EntryStates.CommaSign; // graceful termination ;)
break;
}
else if (nextTokenComplexVlaue == ComplexValueStates.Exited)
{
//nextExpectedSymbol = EntryStates.CommaSign; // graceful termination ;)
break;
}
else
{
throw new BibTeXParserException(Properties.Resources.BIBTEXTPARSER_UNEXPECTED_TOKEN,
enumerator.Current.LineNumber, enumerator.Current.ColumnNumber, enumerator.Current.Value);
}
}
else
{
if (AreEqual(allTokens[2].Value, BibTeXHelper.BT_ENTRY_LEFT_PARENTHESIS))
{
throw new BibTeXParserException("')' expected",
enumerator.Current.LineNumber, enumerator.Current.ColumnNumber, enumerator.Current.Value);
}
else
{
throw new BibTeXParserException("'}' expected",
enumerator.Current.LineNumber, enumerator.Current.ColumnNumber, enumerator.Current.Value);
}
}
}
switch (nextExpectedSymbol)
{
case EntryStates.CommaSign:
if (!AreEqual(enumerator.Current.Value, BibTeXHelper.BT_ENTRY_COMMA))
{
throw new BibTeXParserException("',' expected",
enumerator.Current.LineNumber, enumerator.Current.ColumnNumber, enumerator.Current.Value);
}
nextExpectedSymbol = EntryStates.KeyName;
break;
case EntryStates.KeyName:
if (!BibTeXHelper.IsValidPropertyName(enumerator.Current.Value))
{
throw new BibTeXParserException("Invalid property name",
enumerator.Current.LineNumber, enumerator.Current.ColumnNumber, enumerator.Current.Value);
}
// Key name is always converted to lower case. Hence, 'EDITOR', 'EDItor' and 'editor' are same.
key = enumerator.Current.Value.ToLowerInvariant();
nextExpectedSymbol = EntryStates.EqualSign;
break;
case EntryStates.EqualSign:
if (!AreEqual(enumerator.Current.Value, BibTeXHelper.BT_ENTRY_EQUAL))
{
throw new BibTeXParserException("'=' expected",
enumerator.Current.LineNumber, enumerator.Current.ColumnNumber, enumerator.Current.Value);
}
nextExpectedSymbol = EntryStates.OpeningValue;
break;
case EntryStates.OpeningValue:
if (AreEqual(enumerator.Current.Value, BibTeXHelper.BT_ENTRY_LEFT_BRACE))
{
//encapsulator = ValueEncapsulator.LeftBrace;
nextExpectedSymbol = EntryStates.ValueSimple;
//skipMoveNext = true;
}
else if (AreEqual(enumerator.Current.Value, BibTeXHelper.BT_ENTRY_QUOTATION))
{
//encapsulator = ValueEncapsulator.Quotation;
nextExpectedSymbol = EntryStates.ValueComplex;
skipMoveNext = true;
}
else if (this.symbolTable.ContainsKey(enumerator.Current.Value))
{
nextExpectedSymbol = EntryStates.ValueComplex;
skipMoveNext = true; // skip as we need to process the token ;)
}
else if (!nonAlphaNumericPattern.IsMatch(enumerator.Current.Value))
{
// Hmm... the value is -
// 1. not encapsulated with braces or quotation mark
// 2. is not defined as symbol name
// 3. and alphanumeric.
// Hence, accept it as value itself.
value = enumerator.Current.Value;
bibtex.Properties[key] = value;
key = string.Empty;
value = string.Empty;
nextExpectedSymbol = EntryStates.CommaSign;
}
else
{
throw new BibTeXParserException("'{' or '\"' or symbol name expected",
enumerator.Current.LineNumber, enumerator.Current.ColumnNumber, enumerator.Current.Value);
}
break;
case EntryStates.ValueSimple:
if (AreEqual(enumerator.Current.Value, BibTeXHelper.BT_ENTRY_RIGHT_BRACE))
{ // if a pair is like --> title={} <<- the value must be empty
value = string.Empty;
skipMoveNext = true;
}
else
{
value = enumerator.Current.Value;
}
nextExpectedSymbol = EntryStates.ClosingValueBrace;
break;
case EntryStates.ValueComplex:
#region Process Complex Vlaues: may be formed of symbol names, concatenation operatios, etc;
if (nextTokenComplexVlaue == ComplexValueStates.Exited)
{
nextTokenComplexVlaue = ComplexValueStates.Started;
}
switch (nextTokenComplexVlaue)
{
case ComplexValueStates.Started:
// First symbol can only be a variable name or quotation mark
if (this.symbolTable.ContainsKey(enumerator.Current.Value))
{
value += this.symbolTable[enumerator.Current.Value];
nextTokenComplexVlaue = ComplexValueStates.ConcatenationOrComma;
}
else if (AreEqual(enumerator.Current.Value, BibTeXHelper.BT_ENTRY_QUOTATION))
{
nextTokenComplexVlaue = ComplexValueStates.Value;
}
else
{
throw new BibTeXParserException("'\"' or symbol name expected",
enumerator.Current.LineNumber, enumerator.Current.ColumnNumber, enumerator.Current.Value);
}
break;
case ComplexValueStates.VariableName:
break;
case ComplexValueStates.ConcatenationOrComma:
if (AreEqual(enumerator.Current.Value, BibTeXHelper.BT_ENTRY_CONCATENATION))
{
// move back to started, i.e. it may be variableName or QUOTATION mark
nextTokenComplexVlaue = ComplexValueStates.Started;
skipMoveNext = false;
}
else if (AreEqual(enumerator.Current.Value, BibTeXHelper.BT_ENTRY_COMMA))
{
// if next is ',' then value is built
// 1. Save the key-value ; and reset key/value
// 2. exit from inner switch
// 3. move next in the outer switch,
// 4. skip the call to enumerator.MoveNext() as the comma is already fetched but yet to be processed
bibtex.Properties[key] = value;
key = value = string.Empty;
nextTokenComplexVlaue = ComplexValueStates.Exited;
nextExpectedSymbol = EntryStates.CommaSign;
skipMoveNext = true;
}
else
{
throw new BibTeXParserException("',' expected.",
enumerator.Current.LineNumber, enumerator.Current.ColumnNumber, enumerator.Current.Value);
}
break;
case ComplexValueStates.Concatenation:
nextTokenComplexVlaue = ComplexValueStates.VariableName;
break;
case ComplexValueStates.OpeningQuotation:
nextTokenComplexVlaue = ComplexValueStates.Value;
break;
case ComplexValueStates.Value:
if (AreEqual(enumerator.Current.Value, BibTeXHelper.BT_ENTRY_QUOTATION))
{ // if a pair is like --> title="" <<- the value must be empty
value += string.Empty;
skipMoveNext = true;
}
else
{
value += enumerator.Current.Value;
}
nextTokenComplexVlaue = ComplexValueStates.ClosingQuotation;
break;
case ComplexValueStates.ClosingQuotation:
if (!AreEqual(enumerator.Current.Value, BibTeXHelper.BT_ENTRY_QUOTATION))
{
throw new BibTeXParserException("'}' expected",
enumerator.Current.LineNumber, enumerator.Current.ColumnNumber, enumerator.Current.Value);
}
nextTokenComplexVlaue = ComplexValueStates.ConcatenationOrComma;
break;
case ComplexValueStates.Exited:
nextExpectedSymbol = EntryStates.CommaSign;
break;
default:
// This case should not be called in any case
throw new BibTeXParserException("Unexpected error");
}
#endregion
break;
case EntryStates.ClosingValueBrace:
if (!AreEqual(enumerator.Current.Value, BibTeXHelper.BT_ENTRY_RIGHT_BRACE))
{
throw new BibTeXParserException("'}' expected",
enumerator.Current.LineNumber, enumerator.Current.ColumnNumber, enumerator.Current.Value);
}
// So the value is well encapsulated. Add it to the list. and clear key and value.
bibtex.Properties[key] = value;
key = string.Empty;
value = string.Empty;
//proceed to the next key-value pair.
nextExpectedSymbol = EntryStates.CommaSign;
break;
default:
// This case should not be called any how
throw new BibTeXParserException("Unexpected error");
}
}
if (nextExpectedSymbol != EntryStates.CommaSign && nextExpectedSymbol != EntryStates.KeyName)
{
throw new BibTeXParserException("Not well formed property value. Last symbol processed: " + enumerator.Current.Value, enumerator.Current.LineNumber, enumerator.Current.ColumnNumber, enumerator.Current.Value);
}
#endregion
return(bibtex);
}