public static ExprEntry Create(ExprLogic parent, string keyword = "")
{
return(new ExprEntry()
{
Parent = parent, Keyword = keyword, EntryLogic = parent.ChildEntryLogic, Operator = Operator.Nop, Value = ""
});
}
static (bool, int, ExprLogic) ReadKeword(int pos, string source, ExprLogic currectGrp)
{
var x = source[pos];
var sb = new StringBuilder();
if (!IsKeywordFirstSymbol(x))
{
return(false, pos, currectGrp);
}
while (char.IsLetterOrDigit(x))
{
sb.Append(x);
pos++;
if (pos < source.Length)
{
x = source[pos];
}
else
{
break;
}
}
currectGrp.ExprEntries.Add(ExprEntry.Create(currectGrp, sb.ToString()));
currectGrp.ChildEntryLogic = Logic.None;
return(true, pos, currectGrp);
}
public static ExprLogic Parse(string exprText)
{
var exprSchema = DeclareSchema();
var refPointer = exprSchema[0];
var resultLogic = ExprLogic.CreateGroup(null);
var currentGroup = resultLogic;
var i = 0;
var exprTextLen = exprText.Length;
while (i < exprTextLen)
{
var(pos, exprGrp, schemaNode) = HandleNode(refPointer, currentGroup, i, exprText);
refPointer = schemaNode;
currentGroup = exprGrp;
i = pos;
}
if (currentGroup.Parent != null)
{
throw new KeywordParserException("Open and close brackets mismatch!");
}
return(resultLogic);
}
static (bool, int, ExprLogic) ReadLogic(Dictionary <Logic, List <string> > logicDict, bool entry,
int pos, string source, ExprLogic currectGrp)
{
var res = false;
var startPos = pos;
foreach (var key in logicDict.Keys)
{
var logop = "";
var logics = logicDict[key];
foreach (var lop in logics)
{
if (pos + lop.Length > source.Length)
{
continue;
}
if (pos != source.IndexOf(lop, pos, lop.Length))
{
continue;
}
logop = lop;
break;
}
if (string.IsNullOrEmpty(logop))
{
continue;
}
if (entry)
{
currectGrp.ChildEntryLogic = key;
}
else
{
currectGrp.ActiveEntry.JoinLogic = key;
}
pos += logop.Length;
res = true;
break;
}
if (res)
{
//if (startPos > 0 && !char.IsWhiteSpace(source[startPos-1]))
// throw new KeywordParserException($"The space must precede the logical operator. Expected space in the the position {startPos + 1}");
if (pos < source.Length && IsKeywordFirstSymbol(source[pos]))
{
throw new KeywordParserException($"A logical operator must be followed by a space. Expected space in the the position {pos + 1}");
}
}
return(res, pos, currectGrp);
}
public static ExprLogic CreateGroup(ExprLogic parent)
{
return(new ExprLogic()
{
Parent = parent,
EntryLogic = parent != null ? parent.ChildEntryLogic : Logic.None,
ExprEntries = new List <ExprEntryBase>()
});
}
static (bool, int, ExprLogic) PassWhitespace(int pos, string source, ExprLogic currectGrp)
{
var res = false;
while (pos < source.Length && char.IsWhiteSpace(source[pos]))
{
pos++; res = true;
}
return(res, pos, currectGrp);
}
static (int, ExprLogic, GraphNode) HandleNode(GraphNode graphNode, ExprLogic currentGroup, int pos, string source)
{
foreach (GraphNodeItem nodeItem in graphNode)
{
var(res, newPos, exprGrp) = nodeItem.Handler(pos, source, currentGroup);
if (!res)
{
continue;
}
return(newPos, exprGrp, nodeItem.Next);
}
throw new KeywordParserException($"Unexpected character '{source[pos]}' in the position {pos + 1}.");
}
static (bool, int, ExprLogic) CloseGroup(int pos, string source, ExprLogic currectGrp)
{
// close group
var res = false;
if (source[pos] == CloseGrp)
{
if (currectGrp.Parent == null)
{
throw new KeywordParserException($"Unexpected character '{CloseGrp}' in the position {pos}.");
}
pos++; res = true;
}
return(res, pos, currectGrp.Parent);
}
static (bool, int, ExprLogic) OpenGroup(int pos, string source, ExprLogic currectGrp)
{
// open group
var res = false;
ExprLogic newGroup = null;
if (source[pos] == OpenGrp)
{
pos++; res = true;
}
if (res)
{
newGroup = currectGrp.AddGroup(ExprLogic.CreateGroup(currectGrp));
currectGrp.ChildEntryLogic = Logic.None;
}
return(res, pos, res ? newGroup : currectGrp);
}
static (bool, int, ExprLogic) ReadOperator(int pos, string source, ExprLogic currectGrp)
{
var res = false;
foreach (var key in GraphMeta.Operators.Keys)
{
var oper = GraphMeta.Operators[key];
if (pos + oper.Length > source.Length)
{
continue;
}
if (pos != source.IndexOf(oper, pos, oper.Length))
{
continue;
}
currectGrp.ActiveExpr.Operator = key;
pos += oper.Length;
res = true;
break;
}
return(res, pos, currectGrp);
}
public ExprLogic AddGroup(ExprLogic group)
{
return((ExprLogic)AddEntry(group));
}
static (bool, int, ExprLogic) ReadValue(int pos, string source, ExprLogic currectGrp)
{
var x = source[pos];
var sb = new StringBuilder();
if (char.IsWhiteSpace(x))
{
return(false, pos, currectGrp);
}
bool handleEscaped(char ch)
{
if (pos < source.Length - 1 && source[pos] == ch && source[pos + 1] == ch)
{
sb.Append(ch);
pos++;
return(false);
}
return(true);
}
var inQuote = (x == Quote);
if (inQuote)
{
pos++;
}
while (pos < source.Length)
{
x = source[pos];
if (!inQuote)
{
if (x == Quote)
{
if (handleEscaped(x))
{
throw new KeywordParserException($"Unescaped quote symbol {Quote} found in the position {pos + 1}!");
}
}
else if (IsStopSymbol(x))
{
break;
}
else
{
if (!char.IsWhiteSpace(x))
{
sb.Append(x);
}
else
{
break;
}
}
}
else
{
if (x == Quote)
{
if (handleEscaped(x))
{
inQuote = false; pos++; break;
}
}
else if (IsStopSymbol(x))
{
if (handleEscaped(x))
{
throw new KeywordParserException($"Unescaped symbol {Quote} found in the position {pos + 1}!");
}
}
else
{
sb.Append(x);
}
}
pos++;
}
if (inQuote)
{
throw new KeywordParserException($"Unexpected end of quoted string found!");
}
currectGrp.ActiveExpr.Value = sb.ToString();
return(true, pos, currectGrp);
}
static (bool, int, ExprLogic) ReadEntryLogic(int pos, string source, ExprLogic currectGrp)
{
return(ReadLogic(GraphMeta.Unaries, true, pos, source, currectGrp));
}
static (bool, int, ExprLogic) ReadJoinLogic(int pos, string source, ExprLogic currectGrp)
{
return(ReadLogic(GraphMeta.Logics, false, pos, source, currectGrp));
}