private bool check(char ch)
{
if (_reader.Peek() == ch)
{
_reader.Read();
return(true);
}
return(false);
}
/// <summary>
/// Parse stream and return the expression tree
/// </summary>
/// <param name="r">Stream</param>
/// <returns>Parsed expression or null if no expression is found on stream</returns>
public IOperation Parse(ParsingReader r)
{
List <IOperation> data = new List <IOperation>();
while (!r.IsEOF)
{
TokenQueue tokenQueue = new TokenQueue(this, r);
var ex = parseSingleStatement(tokenQueue, -1);
if (ex == null)
{
break;
}
if (data.Count > 0)
{
data.Add(new Operations.OperationPop());
}
data.Add(ex);
r.SkipWhiteSpaceAndComments();
if (r.Peek() != ';')
{
break;
}
do
{
r.Read();
r.SkipWhiteSpaceAndComments();
} while (r.Peek() == ';');
}
if (data.Count == 0)
{
return(null);
}
if (data.Count == 1)
{
return(data[0]);
}
return(new Operations.OperationExpression(data.ToArray()));
}
/// True if str is a number
public static bool IsNumber(string str)
{
if (str == null)
{
throw new ArgumentNullException("str");
}
using (var sr = new ParsingReader(str))
{
if (sr.ReadNumber() == null)
{
return(false);
}
sr.SkipWhiteSpaceAndComments();
if (sr.Peek() != -1)
{
return(false);
}
}
return(true);
}
/// Returns null if str is not a number, or its value otherwise
public static ValueType TryParseNumber(string stringToParse)
{
if (stringToParse == null)
{
return(null);
}
using (var sr = new ParsingReader(stringToParse))
{
sr.SkipWhiteSpaceAndComments();
ValueType o = sr.ReadNumber();
if (o == null)
{
return(null);
}
sr.SkipWhiteSpaceAndComments();
if (sr.Peek() != -1)
{
return(null);
}
return(o);
}
}
/// Parse string to a number. 10 and hex numbers (like 0x222) are allowed. Suffixes like 20.3f are also allowed.
public static ValueType ParseNumber(string str)
{
if (str == null)
{
throw new ArgumentNullException("str");
}
using (var sr = new ParsingReader(str))
{
sr.SkipWhiteSpaceAndComments();
ValueType o = sr.ReadNumber();
if (o == null)
{
throw new ParsingException("Invalid numeric expression at " + sr.ReadLine());
}
sr.SkipWhiteSpaceAndComments();
if (sr.Peek() != -1)
{
throw new ParsingException("Invalid numeric expression, unexpected characters at " + sr.ReadLine());
}
return(o);
}
}
/// Parse multi-expression, like ${a|b|=2+3}
public IOperation ParseMulti(ParsingReader reader)
{
Operations.OperationVariableAccess va = new Operations.OperationVariableAccess();
StringBuilder sb = new StringBuilder();
bool orMet = true;
int n;
while ((n = reader.Peek()) != -1)
{
var q = (char)n;
if (q == '}' || q == ')' || q == ']')
{
break;
}
switch (q)
{
case '|':
reader.Read();
va.AddName(sb.ToString());
sb.Length = 0;
orMet = true;
break;
case '\'':
case '\"':
case '`':
orMet = false;
if (sb.Length != 0)
{
reader.ThrowParsingException("Quote must be a first character");
}
va.AddValue(reader.ReadQuote());
reader.SkipWhiteSpaceAndComments();
if (reader.Peek() != '}' && reader.Peek() != '|')
{
reader.ThrowParsingException("Unexpected character '" + (char)reader.Peek() + "'");
}
sb.Length = 0;
break;
case '=':
orMet = false;
reader.Read();
var v = Parse(reader);
if (v != null)
{
va.AddExpression(v);
}
else
{
va.AddValue(null);
}
break;
default:
orMet = false;
sb.Append(q);
reader.Read();
break;
}
}
if (sb.Length > 0 || orMet)
{
va.AddName(sb.ToString());
}
return(va);
}