public List <ColumnExpressionMsx> ColExprList = new List <ColumnExpressionMsx>(); // list of parsed column expressions in axis expression
/// <summary>
/// Parse an axis expression
/// </summary>
/// <param name="axisExpr"></param>
/// <returns></returns>
public static AxisExpressionMsx Parse(string axisExpr)
{
AxisExpressionMsx ax = new AxisExpressionMsx();
ax.Expression = axisExpr;
List <string> colExprs = Split(axisExpr);
foreach (string colExpr in colExprs)
{
ax.ColExprList.Add(ColumnExpressionMsx.Parse(colExpr));
}
return(ax);
}
public static ColumnExpressionMsx Parse(string expr)
{
Lex lex = new Lex();
lex.SetDelimiters(" , ; ( ) [ ]");
lex.OpenString(expr);
StringBuilder sb = new StringBuilder();
PositionedToken lastTok = null, leftBracket = null;
ColumnExpressionMsx colExpr = new ColumnExpressionMsx();
List <PositionedToken> tokens = new List <PositionedToken>(); // list of tokens seen
int parenDepth = 0;
while (true)
{
PositionedToken pTok = lex.GetPositionedToken();
if (pTok == null)
{
break;
}
tokens.Add(pTok);
if (lastTok != null)
{ // include same white space between tokens
int wsBeg = lastTok.Position + lastTok.Text.Length;
sb.Append(expr.Substring(wsBeg, pTok.Position - wsBeg));
}
string tok = pTok.Text;
if (pTok.Text == "(")
{
parenDepth++;
}
else if (pTok.Text == ")")
{
parenDepth--;
}
else if (tok == "[")
{
leftBracket = pTok;
}
else if (tok == "]")
{
if (leftBracket != null)
{
int p = leftBracket.Position + 1;
int l = pTok.Position - p;
string colName = expr.Substring(p, l);
colExpr.ColumnNames.Add(colName);
leftBracket = null;
}
}
}
return(colExpr);
}
