private IReadOnlyList <Token> ParseTokens(string query, out Expr immediateResult)
{
try
{
if (string.IsNullOrEmpty(query))
{
immediateResult = new IdentityExpr(new Location(1, 1));
return(null);
}
var lexer = new Lexer(
operators: new [] {
"|", "|<", "&", ".", "(", "[?", "[", "{", "}", "]", ")", ".", "@", "*",
"?", ":", ",", "-", "+", "/", "%", "==", "!=", "&&", "||", "??", "..",
"<", "<=", ">", ">=", "=", "$", ";", "...", "!"
},
charKind: "STRING",
charsMustBeOneChar: false,
backtickStringKind: "STRING",
intKind: "NUMBER",
floatKind: "NUMBER",
stringKind: "STRING",
hasVariables: true
);
// Take a guess as to the size of the list so that it doesn't have to get rebuilt a bunch.
var tokens = new List <Token>(query.Length / 3);
foreach (var token in lexer.Parse(query))
{
tokens.Add(token);
}
immediateResult = null;
return(tokens);
}
catch (ParseException ex)
{
immediateResult = new ErrorExpr(ex.Location, ex.Message);
return(null);
}
catch (Exception ex)
{
immediateResult = new ErrorExpr(new Location(0, 0), ex.Message);
return(null);
}
}
private Expr _Substitute(ErrorExpr e)
{
return e;
}
private Expr _Numericize(ErrorExpr e)
{
return e;
}
private Expr _Canonicalize(ErrorExpr e)
{
return e;
}
private List<Expr> GetFieldExpressions()
{
List<Expr> fieldExprs = new List<Expr>();
ExpectWhitespace();
while (fieldExprs.Count == 0 || ExpectSymbol(","))
{
ExpectWhitespace();
// TODO: Add support for *
Expr fieldExpr = GetFieldExpression();
if (fieldExpr == null)
{
fieldExpr = new ErrorExpr("Syntax error: Unable to parse field expression");
}
fieldExprs.Add(fieldExpr);
ExpectWhitespace();
}
return fieldExprs;
}
public virtual void Visit(ErrorExpr expr)
{
}
