/// <summary>
/// Parse expression
/// </summary>
/// <param name="parameter"></param>
/// <param name="context"></param>
/// <returns></returns>
private Expression ParseWhereExpression(ParameterExpression parameter,
SqlSelectParser.ExprContext context)
{
if (context.NOT() != null)
{
return(Expression.Not(
ParseWhereExpression(parameter, context.expr(0))));
}
if (context.AND() != null)
{
return(Expression.And(
ParseWhereExpression(parameter, context.expr(0)),
ParseWhereExpression(parameter, context.expr(1))));
}
if (context.OR() != null)
{
return(Expression.Or(
ParseWhereExpression(parameter, context.expr(0)),
ParseWhereExpression(parameter, context.expr(1))));
}
if (context.scalarFunction() != null)
{
return(ParseScalarFunction(parameter, context));
}
if (context.BR_OPEN() != null)
{
return(ParseWhereExpression(parameter, context.expr(0)));
}
return(ParseComparisonExpression(parameter, context));
}
/// <summary>
/// Parse scalar function
/// </summary>
/// <param name="parameter"></param>
/// <param name="context"></param>
/// <returns></returns>
private Expression ParseScalarFunction(ParameterExpression parameter,
SqlSelectParser.ExprContext context)
{
var scalarFunctionContext = context.scalarFunction();
var expr = scalarFunctionContext.scalarTypeFunction() != null?
ParseScalarLambda(scalarFunctionContext.scalarTypeFunction()) :
ParseScalarLambda(scalarFunctionContext);
var lhs = Expression.Invoke(expr,
ParseParameterBinding(parameter, scalarFunctionContext.columnName()));
var rhs = Expression.Constant(context.literal_value() != null ?
ParseLiteralValue(context.literal_value()) : _serializer.FromObject(true));
return(CreateBinaryExpression(context.COMPARISON_OPERATOR()?.GetText() ?? "=",
lhs, rhs));
}
/// <summary>
/// Parse comparison expression
/// </summary>
/// <param name="parameter"></param>
/// <param name="context"></param>
/// <returns></returns>
private Expression ParseComparisonExpression(ParameterExpression parameter,
SqlSelectParser.ExprContext context)
{
var lhs = ParseParameterBinding(parameter, context.columnName(0));
Expression rhs;
if (context.columnName().Length > 1)
{
rhs = ParseParameterBinding(parameter, context.columnName(1));
}
else if (context.array_literal() != null)
{
rhs = Expression.Constant(context.array_literal().literal_value()
.Select(ParseLiteralValue)
.ToArray());
}
else
{
rhs = Expression.Constant(ParseLiteralValue(context.literal_value()));
}
return(CreateBinaryExpression(context.COMPARISON_OPERATOR().GetText(), lhs, rhs));
}
