public AstTernaryExpression(AstTernaryOperator @operator, AstExpression arg1, AstExpression arg2, AstExpression arg3)
{
_operator = @operator;
_arg1 = Ensure.IsNotNull(arg1, nameof(arg1));
_arg2 = Ensure.IsNotNull(arg2, nameof(arg2));
_arg3 = Ensure.IsNotNull(arg3, nameof(arg3));
}
public static string Render(this AstTernaryOperator @operator)
{
return(@operator switch
{
AstTernaryOperator.Substr => "$substr",
AstTernaryOperator.SubstrBytes => "$substrBytes",
AstTernaryOperator.SubstrCP => "$substrCP",
_ => throw new InvalidOperationException($"Unexpected ternary operator: {@operator}.")
});
private static AggregationExpression TranslateHelper(TranslationContext context, Expression expression, Expression stringExpression, Expression startIndexExpression, Expression lengthExpression, AstTernaryOperator substrOperator)
{
var stringTranslation = ExpressionToAggregationExpressionTranslator.Translate(context, stringExpression);
var startIndexTranslation = ExpressionToAggregationExpressionTranslator.Translate(context, startIndexExpression);
AstExpression ast;
if (lengthExpression == null)
{
var strlenOperator = substrOperator == AstTernaryOperator.SubstrCP ? AstUnaryOperator.StrLenCP : AstUnaryOperator.StrLenBytes;
var(stringVar, stringAst) = AstExpression.UseVarIfNotSimple("string", stringTranslation.Ast);
var(indexVar, indexAst) = AstExpression.UseVarIfNotSimple("index", startIndexTranslation.Ast);
var lengthAst = AstExpression.StrLen(strlenOperator, stringAst);
var countAst = AstExpression.Subtract(lengthAst, indexAst);
var inAst = AstExpression.Substr(substrOperator, stringAst, indexAst, countAst);
ast = AstExpression.Let(stringVar, indexVar, inAst);
}
else
{
var lengthTranslation = ExpressionToAggregationExpressionTranslator.Translate(context, lengthExpression);
ast = AstExpression.Substr(substrOperator, stringTranslation.Ast, startIndexTranslation.Ast, lengthTranslation.Ast);
}
return(new AggregationExpression(expression, ast, new StringSerializer()));
}
