public static IEnumerable <RewriteRule> AtomInvokeParam(SqlExprParams pars)
{
var invokeRule = RewriteRule.Create(
"atomInvokeParam",
() => RewriteSpecial.Call <RewriteTypes.C2>(null, "Invoke"),
null,
null,
(match, expr, visit) =>
{
var exprCall = (MethodCallExpression)expr;
var origArgs = exprCall.Arguments;
//Aplicar la transformación del from a los parametros, esto es importante porque el from
//en algunos casos se usa sólo para especificar el tipo en un método generico pero su valor
//no es importante.
var fromArgs = origArgs
.Select(x => Rewriter.RecApplyRules(x, ExprParamsRules(pars), ExcludeFromRewrite))
.ToList()
;
var arg = fromArgs[0];
var args = fromArgs;
var atomArg = Expression.Call(typeof(RewriteSpecial), "Atom", new[] { arg.Type }, arg);
var atomArgs = new[] { atomArg }.Concat(args.Skip(1)).ToList();
var retCall = Expression.Call(exprCall.Object, exprCall.Method, atomArgs);
return(retCall);
});
return(new[] { invokeRule });
}
public void EvalBooleanRule()
{
//Evalua las expresiones booleanas, sólo se aplica la regla si la expresión no es ya una constante
var evalBool = RewriteRule.Create("", (bool x) => RewriteSpecial.NotConstant(x), null, null, (_, x, visit) => ExprEval.EvalExprExpr(x));
var rules = new[]
{
evalBool
};
var a = true;
Expression <Func <bool, bool, bool> > expr = (x, y) => x && y || !(true || a);
var red = ApplyRules(expr, rules);
//Note que la expresión !(true || a) se evaluó por completo:
Assert.AreEqual("(x, y) => ((x AndAlso y) OrElse False)", red.ToString());
}
public static IEnumerable <RewriteRule> ExprParamsRules(SqlExprParams pars)
{
var ret = new List <RewriteRule>();
//Puede ser null el param en caso de que todo sea por sustituciones del replace
if (pars.Param != null)
{
//Es posible que el fromParam este envuelto en un Convert, por ejemplo cuando se usan propiedades de una interfaz
ret.Add(
RewriteRule.Create(
"convertFromParam",
(RewriteTypes.C1 p) => RewriteSpecial.Operator <RewriteTypes.C1, RewriteTypes.C2>(p, ExpressionType.Convert),
(RewriteTypes.C1 p) => Sql.FromParam <RewriteTypes.C2>(),
(match, expr) => match.Args[0] == pars.Param
));
ret.Add(
new RewriteRule(
"fromParam",
Expression.Lambda(pars.Param), Expression.Lambda(Expression.Call(typeof(Sql), nameof(Sql.FromParam), new[] { pars.Param.Type })), null, null)
);
}
return(ret);
}
/// <summary>
/// La regla que se aplica a las llamadas Atom(Raw(x)), lo que hace es convertir las llamadas ToSql del Atom(Raw(x))
/// </summary>
public static IEnumerable <RewriteRule> AtomRawRule(SqlExprParams pars)
{
var deferredToSqlRule = RewriteRule.Create(
"deferredToSql",
(RewriteTypes.C1 x) => SqlFunctions.ToSql <RewriteTypes.C1>(x),
null,
null,
(match, expr, visit) => Expression.Call(
typeof(SqlExpression),
nameof(SqlExpression.ExprToSql),
new Type[0],
Expression.Constant(match.Args[0]),
Expression.Constant(pars),
Expression.Constant(true)));
var toSqlRule = RewriteRule.Create(
"toSql",
() => RewriteSpecial.Call <string>(typeof(SqlFunctions), nameof(ToSql)),
null,
null,
(match, expr, visit) => Expression.Constant(SqlExpression.ExprToSql(((MethodCallExpression)expr).Arguments[0], pars, true)));
var toSelectBodySqlRule = RewriteRule.Create(
"toSelectBodySqlRule",
() => RewriteSpecial.Call <string>(typeof(SqlFunctions), nameof(ToSelectBodySql)),
null,
null,
(match, expr, visit) =>
Expression.Constant(
SqlSelect.SelectExprToStr(SqlSelect.SelectBodyToStr(((MethodCallExpression)expr).Arguments[0], pars).Values)
)
);
var windowToSqlRule = RewriteRule.Create(
"windowToSql",
(ISqlWindow a) => WindowToSql(a),
null,
null,
(match, expr, visit) => Expression.Constant(SqlCalls.WindowToSql(match.Args[0]))
);
var toSqlRules = new[]
{
toSelectBodySqlRule,
toSqlRule,
windowToSqlRule
};
Func <Expression, Expression> applySqlRule = (Expression ex) => new RewriteVisitor(toSqlRules, ExcludeFromRewrite).Visit(ex);
var atomRawRule = RewriteRule.Create(
"executeAtomRaw",
(string x) => RewriteSpecial.Atom(Sql.Raw <RewriteTypes.C1>(RewriteSpecial.NotConstant(x))),
null,
null,
(match, expr, visit) =>
{
var arg = match.Args[0];
var applySql = applySqlRule(arg);
if (applySql == arg)
{
return(expr);
}
var type = match.Types[typeof(RewriteTypes.C1)];
var value = ExprEval.EvalExpr <string>(applySql).Value;
var ret = Expression.Call(typeof(RewriteSpecial), nameof(RewriteSpecial.Atom), new[] { type },
Expression.Call(typeof(Sql), nameof(Sql.Raw), new[] { type }, Expression.Constant(value))
);
return(ret);
});
return(new[] { atomRawRule });
}
