Signum Documentation

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Compiles and stores the result function in a cache.

Important Note: The cache uses simple reference comparison, so this method should only be used for constant compile-generated expressions stored in a static field otherwise the cache will eat all your memory!. In order to avoid this problem, the method can not be called with two different instances of identical expressions.

   public static T CompileAndStore<T>(this Expression<T> expression)


Compiles and stores the result function in a cache, then evaluates the result function. It uses CompileAndStore for the first two steps, so the same restrictions apply.

public static T Evaluate<T>(this Expression<Func<T>> expr)
public static T Evaluate<A0, T>(this Expression<Func<A0, T>> expr, A0 a0)
public static T Evaluate<A0, A1, T>(this Expression<Func<A0, A1, T>> expr, A0 a0, A1 a1)
public static T Evaluate<A0, A1, A2, T>(this Expression<Func<A0, A1, A2, T>> expr, A0 a0, A1 a1, A2 a2)
public static T Evaluate<A0, A1, A2, A3, T>(this Expression<Func<A0, A1, A2, A3, T>> expr, A0 a0, A1 a1, A2 a2, A3 a3)
static Expression<Func<Entity, IQueryable<NoteEntity>>> NotesExpression =
    ident => Database.Query<NoteEntity>().Where(n => n.Target.RefersTo(ident));
public static IQueryable<NoteEntity> Notes(this Entity ident)
    return NotesExpression.Evaluate(ident);

This method can also be used in database queries to apply expressions, in this case the cache won't be used so is not an issue.

Expression<Func<int, int>> dup = n => n  * 2; 

    .Where(p=>dup.Evaluate(p.Id) == 2 || dup.Evaluate(p.Id) == 4)