Examples of using Monadic value in English and their translations into Vietnamese
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Colloquial
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Ecclesiastic
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Computer
Then, we feed that monadic value to g.
Mf is a monadic value whose result is a function.
With do expressions however, each line must feature a monadic value.
The result of this monadic value is a function.
If the monadic value on the left is a Nothing, the whole thing is Nothing.
Well, to do that, it has to take into account the context of that monadic value.
We have one monadic value, m and two monadic functions f and g.
To ensure that the context is reflected in the final result,the result is also a monadic value.
When we have a monadic value that has() as its result, we don't bind it to a variable.
Once we're inside that lambda,it's just a normal value rather than a monadic value.
The last monadic value in a do expression, like Just(show x++ y) here, can't be used with.
Now what if those two functions were monadic, that is,what if the values they returned were monadic values?
F returns a monadic value, which is a function in our case, so we apply it to w as well.
So this is sort of like assigning values to variables in let expressions,only that the values in question are monadic values.
The result of that was another monadic value which got bound into the next monadic function, and so on.
It's an important function for making normal values into monadic ones andit wouldn't be good if the monadic value that it produced did a lot of other stuff.
It turns out that any nested monadic value can be flattened and that this is actually a property unique to monads.
We can see that it's a stateful computation, so we can wrap it in the State newtype constructor andthen use it as a monadic value so that passing of the state gets handled for us.
We feed the monadic value m into the function and then we apply the function f to its result before putting it back into a default context.
If we just map that function over the monadic value, we have a monadic value inside a monadic value.
The predicate returns a monadic value whose result is a Bool, but because it's a monadic value, its context can be anything from a possible failure to non-determinism and more!
In this section,we're going to explore a few functions that either operate on monadic values or return monadic values as their results(or both!).
Because the result of mm is a monadic value, we get that result and then just put it on a line of its own because it's a monadic value.
Instead of making functions that ignore their inputand just return a predetermined monadic value, we can use thegt;gt; function, whose default implementation is this.
Well, return x is supposed to make a monadic value that always presents x as its result, so it doesn't make sense for the probability to be 0.
Now that we have seen that a value with an attached monoid acts like a monadic value, let's examine the Monad instance for types of such values. .
In Writer, after doing that and getting the new monadic value, we still had to make sure that the context was taken care of by mappending the old monoid value with the new one.
It's like function application, only instead of taking a normal value and feeding it to a normal function,it takes a monadic value(that is, a value with a context) and feeds it to a function that takes a normal value but returns a monadic value.
If we compare these two,it's easy to see why the result of the whole monadic value is the result of the last monadic value in the do expression with all the previous ones chained into it.
Rather, its result is the result of the whole glued up monadic value, taking into account the possible failure of any of the previous ones.