Flesh | An app full of benefits on Android , an artifact for otaku | Database library

I have a Flatlist. The data array is the contents of a book(paragraphs, images, subHeadings). How do I implement the getItemLayout prop correctly on my FlatList? I understand this is suppose to tell the FlatList the height of each item to make it more performant. However how am I to find out the size of each item? Is that something that I am to determine arbitrarily meaning by guesstimating? Every item is a different size. I have tried entering random values in getItemLayout just to see what happens however I don't really know how to tell which value would be the correct value.

This is my FlatList

I've been using Identity Server 4.0 as my OpenId Connect provider. I can setup clients in Identity Server with Redirect Uris and Post Logout Redirect Uris. I've also been using the angular-auth-oidc-client to login/logout via the Identity server.

When logging in, my client library (angular-auth-oidc-client) does pass in the correct Uri specified in the config when calling the authorize endpoint. When I try to login with an incorrect Redirect Uri, Identity Server checks and validates that the Uri provided by the client is one of the accepted one for that client, and shows an error if it isnt (as expected).

When it comes to logout, none of it seems to be built in. My client library does not send the PostLogoutRedirectUri when calling the logout endpoint. Identity Server's sample code for logout does not except any URIs to be passed in. It's sample code simply gets the Post Logout Redirect Uri value from the database and creates a link on the logged out page. Not only does the sample code not allow the user to specify the Redirect Uri for logout, but it doesn't do any checks or even do a redirect (granted its only sample code and I can change it). I would expect my client library to pass the Uri along and Identity Server to redirect to the Uri after successful logout as long as its one of the "approved" Uris for the client.

My question is: What even is the point of PostLogoutRedirectUri? Neither Identity Server nor the OIDC client library I'm using do anything useful with it. There doesn't even seem to be an agreed upon convention for the name of the query string parameters to use to pass this Uri to Identity Server. And yet, both the Identity Server and the angular client library seem to have some support for it. So what's the point of this thing? Is it something that will be added or fleshed out later? Did I miss some documentation describing what its for and how to use it?

Move operations should be noexcept; in the first place for intuitive and reasonable semantics. The second argument is runtime performance. From the Core Guidelines, C.66, "Make move operations noexcept":

A throwing move violates most people’s reasonably assumptions. A non-throwing move will be used more efficiently by standard-library and language facilities.

The canonical example for the performance-part of this guideline is the case when std::vector::push_back or friends need to grow the buffer. The standard requires a strong exception guarantee here, and this can only move-construct the elements into the new buffer if this is noexcept - otherwise, it must be copied. I get that, and the difference is visible in benchmarks.

However, apart from this, I have a hard time finding real-world evidence of the positive performance impact of noexcept move semantics. Skimming through the standard library (libcxx + grep), we see that std::move_if_noexcept exists, but it's almost not used within the library itself. Similarly, std::is_noexcept_swappable is merely used for fleshing out conditional noexcept qualifiers. This doesn't match existing claims, for example this one from "C++ High Performance" by Andrist and Sehr (2nd ed., p. 153):

All algorithms use std::swap() and std::move() when moving elements around, but only if the move constructor and move assignment are marked noexcept. Therefore, it is important to have these implemented for heavy objects when using algorithms. If they are not available and exception free, the elements will be copied instead.

To break my question into pieces:

1. Are there code paths in the standard library similar to the std::vector::push_back, that run faster when fed with std::is_nothrow_move_constructible types?
2. Am I correct to conclude that the cited paragraph from the book is not correct?
3. Is there an obvious example for when the compiler will reliably generate more runtime-efficient code when a type adheres to the noexcept guideline?

I know the third one might be a bit blurry. But if someone could come up with a simple example, this would be great.

I'm redoing the backend of a very basic framework that connects to a completely customizable frontend. It was originally in PHP but for the refactor have been plodding away in F#. Although it seems like PHP might be the more suited language. But people keep telling me you can do everything in F# and I like the syntax and need to learn and this seemingly simple project has me stumped when it comes to JSON. This is a further fleshed out version of my question yesterday, but it got alot more complex than I thought.

Here goes.

The frontend is basically a collection of HTML files, which are simply loaded in PHP and preg_replace() is used to replace things like [var: varName] or [var: array|key] or the troublesome one: [lang: hello]. That needs to be replaced by a variable defined in a translation dictionary, which is stored as JSON which is also editable by a non-programmer.

I can't change the frontend or the JSON files, and both are designed to be edited by non-programmers so it is very likely that there will be errors, calls to language variables that don't exist etc.

So we might have 2 json files, english.json and french.json

english.json contains:

Is it possible to use Try::Tiny in a Perl program that has a 'overloaded' $SIG{__DIE__}? For example, the desired output of this program would be "caught it":

I have been trying to sort this list of strings for ten hours now. The ten hours was mostly spent fleshing out a workaround but fate is cruel and after all of that effort my workaround still requires me to sort a list of strings without regard for case.

An example of what I would like this function to do:

I'm attempting to use ServiceStack.Redis to connect to a cloud based Redis instance using SSL Certificates. The ServiceStack documentation provides information on how to connect to an Azure based Redis using SSL, but has no information or examples on how to connect to a non Azure Redis instance.

I've got a pem, crt, and key file but nothing I do with them seems to actually pass them across to the service. I've set ssl=true&sslprotocols=tls12 in the connectionstring which seems like the first step, but beyond that I'm not sure what I should be doing to correctly pass across the certificate for verification

EDIT: Current Code

I'm working with dbus in haskell, and I'm having difficulties figuring out how to export dbus methods that perform stateful operations. Below is a fully fleshed out example to illustrate where I'm stuck.

Let's say you're writing a counter service with dbus. When the service starts, the counter is initially at 0. The service defines a dbus API that exposes a count method, which returns the current value of the counter, and an update method, which increments that counter, and returns the new value.

Here's a pseudocodey implementation of the behavior I just described, using a message-passing-style of communication:

I am working on this visualization at https://observablehq.com/d/88fa7afb1d32ebc8 below is the spot that I am trying to flesh out with user input from a drop down menu