If you pass through the order of colors in Prismatic Wall one way, do you reverse the order of colors passing through the other way?

I set up a Prismatic Wall and a non-protected creature passes through it, say from left to right. On page 269 of the 5e Player’s Handbook, the spell reads:

“When a creature attempts to reach into or pass through the wall, it does so one layer at a time through all the wall’s layers. As it passes or reaches through each layer, the creature must make a Dexterity saving throw or be affected by that layer’s properties as described below.”

The layers are listed from Red to Violet, so the enemy passed through my wall in that order and made it through. They are now on the right side, and I have contrived a way to push them back through the wall to the left side. Do I reverse the order they encounter the layers and go Violet to Red, or do I always go Red to Violet whenever anything passes through the wall?

In other words, does a Prismatic Wall have a “sidedness” to it, and, if so, when is that sidedness established?

What are the relation and differences between reification and type passing semantics?

https://en.wikipedia.org/wiki/Type_erasure says

type erasure refers to the load-time process by which explicit type annotations are removed from a program, before it is executed at run-time. Operational semantics that do not require programs to be accompanied by types are called type-erasure semantics, to be contrasted with type-passing semantics. The possibility of giving type-erasure semantics is a kind of abstraction principle, ensuring that the run-time execution of a program does not depend on type information. In the context of generic programming, the opposite of type erasure is called reification.

  • Are both reification and type passing semantics opposite to type erasure?
  • What are the relation and differences between reification and type passing semantics? Do they mean the same?

The best that I can find about them are from the two following books. But I am still not quite sure about my question.

About type erasure vs type passing, Types and Programming Languages by Pierce says:

23.7 Erasure and Evaluation Order

The operational semantics given to System F in Figure 23-1 is a type-passing semantics: when a polymorphic function meets a type argument, the type is actually substituted into the body of the function. The ML implementation of System F in Chapter 25 does exactly this. In a more realistic interpreter or compiler for a programming language based on System F, this manipulation of types at run time could impose a significant cost. Moreover, it is easy to see that type annotations play no significant role at run time, in the sense that no run-time decisions are made on the basis of types: we can take a well-typed program, rewrite its type annotations in an arbitrary way, and obtain a program that behaves just the same.

For these reasons, many polymorphic languages instead adopt a type-erasure semantics, where, after the typechecking phase, all the types are erased and the resulting untyped terms are interpreted or compiled to machine code.

About type erasure vs reification, Programming Language Pragmatics by Scott says:

C# 2.0 was able to employ an implementation based on reification rather than erasure. Reification creates a different concrete type every time a generic is instantiated with different arguments. Reified types are visible to the reflection library (csNames.GetType().ToString() returns “Arbiter 1[System.Double]”), and it is perfectly acceptable to call new T() if T is a type parameter with a zero-argument constructor (a constraint to this effect is required). Moreover where the Java compiler must generate implicit type casts to satisfy the requirements of the virtual machine (which knows nothing of generics) and to ensure type-safe interaction with legacy code (which might pass a parameter or return a result of an inappropriate type), the C# compiler can be sure that such checks will never be needed, and can therefore leave them out. The result is faster code.


Passing Data between Mobile / Web Apps

We have a third party mobile app that will link to a dashboard in our web app. The user id needs to be passed in this interaction so that we can retrieve the user’s data. The user is logged in in the mobile app and we need to sign them into the web dashboard without prompting again for credentials. I’m considering using Encrypt-Then-Mac approach OR a pseudo SSO approach where the mobile app retrieves a one time token by calling a background API and passes that along with the user id. Can you comment on the pros/cons of these approaches or suggest a better one?

Many thanks!

Problem with passing through a value typed in TextField in SPFx and add it to a SharePoint List

I am doing a small project there I want to add Tulips in to a SharePoint list using SharePoint Framework with React.

I am using Textfield and so from UI Fabrics and PnPJs for getting data from Lists and so. It works fine to add hardcoded states when clicking the “ADD” button does not work when trying to type in value from textfield.

This is how the app looks like now: enter image description here

Here is code:


import * as React from 'react'; import styles from './EnfokamTulips.module.scss'; import { IEnfokamTulipsProps } from './IEnfokamTulipsProps';  import AddTulips from './AddTulips'  export default class EnfokamTulips extends React.Component<IEnfokamTulipsProps, {}> {   public render(): React.ReactElement<IEnfokamTulipsProps> {     return (       <div className={ styles.enfokamTulips }>         <div className={ styles.container }>           <div className={ styles.row }>             <div className={ styles.column }>               <span className={ styles.title }>Tulips!</span>               <AddTulips></AddTulips>             </div>           </div>         </div>       </div>     );   } } 


import * as React from 'react'; import { TextField } from 'office-ui-fabric-react/lib/TextField'; import { DefaultButton } from 'office-ui-fabric-react'; import { sp, ItemAddResult } from '@pnp/sp';  export interface IEnfokamTulipsState {     title: string;     manufacturingCost: number; }  this.state = {     title: 'book',     manufacturingCost: 2 }   function addTulipsToList(event) {      // get all the items from a list     sp.web.lists.getByTitle("Tulips").items.select("Title").get().then((items: any[]) => {     console.log(items); });  // add an item to the list     sp.web.lists.getByTitle("Tulips").items.add({         Title: event.target.value,         Manufacturing_x0020_cost: event.target.manufacturingCost //Internal name of column         }).then((iar: ItemAddResult) => {             console.log(iar);     }); }  let addTulips = (event) => {     return(         <div>             <TextField label="Tulip Name " value={this.state.title} required />             <TextField label="Manufacturing Cost" value={this.state.manufacturingCost} required type='number'/>             <DefaultButton text='ADD' onClick={addTulipsToList}></DefaultButton>         </div>     ) }  export default addTulips; 


export interface IEnfokamTulipsProps {   description: string; }  export interface IEnfokamTulipsState {   title: string;   manufacturingCost: number; }  export interface TulipsLists{   value: TulipsList[]; } export interface TulipsList{   Title: string;   Manufacturing_x0020_cost: number;  }  

The only thing that happens at the moment when I click the “ADD” button is this: enter image description here

All data in every colomn shows up blank. What am I doing wrong? What I want is that what ever I type in the textfields, I want to pass it through and show it in the list when I click “ADD”.

All help is appreciated.

Properly passing objects between my applications models/modules

I have several models/modules such as User, Wallet, both these modules that are called from the express application such as User.login(req,res);

right now in each User.js and Wallet.js I am including database.js which looks like this:

 var mysql = require('mysql2/promise') var pool = mysql.createPool({     connectionLimit: 10,     host: 'localhost',     user: 'x',     password: 'x',     database: 'x' }); pool.getConnection((err, connection) => {     if (err) {         if (err.code...
Code (markup):

Properly passing objects between my applications models/modules

Keep $post->ID unchanged while passing through W3TC mfunc

Is there a way of keeping $ post->ID unchanged while passing through W3TC Fragment Cache “mfunc” ?

I’m dealing with an archive and when wrapping my function with , all the $ post->ID reflect the id of the page they are contained in but not the id they originally come from.

Thus the mfunc is outside the loop and losing the specific post id I need to generate specific content for every post in the archive.

I’m explaining badly since I’m beginning in all this, but would you have an idea on how to fix this ?

Thanks !

Passing Sessions via link not working

I have a customized form where it uses sessions to prepopulate some of the fields based on the previous item from a list. The sessions looks like the following:

sessionStorage.setItem("systemStuff" + index, stuffItem[index].System); 

Works great. However when we send the link to the customized form via email, the prepopulated fields are blank. Is this because it’s an empty session value? Sorry, still trying to figure out SharePoint.

Language independent protocols describing argument passing and parsing?


I wrote a powershell installation script that passes a line of arguments to a .jar file through the command line. It comes down to:

  1. Converting an object into a list of strings
  2. Concatenating them into a single single string:
  3. Executing the `java -jar .jar
  4. Parsing the back into an object inside Java.

Several design choices I face are:

  • When I update the list of features, I will have changed the number of options the java parser should convert into the features property of the installation object. It might be wise to pass an explicit argument that contains the number of features, so that, in the future the script will immediately throw an error, if for some reason I/someone has forgotten to update the number of features that the argument parser should facilitate.
  • It feels like a work around of implementing a proper integration. It might be better to store the object as a temporary configurations.txt file that is read explicitly by the custom java parser.
  • Do I prepend every argument value with an -<argument name> or just hardCode the argument order into the argument order in both in the .ps1 script, as well as in the .jar script.

Since this is such a wide range of questions, I was wondering whether:


What are the language-independent argument passing protocols?

Error Passing a script via ssh

i am trying to execute the following script to a remote machine via ssh :


git clone https://github.com/vmwarelab/oc-electro-theme.git

cd ./oc-electro-theme

mysql -u ocuser opencart < cmd.txt


i thought each command will simply wait until the command before it is complete but what ends up happening, the 2nd command “cd” executes trying to change to the folder before git clone finishes resulting in a failure..

if i put sleep for 60 sec “sleep 60” it endup adding strange character to it and get passed as “sleep 60\r” which is again invalid syntax

is that the expected behaviour ? how can i fix that ? any help is much appriciated

Passing entity constructor to a player

I created an entity class with its constructor:

class Entity { public:     Entity(sf::Vector2f Size, sf::Vector2f Position, std::string File_name, int Damage, int Life, float Speed);     int Entity_damage, Entity_life, Counter = 0, Direction = 2;     float Entity_movement_speed;     std::shared_ptr< sf::Texture > Entity_texture;     sf::Vector2f Map_margin;     sf::RectangleShape Entity_rect;   }; 

The Constructor:

Entity::Entity(sf::Vector2f Size, sf::Vector2f Position, std::string File_name, int Damage, int Life, float Speed) {     Entity_rect.setSize(Size);     Entity_rect.setPosition(Position);     Entity_texture = Shared_resources::Acquire(File_name);     Entity_rect.setTexture(&*Entity_texture);     Entity_damage = Damage;     Entity_life = Life;     Entity_movement_speed = Speed; } 

and now I have a player class which inheritances from entity, but i don’t know how to access entity constructor.