P (programming language): Difference between revisions

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{{Short description|Event-driven programming language}}

{{Infobox programming language

| name = P

| logo = P logo.png

| logo sizelogo_size = 64px120px

| logo alt =

| logo caption =

| paradigm =

| designer =

| developer = Ankush Desai, Vivek Gupta: not the politician, [[Ethan Jackson]], [[Shaz Qadeer]], [[Sriram Rajamani]], [[Microsoft]]

| latest release version = 2.3.5

| latest release date = {{Start date and age|20122025|1102|19}}

| typing =

| implementations =

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| file ext = .p

| license = [[MIT License]]

| website = {{URLurl|https://p-org.github.io/P/}}

}}

'''P''' is a [[programming language]] for asynchronous [[event-driven programming]] and the [[Internet of things|IoT]] that was developed by [[Microsoft]] and [[University of California, Berkeley]].<ref>[https://www.infoworld.com/article/3130998/microsoft-open-sources-p-language-for-iot.html Microsoft open-sources P language for IoT]</ref>

P enables programmers to specify systems consisting of a collection of [[finite state machine|state machines]]s that communicate asynchronously in terms of events.<ref>{{cite web |url=https://www.microsoft.com/en-us/research/publication/p-safe-asynchronous-event-driven-programming/ |title=P: Safe Asynchronous Event-Driven Programming |author=Ankush Desai |author2=Vivek Gupta |author3=Ethan Jackson |author4=Shaz Qadeer |author5=Sriram Rajamani |website=[[Microsoft]] |date=November 2012 |access-date=20 February 2017}}</ref> P programs can run and be analyzed on any platform supported by [[.NET]]. Additionally, P programs can generate C# and C code.

P is [[open-source model|open source]], licensed under [[MIT License]], and available on [[GitHub]].<ref>{{cite web|last1=Sergio De Simone|title=Microsoft Open-Sources P Language for Safe Async Event-Driven Programming|url=https://www.infoq.com/news/2016/10/microsoft-p-language-opensourced|website=InfoQ|access-date=20 October 2016}}</ref>

== Example ==

<pre>

machine BankServer

{

var database: Database;

start state Init {

entry (initialBalance: map[int, int]){

database = new Database((server = this, initialBalance = initialBalance));

goto WaitForWithdrawRequests;

}

}

state WaitForWithdrawRequests {

on eWithDrawReq do (wReq: tWithDrawReq) {

var currentBalance: int;

var response: tWithDrawResp;

// read the current account balance from the database

currentBalance = ReadBankBalance(database, wReq.accountId);

// if there is enough money in account after withdrawal

if(currentBalance - wReq.amount >= 10)

{

UpdateBankBalance(database, wReq.accountId, currentBalance - wReq.amount);

response = (status = WITHDRAW_SUCCESS, accountId = wReq.accountId, balance = currentBalance - wReq.amount, rId = wReq.rId);

}

else // not enough money after withdraw

{

response = (status = WITHDRAW_ERROR, accountId = wReq.accountId, balance = currentBalance, rId = wReq.rId);

}

// send response to the client

send wReq.source, eWithDrawResp, response;

}

}

}

</pre>

== See also ==