RxPerl - an implementation of Reactive Extensions / rxjs for Perl
use RxPerl::AnyEvent ':all'; use AnyEvent; sub make_subscriber ($i) { return { next => sub {say "next #$i: ", $_[0]}, error => sub {say "error #$i: ", $_[0]}, complete => sub {say "complete #$i"}, }; } my $o = rx_interval(0.7)->pipe( op_map(sub {$_[0] * 2}), op_take_until( rx_timer(5) ), ); $o->subscribe(make_subscriber(1)); AnyEvent->condvar->recv;
use RxPerl::IOAsync ':all'; use IO::Async::Loop; my $loop = IO::Async::Loop->new; RxPerl::IOAsync::set_loop($loop); sub make_subscriber ($i) { return { next => sub {say "next #$i: ", $_[0]}, error => sub {say "error #$i: ", $_[0]}, complete => sub {say "complete #$i"}, }; } my $o = rx_interval(0.7)->pipe( op_map(sub {$_[0] * 2}), op_take_until( rx_timer(5) ), ); $o->subscribe(make_subscriber(1)); $loop->run;
use RxPerl::Mojo ':all'; use Mojo::IOLoop; sub make_subscriber ($i) { return { next => sub {say "next #$i: ", $_[0]}, error => sub {say "error #$i: ", $_[0]}, complete => sub {say "complete #$i"}, }; } my $o = rx_interval(0.7)->pipe( op_map(sub {$_[0] * 2}), op_take_until( rx_timer(5) ), ); $o->subscribe(make_subscriber(1)); Mojo::IOLoop->start;
This module is an implementation of Reactive Extensions in Perl. It replicates the behavior of rxjs 6 which is the JavaScript implementation of ReactiveX.
Currently 26 of the 100+ operators in rxjs are implemented in this module.
The code samples in this section assume $subscriber has been set to:
$subscriber = { next => sub {say "next: ", $_[0]}, error => sub {say "error: ", $_[0]}, complete => sub {say "complete"}, };
Creation operators create and return an observable. They are usually unicast, which means that when an "rx_interval" observable is subscribed to three seperate times there will be three different & distinct recurring intervals. Exceptions to this are with subjects, and that any observable can be transformed into a multicasting one using the "op_share" pipeable operator (or by other similar operators).
The following list is the currently implemented creation operators with links to relevant rxjs documentation (which should apply to RxPerl too).
https://rxjs.dev/api/index/function/concat
# 10, 20, 30, 10, 20, 30, 40, complete rx_concat( rx_of(10, 20, 30), rx_of(10, 20, 30, 40), )->subscribe($subscsriber);
https://rxjs.dev/api/index/function/defer
# Suppose "int rand 10" here evaluates to 7. Then if after 7 seconds $special_var holds a true value, # output will be: 0, 1, 2, 3, 4, 5, 6, 10, 20, 30, complete, otherwise it will be: # 0, 1, 2, 3, 4, 5, 6, 40, 50, 60, complete. rx_concat( rx_interval(1)->pipe( op_take(int rand 10) ), rx_defer(sub { return $special_var ? rx_of(10, 20, 30) : rx_of(40, 50, 60) }) )->subscribe($subscriber);
https://rxjs.dev/api/index/const/EMPTY
# complete rx_EMPTY->subscribe($subscriber); # 10, 20, 30, 40, 50, 60, complete rx_concat( rx_of(10, 20, 30), rx_EMPTY, rx_EMPTY, rx_EMPTY, rx_of(40, 50, 60), )->subscribe($subscriber);
https://rxjs.dev/api/index/function/fromEvent
Currently, only instances of the Mojo::EventEmitter class are allowed as the first argument of this function.
# 4 seconds after Mojolicious hypnotoad is gracefully reloaded, websocket # connection will close sub websocket ($c) { rx_from_event($ioloop, 'finish')->pipe( op_delay(4), )->subscribe( next => sub { $c->finish }, ); }
Similar to: "rx_from_event".
Observables may emit at most one value per event, however Mojo::EventEmitter's are able to emit more. So this function serves to pack all of them in an arrayref, and emit that as a single value instead.
https://rxjs.dev/api/index/function/interval
Works like rxjs's "interval", except the parameter is in seconds instead of ms.
# 0, 1, 2, ... every 0.7 seconds rx_interval(0.7)->subscribe($subscriber);
https://rxjs.dev/api/index/function/merge
# 0, 0, 1, 1, 2, 2, 3, 4, 3, ... rx_merge( rx_interval(0.7), rx_interval(1), )->subscribe($subscriber);
https://rxjs.dev/api/index/const/NEVER
# 10, 20, 30 (and no complete) rx_concat( rx_of(10, 20, 30), rx_NEVER, rx_of(40, 50, 60), )->subscribe($subscriber);
https://rxjs.dev/api/index/class/Observable
0.578, 0.234, 0.678, ... (every 1 second) my $o = rx_observable->new(sub ($subscriber) { # your code goes here Mojo::IOLoop->recurring(1, sub {$subscriber->next(rand())}); });
https://rxjs.dev/api/index/function/of
# 10, 20, 30, complete rx_of(10, 20, 30)->subscribe($subscriber);
https://rxjs.dev/api/index/function/race
# 0, 10, 20, 30, ... (every 0.7 seconds) rx_race( rx_interval(1)->pipe( op_map(sub {$_[0] * 100}) ), rx_interval(0.7)->pipe( op_map(sub {$_[0] * 10) ), )->subscribe($subscriber);
https://rxjs.dev/api/index/class/Subject
my $subject = rx_subject->new; $subject->subscribe($subscriber); # elsewhere... $subject->next($_) for 1 .. 10; $subject->complete;
https://rxjs.dev/api/index/function/throwError
# 0, 1, 2, 3, foo, 4, 5, 6, ... rx_merge( rx_of('foo')->pipe( op_delay(4.5) ), rx_interval(1), )->subscribe($subscriber);
https://rxjs.dev/api/index/function/timer
Works like rxjs's "timer", except the parameter is in seconds instead of ms.
# (pause 10 seconds) 0, 1, 2, 3, ... (every 1 second) rx_timer(10, 1)->subscribe($subscriber); # (pause 10 seconds) 0, complete rx_timer(10)->subscriber($subscriber);
Pipeable operators (also referred to as "operators") are passed as arguments to the "pipe" method of observables. Their function is to take an observable, transform it somehow, then (similar to piped shell commands) pass the result of the transformation to the next pipeable operator in the pipe, or return it to the user.
The following list is the currently implemented operators, with links to relevant rxjs documentation (which should apply to RxPerl too).
https://rxjs.dev/api/operators/delay
# (pause 10 seconds) 0, 1, 2, 3 rx_interval(1)->pipe( op_delay(10) )->subscribe($subscriber);
https://rxjs.dev/api/operators/filter
# 0, 2, 4, 6, ... (every 1.4 seconds) rx_interval(0.7)->pipe( op_filter(sub {$_[0] % 2 == 0}), )->subscribe($subscriber);
https://rxjs.dev/api/operators/map
# 10, 11, 12, 13, ... rx_interval(1)->pipe( op_map(sub {$_[0] + 10}), )->subscribe($subscriber);
https://rxjs.dev/api/operators/mapTo
# 123, 123, 123, ... (every 1 second) rx_interval(1)->pipe( map_to(123), )->subscribe($subscriber);
https://rxjs.dev/api/operators/multicast
https://rxjs.dev/api/operators/pairwise
# [0, 1], [1, 2], [2, 3], ... rx_interval(1)->pipe( op_pairwise, )->subscribe(sub {print Dumper($_[0])});
https://rxjs.dev/api/operators/refCount
https://rxjs.dev/api/operators/scan
https://rxjs.dev/api/operators/share
https://rxjs.dev/api/operators/take
# 0, 1, 2, 3, 4, complete rx_interval(1)->pipe( op_take(5), )->subscribe($subscriber);
https://rxjs.dev/api/operators/takeUntil
# 0, 1, 2, 3, 4, complete rx_interval(1)->pipe( op_take_until( rx_timer(5.5) ), )->subscribe($subscriber);
https://rxjs.dev/api/operators/tap
# foo0, 0, foo1, 1, foo2, 2, ... rx_interval(1)->pipe( op_tap(sub {say "foo$_[0]"}), )->subscribe($subscriber);
http://reactivex.io/rxjs/class/es6/Observable.js~Observable.html#instance-method-subscribe
$o->subscribe( sub {say "next: $_[0]"}, sub {say "error: $_[0]"}, sub {say "complete"}, ); $o->subscribe( undef, sub {say "error: $_[0]"}, ); $o->subscribe({ next => sub {say "next: $_[0]"}, complete => sub {say "complete"}, });
http://reactivex.io/rxjs/class/es6/Observable.js~Observable.html#instance-method-pipe
# 2, 6 rx_interval(1)->pipe( op_take(5), op_filter(sub {$_[0] % 2 == 1}), op_map(sub {2 * $_[0]}), )->subscribe(...)
Connectable observables are a subclass of observables, which (like Subjects) are multicasting and can start emitting even before anyone subscribes to them, by invoking a method. They are usually created and returned by the "op_multicast" pipeable operator.
Makes the connectable observable start emitting.
$o->connect;
Subjects multicast, and apart from being observables themselves (with their own subscribers), also have next, error and complete methods of their own, so can be used as the subscriber argument to another observable's subscribe method. That observable's events will then be "forwarded" to the subject's own subscribers, as if next/error/complete had been called on the subject directly.
Calling these methods manually will cause the subject's subscribers to receive the corresponding events.
Typically subjects don't emit anything on their own (as opposed to "rx_interval" et al), although it is possible to create a subclass of Subject that behaves differently. An example is a queueing subject that accumulates events from the observable it has been subscribed to, then emits all of them at once to the first subscriber that subscribes to it.
To prevent naming collisions with Perl’s built-in functions (or the user’s own), as rxjs’s operators are often small english words (such as map), the names of this module’s operators start with rx_ or op_.
map
rx_
op_
Functions that in the JS world would be imported from 'rxjs' have their corresponding RxPerl names prepended with rx_, whereas functions imported from 'rxjs/operators' (namely pipeable opreators) start with op_ in RxPerl.
import {Observable, Subject, timer, interval} from 'rxjs'; import {map, filter, delay} from 'rxjs/operators';
becomes:
use RxPerl::IOAsync qw/ rx_observable rx_subject rx_timer rx_interval op_map op_filter op_delay /;
Since the rxjs implementation differs from the ReactiveX API at a few points (as do most of the Rx* libraries), RxPerl chose to behave like rxjs rather than ReactiveX to cater for web developers already familiar with rxjs.
Unhandled error events ought to throw an exception
Fix the occasional bug
Short guide on how to create a creation or a pipeable operator
Copyright (C) Karelcom OÜ.
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
KARJALA Corp <karjala@cpan.org>
To install RxPerl, copy and paste the appropriate command in to your terminal.
cpanm
cpanm RxPerl
CPAN shell
perl -MCPAN -e shell install RxPerl
For more information on module installation, please visit the detailed CPAN module installation guide.