How do rule-based systems deal with recursion? -


i beginning learn rule-based systems, , having trouble understanding how can handle recursion.

some quick background. have studied little programming language theory , pretty familiar context-free grammars , stuff that. have come across rule-based systems , wondering how may related automata , recursion.

my question is: how rule-based systems handle recursion? in particular, rule-based system used parsing nested parentheses? (or parsing cfg)?

i don't have deep understanding of rule-based systems yet, seems, rules never organized hierarchy or network. true, or there way represent them hierarchy or network?

without ability create hierarchy of rules, seems rule-system memory have keep track of context manually, , context used test conditions. like:

if parentconditionx , parentparentconditiony {   perform action }

but problem is, how return "parent" rule (like parent function context)? if rules can't organized/executed hierarchically, seems can't recursion? that's i'm confused.

any ideas?


Comments

Post a Comment

Popular posts from this blog

node.js - Using Node without global install -

i'm working on few node & electron (atom shell) projects , i'm curious how them work without user having install node globally. i've seen few applications including node directory in project contains node.exe binary. how go setting node project use binary? edit: thought should add, i've searched everywhere answer this, unrelated results.
Read more

How to access a php class file from PHPFox framework into javascript code written in simple HTML file? -

i've website developed using phpfox v3.0.7 . now i'm trying implement 'sse(server sent events)' 1 of php files. reference i'm giving below necessary code part of file. file titled process.class.php , present @ location /var/www/module/notification/include/service/process.class.php present on server having ip http://34.124.40.142/ . <?php /** * [phpfox_header] */ header('content-type: text/event-stream'); header('cache-control: no-cache'); defined('phpfox') or exit('no dice!'); /** * * * @copyright [phpfox_copyright] * @author raymond benc * @package phpfox_service * @version $id: service.class.php 67 2009-01-20 11:32:45z raymond_benc $ */ class notification_service_process extends phpfox_service { /** * class constructor */ public function __construct() { $this->_stable = phpfox::gett('notification'); } public function add($...
Read more

java - Null response to php query in android, even though php works properly -

Image
table i'm trying retrieve above data using 2 php files below. want pass email parameter , return bets user = email. work fine when tested advanced rest client, problem not php. however, when try through android 2 java classes below, null pointer exception (logcat below) , json object returned null. i'm not sure error is, think i'm not passing parameter php , that's why it's producing null response. logcat 05-31 15:10:50.227 26074-26074/com.example.albert.betterapp e/androidruntime﹕ fatal exception: main process: com.example.albert.betterapp, pid: 26074 java.lang.runtimeexception: unable start activity componentinfo{com.example.albert.betterapp/com.example.albert.betterapp.displayallbets}: java.lang.nullpointerexception @ android.app.activitythread.performlaunchactivity(activitythread.java:2292) @ android.app.activitythread.handlelaunchactivity(activitythread.java:2350) @ android.app.activitythread.acce...
Read more