This page (revision-59) was last changed on 13-Jun-2014 18:25 by Albrecht Striffler

This page was created on 26-Oct-2012 10:15 by Joachim Baumeister

Only authorized users are allowed to rename pages.

Only authorized users are allowed to delete pages.

Page revision history

Version Date Modified Size Author Changes ... Change note
59 13-Jun-2014 18:25 7 KB Albrecht Striffler to previous
58 13-Jun-2014 18:25 7 KB Albrecht Striffler to previous | to last
57 13-Jun-2014 18:24 7 KB Albrecht Striffler to previous | to last
56 13-Jun-2014 18:23 7 KB Albrecht Striffler to previous | to last
55 13-Jun-2014 18:22 6 KB Albrecht Striffler to previous | to last
54 13-Jun-2014 18:21 6 KB Albrecht Striffler to previous | to last
53 13-Jun-2014 18:20 6 KB Albrecht Striffler to previous | to last
52 13-Jun-2014 18:20 6 KB Albrecht Striffler to previous | to last
51 13-Jun-2014 18:17 6 KB Albrecht Striffler to previous | to last
50 13-Jun-2014 18:11 5 KB Albrecht Striffler to previous | to last
49 13-Jun-2014 18:11 5 KB Albrecht Striffler to previous | to last
48 13-Jun-2014 18:10 5 KB Albrecht Striffler to previous | to last
47 13-Jun-2014 17:56 4 KB Albrecht Striffler to previous | to last
46 13-Jun-2014 17:48 4 KB Albrecht Striffler to previous | to last
45 13-Jun-2014 17:48 4 KB Albrecht Striffler to previous | to last
44 13-Jun-2014 17:40 4 KB Albrecht Striffler to previous | to last
43 13-Jun-2014 17:39 4 KB Albrecht Striffler to previous | to last
42 13-Jun-2014 17:26 4 KB Albrecht Striffler to previous | to last
41 13-Jun-2014 17:24 4 KB Albrecht Striffler to previous | to last

Page References

Incoming links Outgoing links

Version management

Difference between version and

At line 13 removed one line
At line 15 removed one line
At line 19 removed one line
At line 25 added one line
A condition can look like {{"temperature" > 38}} or {{"weather" = raining}}. Such simple conditions can be combined to more complex ones, using the following syntax:
At line 29 removed 2 lines
A condition can look like ''"temperature > 38"'' or ''"weather = rain'"'. Such simple conditions can be combined to more complex ones, using the following syntax:
At line 34 added one line
Actions might be {{"Show warning" = Yes}} or {{umbrella = Yes}}
At line 39 removed one line
In a rule action we can set other questions or variables. Examples could be ''"Show warning = Yes"'' or ''"umbrella = Yes"''\\
At line 41 removed one line
It is also possible to set more complex values and values depending on other variables. For more information, go to [Extended Expressions: Conditions and actions | Doc Expressions], but be aware, that this extension is non-LGPL-licensed for commercial use.
At line 43 removed one line
At line 47 changed 2 lines
{{{
{{{%%Rule
At line 53 changed one line
}}}
%}}}
At line 55 changed one line
!!EXCEPT Conditions
!!Except Conditions
At line 57 changed one line
Furthermore, it is possible to add an exception condition to the rule, like in the following example:
Furthermore it is possible to add an exception condition to the rule, like in the following example:
At line 67 changed one line
!!ELSE Actions
!!Combining Rules
At line 69 changed one line
Using such rules, we often not only want something to happen if the condition is true (e.g. ''temperature <= 0''), but also when the condition is false. We can of course always do this, by writing a second rule, using the negated condition of the first rule (e.g. ''temperature > 0''). With d3web/KnowWE, we provide the possibility, to just use the keyword ELSE, similar to how it is known and done in software engineering.
Using such rules, we often not only want something to happen if the condition is true (e.g. temperature <= 0), but also when the condition is false. We can of course always do this, by writing a second rule, using the negated condition of the first rule (temperature > 0). With d3web KnowWE, we provide the possibility, to just use the keyword ELSE, similar to how it is known and done in software engineering.
At line 77 removed 44 lines
!!UNKNOWN Actions
In d3web/KnowWE, every question can, besides their normal values, also have the value ''Unknown''. This means, that the value of the question is currently actually unknown or unknowable (which is different from not answering the question).\\
If a rule uses a question which currently has the value ''Unknown'' will result in the rule not being evaluated and therefor the action will not fire.
__Example:__ Lets assume, the temperature is currently unknown, because the sensor is broken. In this case, we really do not know whether the roads are icy or not. So to expand on the example above, we can do the following:
{{{
IF temperature < 0
THEN icy roads = Yes
ELSE icy roads = No
UNKNOWN icy roads = No
}}}This way, if the ''temperature'' is ''Unknown'', we also set the variable/question ''icy roads'' to ''Unknown'', without having the write rules for each of the actions.
Be aware that, if you just use THEN and ELSE __without__ an action for UNKNOWN, the action of ELSE will also fire if ''temperature'' is ''Unknown''.
!!ELSE and UNKNOWN in combination with EXCEPT
It is also possible to use an EXCEPT condition together with ELSE and UNKNOWN. If the EXCEPT condition is true, the ELSE action will fire. The UNKNOWN action only fires if the original IF condition is ''Unknown''. For clarification, check out the following truth tables:
\\
__Rule with THEN and ELSE action only__:
|| IF Condition || EXCEPT Condition || THEN Action || ELSE Action
| %%(color:green)true%% | %%(color:green)true%% |   | %%(color:green)fire%%
| %%(color:red)false%% | %%(color:green)true%% |   | %%(color:green)fire%%
| %%(color:grey)unknown%% | %%(color:green)true%% |   | %%(color:green)fire%%
| %%(color:green)true%% | %%(color:red)false%% | %%(color:green)fire%% |  
| %%(color:red)false%% | %%(color:red)false%% |   | %%(color:green)fire%%
| %%(color:grey)unknown%% | %%(color:red)false%% |   | %%(color:green)fire%%
| %%(color:green)true%% | %%(color:grey)unknown%% | %%(color:green)fire%% |  
| %%(color:red)false%% | %%(color:grey)unknown%% |   | %%(color:green)fire%%
| %%(color:grey)unknown%% | %%(color:grey)unknown%% |   | %%(color:green)fire%%
__Rule with THEN and ELSE and UNKNOWN action__:
|| IF Condition || EXCEPT Condition || THEN Action || ELSE Action || UNKNOWN Action
| %%(color:green)true%% | %%(color:green)true%% |   | %%(color:green)fire%% |  
| %%(color:red)false%% | %%(color:green)true%% |   | %%(color:green)fire%% |  
| %%(color:grey)unknown%% | %%(color:green)true%% |   | %%(color:green)fire%% |  
| %%(color:green)true%% | %%(color:red)false%% | %%(color:green)fire%% |   |  
| %%(color:red)false%% | %%(color:red)false%% |   | %%(color:green)fire%% |  
| %%(color:grey)unknown%% | %%(color:red)false%% |   |   | %%(color:green)fire%%
| %%(color:green)true%% | %%(color:grey)unknown%% | %%(color:green)fire%% |   |  
| %%(color:red)false%% | %%(color:grey)unknown%% |   | %%(color:green)fire%% |  
| %%(color:grey)unknown%% | %%(color:grey)unknown%% |   |   | %%(color:green)fire%%
At line 174 removed 11 lines