Understand Expression Editor

  • Updated

The expression editor supports a variety of math, string, form expressions and logical functions.

The Expression Editor is a powerful tool that allows you to edit various expressions in form controls or workflow actions.

Yeeflow has different elements of the expression editor based on various scenarios. You may use the expression editor when you are intending to:



Overview of Expression Elements

Yeeflow offers five expression elements that you can use in the Expression Editor. 

  1. Values 
  2. Expressions
  3. Functions
  4. Operators



① Values

You use Values to make outcome return, or to process logical calculations. It provides a simple value of a number (a) or a text input(b); also it also supports "true/false/[empty]"(c) per some logic values, such as a Boolean control of Switch that you may use in your form. 

Values Description


Return the logical value TRUE(YES), or determine if a value is TRUE(YES).


 Return the logical value FALSE(NO), or determine if a value is FALSE(NO).


Return the value as a null or determine if a value is null.


<Return to Top>


② Expressions

You use Expressions to conduct logical rules and processing based on associated values or information.  Yeeflow offers most of related expressions in workflow and applications and there are some different items based on both of them.

  • Workflow Related

Item Form Designer

Workflow Task

(differ based on Action Palette)

Flow Condition

Workflow Variables

(list all form controls)

Instance Context

Static Variables

(application and task status)

- -
Task Context -
Current Task Context -

(task palette only)



(Task Outcomes)



(system data)


User Group

(system data)


(system data)


Please note: List workflow includes all workflow items as mentioned above. 

Item Calculated

List Form

Workflow Task 


Flow Condition

List Fields

List Context

Temp Variables

- -


(system data)


<Return to Top>


③ Functions

A function is a processor or relation that associates over two sets, and which associates every item of the first set, to exactly one item of the second set. A expression support multiple predefined functions.

You use Functions to create expressions that convert values. Yeeflow offers five types of functions by now. 

>> Learn more about expression Functions.


<Return to Top>


④ Operators

Operators are used to specify comparisons between expressions. Yeeflow offers various types of operators. You use Operators to perform a logical conjunction between expression(s).

>> Learn more about Operators in Expression Editor


<Return to Top>


Various views based scenarios

Base on the use of scenarios, Yeeflow offers different views and available elements in Expression Editor. 

Ⅰ. Create a rule or condition on a control

You will be directed to expression editor when you're intending to create a rule/condition for a field control:

When you set a dynamic display rule, It behaves differently based on specific conditions and rules. You will have full-elements to define its Rules.


When you set a custom error message that will display under any field(bound control) when specified conditions become true. You will have full-elements to define its Rules.


  • Actions

When you set actions that should be taken on events that meet your designated rule criteria. You will have full-elements to define its Conditions and Values.



<Return to Top>


Ⅱ. Execute a calculation control

A calculation can be a simple value of some number or text words, or a logic display value that you use expression elements to conduct operations. 

When you add a calculation, you will have full-elements to define a form variable, and you will have limited-elements to define a list field.

>> Learn more about Calculation control/field

<Return to Top>

Ⅲ. Conduct a flow condition

You can add some condition(s) on the flow direction. Then you will be directed to Condition Editor.

The Expression Editor in this section is different. It consists of three parts:

Expressions only of Expression Editor

② Corresponding Properties that Expression related

③ Auto-corresponding Operators based on left properties.


Please Note: Yeeflow does not offer the predefined Functions in flow conditions.


<Return to Top>


Ⅳ. Set a task title and assignee

Yeeflow offers you custom Task Title that associated with Expression. It allows you to add any available expression as a part of your task title. 


Yeeflow also offers an Expression to get your task assignee(s). It allows you to add any available expression as this task assignee(s). 


Please Note: Yeeflow does not offer the predefined Functions in task assignments.


<Return to Top>

Was this article helpful?




Please sign in to leave a comment.