Logic

Apply/Template
Conditional

Apply/Template

Apply and Template are special tags that are used to save and restore sets of nodes and provide them with user-defined macros to fill out their attributes. Both apply and template are tags applied to a name that gets associated with the set of nodes.

So, when defining a template that you wish to refer to as “io_label”, you would use the type “!Template:io_label”. Then, when including those templated nodes into a different part of your yaml file, you would use “!Apply:io_label”.

A Template definition is a list with a single Node and an optional set of defaults for the macros used within the Template. Defaults are just a dictionary of names and values, but can be tagged with the do-nothing tag “!Defaults” to make the intention clear.

For the Apply node, its definition is a dictionary with a set of macros you wish to provide the Template.

Example

LblRbkTemplate: !Template:lbl_rbk
    - !Defaults
        spacing: 10
        
    - !hflow
        padding: "{spacing}"
        
        children:
            - !Text { geometry: 150x20, text: "{TITLE}" }
            - !TextMonitor
                <<: *FixedFeedback
                pv: "$(P){PV}"


Status: !hcenter:hflow
    geometry: 20x65 x 0x0
    padding: 20

    children:
        - !vflow
            padding: 5
        
            children:
                - !Apply:lbl_rbk { TITLE: "Model Name",  PV: "ModelName" }
                - !Apply:lbl_rbk { TITLE: "Serial Num",  PV: "SerialNumber" }                            
                - !Apply:lbl_rbk { TITLE: "LJM Version", PV: "LJMVersion" }
                    
        - !vflow
            padding: 5
        
            children:
                - !Apply:lbl_rbk { TITLE: "Firmware Version", PV: "FirmwareVersion" }                    
                - !Apply:lbl_rbk { TITLE: "Temperature (C)",  PV: "DeviceTemperature" }
                - !Apply:lbl_rbk { TITLE: "Driver Version",   PV: "DriverVersion" }

Conditional

Conditionally adds children widgets into the final output based upon a specified macro in the input data.

The macro named by the condition macro is parsed and treated as a truthy value in python. If the macro’s data is equivalent to a true value, then the conditional’s contents are included in the resulting UI screen. Otherwise, none of the children widgets are included. The condition can be negated by using the ‘!Not’ type indicator.

Two aliases are also allowed, ‘!If’ and ‘!IfNot’. These include the necessary condition in their tag name. So, using the tag ‘!If:my-condition’ would be equivalent to creating a ‘!Conditional’ with the condition of ‘“my-condition”’. And ‘!IfNot:my-condition’ is the equivalent of creating a ‘!Conditional’ with the condition of ‘!Not “my-condition”’.

Special Attributes

Name	Type	Description
children	List	A list of widgets to conditionally include
condition	String	The name of a macro that will determine the children widget’s inclusion
background	Color	A fill color behind the entirety of all children
border-color	Color	The color of the group’s border surrounding the children widgets
border-width	Number	The thickness of the group’s border in pixels
visibility	String	A pv that determines the visibility of the layout, visibility is turned off if the PV’s value is zero. This logic is inverted if the !Not tag is used instead of String

Example

HaveLED: !conditional
    condition: "INCLUDE_LED"
    
    geometry: 0x20 x 0x0
    
    children:
        - !LED
            pv: "xxx:yyy:bi.VAL"
            true-color: *alarm_red
            false-color: *alarm_green
            
            border-color: *transparent
            
            geometry: 15x0 x 22x22
            
SimplerVersion: !If:INCLUDE_LED
    - !LED
        pv: "xxx:yyy:bi.VAL"
        true-color: *alarm_red
        false-color: *alarm_green
        
        border-color: *transparent
        
        geometry: 15x0 x 22x22

Logic

Table of contents

Apply/Template

Conditional