This documentation covers logical operations, including conditionals, comparisons, and boolean logic, detailing how to execute actions based on various true or false conditions.
Conditionals
Continue Steps If It is Correct
If true then
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"controls_if\"><value name=\"IF0\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value></block></xml>"}
This block is used to check if the value is true, then do some actions.
Parameters: Logic (Comparison)
Output: N/A
Sample code:
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>index</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"variables_set\"><field name=\"VAR\">index</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">3</field></shadow></value><next><block type=\"controls_if\"><value name=\"IF0\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"logic_compare\"><field name=\"OP\">EQ</field><value name=\"A\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"variables_get\"><field name=\"VAR\">index</field></block></value><value name=\"B\"><shadow type=\"math_number\"><field name=\"NUM\">3</field></shadow></value></block></value><statement name=\"DO0\"><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"1\" _input_init=\"true\"></mutation><value name=\"text\"><shadow type=\"text\"><field name=\"TEXT\">The number of index is 3.</field></shadow></value></block></value></block></statement></block></next></block></next></block></next></block></statement></block></xml>"}
The output:

Checking True or False and Do some Related Actions
If true then … else …
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"controls_if\"><mutation else=\"1\"/><value name=\"IF0\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value></block></xml>"}
This block is used to check the value is true or false. If it is true, then do the first action. Otherwise, do the second action.
Parameters: Logic (Comparison)
Output: N/A
Sample code:
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>number</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"variables_set\"><field name=\"VAR\">number</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">4</field></shadow></value><next><block type=\"controls_if\"><mutation else=\"1\"/><value name=\"IF0\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"logic_compare\"><field name=\"OP\">EQ</field><value name=\"A\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"variables_get\"><field name=\"VAR\">number</field></block></value><value name=\"B\"><shadow type=\"math_number\"><field name=\"NUM\">3</field></shadow></value></block></value><statement name=\"DO0\"><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"1\" _input_init=\"true\"></mutation><value name=\"text\"><shadow type=\"text\"><field name=\"TEXT\">The number is same as 3.</field></shadow></value></block></value></block></statement><statement name=\"ELSE\"><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"1\" _input_init=\"true\"></mutation><value name=\"text\"><shadow type=\"text\"><field name=\"TEXT\">The number is not same as 3.</field></shadow></value></block></value></block></statement></block></next></block></next></block></next></block></statement></block></xml>"}
The output:

Comparison
When They are the Same
0 = 0
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"logic_compare\"><field name=\"OP\">EQ</field><value name=\"A\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow></value><value name=\"B\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow></value></block></xml>"}
This block is used to return true if two values are the same.
Parameters: Condition:
- Number (Default: 0)
- Operator: =(Default)/≠/</≤/>/≥
Output: Boolean (True/False)
Sample code:
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>number</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"variables_set\"><field name=\"VAR\">number</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">3</field></shadow></value><next><block type=\"controls_if\"><value name=\"IF0\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"logic_compare\"><field name=\"OP\">EQ</field><value name=\"A\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"variables_get\"><field name=\"VAR\">number</field></block></value><value name=\"B\"><shadow type=\"math_number\"><field name=\"NUM\">3</field></shadow></value></block></value><statement name=\"DO0\"><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"1\" _input_init=\"true\"></mutation><value name=\"text\"><shadow type=\"text\"><field name=\"TEXT\">The number is 3.</field></shadow></value></block></value></block></statement></block></next></block></next></block></next></block></statement></block></xml>"}
When it sets to number = 3, the output:

When it sets to number != 4, the output:

When the First Number is Smaller than the Second Number
0 < 0
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"logic_compare\"><field name=\"OP\">LT</field><value name=\"A\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow></value><value name=\"B\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow></value></block></xml>"}
This block is used to return true if the first value is smaller than the second value.
Parameters: Condition:
- Number (Default: 0)
- Operator: =(Default)/≠/</≤/>/≥
Output: Boolean (True/False)
Sample code:
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>number</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"variables_set\"><field name=\"VAR\">number</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">3</field></shadow></value><next><block type=\"controls_if\"><value name=\"IF0\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"logic_compare\"><field name=\"OP\">LT</field><value name=\"A\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"variables_get\"><field name=\"VAR\">number</field></block></value><value name=\"B\"><shadow type=\"math_number\"><field name=\"NUM\">4</field></shadow></value></block></value><statement name=\"DO0\"><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"1\" _input_init=\"true\"></mutation><value name=\"text\"><shadow type=\"text\"><field name=\"TEXT\">The number is smaller than 4.</field></shadow></value></block></value></block></statement></block></next></block></next></block></next></block></statement></block></xml>"}
When it sets to number < 4, the output:

When it set to number ≤ 4, the output:

When it sets to number > 2, the output:

When it sets to number ≥ 2, the output:

When Two Text are the Same
Text = Text
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"logic_compare\"><field name=\"OP\">EQ</field><value name=\"A\"><shadow type=\"text\"><field name=\"TEXT\"/></shadow></value><value name=\"B\"><shadow type=\"text\"><field name=\"TEXT\"/></shadow></value></block></xml>"}
This block is used to return true if two text are the same.
Parameters: Condition:
- Number (Default: 0)
- Operator: =(Default)/≠/</≤/>/≥
Output: Boolean (True/False)
Sample code:
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>Text</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"variables_set\"><field name=\"VAR\">Text</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"text\"><field name=\"TEXT\">Hello</field></block></value><next><block type=\"controls_if\"><value name=\"IF0\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"logic_compare\"><field name=\"OP\">EQ</field><value name=\"A\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"variables_get\"><field name=\"VAR\">Text</field></block></value><value name=\"B\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"text\"><field name=\"TEXT\">Hello</field></block></value></block></value><statement name=\"DO0\"><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"1\" _input_init=\"true\"></mutation><value name=\"text\"><shadow type=\"text\"><field name=\"TEXT\">Two texts are the same.</field></shadow></value></block></value></block></statement></block></next></block></next></block></next></block></statement></block></xml>"}
The output:

Boolean
Continuing the Action if Two Comparisons are True
… and …
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"logic_operation\"><field name=\"OP\">AND</field></block></xml>"}
This block is used to return true if two comparison is true.
Parameters:
- Logic (Comparison)
- Condition: and (Default)/or
Output: Boolean (True/False)
Sample code:
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>number</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"variables_set\"><field name=\"VAR\">number</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">3</field></shadow></value><next><block type=\"controls_if\"><value name=\"IF0\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"logic_operation\"><field name=\"OP\">AND</field><value name=\"A\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"logic_compare\"><field name=\"OP\">LT</field><value name=\"A\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"variables_get\"><field name=\"VAR\">number</field></block></value><value name=\"B\"><shadow type=\"math_number\"><field name=\"NUM\">4</field></shadow></value></block></value><value name=\"B\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"logic_compare\"><field name=\"OP\">GT</field><value name=\"A\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"variables_get\"><field name=\"VAR\">number</field></block></value><value name=\"B\"><shadow type=\"math_number\"><field name=\"NUM\">2</field></shadow></value></block></value></block></value><statement name=\"DO0\"><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"1\" _input_init=\"true\"></mutation><value name=\"text\"><shadow type=\"text\"><field name=\"TEXT\">The number is smaller than 4 and larger than 2.</field></shadow></value></block></value></block></statement></block></next></block></next></block></next></block></statement></block></xml>"}
The output:

Continuing the Action if At Least One Comparison is True
… or …
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"logic_operation\"><field name=\"OP\">OR</field></block></xml>"}
This block is used to return true if at least one of the comparisons is true.
Parameters:
- Logic (Comparison)
- Condition: and (Default)/or
Output: Boolean (True/False)
Sample code:
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>number</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"variables_set\"><field name=\"VAR\">number</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">3</field></shadow></value><next><block type=\"controls_if\"><value name=\"IF0\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"logic_operation\"><field name=\"OP\">OR</field><value name=\"A\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"logic_compare\"><field name=\"OP\">LT</field><value name=\"A\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"variables_get\"><field name=\"VAR\">number</field></block></value><value name=\"B\"><shadow type=\"math_number\"><field name=\"NUM\">4</field></shadow></value></block></value><value name=\"B\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"logic_compare\"><field name=\"OP\">NEQ</field><value name=\"A\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"variables_get\"><field name=\"VAR\">number</field></block></value><value name=\"B\"><shadow type=\"math_number\"><field name=\"NUM\">3</field></shadow></value></block></value></block></value><statement name=\"DO0\"><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"1\" _input_init=\"true\"></mutation><value name=\"text\"><shadow type=\"text\"><field name=\"TEXT\">The number is smaller than 4.</field></shadow></value></block></value></block></statement></block></next></block></next></block></next></block></statement></block></xml>"}
The output:

Return True If Comparison is Incorrect
Not …
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"logic_negate\"/></xml>"}
This is used to return true if the comparison is wrong.
Parameters: Logic (Comparison)
Output: Boolean (True/False)
Sample code:
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>number</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"variables_set\"><field name=\"VAR\">number</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">3</field></shadow></value><next><block type=\"controls_if\"><value name=\"IF0\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"logic_negate\"><value name=\"BOOL\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"logic_compare\"><field name=\"OP\">EQ</field><value name=\"A\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"variables_get\"><field name=\"VAR\">number</field></block></value><value name=\"B\"><shadow type=\"math_number\"><field name=\"NUM\">2</field></shadow></value></block></value></block></value><statement name=\"DO0\"><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"1\" _input_init=\"true\"></mutation><value name=\"text\"><shadow type=\"text\"><field name=\"TEXT\">The number is not same as 2.</field></shadow></value></block></value></block></statement></block></next></block></next></block></next></block></statement></block></xml>"}
The output:

Always True
True
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></block></xml>"}
This is used to return true.
Parameters: Condition: true (Default)/false
Output: Boolean (True/False)
Sample code:
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"controls_if\"><value name=\"IF0\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></block></value><statement name=\"DO0\"><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"1\" _input_init=\"true\"></mutation><value name=\"text\"><shadow type=\"text\"><field name=\"TEXT\">This text will appear.</field></shadow></value></block></value></block></statement></block></next></block></next></block></statement></block></xml>"}
The output:

Always False
False
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"logic_boolean\"><field name=\"BOOL\">FALSE</field></block></xml>"}
This is used to return false.
Parameters: Condition: false (Default)/true
Output: Boolean (True/False)
Sample code:
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"controls_if\"><value name=\"IF0\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">FALSE</field></shadow><block type=\"logic_boolean\"><field name=\"BOOL\">FALSE</field></block></value><statement name=\"DO0\"><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"1\" _input_init=\"true\"></mutation><value name=\"text\"><shadow type=\"text\"><field name=\"TEXT\">This text will not appear.</field></shadow></value></block></value></block></statement></block></next></block></next></block></statement></block></xml>"}
The output:

Table of Content