Boolean

Boolean blocks are value blocks used to test whether a specified condition is True (1) or False (0). See Fig. 56.

Comparison

This Comparison block compares the two value blocks that are given with the rule selected from the dropdown menu and outputs a result of True or False.

The options available in the drop-down selection box are:

the inputs are equal (=)
the inputs are not equal (≠)
the first input is less than (<) the second input
the first input is less than or equal to (≤) the second input
the first inputs is greater than (>) the second input
the first input is greater than or equal to (≥) the second input.

Equal to (=) and not equal to (≠) work for almost anything including numbers, lists (arrays) and character strings.

The other operands only work for numbers.

Boolean And / Or

The Boolean And / Or block performs the selected Boolean operation on its two inputs.

Both inputs are required to be Boolean. It is not possible to plug numbers or text strings into the inputs.

and will give back a True only if both of its inputs are True.
or will give back True if either or both of its inputs are True.

Not

This block takes a True/False Boolean value block input and logically inverts it.

That is, True becomes False, and False become True.

True / False

This value block gives a Boolean True or False value depending on which option is selected. It is generally used to initialise variables that are subsequently used in a program.

Null

This value block is the value that variables have before they are given a value. It is a special value that represents “none” or “nothing” but is distinct from 0. However it is treated as a zero or False value if used.

Test If

This block will output one of two input values depending on whether the test input is True or False.

If the block in the Test input socket is True, the value in the if true input is transferred to the output.

If the block in the Test input socket is False, the value in the if false input is transferred to the output.