Logic

logical operations (AND, OR, XOR, etc), helpers and constants for boolean values

Predicates

Constants

The Logic module provides boolean operations and logical value manipulation. Beyond traditional true/false operations, it includes support for ternary logic with maybe and optimized evaluation strategies.

Key Concepts

  • Three-valued logic: true, false, and maybe
  • Standard boolean operations (AND, OR, XOR, etc.)
  • Short-circuit evaluation for improved performance

Basic Usage

Basic Logical Values

print true?  true     ; true
print false? false    ; true
print true?  maybe    ; maybe

Logical Operations

and? true true      ; true
or?  true false     ; true
xor? true true      ; false

; with maybe
and? true maybe     ; maybe
or?  true maybe     ; true

Short-Circuit Evaluation

; if first block is false,
; the second one won't be evaluated 
if and? [1=2][print "never runs"] -> 
    print "not true"

; if first block is true,
; the second one won't be evaluated 
if or? [1=1][print "never runs"] -> 
    print "was true"

; was true

Note
Using blocks with and? and or? enables short-circuit evaluation. In a few words: blocks are only evaluated when needed.

Common Patterns

Testing Multiple Conditions

conditions: @[true false true true]

; check if all conditions are true
all? conditions     ; => false

; check if any condition is true
any? conditions     ; => true

Tip
Combining conditions in blocks with and? and or? (or more than one condition inside all? or any? blocks) is more efficient than checking them separately!

Advanced Logical Operations

a: true
b: false

print nand? a b    ; true  = not (a and b)
print nor? a b     ; false = not (a or b)
print xnor? a b    ; false = not (a xor b)