AND

Logical conjunction operator. Returns TRUE only if both operands are TRUE.

Syntax

expression1 AND expression2
expression1 && expression2

Truth Table

A	B	A AND B
TRUE	TRUE	TRUE
TRUE	FALSE	FALSE
FALSE	TRUE	FALSE
FALSE	FALSE	FALSE

Examples

Example file:

-- AND keyword examples

-- Basic AND Operations

#EVAL TRUE AND TRUE
#EVAL TRUE AND FALSE
#EVAL FALSE AND TRUE
#EVAL FALSE AND FALSE

-- Symbolic Alternative (&&)

#EVAL TRUE && TRUE
#EVAL TRUE && FALSE

-- In Conditional Logic

ASSUME age IS A NUMBER
ASSUME hasLicense IS A BOOLEAN

DECIDE canDrive IS age >= 16 AND hasLicense

#CHECK canDrive

-- Chaining Multiple Conditions

GIVEN a IS A BOOLEAN
      b IS A BOOLEAN
      c IS A BOOLEAN
allTrue a b c MEANS a AND b AND c

#EVAL allTrue TRUE TRUE TRUE
#EVAL allTrue TRUE TRUE FALSE

-- Layout-Sensitive AND (Vertical Format)

ASSUME personAge IS A NUMBER
ASSUME personIncome IS A NUMBER
ASSUME hasCriminalRecord IS A BOOLEAN

DECIDE isEligible IS
      personAge >= 18
  AND personIncome > 30000
  AND NOT hasCriminalRecord

#CHECK isEligible

-- Complex Expressions with AND

GIVEN x IS A NUMBER, y IS A NUMBER
inRange x y MEANS x >= 0 AND x <= 100 AND y >= 0 AND y <= 100

#EVAL inRange 50 50
#EVAL inRange 150 50

-- AND with Comparisons

GIVEN score IS A NUMBER
passingGrade score MEANS score >= 60 AND score <= 100

#EVAL passingGrade 75
#EVAL passingGrade 55

-- AND in IF Expressions

GIVEN userAge IS A NUMBER, hasPermission IS A BOOLEAN
accessLevel userAge hasPermission MEANS
  IF userAge >= 18 AND hasPermission
  THEN "full access"
  ELSE "restricted"

#EVAL accessLevel 25 TRUE
#EVAL accessLevel 25 FALSE

Basic Usage

#EVAL TRUE AND TRUE     -- TRUE
#EVAL TRUE AND FALSE    -- FALSE
#EVAL FALSE AND TRUE    -- FALSE
#EVAL FALSE AND FALSE   -- FALSE

In Conditions

GIVEN age IS A NUMBER
GIVEN hasLicense IS A BOOLEAN
DECIDE canDrive IS age >= 16 AND hasLicense

Symbolic Alternative

DECIDE result IS TRUE && FALSE

Chaining Multiple Conditions

GIVEN a IS A BOOLEAN
GIVEN b IS A BOOLEAN
GIVEN c IS A BOOLEAN
allTrue a b c MEANS a AND b AND c

Layout-Sensitive AND

L4 supports vertical AND with indentation:

DECIDE eligible IS
      age >= 18
  AND income > 30000
  AND NOT hasCriminalRecord

Asyndetic AND

Implicit operators using punctuation.

Ellipsis (...) - Implicit AND

Example:

-- Example: Asyndetic operators (... and ..)
-- Implicit AND and OR using punctuation

citizen MEANS TRUE
over18 MEANS TRUE
hasID MEANS TRUE

approved MEANS TRUE
pending MEANS FALSE
review MEANS FALSE

-- Ellipsis (...) = implicit AND
eligible1 MEANS citizen ... over18 ... hasID
-- Equivalent to: (citizen AND over18 AND hasID)

-- Double dot (..) = implicit OR
inProgress MEANS approved .. pending .. review
-- Equivalent to: (approved OR pending OR review)

#EVAL eligible1
#EVAL inProgress

Short-Circuit Evaluation

AND evaluates lazily - if the first operand is FALSE, the second is not evaluated.

OR - Logical disjunction
NOT - Logical negation
IMPLIES - Logical implication

AND