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ASSUME

Declares a variable or function with a specified type, without providing a definition. Used for external values or assumptions about inputs.

Syntax

ASSUME name IS A Type
ASSUME name IS A FUNCTION FROM Type1 TO Type2

Purpose

ASSUME is used to:

  1. Declare input variables for decision logic
  2. Declare external functions whose implementation is provided elsewhere
  3. State assumptions about values that will be provided at runtime

Examples

Example file:

-- ASSUME keyword examples

-- Basic Variable Assumptions

-- Assume primitive types
ASSUME `is employed` IS A BOOLEAN
ASSUME `annual income` IS A NUMBER
ASSUME `applicant name` IS A STRING

-- Function Assumptions

-- Single parameter function
ASSUME `calculate tax` IS A FUNCTION FROM NUMBER TO NUMBER

-- The assumed function can be used in expressions
DECIDE `tax on income` IS `calculate tax` `annual income`

-- Using Assumed Values in Decisions

ASSUME age IS A NUMBER
ASSUME `has valid license` IS A BOOLEAN

-- Combine assumed values in logic
DECIDE `can drive` IS
  age >= 16 AND `has valid license`

-- Evaluating with Assumed Values

-- The expression uses assumed values
#CHECK `can drive`

-- Complex Example: Eligibility Check

ASSUME `applicant age` IS A NUMBER
ASSUME `years of residence` IS A NUMBER
ASSUME `has criminal record` IS A BOOLEAN

DECIDE `is eligible for benefit` IS
      `applicant age` >= 21
  AND `years of residence` >= 5
  AND NOT `has criminal record`

#CHECK `is eligible for benefit`

Basic Variable Assumptions

-- Assume a boolean input
ASSUME isEmployed IS A BOOLEAN

-- Assume a numeric value
ASSUME income IS A NUMBER

-- Assume a string
ASSUME applicantName IS A STRING

Function Assumptions

-- Assume an external function
ASSUME calculateTax IS A FUNCTION FROM NUMBER TO NUMBER

-- Multi-parameter function (using AND)
ASSUME addNumbers IS A FUNCTION FROM NUMBER AND NUMBER TO NUMBER

Using Assumed Values

ASSUME age IS A NUMBER
ASSUME income IS A NUMBER

DECIDE isEligible IS
  age >= 18 AND income > 50000

Behavior

  • Assumed values can be used in expressions but have no defined value
  • When evaluated directly, assumed values remain symbolic
  • Assumed values are typically bound via #CHECK ... WITH or #TRACE ... WITH

Binding Assumed Values

ASSUME age IS A NUMBER

DECIDE isAdult IS age >= 18

-- Bind the assumed value for checking
#CHECK isAdult WITH age IS 25
  • DECIDE - Define a value or function with a body
  • GIVEN - Introduce function parameters
  • TYPE-KEYWORDS - Type syntax (IS, FUNCTION, etc.)

See Also