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BRANCH

BRANCH chooses between several values by a list of conditions. The conditions are tried from top to bottom, and the first one that holds gives the result. OTHERWISE gives the result when none holds.

Syntax

BRANCH IF condition1 THEN value1
       IF condition2 THEN value2
       OTHERWISE default-value

BRANCH
  IF condition1 THEN value1
  IF condition2 THEN value2
  OTHERWISE default-value
  • Each IF … THEN and the OTHERWISE must be indented further than the BRANCH keyword. Put them in one column, either after BRANCH on its line or on the lines below.
  • OTHERWISE is required.
  • Every value must have the same type.

Example file:

-- BRANCH examples

-- The conditions are tried from top to bottom; the first that holds gives the result.

DECLARE Category IS ONE OF Standard, Premium, Enterprise

GIVEN category IS A Category
GIVETH A NUMBER
`monthly price for` category MEANS
  BRANCH IF category EQUALS Standard   THEN 10
         IF category EQUALS Premium    THEN 25
         IF category EQUALS Enterprise THEN 100
         OTHERWISE 0

#EVAL `monthly price for` Premium

-- The IF lines can also start on the line below BRANCH,
-- indented further than BRANCH itself.

GIVEN `annual income` IS A NUMBER
GIVETH A NUMBER
`tax rate for` `annual income` MEANS
  BRANCH
    IF `annual income` > 120000 THEN 0.4
    IF `annual income` > 50000  THEN 0.3
    IF `annual income` > 20000  THEN 0.2
    OTHERWISE 0

-- 150000 is above 50000 too, but the first condition that holds wins.
#EVAL `tax rate for` 150000
#EVAL `tax rate for` 60000
#EVAL `tax rate for` 10000

Example

GIVEN `annual income` IS A NUMBER
GIVETH A NUMBER
`tax rate for` `annual income` MEANS
  BRANCH
    IF `annual income` > 120000 THEN 0.4
    IF `annual income` > 50000  THEN 0.3
    IF `annual income` > 20000  THEN 0.2
    OTHERWISE 0

`tax rate for` 150000 gives 0.4: 150000 is above 50000 as well, but the first condition that holds wins.

BRANCH, IF or CONSIDER

Situation Use
one condition, two outcomes IF
several conditions, tried in order BRANCH
the value's shape: enumeration values, JUST/NOTHING, list or record fields CONSIDER

BRANCH gives the same result as IF … ELSE IF … ELSE, without nesting each IF deeper.