List Operations

cons

Construct a pair (cons cell) - the fundamental building block of Lisp lists.

Syntax:

(cons first second)

Examples:

(cons 1 2)           ; => (1 . 2)
(cons 1 ())          ; => (1)
(cons 1 (cons 2 ())) ; => (1 2)

Usage:

; Create a list with the first transaction only
(cons (car table) ())

car

Get the first element of a pair.

Syntax:

(car pair)

Examples:

(car (cons 1 2))     ; => 1
(car '(1 2 3))       ; => 1
(car table)          ; => first transaction

Usage:

# Get the first transaction
kakei transform --program "(car table)"

cdr

Get the second element of a pair (everything after the first element).

Syntax:

(cdr pair)

Examples:

(cdr (cons 1 2))     ; => 2
(cdr '(1 2 3))       ; => (2 3)
(cdr table)          ; => all transactions except first

Usage:

# Skip the first transaction
kakei transform --program "(cdr table)"