XLISP pop

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# pop

Type: | - | Lisp macro
Source: | - | misc.lsp

## Syntax

(pop list)
  list - a list
  returns - the first element from the list

'pop' is implemented as a Lisp macro:

    (defmacro pop (lis)
      `(prog1 (car ,lis)
              (setf ,lis (cdr ,lis))))

## Description

The 'pop' macro reads, removes and returns the first element from the list.

## Examples

    (setq stack '(a b c))  => (A B C)
    (pop stack)            => A
    stack                  => (B C)
    (pop stack)            => B
    stack                  => (C)
    (pop stack)            => C
    stack                  => NIL
    (pop stack)            => NIL
    stack                  => NIL

See setq. See also the push macro.

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Nyquist / XLISP 2.0 - Contents | Tutorials | Examples | Reference