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Learn Red ? Fundamentals of Red
book

Learn Red ? Fundamentals of Red

by Ivo Balbaert
May 2018
Beginner content levelBeginner
252 pages
6h 19m
English
Packt Publishing
Content preview from Learn Red ? Fundamentals of Red

A step at a time – head, tail, index?, and next

The data word from the previous section is not only a name for the series—it is also a pointer to where we are in the series at a particular moment. You could call that position the current index, which is given by the index? function. Right after the series is created, we have index? data ;== 1 . Here is a diagram so you can quickly see what is going on:

Remember that in Red, an index starts from 1, not from 0, as in most other (C-based) languages.

When the current index is 1, we are also at the head of the series:

;-- see Chapter05/navigating-and-looping.red:head? data   ;== true

The head data ...

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Publisher Resources

ISBN: 9781789130706Supplemental Content