Tab stop

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"Fixed width" redirects here. For the class of fonts with fixed character widths, see Monospaced font.
A ruler depicting tab stops in a word processor

A tab stop on a typewriter is a location where the carriage movement is halted by mechanical gears. Tab stops are set manually, and pressing the tab key causes the carriage to go to the next tab stop. In text editors on a computer, the same concept is implemented simplistically with automatic, fixed tab stops.

Modern word processors generalize this concept by offering tab stops that have an alignment attribute and cause the text to be automatically aligned at left, at right or center of the tab stop itself. Such tab stops are paragraph-specific properties and can be moved to a different location in any moment, or even removed.

Types of tab stops

A tab stop is a horizontal position which is set for placing and aligning text on a page. There are at least five kinds of tab stops in general usage in word processing.

Left
text extends to the right from the tab stop.
Center
text is centered at the tab stop.
Right
text extends to the left from the tab stop until the tab's space is filled, and then the text extends to the right.
Decimal
text before the decimal point extends to the left, and text after the decimal point extends to the right.
Bar
a vertical line at the specified position on each line in a document.

Elastic tabstops

Text aligned to tabstops is shown as different coloured blocks. The animation shows an elastic tabstop, which keeps several lines of text aligned when one line is edited.

In 2006, Nick Gravgaard invented elastic tabstops, an alternative way to handle tabstops, with a primary focus on editing source code in computer programming,[1] He also has written 2 plugins for Gedit implementing elastic tabstops. Elastic tabstops are also implemented in the "tabwriter" package of Go (programming language),[2] as a solution for programmers who argue about what kind of indentation is best; tab or space characters.[3]

Elastic tabstops differ from traditional fixed tabstops because columns in lines above and below the "cell" that is being changed are always kept aligned. As the width of text before a tab character changes, the tabstops on adjacent lines are automatically changed to fit the widest piece of text in that column.

See also

References

  1. ↑ Elastic tabstops.
  2. ↑ Package tabwriter
  3. ↑ A solution to tabs-vs.-spaces by Joel Spolsky


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