bar

Use for category × number comparisons where row order matters (months, regions, ranked lists). One mark per category; optional series for grouped bars.

Do not use for continuous x (prefer line / scatter), part-to-whole slices (pie), or raw distribution bins (hist).

Optional layout: grouped | stacked | percent. Omit or grouped keeps side-by-side bars. Optional orient: horizontal for long category labels. An empty y is a missing mark, not a zero. Stacked and percent require every cell.

x category · y number · series optional; layout controls grouping

Rules. Keep input row order. Never sort x. layout: grouped (default) | stacked | percent. orient: horizontal puts categories on the side. A repeated category/series key → E_DUP_KEY. An empty y is a missing mark, not a zero, except stacked and percent, which require every cell (E_MISSING_VALUE). Text that is not a number → E_BAD_NUMBER.

Example

markvis: 2
type: bar
layout: stacked
title: Tickets by month
x: month
y: tickets
series: team

month,team,tickets
Jan,alpha,80
Jan,beta,40
Feb,alpha,100
Feb,beta,80

Tickets by month

month	team	tickets
Jan	alpha	80
Jan	beta	40
Feb	alpha	100
Feb	beta	80

When the block is wrong

The rows stay, with one line that names the error.

markvis: 2
type: bar
innerRadius: 0.4
title: Wrong-type extra field
x: month
y: tickets

month,tickets
Jan,120
Feb,180

month	tickets
Jan	120
Feb	180

E_UNKNOWN_FIELD: undeclared fence field: innerRadius

Generated from packages/types/bar/ and the type's row in SPEC.md.