API

Read

Read a width: The query container’s width, as a whole number.
Read a position: A box’s position in pixels from its row’s start, read through an anchor.
Item i: Item i’s width, for a computed i, counted from 1.

Largest and smallest

max(): The largest number in a list.
min(): The smallest number in a list.
extent(): The smallest and the largest number of a list.
Max of sums: The largest of several sums.
Max plus min: The largest positive number plus the most negative one: max(0, positives) + min(0, negatives).
Sum of two maxes: The largest ascent plus the largest descent: max(a) + max(d), from one row.
Size of an fr: The largest of the items’ widths, each divided by its weight: the size of one fr.

Totals

sum(): The total of a list: its numbers added up.
mean(): The average of a list of numbers.
count(): How many numbers a list has.
cumsum(): The running total: each number added to the ones before it.
Weighted sum: The items’ widths, each times its own factor, added up.
Line count: How many lines a row of widths takes when it wraps at a given width.

Which item

maxIndex(): Where the largest number is: its position, from 0.
minIndex(): Where the smallest number is: its position, from 0.

In order

sort(): The numbers in order.
rank(): Each number’s place in the list sorted smallest first, from 0.
median(): The middle number of the sorted list, or the mean of the two middle ones.
quantile(): The number at place p along the sorted list: p = 0 gives the smallest, 1 the largest.
bisectLeft(): Where a number goes in a sorted list, before any equal ones.
bisectRight(): Where a number goes in a sorted list, after any equal ones.

Split a width

Share of the total: Each weight’s share of the weights’ total, as a percent.
Percent of the max: Each item as a percent of the largest, at every row.
Share with limits: Each item’s part of a fixed width by weight, when some items have a cap or a floor.
Equal growth with a cap: Each track’s width when a grid’s width is shared among tracks with caps.

These have no layout example here; dCSS has them: bin(), bisector(), ascending(), descending(), medianIndex(), quantileIndex(), variance(), deviation(), ticks(), tickIncrement(), tickStep(), nice(), range().