Expression nodes

Where in the UI. Structure → expression library → graph canvas palette.

Palette id	Name	Role
`literal`	Literal	Constant string, number, boolean, color, or datetime.
`fieldRef`	Field ref	Reads a DataRef (item field, category property, …).
`expressionRef`	Expression ref	Uses another library expression. Cycles are rejected.
`itemMetricRef`	Item metric	Lazy metric key.
`itemVariableRef`	Item variable	Scratch key on the item.
`itemHasClassRef`	Has class	Membership test.
`itemHasCategoryRef`	Has category	Membership test.
`itemHasElementRef`	Has element	Membership test.
`runtimeContextRef`	Runtime context	Host clock, user, privacy, canvas, scheme.
`currentDateTime`	Current date/time	Now.
`compare`	Compare	eq, neq, gt, gte, lt, lte (binary node).
`calculate`	Calculate	add, sub, mul, div.
`booleanAlgebra`	Boolean algebra	and, or, xor, nand, nor.
`unary`	Unary	not / negate.
`if`	If / else	Condition → then / else.
`elseifChain`	Else-if chain	Nested if compiled from branches.
`timeBetween`	Time between	Duration between two datetimes (unit).
`dateTimeSplit`	Date-time split	Year…second parts, local or UTC.
`dateTimeMerge`	Date-time merge	Build a datetime from parts.
`convertQuantity`	Convert quantity	Unit conversion; optional material and locale.
`listUnits`	List units	Catalog of units as JSON text.
`themeColorRef`	Theme color	Theme token.
`colorWithAlpha`	Color + alpha	Set opacity.
`colorBrighter`	Brighter	Lighten.
`colorDarker`	Darker	Darken.
`colorSaturate`	Saturate	Increase chroma.
`colorDesaturate`	Desaturate	Decrease chroma.
`colorShiftHue`	Shift hue	Rotate hue.
`colorSplit`	Color split	RGB or HSL channels.
`colorMerge`	Color merge	Build #RRGGBB from channels.
`computedRef`	Computed ref (advanced)	Template computed id.

Binary ops split in the palette as compare / calculate / booleanAlgebra but compile to a binary AST node. Source: app/lib/expressions/graph/graphSchema.ts.