Attribute types

Every value in Chalk is a string until an attribute's declared type parses it. These are the types the element reference links to — what each accepts, and what it looks like written down.

stringprimitive

Plain text value.

Accepts

Any text

hello
Introduction to Graphs
x-axis label

numberprimitive

Numeric value (integer or decimal).

Accepts

IntegerDecimal

0
2
-3.5

booleanprimitive

True/false toggle.

Accepts

truefalse

true
false

colourenum

Theme-aware named colour token.

Values

neutralredorangeyellowgreentealbluepurplepinkgreywhiteblack

blue
neutral

programming-languageenum

Language identifier for code/editor blocks. Supports many aliases.

Values

autoplaintextjavascripttypescriptpythonjavagorustsqlchalkother

typescript
auto

histogram-orientationenum

Direction of histogram bars.

Values

verticalhorizontal

vertical
horizontal

icon-nameenum

Name of the inline icon to display.

Values

tickcross

tick
cross

shape-typeenum

Marker shape used for scatter points.

Values

circlesquarerectangletrianglestardiamondhexagon

circle
triangle

easing-functionenum

Animation timing function. `smooth` is the default; `linear` is constant speed.

Values

linearsmooth

smooth
linear

intervalcustom

Interval notation with inclusive/exclusive bounds.

Accepts

[start, end](start, end)[start, end)(start, end]

[-10, 10]
(0, inf)
[-inf, inf]

parametised-intervalcustom

Interval that can include parameter expressions in bounds.

Accepts

Interval-like syntax with expressions

[-10, 10]
[a, b]

grid-stepcustom

Grid spacing mode.

Accepts

autoPositive integer

auto
2
5

index-listcustom

Comma-separated indices and ranges. Letters map to positions (A=1).

Accepts

Single indexComma-separated listRange

1,3,5
1-4
A,C-E

cell-listcustom

Spreadsheet-like cell references and ranges.

Accepts

A1A1,B2A1-C3

A1,B2
C3-C5

single-charcustom

Exactly one alphabetical character.

Accepts

Single letter

x
t

parametised-numbercustom

Number value that may reference parameters/expressions.

Accepts

NumberParameter-based expression

2
a
2*a+1

parametised-expressioncustom

Math expression that may include parameter variables.

Accepts

Expression string

x^2 + 2x + 1
sin(a*x)

parametised-coordinate-listcustom

Coordinate pairs with optional parameterized values.

Accepts

(x,y) pairs

(0,0),(1,1)
(a,2),(b,3)

durationcustom

Animation duration value in milliseconds (internally normalized).

Accepts

Integer duration

500
750
1200

duration-autocustom

Either explicit duration or auto-calculated timing.

Accepts

autoInteger duration

auto
1200

duration-or-integercustom

Either a duration value or a scene index integer.

Accepts

DurationInteger index

0
500
2

optional-duration-or-integercustom

Nullable version of duration-or-integer.

Accepts

nullDurationInteger index

null
0
500

optional-durationcustom

Nullable duration value.

Accepts

nullInteger duration

null
300

string-listcustom

Comma-separated list of strings.

Accepts

Comma-separated text values

Chrome, Safari, Firefox

number-listcustom

Comma-separated list of numbers.

Accepts

Comma-separated integers or decimals

65, 19, 4, 12
1.5, 2.0, 3.7

colour-listcustom

Comma-separated list of colour names from the colour enum.

Accepts

Comma-separated colour names

blue, teal, orange, grey

orientationenum

Direction of a two-pane split.

Values

horizontalvertical

horizontal
vertical

ratiocustom

One share over another, written as a fraction — the first pane's share of a split over the second's.

Accepts

a/b

3/2
1/1

interpolationenum

How a line gets from one reading to the next: `linear` joins them, `step` holds and jumps.

Values

linearstep

linear
step

fit-modelenum

Model family for a fit.

Values

polynomiallinear

polynomial

element-render-modeenum

How the element presents: 'inline' for a static display in place, 'environment' to expand into the board.

Values

inlineenvironment

inline
environment

rich-textcustom

Inline Chalk content — formatted text, `$maths$`, links, and inline elements all render.

Accepts

Any inline Chalk

local maximum
the mean $\mu$

referencecustom

A `#id` reference to an element or dataset declared elsewhere in the document — with member access where an attribute or column is wanted.

Accepts

#id#id.member

#survey
#fit-graph
#f.slope

coordinatecustom

A single (x, y) pair; either value may be a parameter expression.

Accepts

(x, y)

(0, 0)
(a, 2)

curve-pathcustom

The curve to follow: a `#id` reference to a curve or fit, or an expression in x given directly.

Accepts

#idExpression in x

#flight
x^2 - 1

parametised-number-listcustom

Comma-separated numbers, each of which may be a parameter expression.

Accepts

Comma-separated numbers or expressions

1, 2, 4
a, 2*a

parametised-surface-expressioncustom

Math expression over the plane — the one place `y` is legal alongside `x` — that may also reference parameters.

Accepts

Expression in x and y

x^2 + y^2
sin(x) * cos(y) + a

surface-colourcustom

How a surface is painted: a single hue from the colour palette, or a ramp — `multicolour` (full spectrum) or `temperature` (blue through white to red).

Accepts

Colour namemulticolourtemperature

multicolour
temperature
blue

cue-anchorcustom

When something fires, in scene time: a step index, an absolute time, or a step with a time offset.

Accepts

Step indexAbsolute timestep + offset

2
1500ms
2 + 500ms

optional-cue-anchorcustom

Nullable cue anchor — null means the cue never fires on its own.

Accepts

nullStep indexAbsolute timestep + offset

null
2
4 + 1.5s

Attribute types

Every value in Chalk is a string until an attribute's declared type parses it. These are the types the element reference links to — what each accepts, and what it looks like written down.

stringprimitive

Plain text value.

Accepts

Any text

hello
Introduction to Graphs
x-axis label

numberprimitive

Numeric value (integer or decimal).

Accepts

IntegerDecimal

0
2
-3.5

booleanprimitive

True/false toggle.

Accepts

truefalse

true
false

colourenum

Theme-aware named colour token.

Values

neutralredorangeyellowgreentealbluepurplepinkgreywhiteblack

blue
neutral

programming-languageenum

Language identifier for code/editor blocks. Supports many aliases.

Values

autoplaintextjavascripttypescriptpythonjavagorustsqlchalkother

typescript
auto

histogram-orientationenum

Direction of histogram bars.

Values

verticalhorizontal

vertical
horizontal

icon-nameenum

Name of the inline icon to display.

Values

tickcross

tick
cross

shape-typeenum

Marker shape used for scatter points.

Values

circlesquarerectangletrianglestardiamondhexagon

circle
triangle

easing-functionenum

Animation timing function. `smooth` is the default; `linear` is constant speed.

Values

linearsmooth

smooth
linear

intervalcustom

Interval notation with inclusive/exclusive bounds.

Accepts

[start, end](start, end)[start, end)(start, end]

[-10, 10]
(0, inf)
[-inf, inf]

parametised-intervalcustom

Interval that can include parameter expressions in bounds.

Accepts

Interval-like syntax with expressions

[-10, 10]
[a, b]

grid-stepcustom

Grid spacing mode.

Accepts

autoPositive integer

auto
2
5

index-listcustom

Comma-separated indices and ranges. Letters map to positions (A=1).

Accepts

Single indexComma-separated listRange

1,3,5
1-4
A,C-E

cell-listcustom

Spreadsheet-like cell references and ranges.

Accepts

A1A1,B2A1-C3

A1,B2
C3-C5

single-charcustom

Exactly one alphabetical character.

Accepts

Single letter

x
t

parametised-numbercustom

Number value that may reference parameters/expressions.

Accepts

NumberParameter-based expression

2
a
2*a+1

parametised-expressioncustom

Math expression that may include parameter variables.

Accepts

Expression string

x^2 + 2x + 1
sin(a*x)

parametised-coordinate-listcustom

Coordinate pairs with optional parameterized values.

Accepts

(x,y) pairs

(0,0),(1,1)
(a,2),(b,3)

durationcustom

Animation duration value in milliseconds (internally normalized).

Accepts

Integer duration

500
750
1200

duration-autocustom

Either explicit duration or auto-calculated timing.

Accepts

autoInteger duration

auto
1200

duration-or-integercustom

Either a duration value or a scene index integer.

Accepts

DurationInteger index

0
500
2

optional-duration-or-integercustom

Nullable version of duration-or-integer.

Accepts

nullDurationInteger index

null
0
500

optional-durationcustom

Nullable duration value.

Accepts

nullInteger duration

null
300

string-listcustom

Comma-separated list of strings.

Accepts

Comma-separated text values

Chrome, Safari, Firefox

number-listcustom

Comma-separated list of numbers.

Accepts

Comma-separated integers or decimals

65, 19, 4, 12
1.5, 2.0, 3.7

colour-listcustom

Comma-separated list of colour names from the colour enum.

Accepts

Comma-separated colour names

blue, teal, orange, grey

orientationenum

Direction of a two-pane split.

Values

horizontalvertical

horizontal
vertical

ratiocustom

One share over another, written as a fraction — the first pane's share of a split over the second's.

Accepts

a/b

3/2
1/1

interpolationenum

How a line gets from one reading to the next: `linear` joins them, `step` holds and jumps.

Values

linearstep

linear
step

fit-modelenum

Model family for a fit.

Values

polynomiallinear

polynomial

element-render-modeenum

How the element presents: 'inline' for a static display in place, 'environment' to expand into the board.

Values

inlineenvironment

inline
environment

rich-textcustom

Inline Chalk content — formatted text, `$maths$`, links, and inline elements all render.

Accepts

Any inline Chalk

local maximum
the mean $\mu$

referencecustom

A `#id` reference to an element or dataset declared elsewhere in the document — with member access where an attribute or column is wanted.

Accepts

#id#id.member

#survey
#fit-graph
#f.slope

coordinatecustom

A single (x, y) pair; either value may be a parameter expression.

Accepts

(x, y)

(0, 0)
(a, 2)

curve-pathcustom

The curve to follow: a `#id` reference to a curve or fit, or an expression in x given directly.

Accepts

#idExpression in x

#flight
x^2 - 1

parametised-number-listcustom

Comma-separated numbers, each of which may be a parameter expression.

Accepts

Comma-separated numbers or expressions

1, 2, 4
a, 2*a

parametised-surface-expressioncustom

Math expression over the plane — the one place `y` is legal alongside `x` — that may also reference parameters.

Accepts

Expression in x and y

x^2 + y^2
sin(x) * cos(y) + a

surface-colourcustom

How a surface is painted: a single hue from the colour palette, or a ramp — `multicolour` (full spectrum) or `temperature` (blue through white to red).

Accepts

Colour namemulticolourtemperature

multicolour
temperature
blue

cue-anchorcustom

When something fires, in scene time: a step index, an absolute time, or a step with a time offset.

Accepts

Step indexAbsolute timestep + offset

2
1500ms
2 + 500ms

optional-cue-anchorcustom

Nullable cue anchor — null means the cue never fires on its own.

Accepts

nullStep indexAbsolute timestep + offset

null
2
4 + 1.5s