talb
September 16, 2026, 3:25pm
1
Tested on the latest Typst (0.15.1):
#scale(factor: 110%)[Foo]
I get an error:
Unexpected argument: factor
The factor parameter exists in the doc: Scale - Typst Documentation
Is this a bug? Should I file an issue?
aarnent
September 16, 2026, 4:53pm
2
The factor argument is positional:
The scaling factor for both axes, as a positional argument . This is just an optional shorthand notation for setting x and y to the same value.
It should probably be marked more explicitly with the grey positional label, like calc.abs.value
related issue: Documentation inconsistency: `page.body` (and `text.body`) behave as required positional parameters but are not documented as such · Issue #7580 · typst/typst · GitHub
talb
September 16, 2026, 5:00pm
3
Thanks. Yes I don’t know why the doc didn’t put the positional label. This is especially confusing since factor has a default value. I didn’t know you could have default values for positional arguments. I don’t even know how to implement that.
aarnent
September 16, 2026, 5:06pm
4
It’s not possible for user-defined functions. In this example, scale.factor is defined here:
/// #scale(x: -100%, reflow: true)[This is mirrored.]
/// ```
#[elem]
pub struct ScaleElem {
/// The scaling factor for both axes, as a positional argument. This is just
/// an optional shorthand notation for setting `x` and `y` to the same
/// value.
#[external]
#[positional]
#[default(Smart::Custom(ScaleAmount::Ratio(Ratio::one())))]
pub factor: Smart<ScaleAmount>,
/// The horizontal scaling factor.
///
/// The body will be mirrored horizontally if the parameter is negative.
#[parse(
let all = args.find()?;
args.named("x")?.or(all)
)]
#[default(Smart::Custom(ScaleAmount::Ratio(Ratio::one())))]
pub x: Smart<ScaleAmount>,