Could `theme(palette.shape.discrete)` etc work with number values?

[davidhodge931]

library(tidyverse)

palmerpenguins::penguins |>
  ggplot() +
  geom_point(
    aes(x = flipper_length_mm,
    y = body_mass_g,
    shape = species),
  ) +
  theme(palette.shape.discrete = c(21, 24, 22))
#> Error in `as_discrete_pal()`:
#> ! Cannot convert `x` to a discrete palette.

palmerpenguins::penguins |>
  ggplot() +
  geom_path(
    aes(x = flipper_length_mm,
        y = body_mass_g,
        linetype = species),
  ) +
  theme(palette.linetype.discrete = c(1, 2, 3))
#> Error in `as_discrete_pal()`:
#> ! Cannot convert `x` to a discrete palette.

^{Created on 2025-09-22 with reprex v2.1.1}

[teunbrand]

This is more of an issue for the scales package, because automatic conversion of palettes is implemented in as_discrete_pal(). You can use scales::manual_pal(c(1, 2, 3)) instead. That said, I don't think it'd make too much sense to allow an automatic 'numeric as discrete' interpretation, so I like the explicitness of having to specify it is a manual palette.

[davidhodge931]

Sounds good, thanks!