The tedium can be reduced, somewhat. `{munsell}`

exposes 40 hues:

```
library(munsell)
mnsl_hues()
#> [1] "2.5R" "5R" "7.5R" "10R" "2.5YR" "5YR" "7.5YR" "10YR" "2.5Y"
#> [10] "5Y" "7.5Y" "10Y" "2.5GY" "5GY" "7.5GY" "10GY" "2.5G" "5G"
#> [19] "7.5G" "10G" "2.5BG" "5BG" "7.5BG" "10BG" "2.5B" "5B" "7.5B"
#> [28] "10B" "2.5PB" "5PB" "7.5PB" "10PB" "2.5P" "5P" "7.5P" "10P"
#> [37] "2.5RP" "5RP" "7.5RP" "10RP"
```

However, hues differ in the distinctions that the encoding system makes:

```
library(munsell)
hue_slice(hue.name = "all", back.col = "white")
```

As a consequence, the number of times that `mnsl(seq_mnsl()`

can be called with different values of of the \dots parameter varies, because

Not all possible correctly formatted Munsell colours result in a colour representable in RGB space.

For example,

```
library(munsell)
in_gamut(c("5R 5/8","2.5R 9/28"), fix = TRUE)
#> [1] "5R 5/8" "2.5R 9/2"
```

For the case in the OP example for `2.5R`

, there's no problem in automating

```
library(munsell)
by_hand <- c(mnsl(seq_mnsl("2.5R 1/2", "2.5R 9/2", 9)),
mnsl(seq_mnsl("2.5R 1/4", "2.5R 8/4", 8)),
mnsl(seq_mnsl("2.5R 1/6", "2.5R 8/6", 8)),
mnsl(seq_mnsl("2.5R 2/8", "2.5R 7/8", 6)),
mnsl(seq_mnsl("2.5R 3/10", "2.5R 7/10", 5)),
mnsl(seq_mnsl("2.5R 4/12", "2.5R 6/12", 3)),
mnsl(seq_mnsl("2.5R 4/14", "2.5R 6/14", 3)),
mnsl("2.5R 5/16"))
by_hand
#> [1] "#2D161E" "#412C32" "#58424B" "#715C63" "#8A767A" "#A39094" "#BDABAE"
#> [8] "#D7C6C6" "#F2E2E2" "#360E1F" "#4C2533" "#5B4246" "#7F5561" "#9A7075"
#> [15] "#B48A8F" "#D0A5A5" "#EBC0BF" "#3E0320" "#551E34" "#683B45" "#825558"
#> [22] "#A96973" "#C4848C" "#E09EA0" "#FDB9BA" "#610E2E" "#75333D" "#9B4559"
#> [29] "#B76170" "#D27D81" "#F0979A" "#8C1737" "#A73B4D" "#C55864" "#E0747C"
#> [36] "#FE8F95" "#B22D4A" "#D24C60" "#ED6B78" "#BE1547" "#DC405D" "#F96174"
#> [43] "#E72D5A"
# get list of hues
hues <- mnsl_hues()
hues
#> [1] "2.5R" "5R" "7.5R" "10R" "2.5YR" "5YR" "7.5YR" "10YR" "2.5Y"
#> [10] "5Y" "7.5Y" "10Y" "2.5GY" "5GY" "7.5GY" "10GY" "2.5G" "5G"
#> [19] "7.5G" "10G" "2.5BG" "5BG" "7.5BG" "10BG" "2.5B" "5B" "7.5B"
#> [28] "10B" "2.5PB" "5PB" "7.5PB" "10PB" "2.5P" "5P" "7.5P" "10P"
#> [37] "2.5RP" "5RP" "7.5RP" "10RP"
# construct pieces for arguments to seq_mnsl
nume1 <- c(1,1,1,2,3,4,4,5)
nume2 <- c(9,8,8,7,7,6,6,5)
denom <- seq(2,16,2)
# lengths of seq_mnsl
outs <- c(9,8,8,6,6,3,3,1)
# number of seq_mnsl call per hue
runs <- length(outs)
# create first argument to seq_mnsl
get_start <- function(x,y) paste0(hues[x]," ",nume1[y],"/",denom[y])
# create second argument to seq_mnsl
get_end <- function(x,y) paste0(hues[x]," ",nume2[y],"/",denom[y])
# display the results for a single hue
show_hues <- function(x,y) mnsl(seq_mnsl(get_start(x,y), get_end(x,y), outs[y]), fix = TRUE)
show_hues(1,1) == by_hand[1:9]
#> [1] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
show_hues(1,2) == by_hand[10:17]
#> [1] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
show_hues(1,3) == by_hand[18:25]
#> [1] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
show_hues(1,4) == by_hand[26:31]
#> [1] TRUE TRUE TRUE TRUE TRUE TRUE
show_hues(1,5) == by_hand[32:36]
#> Warning in show_hues(1, 5) == by_hand[32:36]: longer object length is not a
#> multiple of shorter object length
#> [1] TRUE TRUE TRUE FALSE FALSE FALSE
show_hues(1,6) == by_hand[37:39]
#> [1] TRUE TRUE TRUE
show_hues(1,7) == by_hand[40:42]
#> [1] TRUE TRUE TRUE
show_hues(1,8) == by_hand[43]
#> [1] TRUE
```

The problem comes when trying to feed all forty colors through the `show_hue`

function, which assumes that the third arguments will work for each of them.

It's possible to write a chain of functions that would check each of the hues to find out how may hexes it supports, but that is probably more trouble than doing it by hand in the absence of a different use case. Doing it by hand involves the trial and error of checking each hue with a different last argument interactively until an error returned.

```
library(munsell)
# get list of hues
hues <- mnsl_hues()
# construct pieces for arguments to seq_mnsl
nume1 <- c(1,1,1,2,3,4,4,5)
nume2 <- c(9,8,8,7,7,6,6,5)
denom <- seq(2,16,2)
# lengths of seq_mnsl
outs <- c(9,8,8,6,6,3,3,1)
# number of seq_mnsl call per hue
runs <- length(outs)
# create first argument to seq_mnsl
get_start <- function(x,y) paste0(hues[x]," ",nume1[y],"/",denom[y])
# create second argument to seq_mnsl
get_end <- function(x,y) paste0(hues[x]," ",nume2[y],"/",denom[y])
# display the results for a single hue
show_hues <- function(x,y) mnsl(seq_mnsl(get_start(x,y), get_end(x,y), outs[y]), fix = TRUE)
show_hues(10,1)
#> [1] "#241C08" "#383120" "#504834" "#696149" "#817B62" "#9D957B" "#B8AF94"
#> [8] "#D3CAAD" "#EEE6C6"
show_hues(10,2)
#> Warning in in_gamut(c(from, to), fix = fix): some specified colours are
#> undefined. You could try fix = TRUE
#> Error in seq_mnsl(get_start(x, y), get_end(x, y), outs[y]): Colors must be in gamut
```