New {.bullets } style

To collapse vectors into bullets:

```
❯ cli_text("Some values {.bullets {letters[1:5]}} blah blah")
Some values • a
• b
• c
• d
• e blah blah
```

Closes #265.

R/cliapp-docs.R

@@ -328,10 +328,16 @@ NULL
 #' * `transform`: A function to call on glue substitutions, before
 #'   collapsing them. Note that `transform` is applied prior to
 #'   implementing color via ANSI sequences.
-#' * `vec_last`: The last separator when collapsing vectors.
-#' * `vec_sep`: The separator to use when collapsing vectors.
+#' * `vec_last`: The last separator when collapsing vectors. It may be a
+#'   function.
+#' * `vec_after`: Added after vector elements. It may be a function.
+#' * `vec_before`: Added before vector elements. It may be a function.
+#' * `vec_sep`: The separator to use when collapsing vectors. It may be
+#'   a function. It may be a function.
+#' * `vec_sep2`: The separator to use when collapsing a length 2 vector.
+#'   It may be a function.
 #' * `vec_trunc`: Vectors longer than this will be truncated. Defaults to
-#'   100.
+#'   100. It may be a function that returns the limit.
 #'
 #' More properties might be added later. If you think that a property is
 #' not applied properly to an element, please open an issue about it in

R/inline.R

@@ -32,18 +32,24 @@ inline_generic <- function(app, x, style) {
 }
 
 inline_collapse <- function(x, style = list()) {
-  sep <- style[["vec_sep"]] %||% ", "
+  sep <- call_if_fun(style[["vec_sep"]]) %||% ", "
   if (length(x) >= 3) {
-    last <- style$vec_last %||% ", and "
+    last <- call_if_fun(style$vec_last) %||% ", and "
   } else {
-    last <- style$vec_sep2 %||% style$vec_last %||% " and "
+    last <- call_if_fun(style$vec_sep2) %||%
+      call_if_fun(style$vec_last) %||%
+      " and "
   }
-  trunc <- style$vec_trunc %||% 100L
+  trunc <- call_if_fun(style$vec_trunc) %||% 100L
   if (length(x) > trunc) {
     x <- c(x[1:trunc], cli::symbol$ellipsis)
     last <- sep
   }
-  glue::glue_collapse(as.character(x), sep = sep, last = last)
+
+  before <- call_if_fun(style[["vec_before"]]) %||% ""
+  after <- call_if_fun(style[["vec_after"]]) %||% ""
+  ft <- paste0(before, as.character(x), after)
+  glue::glue_collapse(ft, sep = sep, last = last)
 }
 
 #' This glue transformer performs the inline styling of cli

R/themes.R

@@ -224,7 +224,14 @@ builtin_theme <- function(dark = getOption("cli_theme_dark", "auto")) {
       color = "green"
     ),
     span.or = list(vec_sep2 = " or ", vec_last = ", or "),
-    span.timestamp = list(before = "[", after = "]", color = "grey")
+    span.timestamp = list(before = "[", after = "]", color = "grey"),
+
+    # bullet list
+    span.bullets = list(
+      vec_before = function() paste0(symbol$bullet, " "),
+      vec_sep = "\f",
+      vec_last = "\f"
+    )
   )
 }