Pass user-supplied calling handlers to evaluate()

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: knitr
 Type: Package
 Title: A General-Purpose Package for Dynamic Report Generation in R
-Version: 1.21.6
+Version: 1.21.6.9000
 Authors@R: c(
     person("Yihui", "Xie", role = c("aut", "cre"), email = "xie@yihui.name", comment = c(ORCID = "0000-0003-0645-5666")),
     person("Adam", "Vogt", role = "ctb"),
@@ -101,7 +101,7 @@ Description: Provides a general-purpose tool for dynamic report generation in R
 Depends:
     R (>= 3.1.0)
 Imports:
-    evaluate (>= 0.10),
+    evaluate (>= 0.11.1.9000),
     highr,
     markdown,
     stringr (>= 0.6),
@@ -131,6 +131,8 @@ Suggests:
     showtext,
     tibble,
     styler
+Remotes:
+    lionel-/evaluate@add-calling-handlers
 License: GPL
 URL: https://yihui.name/knitr/
 BugReports: https://github.com/yihui/knitr/issues

R/utils.R

@@ -756,9 +756,12 @@ knit_handlers = function(fun, options) {
   if (length(formals(fun)) < 2)
     stop("the chunk option 'render' must be a function of the form ",
          "function(x, options) or function(x, ...)")
-  merge_list(default_handlers, list(value = function(x, visible) {
-    if (visible) fun(x, options = options)
-  }))
+  merge_list(default_handlers, list(
+    value = function(x, visible) {
+      if (visible) fun(x, options = options)
+    },
+    calling_handlers = options$calling.handlers
+  ))
 }
 
 # conditionally disable some features during R CMD check