![[Deprecated]](figures/lifecycle-deprecated.svg)
ctxt_stack() can be tricky to use in real code because all
intervening frames are returned with the stack, including those at
ctxt_stack() own call site. stack_trim() makes it easy to
remove layers of intervening calls.
stack_trim(stack, n = 1)
Arguments
| stack | An evaluation stack. |
|---|---|
| n | The number of call frames (not eval frames) to trim off the top of the stack. In other words, the number of layers of intervening frames to trim. |
Life cycle
These functions are deprecated and replaced by trace_back().
Examples
#> [[1]] #> <frame 26> (24) #> expr: identity(ctxt_stack()) #> env: [local 0x55ba49643a90] #> #> [[2]] #> <frame 25> (24) #> expr: identity(identity(ctxt_stack())) #> env: [local 0x55ba49643978] #> #> [[3]] #> <frame 24> (23) #> expr: eval(expr, envir, enclos) #> env: [local 0x55ba4966b898] #> #> [[4]] #> <frame 23> (13) #> expr: eval(expr, envir, enclos) #> env: [local 0x55ba496437b8] #> #> [[5]] #> <frame 22> (13) #> expr: withVisible(eval(expr, envir, enclos)) #> env: [local 0x55ba49643588] #> #> [[6]] #> <frame 21> (13) #> expr: withCallingHandlers(withVisible(eval(expr, envir, enclos)), warning = wHandler, <...> #> env: [local 0x55ba49646dd0] #> #> [[7]] #> <frame 20> (19) #> expr: doTryCatch(return(expr), name, parentenv, handler) #> env: [local 0x55ba49646820] #> #> [[8]] #> <frame 19> (18) #> expr: tryCatchOne(expr, names, parentenv, handlers[[1L]]) #> env: [local 0x55ba49646468] #> #> [[9]] #> <frame 18> (17) #> expr: tryCatchList(expr, classes, parentenv, handlers) #> env: [local 0x55ba49646120] #> #> [[10]] #> <frame 17> (16) #> expr: tryCatch(expr, error = function(e) { <...> #> env: [local 0x55ba496459e8] #> #> [[11]] #> <frame 16> (15) #> expr: try(f, silent = TRUE) #> env: [local 0x55ba49645780] #> #> [[12]] #> <frame 15> (13) #> expr: handle(ev <- withCallingHandlers(withVisible(eval(expr, envir, <...> #> env: [local 0x55ba496455f8] #> #> [[13]] #> <frame 14> (13) #> expr: timing_fn(handle(ev <- withCallingHandlers(withVisible(eval(expr, <...> #> env: [local 0x55ba49645518] #> #> [[14]] #> <frame 13> (12) #> expr: evaluate_call(expr, parsed$src[[i]], envir = envir, enclos = enclos, <...> #> env: [frame 0x55ba4965ae50] #> #> [[15]] #> <frame 12> (11) #> expr: evaluate::evaluate(code, child_env(env), new_device = TRUE) #> env: [frame 0x55ba498b6960] #> #> [[16]] #> <frame 11> (10) #> expr: downlit::evaluate_and_highlight(code, fig_save = fig_save_topic, <...> #> env: [frame 0x55ba498baf10] #> #> [[17]] #> <frame 10> (9) #> expr: highlight_examples(code, topic, env = env) #> env: [frame 0x55ba498c4998] #> #> [[18]] #> <frame 9> (8) #> expr: run_examples(tags$tag_examples[[1]], env = new.env(parent = globalenv()), <...> #> env: [frame 0x55ba498fdc78] #> #> [[19]] #> <frame 8> (6) #> expr: data_reference_topic(topic, pkg, examples = examples, run_dont_run = run_dont_run) #> env: [frame 0x55ba49b85938] #> #> [[20]] #> <frame 7> (6) #> expr: withCallingHandlers(data_reference_topic(topic, pkg, examples = examples, <...> #> env: [frame 0x55ba49b85200] #> #> [[21]] #> <frame 6> (5) #> expr: .f(.x[[i]], ...) #> env: [frame 0x55ba49ba3040] #> #> [[22]] #> <frame 5> (4) #> expr: purrr::map(topics, build_reference_topic, pkg = pkg, lazy = lazy, <...> #> env: [frame 0x55ba48927d98] #> #> [[23]] #> <frame 4> (3) #> expr: build_reference(pkg, lazy = lazy, examples = examples, run_dont_run = run_dont_run, <...> #> env: [frame 0x55ba48d0d4a0] #> #> [[24]] #> <frame 3> (2) #> expr: build_site_local(pkg = pkg, examples = examples, run_dont_run = run_dont_run, <...> #> env: [frame 0x55ba4836fa10] #> #> [[25]] #> <frame 2> (1) #> expr: build_site(pkg, devel = FALSE, preview = FALSE, install = FALSE, <...> #> env: [frame 0x55ba48368f20] #> #> [[26]] #> <frame 1> (0) #> expr: pkgdown::deploy_to_branch(new_process = FALSE) #> env: [frame 0x55ba45e8ffb0] #> #> [[27]] #> <frame 0> [global] #> expr: NULL #> env: [global] #> #> attr(,"class") #> [1] "ctxt_stack" "stack"#> [[1]] #> <frame 24> (23) #> expr: eval(expr, envir, enclos) #> env: [local 0x55ba4966b898] #> #> [[2]] #> <frame 23> (13) #> expr: eval(expr, envir, enclos) #> env: [local 0x55ba4926d000] #> #> [[3]] #> <frame 22> (13) #> expr: withVisible(eval(expr, envir, enclos)) #> env: [local 0x55ba4926cdd0] #> #> [[4]] #> <frame 21> (13) #> expr: withCallingHandlers(withVisible(eval(expr, envir, enclos)), warning = wHandler, <...> #> env: [local 0x55ba49274420] #> #> [[5]] #> <frame 20> (19) #> expr: doTryCatch(return(expr), name, parentenv, handler) #> env: [local 0x55ba4927ddc8] #> #> [[6]] #> <frame 19> (18) #> expr: tryCatchOne(expr, names, parentenv, handlers[[1L]]) #> env: [local 0x55ba4927da80] #> #> [[7]] #> <frame 18> (17) #> expr: tryCatchList(expr, classes, parentenv, handlers) #> env: [local 0x55ba4927d700] #> #> [[8]] #> <frame 17> (16) #> expr: tryCatch(expr, error = function(e) { <...> #> env: [local 0x55ba4927d000] #> #> [[9]] #> <frame 16> (15) #> expr: try(f, silent = TRUE) #> env: [local 0x55ba4927cdd0] #> #> [[10]] #> <frame 15> (13) #> expr: handle(ev <- withCallingHandlers(withVisible(eval(expr, envir, <...> #> env: [local 0x55ba4927cc10] #> #> [[11]] #> <frame 14> (13) #> expr: timing_fn(handle(ev <- withCallingHandlers(withVisible(eval(expr, <...> #> env: [local 0x55ba4927cb30] #> #> [[12]] #> <frame 13> (12) #> expr: evaluate_call(expr, parsed$src[[i]], envir = envir, enclos = enclos, <...> #> env: [frame 0x55ba4928fef0] #> #> [[13]] #> <frame 12> (11) #> expr: evaluate::evaluate(code, child_env(env), new_device = TRUE) #> env: [frame 0x55ba498b6960] #> #> [[14]] #> <frame 11> (10) #> expr: downlit::evaluate_and_highlight(code, fig_save = fig_save_topic, <...> #> env: [frame 0x55ba498baf10] #> #> [[15]] #> <frame 10> (9) #> expr: highlight_examples(code, topic, env = env) #> env: [frame 0x55ba498c4998] #> #> [[16]] #> <frame 9> (8) #> expr: run_examples(tags$tag_examples[[1]], env = new.env(parent = globalenv()), <...> #> env: [frame 0x55ba498fdc78] #> #> [[17]] #> <frame 8> (6) #> expr: data_reference_topic(topic, pkg, examples = examples, run_dont_run = run_dont_run) #> env: [frame 0x55ba49b85938] #> #> [[18]] #> <frame 7> (6) #> expr: withCallingHandlers(data_reference_topic(topic, pkg, examples = examples, <...> #> env: [frame 0x55ba49b85200] #> #> [[19]] #> <frame 6> (5) #> expr: .f(.x[[i]], ...) #> env: [frame 0x55ba49ba3040] #> #> [[20]] #> <frame 5> (4) #> expr: purrr::map(topics, build_reference_topic, pkg = pkg, lazy = lazy, <...> #> env: [frame 0x55ba48927d98] #> #> [[21]] #> <frame 4> (3) #> expr: build_reference(pkg, lazy = lazy, examples = examples, run_dont_run = run_dont_run, <...> #> env: [frame 0x55ba48d0d4a0] #> #> [[22]] #> <frame 3> (2) #> expr: build_site_local(pkg = pkg, examples = examples, run_dont_run = run_dont_run, <...> #> env: [frame 0x55ba4836fa10] #> #> [[23]] #> <frame 2> (1) #> expr: build_site(pkg, devel = FALSE, preview = FALSE, install = FALSE, <...> #> env: [frame 0x55ba48368f20] #> #> [[24]] #> <frame 1> (0) #> expr: pkgdown::deploy_to_branch(new_process = FALSE) #> env: [frame 0x55ba45e8ffb0] #> #> [[25]] #> <frame 0> [global] #> expr: NULL #> env: [global] #> #> attr(,"class") #> [1] "ctxt_stack" "stack"# Note that it also takes care of calls intervening at its own call # site: identity(identity( stack_trim(identity(identity(ctxt_stack()))) ))#> [[1]] #> <frame 24> (23) #> expr: eval(expr, envir, enclos) #> env: [local 0x55ba4966b898] #> #> [[2]] #> <frame 23> (13) #> expr: eval(expr, envir, enclos) #> env: [local 0x55ba48eae708] #> #> [[3]] #> <frame 22> (13) #> expr: withVisible(eval(expr, envir, enclos)) #> env: [local 0x55ba48eae4d8] #> #> [[4]] #> <frame 21> (13) #> expr: withCallingHandlers(withVisible(eval(expr, envir, enclos)), warning = wHandler, <...> #> env: [local 0x55ba48eb1cb0] #> #> [[5]] #> <frame 20> (19) #> expr: doTryCatch(return(expr), name, parentenv, handler) #> env: [local 0x55ba48eb14d0] #> #> [[6]] #> <frame 19> (18) #> expr: tryCatchOne(expr, names, parentenv, handlers[[1L]]) #> env: [local 0x55ba48eb10e0] #> #> [[7]] #> <frame 18> (17) #> expr: tryCatchList(expr, classes, parentenv, handlers) #> env: [local 0x55ba48eb0d60] #> #> [[8]] #> <frame 17> (16) #> expr: tryCatch(expr, error = function(e) { <...> #> env: [local 0x55ba48eb0200] #> #> [[9]] #> <frame 16> (15) #> expr: try(f, silent = TRUE) #> env: [local 0x55ba48eb3e00] #> #> [[10]] #> <frame 15> (13) #> expr: handle(ev <- withCallingHandlers(withVisible(eval(expr, envir, <...> #> env: [local 0x55ba48eb3c78] #> #> [[11]] #> <frame 14> (13) #> expr: timing_fn(handle(ev <- withCallingHandlers(withVisible(eval(expr, <...> #> env: [local 0x55ba48eb3a48] #> #> [[12]] #> <frame 13> (12) #> expr: evaluate_call(expr, parsed$src[[i]], envir = envir, enclos = enclos, <...> #> env: [frame 0x55ba48ee0af8] #> #> [[13]] #> <frame 12> (11) #> expr: evaluate::evaluate(code, child_env(env), new_device = TRUE) #> env: [frame 0x55ba498b6960] #> #> [[14]] #> <frame 11> (10) #> expr: downlit::evaluate_and_highlight(code, fig_save = fig_save_topic, <...> #> env: [frame 0x55ba498baf10] #> #> [[15]] #> <frame 10> (9) #> expr: highlight_examples(code, topic, env = env) #> env: [frame 0x55ba498c4998] #> #> [[16]] #> <frame 9> (8) #> expr: run_examples(tags$tag_examples[[1]], env = new.env(parent = globalenv()), <...> #> env: [frame 0x55ba498fdc78] #> #> [[17]] #> <frame 8> (6) #> expr: data_reference_topic(topic, pkg, examples = examples, run_dont_run = run_dont_run) #> env: [frame 0x55ba49b85938] #> #> [[18]] #> <frame 7> (6) #> expr: withCallingHandlers(data_reference_topic(topic, pkg, examples = examples, <...> #> env: [frame 0x55ba49b85200] #> #> [[19]] #> <frame 6> (5) #> expr: .f(.x[[i]], ...) #> env: [frame 0x55ba49ba3040] #> #> [[20]] #> <frame 5> (4) #> expr: purrr::map(topics, build_reference_topic, pkg = pkg, lazy = lazy, <...> #> env: [frame 0x55ba48927d98] #> #> [[21]] #> <frame 4> (3) #> expr: build_reference(pkg, lazy = lazy, examples = examples, run_dont_run = run_dont_run, <...> #> env: [frame 0x55ba48d0d4a0] #> #> [[22]] #> <frame 3> (2) #> expr: build_site_local(pkg = pkg, examples = examples, run_dont_run = run_dont_run, <...> #> env: [frame 0x55ba4836fa10] #> #> [[23]] #> <frame 2> (1) #> expr: build_site(pkg, devel = FALSE, preview = FALSE, install = FALSE, <...> #> env: [frame 0x55ba48368f20] #> #> [[24]] #> <frame 1> (0) #> expr: pkgdown::deploy_to_branch(new_process = FALSE) #> env: [frame 0x55ba45e8ffb0] #> #> [[25]] #> <frame 0> [global] #> expr: NULL #> env: [global] #> #> attr(,"class") #> [1] "ctxt_stack" "stack"# It is especially useful when used within a function that needs to # inspect the evaluation stack but should nonetheless be callable # within nested calls without side effects: stack_util <- function() { # n = 2 means that two layers of intervening calls should be # removed: The layer at ctxt_stack()'s call site (including the # stack_trim() call), and the layer at stack_util()'s call. stack <- stack_trim(ctxt_stack(), n = 2) stack } user_fn <- function() { # A user calls your stack utility with intervening frames: identity(identity(stack_util())) } # These intervening frames won't appear in the evaluation stack identity(user_fn())#> [[1]] #> <frame 26> (24) #> expr: user_fn() #> env: [local 0x55ba48a389a8] #> #> [[2]] #> <frame 25> (24) #> expr: identity(user_fn()) #> env: [local 0x55ba48a38938] #> #> [[3]] #> <frame 24> (23) #> expr: eval(expr, envir, enclos) #> env: [local 0x55ba4966b898] #> #> [[4]] #> <frame 23> (13) #> expr: eval(expr, envir, enclos) #> env: [local 0x55ba48a38708] #> #> [[5]] #> <frame 22> (13) #> expr: withVisible(eval(expr, envir, enclos)) #> env: [local 0x55ba48a384a0] #> #> [[6]] #> <frame 21> (13) #> expr: withCallingHandlers(withVisible(eval(expr, envir, enclos)), warning = wHandler, <...> #> env: [local 0x55ba48a37d30] #> #> [[7]] #> <frame 20> (19) #> expr: doTryCatch(return(expr), name, parentenv, handler) #> env: [local 0x55ba48a3b540] #> #> [[8]] #> <frame 19> (18) #> expr: tryCatchOne(expr, names, parentenv, handlers[[1L]]) #> env: [local 0x55ba48a3b1f8] #> #> [[9]] #> <frame 18> (17) #> expr: tryCatchList(expr, classes, parentenv, handlers) #> env: [local 0x55ba48a3aeb0] #> #> [[10]] #> <frame 17> (16) #> expr: tryCatch(expr, error = function(e) { <...> #> env: [local 0x55ba48a3a7e8] #> #> [[11]] #> <frame 16> (15) #> expr: try(f, silent = TRUE) #> env: [local 0x55ba48a3a580] #> #> [[12]] #> <frame 15> (13) #> expr: handle(ev <- withCallingHandlers(withVisible(eval(expr, envir, <...> #> env: [local 0x55ba48a3a3f8] #> #> [[13]] #> <frame 14> (13) #> expr: timing_fn(handle(ev <- withCallingHandlers(withVisible(eval(expr, <...> #> env: [local 0x55ba48a3a318] #> #> [[14]] #> <frame 13> (12) #> expr: evaluate_call(expr, parsed$src[[i]], envir = envir, enclos = enclos, <...> #> env: [frame 0x55ba48a50ef8] #> #> [[15]] #> <frame 12> (11) #> expr: evaluate::evaluate(code, child_env(env), new_device = TRUE) #> env: [frame 0x55ba498b6960] #> #> [[16]] #> <frame 11> (10) #> expr: downlit::evaluate_and_highlight(code, fig_save = fig_save_topic, <...> #> env: [frame 0x55ba498baf10] #> #> [[17]] #> <frame 10> (9) #> expr: highlight_examples(code, topic, env = env) #> env: [frame 0x55ba498c4998] #> #> [[18]] #> <frame 9> (8) #> expr: run_examples(tags$tag_examples[[1]], env = new.env(parent = globalenv()), <...> #> env: [frame 0x55ba498fdc78] #> #> [[19]] #> <frame 8> (6) #> expr: data_reference_topic(topic, pkg, examples = examples, run_dont_run = run_dont_run) #> env: [frame 0x55ba49b85938] #> #> [[20]] #> <frame 7> (6) #> expr: withCallingHandlers(data_reference_topic(topic, pkg, examples = examples, <...> #> env: [frame 0x55ba49b85200] #> #> [[21]] #> <frame 6> (5) #> expr: .f(.x[[i]], ...) #> env: [frame 0x55ba49ba3040] #> #> [[22]] #> <frame 5> (4) #> expr: purrr::map(topics, build_reference_topic, pkg = pkg, lazy = lazy, <...> #> env: [frame 0x55ba48927d98] #> #> [[23]] #> <frame 4> (3) #> expr: build_reference(pkg, lazy = lazy, examples = examples, run_dont_run = run_dont_run, <...> #> env: [frame 0x55ba48d0d4a0] #> #> [[24]] #> <frame 3> (2) #> expr: build_site_local(pkg = pkg, examples = examples, run_dont_run = run_dont_run, <...> #> env: [frame 0x55ba4836fa10] #> #> [[25]] #> <frame 2> (1) #> expr: build_site(pkg, devel = FALSE, preview = FALSE, install = FALSE, <...> #> env: [frame 0x55ba48368f20] #> #> [[26]] #> <frame 1> (0) #> expr: pkgdown::deploy_to_branch(new_process = FALSE) #> env: [frame 0x55ba45e8ffb0] #> #> [[27]] #> <frame 0> [global] #> expr: NULL #> env: [global] #> #> attr(,"class") #> [1] "ctxt_stack" "stack"