req-template.md
In httr2: Perform HTTP Requests and Process the Responses

generates useful errors

Code
  req_template(req, 1)
Condition
  Error in `req_template()`:
  ! `template` must be a single string, not the number 1.
Code
  req_template(req, "x", 1)
Condition
  Error in `req_template()`:
  ! All elements of `...` must be named.
Code
  req_template(req, "A B C")
Condition
  Error in `req_template()`:
  ! Can't parse template `template`.
  i Should have form like 'GET /a/b/c' or 'a/b/c/'.

template produces useful errors

Code
  template_process(":b")
Condition
  Error:
  ! Can't find template variable "b".
Code
  template_process(":b", list(b = sum))
Condition
  Error:
  ! Template variable "b" is not a simple scalar value.