do_if.R

library(dplyr)

do_if <- function(.data, condition, call){
  
  if(condition){
    .x <- .data
    
    call_str <- call %>%
      as.character %>%
      .[2] 
    
    out <- eval(rlang::parse_expr(call_str))
    
    return(out)
  } else {
    return(.data)
  }
}

any_condition <- T

mtcars %>%
  do_if(any_condition, ~{
    .x %>% 
      filter(cyl == 6) %>%
      mutate(x = disp > 170)
  })