R .Last.call feature - similar to .Last.value - r

Question

Similarly to .Last.value is there any way to access last call? Below expected results of potential .Last.call.
sum(1, 2)
# [1] 3
str(.Last.call)
# language sum(1, 2)
The bests if it would not require to parse file from file system.

Answer 1

The last.call package is no longer on cran, but you can still get the code:
# -----------------------------------------------------------------------
# FUNCTION: last.call
# Retrieves a CALL from the history and returns an unevaluated
# call.
#
# There are two uses for such abilities.
# - To be able to recall the previous commands, like pressing the up key
# on the terminal.
# - The ability to get the line that called the function.
#
# TODO:
# - does not handle commands seperated by ';'
#
# -----------------------------------------------------------------------
last.call <-
function(n=1) {
f1 <- tempfile()
try( savehistory(f1), silent=TRUE )
try( rawhist <- readLines(f1), silent=TRUE )
unlink(f1)
if( exists('rawhist') ) {
# LOOK BACK max(n)+ LINES UNTIL YOU HAVE n COMMANDS
cmds <- expression()
n.lines <- max(abs(n))
while( length(cmds) < max(abs(n)) ) {
lines <- tail( rawhist, n=n.lines )
try( cmds <- parse( text=lines ), silent=TRUE )
n.lines <- n.lines + 1
if( n.lines > length(rawhist) ) break
}
ret <- rev(cmds)[n]
if( length(ret) == 1 ) return(ret[[1]]) else return(ret)
}
return(NULL)
}
Now, to use it:
sum(1, 2)
# [1] 3
last.call(2)
# sum(1, 2)

Answer 2

I've modified this code to output text strings of the preceding commands / calls in a manner that preserves how there were formatted across lines in the original call, sot that I can use cat() to output the calls (for a function that emails me when the preceding function is done running). Here's the code:
lastCall <- function(num.call = 1) {
history.file <- tempfile()
try(savehistory(history.file), silent = TRUE )
try(raw.history <- readLines(history.file), silent = TRUE )
unlink(history.file)
if (exists('raw.history') ) {
# LOOK BACK max(n)+ LINES UNTIL YOU HAVE n COMMANDS
commands <- expression()
num.line <- max(abs(num.call) + 1)
while (length(commands) < max(abs(num.call) + 1)) {
lines <- tail(raw.history, n = num.line)
try(commands <- parse(text = lines), silent = TRUE)
num.line <- num.line + 1
if (num.line > length(raw.history)) break
}
ret <- rev(commands)[num.call + 1]
if (length(ret) == 1) {
a <- ret[1]
} else {
a <- ret
}
# a <- rev(commands)[num.call + 1]
out <- lapply(a, deparse) %>%
sapply(paste, sep = "\n", collapse = "\n")
}
out
}
Enjoy!