svMisc (version 0.9-69)

captureAll: Run an R expression and capture output and messages in a similar way as it would be done at the command line

Description

This function captures results of evaluating one or several R expressions the same way as it would be issued at the prompt in a R console. The result is returned in a character string. Errors, warnings and other conditions are treated as usual, including the delayed display of the warnings if options(warn = 0).

Usage

captureAll(expr, split = TRUE, echo = TRUE, file = NULL, markStdErr = FALSE)

Arguments

expr

a valid R expression to evaluate (names and calls are also accepted).

split

do we split output, that is, do we also issue it at the R console too, or do we only capture it silently?

echo

do we echo each expression in front of the results (like in the console)? In case the expression spans on more than 7 lines, only first and last three lines are echoed, separated by [...].

file

a file, or a valid opened connection where output is sinked. It is closed at the end, and the function returns NULL in this case. If file = NULL (by default), a textConnection() captures the output and it is returned is

markStdErr

if TRUE, stderr is separated from sddout by STX/ETX character

Value

• Returns a string with the result of the evaluation done in the user workspace.

concept

capturing output for GUI clients

See Also

parseText, parse, expression, capture.output, sourceClipboard

Examples

writeLines(captureAll(expression(1+1), split = FALSE))
writeLines(captureAll(expression(1+1), split = TRUE))
writeLines(captureAll(parseText("search()"), split = FALSE))

writeLines(captureAll(parseText('1:2 + 1:3'), split = FALSE))
writeLines(captureAll(parseText("badname"), split = FALSE))

## Management of incomplete lines
captRes <- captureAll(parseText("1 +")) # Clearly an incomplete command
if (is.na(captRes)) cat("Incomplete line!
") else writeLines(captRes)
rm(captRes)