logical. If true, a newline is appended to each string
character string, partially matched. See details.
pushBack and clearPushBack() return nothing, invisibly.
pushBackLength returns the number of lines currently pushed back.
Several character strings can be pushed back on one or more occasions.
The occasions form a stack, so the first line to be retrieved will be
the first string from the last call to pushBack. Lines which
are pushed back are read prior to the normal input from the
connection, by the normal text-reading functions such as
readLines and scan.
Pushback is only allowed for readable connections in text mode.
Not all uses of connections respect pushbacks, in particular the input
connection is still wired directly, so for example parsing
commands from the console and scan("") ignore pushbacks on
When character strings with a marked encoding (see
Encoding) are pushed back they are converted to the
current encoding if encoding = "". This may involve
representing characters as <U+xxxx> if they cannot be
converted. They will be converted to UTF-8 if encoding =
"UTF-8" or left as-is if encoding = "bytes".