parseSome(con, prev = character(), n = 1)
parseClass(obj)
REQUIRED ARGUMENTS:
con
an S connection, available for input.
obj
an object (of class
parse), typically returned from
parseSome.
OPTIONAL ARGUMENTS:
prev
if a previous call to
parseSome returned a result of
parseClass
equal to
"partial", more input on
con can be used to continue
or complete this expression but providing the previous object as argument
prev
in the next call to
parseSome.
n
how many lines to read from
con, default =
1. In any case,
input will not continue past the point where one complete S expression is parsed.
VALUE:
the object returned by
parseSome is always of class
parse,
with slots
"expr",
"text", and
"message".
The
"expr" slot is of class
expression; if parsing was
complete, it is of length
1 and contains the parsed S expression. Otherwise,
it is of length
0. If there was a parse error, the error message is
in slot
"message". No actual S error is generated by
parseSome
if a syntax error occurs (which means the calling function had better check for such
errors, or an endless loop will likely occur with the calling function asking for
more input but just generating the same syntax error each time). To find out the
result of the last parse, call
parseClass(obj) with
obj
the last value returned from
parseSome. The call to
parseClass
returns one of the three strings
"complete",
"partial",
or
"error".
SEE ALSO:
for forcing in a whole expression (more for non-interactive parsing).