[R] separate commands by semicolon

[Duncan Murdoch]

On 19/09/2016 7:59 AM, Adrian Dușa wrote:
> On Sun, Sep 18, 2016 at 12:34 AM, Peter Langfelder <
> peter.langfelder at gmail.com> wrote:
>
> > On Sat, Sep 17, 2016 at 2:12 PM, David Winsemius <dwinsemius at comcast.net>
> > wrote:
> > > Not entirely clear. If you were intending to just get character output
> > then you could just use:
> > >
> > > strsplit(txt, ";")
> >
> > You would want to avoid splitting within character strings
> > (print(";")) and in comments (print(2); ls() # This prints 2; then
> > lists...) The comment char could also appear in a character string,
> > where it does not mean the start of a comment...
>
>
> Yes, that would be the problem.
> Returning to my original post, modifying the example:
>
> x <- "print(2); bar <- \"don't ; use semicolons\"; foo <- '3;4'; ls("
>
> This should result in a character vector of length 4:
> [1] "print(2)"                          "bar <- \"don't ; use semicolons\""
> [3] "foo <- '3;4'"                      "ls("
>
> even though the last command would cause an error using parse(text = x)
>
> Perhaps this is not that important (I am trying to simulate a normal R
> console), and parse only if it syntactically correct.
> I was merely curious if this could be done, likely using regular
> expressions (surely strsplit doesn't solve it).
>
> Best,
> Adrian
>
See the section on "partial parsing" in the ?parse help page.

Duncan Murdoch