Thanks for your insights. What I'm actually doing is the following:
I modified R in a way that the REPL loop always parses the input into an SEXPR, but depending on if "magic is enabled" or not, let R compute it or compute it via my own "backend". As I wanted to keep the changes to R itself as minimally invasive as possible, there is a simple if-statement at the beginning of the REPL iteration which decides how to compute the expression. using the R commands "enable/disable_magic()" one can change the behavior as required. This works fine when typing R code interactively, but not with a script, since it is only a single REPL iteration. So I was looking for a way to get "interactive behavior" with scripts, without requiring too many changes to R itself. Regards, Marc ________________________________________ Von: Duncan Murdoch [murdoch.dun...@gmail.com] Gesendet: Dienstag, 26. Februar 2013 14:06 An: Marc Aurel Kiefer Cc: r-devel@r-project.org Betreff: Re: [Rd] Running R scripts with interactive-style evaluation On 13-02-26 5:07 AM, Marc Aurel Kiefer wrote: > Hi, > > when running a R-script like this: > > enable_magic() > compute_stuff() > disable_magic() > > the whole script is parsed into a single expression and then evaluated, > whereas when using the interactive shell after each line entered, a REPL loop > happens. It's actually a vector of expressions that are evaluated one at a time, but close enough... > Is there a way to make a script evaluation behave like this, because I need a > single REPL iteration for every expression in the script. You don't say why you need that. From your subject line, I'm guessing you want to do something like a user prompt, then wait for user input, then another user prompt, etc.? So the fact that disable_magic() was parsed at the beginning shouldn't matter. Or does it? > > It doesn't matter if it's a source()-like way or "R CMD BATCH" or even > feeding stdin to R or whatever... I think it all depends on what kind of input users are allowed to type, but basically this is something you'll need to write yourself, I don't think any of the normal running modes of R will suit you. Take a look at the source to source() or to the Sweave-related functions for ideas. Duncan Murdoch ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
