Cannot parse quoted arguments

[aniketschneider]

I have been unable to get this to parse a quoted argument with a space as a single argument. For example:

library(docopt)
library(methods)

doc <- '
Usage:
  exampleScript <arg1>
'
docopt(doc, commandArgs(trailingOnly=TRUE))

$ Rscript exampleScript.R 'multi-word arg'
Error in docopt(doc, commandArgs(trailingOnly = TRUE)) : 
  usage: exampleScript <arg1>
Execution halted

[edwindj]

Thanks for reporting: I will look into it this week.

[edwindj]

I added supportfor quoted arguments in the github repo.

However note that:

• docopt (the python version) has no support for quoted arguments
• this solution does not support nested quotes.

Could you please check if this is solving your problem, so I can close the issue?

Best,

[aniketschneider]

Thanks for looking into this!

Using http://try.docopt.org/ , quoted arguments do seem to work fine. I looked a little further and found a related issue on the docopt repo: docopt/docopt#129

I think the core issue here is not quoting specifically (which in R is handled just fine by commandArgs()), but rather that docopt accepts a list argument, but docopt.R doesn't respect the separation of items in a list when they have spaces in them. That is, if there is a list of two items - "a", "b c" - docopt.R treats this as two arguments:

> doc <- 'Usage:
   exampleScript <arg1> <arg2>'
> docopt(doc, c("a", "b c"))
Error in docopt(doc, c("a", "b c")) : usage: exampleScript <arg1> <arg2>
> docopt(doc, c("a", "b"))
$`<arg1>`
[1] "a"

$`<arg2>`
[1] "b"

Whereas the python docopt treats this as two arguments:

>>> from docopt import docopt
>>> doc = """Usage:
... exampleScript <arg1> <arg2>"""
>>> docopt(doc, ["a", "b c"])
{'<arg1>': 'a',
 '<arg2>': 'b c'}

[edwindj]

I'm not sure what you mean with that quoted arguments seem to work find in http://try.docopt.org

For example (at http://try.docopt.org)
ship Guardian move 1 2 works as expected, but
ship "Guardian II" move 1 2, does not work.

The latest version of docopt:

devtools::install_github("edwindj/docopt.R")

will parse

doc <- 'Usage:
   exampleScript <arg1> <arg2>'
docopt(doc, 'a "b c"')

as

$`<arg1>`
[1] "a"

$`<arg2>`
[1] "b c"

Is this your intended behavior?

[aniketschneider]

I don't know what I thought I saw on http://try.docopt.org/, you're clearly right about that.

The behavior for quoted arguments in the current github version is what I originally wanted, but as you pointed out it is not consistent with the docopt reference implementation in python. I think the best solution here should maintain consistency with the reference implementation.

The python implementation accepts two types of inputs: a string or a list. When presented with a string, it treats the string as a whitespace-delimited sequence of tokens (irrespective of quotation marks). When presented with a list, it treats each element in the list as a single token, even if the element has spaces in it.

It is that last behavior that is not consistent between docopt.R and the reference implementation. When passed a list (or other sequence), docopt.R still splits the individual list elements into multiple tokens at whitespace boundaries.

Specifically, the following example works in the python implementation, and is what I would like to work in this one:

> doc <- 'Usage:
   exampleScript <arg1> <arg2>'
> docopt(doc, c("a", "b c"))
Error in docopt(doc, c("a", "b c")) : usage: exampleScript <arg1> <arg2>

[holgerbrandl]

Hi,
I'm using the latest version including the quoted_args option. However, it seems to be not really robust against what's in the quotes. E.g. try

> doc <- 'Usage: do_something.R [-S] <dirname> [<other>...]'
> docopt(doc, "some_directory '--quoted test'", quoted_args=T)
$`-S`
[1] FALSE

$`--quoted test`
[1] TRUE

$`<dirname>`
[1] "some_directory"

$`<other>`
list()

$S
[1] FALSE

$`quoted test`
[1] TRUE

$dirname
[1] "some_directory"

$other
list()

I would expect '--quoted test' to show up as it is in other but somehow it does not work that way (yet?).

[edwindj]

Thanks for reporting! I will look into it later this week and get back to you. I'm not sure what the golden docopt.py standard is in this matter.

Best,

Edwin

[holgerbrandl]

docopt.R deviated from the reference already by supporting quotes (which is great and very useful).

Some users seem to want quote support also for the reference, see
docopt/try.docopt.org#3
docopt/docopt#207

Quote handling is just not really consistent at the moment in docopt.R.

[edwindj]

@holgerbrandl
Again thanks for reporting. Your reported issue has itself an issue: you are using "--" inside optional arguments, which is againt the docopt spec.

Let me illustrate it with two examples:

doc <- 'Usage: do.R <dirname> [<other>...]'
# omit the double --
docopt(doc, "some_directory 'quoted test'", quoted_args=T)
$`<dirname>`
[1] "some_directory"

$`<other>`
[1] "quoted test"

$dirname
[1] "some_directory"

$other
[1] "quoted test"

which is what you are expecting (and which is parsed by docopt.R, but not by docopt.py)

The other example is using an unquoted optional argument:

doc <- 'Usage: do.R <dirname> [<other>...]'
docopt(doc, "some_directory --notquoted")

which generates an error. This is conform docopt.py (test it on try.docopt.org).

I see quotation as a means to have white spaces in parameters and arguments, and this seems to work right now.

[edwindj]

After a little thought I implemented your wish anyway: should work now.
@holgerbrandl
If not you can reopen the issue.

Best!

[holgerbrandl]

@edwindj Awesome, thanks a lot for this christmas fix/present. I've tried it already, and it works like a charm.