Re: [Caml-list] complications with Arg.parse_argv

[Kenneth Adam Miller <kennethadammiller@gmail.com>]

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*sigh  I fixed it literally the second you sent this email! And you are
right, what fixed it was I put ~current:(ref 0) and it is parsing arguments
now.

On Mon, Nov 24, 2014 at 1:16 PM, Gabriel Scherer <gabriel.scherer@gmail.com>
wrote:

> Looking at the parse_argv documentation (man Arg), I see two possible
> reasons:
> - Arg expects the passed string array to start with the name of the
> program at index 0; does your custom_arguments array follow this
> convention?
> - parse_argv takes an (optional) integer reference ~current that tells
> it where to start parsing the argument array; by default, it points to
> a global mutable reference Arg.current (so that several calls in a row
> start on the next element); if your library has used Arg.parse itself
> before, Arg.current may be set too far. You should try passing
> ~current:(ref 0) to make sure you only use local state.
>
> On Mon, Nov 24, 2014 at 6:42 PM, Kenneth Adam Miller
> <kennethadammiller@gmail.com> wrote:
> > So, I'm using a library that calls Arg.parse to build up it's inputs in
> > another data structure. I don't want to rewrite any code, and I'm
> consuming
> > the library in a different way than how the binary consumes it, which is
> > just to feed it input from the command line.
> >
> > Not wanting to replicate code in two locations, I chose to use
> > Arg.parse_argv, and supplied it with an array that would normally be on
> the
> > command line. For some reason, supplying the exact same speclist as what
> was
> > used in the original statement that works as a command line tool doesn't
> > result in the parameters being parsed.
> >
> > command line tool:
> > Arg.parse speclist anon usage;
> > get_program () (* consumes the mutable list that speclist modified *)
> >
> > (* speclist modifies a mutable list used to hold arguments *)
> >
> > my code that consumes speclist as a library:
> >
> > Arg.parse_argv custom_arguments speclist anon usage
> > get_program () (* exact same function as above, exact same variables to
> > Arg.parse* *)
> >
> > For some reason, Arg.parse_argv seems to complete, but when get_program
> > proceeds, it sees the mutable argument list as being empty. Why?
>

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