Add chapter on commandline arguments #76

vks · 2014-06-04T20:56:46Z

Please let me know if you think the example should be more verbose.

alan-andrade · 2014-06-04T21:01:38Z

examples/arg/args.rs

+fn main() {
+    let args = os::args();
+    println!("My path is {}.", args.get(0));
+    println!("My arguments are {}.", args.slice(1, args.len()));


I believe we could use tail() instead.

I didn't know about tail, thanks!

(I'm surprised that this is in the standard library, seems very specialized to me. Do you know whether it was ever considered to add something more generic like Python's slicing syntax?)

japaric · 2014-06-05T02:18:20Z

Thanks for sending a PR!

This is a very succinct chapter :P. I would like to see more things (if you have the time, otherwise I can take over):

Show the type of the value returned by os::args(), this can be done with a superfluous type annotation.
Show how to get the number of arguments: args.len(). (this could be added to the first example)
Show how to do pattern matching on the cmd arguments, something like

let args = os::args();

match args.as_slice() {
    // no arguments passed
    [ref name] => {
        // some behavior
    },
    // one argument passed
    [ref name, ref num] => {
        // call from_str on `num`
        // another behavior
    },
    // one command and one argument passed
    [ref name, ref cmd, ref num] => {
        match cmd.as_slice() {
            "action1" => {},
            "action2" => {},
            _ => help(),
        }
    },
    // all the other cases
    _ => {
        // show a help message
        help();
    }
}

(^ that should be a second example)

mention that more complex argument parsing can be done with getopts, which will be covered in another chapter.

vks · 2014-06-06T01:15:52Z

Thanks for the feedback! I made some according changes.

The second example became a bit long.

I accidentally committed changes to examples/order.json, is this generated by the build system? If yes, it probably should not be tracked by git.

japaric · 2014-06-07T16:12:09Z

I think we should put this on hold, until #80 is finished.

After that lands, we should split this chapter like this:

Program arguments
|-- Reading the arguments
|-- The match idiom
`-- `getopts``

(name subject to changes)

What do you think about the split? We could leave the getopts subchapter empty for now.

vks · 2014-06-07T19:12:28Z

I think the split makes sense. More structure is good.

2014-06-07 12:12 GMT-04:00 Jorge Aparicio notifications@github.com:

I think we should put this on hold, until #80
#80 is finished.

After that lands, we should split this chapter like this:

Program arguments
|-- Reading the arguments
|-- The match idiom
--getopts``

(name subject to changes)

What do you think about the split? We could leave the getopts subchapter
empty for now.

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#76 (comment)
.

japaric · 2014-06-14T16:35:35Z

This needs a rebase

EDIT: I just had an idea, maybe we can make a "CLI" chapter, and include "args" as a subchapter, and the subchapters could be: "exit code", "stdin", "stdout" and "stderr". What do you think?

japaric · 2014-06-17T14:20:04Z

cc #106

vks · 2014-06-20T03:02:55Z

Rebased and split into subchapters. I added an implementation of echo as a getopts example.

There seems to be an issue with the syntax highlighting of the last example. Also it breaks the playpen, probably because it uses libc::exit.

I would love to have some input on the second example, I'm not very happy with it yet.

@japaric I agree about the CLI chapter, especially since my last example (echo) uses exit codes.

japaric · 2014-06-30T15:58:38Z

examples/arg/getopts/echo.rs

@@ -0,0 +1,71 @@
+/*
+ * For the full copyright and license information, please view the LICENSE


This would look odd, because none of the other examples include a header comment. Maybe we can add a note after the example to indicate that this example is based on coreutils's echo code.

japaric · 2014-06-30T17:35:48Z

Sorry for procrastinating this for so long :-(.

There seems to be an issue with the syntax highlighting of the last example.

Yes, this is related to issue #2. This problem doesn't happen with the live code editor.

Also it breaks the playpen, probably because it uses libc::exit.

Your original program works fine in the playpen.

I would love to have some input on the second example, I'm not very happy with it yet.

Except for the code style issues, I think the coverage of features is good. Does something else bother you?

I agree about the CLI chapter, especially since my last example (echo) uses exit codes.

We can merge this as a chapter for now, and later move it into the CLI chapter as a subchapter.

vks · 2014-07-01T00:00:24Z

@japaric I think I addressed all of your comments.

Does something else bother you?

I think the coverage is fine, I'm just not a big fan of the silly example, but I don't have a better idea so far.

Currently there is a very strange bug, where the getopts chapter shows up as a subchapter of the random chapter.

japaric · 2014-07-01T00:46:06Z

examples/staging/arg/getopts/echo.rs

@@ -0,0 +1,64 @@
+extern crate getopts;
+extern crate libc;


We don't need this anymore, right?

japaric · 2014-07-01T01:05:42Z

examples/staging/arg/getopts/echo.rs

+
+use std::os;
+use std::io::{print, println};
+use std::io::stdio::flush;


The idiomatic way to use functions from other modules is to import the module use std::io::stdio, and call the function using the path: stdio::flush().

japaric · 2014-07-01T01:25:29Z

@japaric I think I addressed all of your comments.

Sorry, I have more comments :P

I think the coverage is fine, I'm just not a big fan of the silly example, but I don't have a better idea so far.

It just occurred to me (although it may be too late) that you could do use echo as a base for the three examples, making it "evolve" in complexity as one progresses through the examples.

First example: just "connect" all the arguments, and print the result. No flag parsing.
Second example: Parse certain flags, but position of the flags is important (this may be tricky)
Third example: Parsing flags regardless of their position.

Of course, this is more work, and the current examples are already good.

Currently there is a very strange bug, where the getopts chapter shows up as a subchapter of the random chapter.

You are right, I see the same thing. That's really weird! I'll have to investigate.

vks · 2014-07-01T02:04:57Z

First example: just "connect" all the arguments, and print the result. No
flag parsing.
Second example: Parse certain flags, but position of the flags is
important (this may be tricky)
Third example: Parsing flags regardless of their position.

This would be a nicer example but cover less:

In the first example it would not mention the 0th argument to os::args
(which I think is crucial for a first example).
Parsing non-strings (here: integers) would not be covered at all, which
is important, because it is not that obvious in Rust (because of Option).

2014-06-30 21:25 GMT-04:00 Jorge Aparicio notifications@github.com:

@japaric /~https://github.com/japaric I think I addressed all of your
comments.

Sorry, I have more comments :P

I think the coverage is fine, I'm just not a big fan of the silly example,
but I don't have a better idea so far.

It just occurred to me (although it may be too late) that you could do use
echo as a base for the three examples, making it "evolve" in complexity
as one progresses through the examples.

First example: just "connect" all the arguments, and print the result. No
flag parsing.
Second example: Parse certain flags, but position of the flags is
important (this may be tricky)
Third example: Parsing flags regardless of their position.

Of course, this is more work, and the current examples are already good.

Currently there is a very strange bug, where the getopts chapter shows up
as a subchapter of the random chapter.

You are right, I see the same thing. That's really weird! I'll have to
investigate.

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#76 (comment)
.

japaric · 2014-07-01T02:31:43Z

This would be a nicer example but cover less:

Oh well, at least I tried :P

japaric · 2014-07-02T16:17:05Z

@vks Can getopts handle arguments like:

--type f and --out-dir bin, where the argument after the flag is like an "input" - this could be translated to a map: "type" -> "f" and "out-dir" -> "bin" in the latter case.
or --type=f and --out-dir=bin, with a similar treatment to the previous case?

vks · 2014-07-02T20:07:33Z

@japaric Yes, you can use optopt instead of optflag.

You can use equivalently

$ command --type=f
$ command --type f
$ command -t=f
$ command -t f
$ command -tf

(Judging from the documentation, I did not actually check that.)

Do you think we should add an example for this?

japaric · 2014-07-03T15:34:37Z

Do you think we should add an example for this?

Yes, that'd be awesome. BTW, the weird bug (getopts example under random chapter) seems to have died with the last commit.

vks · 2014-07-03T19:25:17Z

I might add an example for optional options, but this will be in a separate pull request, because I need to think of a new example (echo cannot be easily extended for this).

vks · 2014-08-27T18:36:02Z

@japaric What's the status on this? Anything that still needs to be addressed?

steveklabnik · 2014-12-10T16:05:20Z

@vks in general, I am interested in adding a chapter like this, but this PR is very old. Do you have any interest in modernizing it? If so, let's get it finally shipped.

vks · 2014-12-10T16:51:27Z

@steveklabnik I will rebase and update the code.

vks · 2014-12-10T18:26:14Z

@steveklabnik This should work with a current version of Rust now.

I think japaric reviewed everything except for the getopts example.

steveklabnik · 2014-12-10T19:10:18Z

I think that overall this looks great, but I'm loathe to add another license. If we address that and squash this up, r=me :)

vks · 2014-12-10T20:42:21Z

I'll ask the uutils maintainers just to be sure. Do you want me to squash
everything into one commit?

On Wed Dec 10 2014 at 2:10:23 PM Steve Klabnik notifications@github.com
wrote:

I think that overall this looks great, but I'm loathe to add another
license. If we address that and squash this up, r=me :)

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#76 (comment)
.

steveklabnik · 2014-12-10T20:43:11Z

Yes please.

steveklabnik · 2014-12-11T13:37:57Z

This is out of date already O_O

vks · 2014-12-11T15:34:06Z

Should be fixed now. (The conflict was a good thing, because I forgot to remove the special mention of the license from the readme.)

Regarding the license, we got green light by Seldaek, who is the copyright holder in uutils' license.

Add chapter on commandline arguments

steveklabnik · 2014-12-11T16:17:33Z

Thank you!

alan-andrade reviewed Jun 4, 2014
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japaric mentioned this pull request Jun 7, 2014

Restructure the book #80

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japaric reviewed Jun 30, 2014
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japaric reviewed Jul 1, 2014
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examples/staging/arg/getopts/echo.rs

@@ -0,0 +1,64 @@

extern crate getopts;

extern crate libc;

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We don't need this anymore, right?

japaric reviewed Jul 1, 2014
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vks mentioned this pull request Jul 3, 2014

args: extend getopts example to show how to pass values #157

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vks force-pushed the args branch from b76513c to c7108e4 Compare December 10, 2014 17:06

vks mentioned this pull request Dec 10, 2014

License for echo.rs and Rust by Example uutils/coreutils#470

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vks force-pushed the args branch from 2620631 to b1e2954 Compare December 10, 2014 22:59

Add chapter on command-line arguments

0eb6bfe

vks force-pushed the args branch from b1e2954 to 0eb6bfe Compare December 11, 2014 15:30

steveklabnik added a commit that referenced this pull request Dec 11, 2014

Merge pull request #76 from vks/args

9e84f2d

Add chapter on commandline arguments

steveklabnik merged commit 9e84f2d into rust-lang:master Dec 11, 2014

vks deleted the args branch December 11, 2014 20:36

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		@@ -0,0 +1,71 @@
		/*
		* For the full copyright and license information, please view the LICENSE

Add chapter on commandline arguments #76

Add chapter on commandline arguments #76

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