Merge pull request #113 from BenWiederhake/dev-fallible-apply

Make Options::apply fallible

README.md

@@ -67,11 +67,12 @@ struct Settings {
 // To implement `Options`, we only need to provide the `apply` method.
 // The `parse` method will be automatically generated.
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::Caps => self.caps = true,
             Arg::ExclamationMarks(n) => self.exclamation_marks += n,
         }
+        Ok(())
     }
 }
 

docs/design/problems_with_clap.md

@@ -108,7 +108,7 @@ uutils and when we opened as issue for it, it was discarded. This makes sense
 from `clap`'s perspective, but it shows that the priorities between `clap` and
 uutils diverge.
 
-## Problem 6: It's stringly typed
+## Problem 7: It's stringly typed
 
 `clap`'s arguments are identified by strings. This leads to code like this:
 
@@ -135,14 +135,14 @@ deal, but a bit annoying.
 
 Of course, we wouldn't have this problem if we were able to use the derive API.
 
-## Problem 7: Reading help string from a file
+## Problem 8: Reading help string from a file
 
 In `uutils` our help strings can get quite long. Therefore, we like to extract
 those to an external file. With `clap` this means that we need to do some custom
 preprocessing on this file to extract the information for the several pieces of
 the help string that `clap` supports.
 
-## Problem 8: No markdown support
+## Problem 9: No markdown support
 
 Granted, this is not really a problem, but more of a nice-to-have. We have
 online documentation for the utils, based on the help strings and these are
@@ -150,6 +150,16 @@ rendered from markdown. Ideally, our argument parser supports markdown too, so
 that we can have nicely rendered help strings which have (roughly) the same
 appearance in the terminal and online.
 
+## Problem 10: No position-dependent argument-error prioritization
+
+This is the question of which error to print if both `-A` and `-B` are given,
+and both are individually an error somehow. In case of the GNU tools, only the
+first error is printed, and then the program is aborted.
+
+This also is not really a problem, but since it can be reasonably easily
+achieved by simply raising an error during argument application, this enables
+matching more closely the exact behavior of the GNU tools.
+
 ## Good things about `clap`
 
 Alright, enough problems. Let's praise `clap` a bit, because it's an excellent

docs/guide/port.md

@@ -94,10 +94,11 @@ enum Arg {
 struct Settings { a: bool }
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::A => self.a = true,
         }
+        Ok(())
     }
 }
 
@@ -137,10 +138,11 @@ impl Default for Settings {
 }
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::A => self.a = false,
         }
+        Ok(())
     }
 }
 
@@ -175,10 +177,11 @@ enum Arg {
 struct Settings { a: u8 }
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::A => self.a += 1,
         }
+        Ok(())
     }
 }
 
@@ -215,10 +218,11 @@ enum Arg {
 struct Settings { a: OsString }
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::A(s) => self.a = s,
         }
+        Ok(())
     }
 }
 
@@ -255,10 +259,11 @@ enum Arg {
 struct Settings { a: Vec<OsString> }
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::A(s) => self.a.push(s),
         }
+        Ok(())
     }
 }
 
@@ -271,4 +276,4 @@ let a = Settings::default().parse(std::env::args_os()).unwrap().0.a;
 [Up](super)
 [Next](next)
 
-</div>
+</div>

docs/guide/quick.md

@@ -59,10 +59,11 @@ struct Settings {
 }
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::Force => self.force = true,
         }
+        Ok(())
     }
 }
 
@@ -100,11 +101,12 @@ struct Settings {
 }
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::Force => self.force = true,
             Arg::NoForce => self.force = false,
         }
+        Ok(())
     }
 }
 
@@ -160,10 +162,11 @@ enum Arg {
 # }
 #
 # impl Options<Arg> for Settings {
-#     fn apply(&mut self, arg: Arg) {
+#     fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
 #         match arg {
 #             Arg::Name(name) => self.name = name,
 #         }
+#         Ok(())
 #     }
 # }
 #
@@ -197,10 +200,11 @@ enum Arg {
 # }
 #
 # impl Options<Arg> for Settings {
-#     fn apply(&mut self, arg: Arg) {
+#     fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
 #         match arg {
 #             Arg::Name(name) => self.name = name,
 #         }
+#         Ok(())
 #     }
 # }
 #
@@ -234,10 +238,11 @@ enum Arg {
 # }
 #
 # impl Options<Arg> for Settings {
-#     fn apply(&mut self, arg: Arg) {
+#     fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
 #         match arg {
 #             Arg::Force(b) => self.force = b,
 #         }
+#         Ok(())
 #     }
 # }
 #
@@ -269,10 +274,11 @@ enum Arg {
 # }
 #
 # impl Options<Arg> for Settings {
-#     fn apply(&mut self, arg: Arg) {
+#     fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
 #         match arg {
 #             Arg::Sort(s) => self.sort = s,
 #         }
+#         Ok(())
 #     }
 # }
 #
@@ -287,4 +293,4 @@ enum Arg {
 [Up](super)
 [Next](next)
 
-</div>
+</div>

examples/completion.rs

@@ -22,18 +22,18 @@ enum Arg {
     // Completion is derived from the `Number` type, through the `Value` trait
     /// Give it a number!
     #[arg("-n N", "--number=N")]
-    Number(Number),
+    Number(#[allow(unused)] Number),
 
     // Completion is derived from the `PathBuf` type
     /// Give it a path!
     #[arg("-p P", "--path=P")]
-    Path(PathBuf),
+    Path(#[allow(unused)] PathBuf),
 }
 
 struct Settings;
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, _arg: Arg) {
+    fn apply(&mut self, _arg: Arg) -> Result<(), uutils_args::Error> {
         panic!("Compile with the 'parse-is-complete' feature!")
     }
 }

examples/deprecated.rs

@@ -34,11 +34,12 @@ struct Settings {
 }
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::Min(n) => self.n1 = n,
             Arg::Plus(n) => self.n2 = n,
         }
+        Ok(())
     }
 }
 

examples/hello_world.rs

@@ -22,12 +22,13 @@ struct Settings {
 }
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::Name(n) => self.name = n,
             Arg::Count(c) => self.count = c,
             Arg::Hidden => {}
         }
+        Ok(())
     }
 }
 

examples/value.rs

@@ -25,10 +25,11 @@ struct Settings {
 }
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::Color(c) => self.color = c,
         }
+        Ok(())
     }
 }
 

src/lib.rs

@@ -166,7 +166,7 @@ impl<T: Arguments> ArgumentIter<T> {
 /// call [`Options::apply`] on the result until the arguments are exhausted.
 pub trait Options<Arg: Arguments>: Sized {
     /// Apply a single argument to the options.
-    fn apply(&mut self, arg: Arg);
+    fn apply(&mut self, arg: Arg) -> Result<(), Error>;
 
     /// Parse an iterator of arguments into the options
     #[allow(unused_mut)]
@@ -191,7 +191,7 @@ pub trait Options<Arg: Arguments>: Sized {
         {
             let mut iter = ArgumentIter::<Arg>::from_args(args);
             while let Some(arg) = iter.next_arg()? {
-                self.apply(arg);
+                self.apply(arg)?;
             }
             Ok((self, iter.positional_arguments))
         }

tests/coreutils.rs

@@ -16,6 +16,9 @@ mod cat;
 #[path = "coreutils/cksum.rs"]
 mod cksum;
 
+#[path = "coreutils/date.rs"]
+mod date;
+
 #[path = "coreutils/dd.rs"]
 mod dd;
 

tests/coreutils/b2sum.rs

@@ -46,7 +46,7 @@ struct Settings {
 }
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::Binary => self.binary = true,
             Arg::Check => self.check = true,
@@ -57,6 +57,7 @@ impl Options<Arg> for Settings {
             Arg::Strict => self.strict = true,
             Arg::Warn => self.check_output = CheckOutput::Warn,
         }
+        Ok(())
     }
 }
 

tests/coreutils/base32.rs

@@ -34,13 +34,14 @@ impl Default for Settings {
 }
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::Decode => self.decode = true,
             Arg::IgnoreGarbage => self.ignore_garbage = true,
             Arg::Wrap(0) => self.wrap = None,
             Arg::Wrap(x) => self.wrap = Some(x),
         }
+        Ok(())
     }
 }
 

tests/coreutils/basename.rs

@@ -26,7 +26,7 @@ struct Settings {
 }
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::Multiple => self.multiple = true,
             Arg::Suffix(s) => {
@@ -35,6 +35,7 @@ impl Options<Arg> for Settings {
             }
             Arg::Zero => self.zero = true,
         }
+        Ok(())
     }
 }
 

tests/coreutils/cat.rs

@@ -48,7 +48,7 @@ struct Settings {
 }
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::ShowAll => {
                 self.show_tabs = true;
@@ -70,6 +70,7 @@ impl Options<Arg> for Settings {
             Arg::NumberNonblank => self.number = NumberingMode::NonEmpty,
             Arg::SqueezeBlank => self.squeeze_blank = true,
         }
+        Ok(())
     }
 }
 

tests/coreutils/cksum.rs

@@ -30,7 +30,7 @@ struct Settings {
 }
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::Binary => self.binary = Tristate::True,
             Arg::Text => self.binary = Tristate::False,
@@ -47,6 +47,7 @@ impl Options<Arg> for Settings {
                 self.tag = Tristate::False;
             }
         }
+        Ok(())
     }
 }
 

tests/coreutils/dd.rs

@@ -32,7 +32,7 @@ enum Arg {
     Bs(usize),
 
     #[arg("cbs=BYTES")]
-    Cbs(usize),
+    Cbs(#[allow(unused)] usize),
 
     #[arg("skip=BYTES", "iseek=BYTES")]
     Skip(u64),
@@ -47,13 +47,13 @@ enum Arg {
     Status(StatusLevel),
 
     #[arg("conv=CONVERSIONS")]
-    Conv(String),
+    Conv(#[allow(unused)] String),
 
     #[arg("iflag=FLAGS")]
-    Iflag(String),
+    Iflag(#[allow(unused)] String),
 
     #[arg("oflag=FLAGS")]
-    Oflag(String),
+    Oflag(#[allow(unused)] String),
 }
 
 #[derive(Debug, PartialEq, Eq)]
@@ -92,7 +92,7 @@ impl Default for Settings {
 }
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::Infile(f) => self.infile = Some(f),
             Arg::Outfile(f) => self.outfile = Some(f),
@@ -111,6 +111,7 @@ impl Options<Arg> for Settings {
             Arg::Iflag(_f) => todo!(),
             Arg::Oflag(_f) => todo!(),
         }
+        Ok(())
     }
 }
 

tests/coreutils/echo.rs

@@ -24,12 +24,13 @@ struct Settings {
 }
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::NoNewline => self.trailing_newline = false,
             Arg::EnableEscape => self.escape = true,
             Arg::DisableEscape => self.escape = false,
         }
+        Ok(())
     }
 }
 

tests/coreutils/head.rs

@@ -188,7 +188,7 @@ struct Settings {
 }
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::Bytes(n) => {
                 self.mode = Mode::Bytes;
@@ -202,6 +202,7 @@ impl Options<Arg> for Settings {
             Arg::Verbose => self.verbose = true,
             Arg::Zero => self.zero = true,
         }
+        Ok(())
     }
 }
 

tests/coreutils/ls.rs

@@ -360,7 +360,7 @@ impl Default for Settings {
 }
 
 impl Options<Arg> for Settings {
-    fn apply(&mut self, arg: Arg) {
+    fn apply(&mut self, arg: Arg) -> Result<(), uutils_args::Error> {
         match arg {
             Arg::All => self.which_files = Files::All,
             Arg::AlmostAll => self.which_files = Files::AlmostAll,
@@ -417,6 +417,7 @@ impl Options<Arg> for Settings {
             }
             Arg::GroupDirectoriesFirst => self.group_directories_first = true,
         }
+        Ok(())
     }
 }