Use colors in output

This is a pretty gross commit, since it also includes a lot of
unrelated refactoring, especially of how error messages are printed.

Also adds a lint recipe that prints lines over 100 characters

To test, I added a `--color=[auto|always|never]` option that defaults to
auto in normal use, but can be forced to `always` for testing. In `auto`
mode it defers to `atty` to figure out if the current stream is a
terminal and uses color if so.

Color printing is controlled by the `alternate` formatting flag.

When printing an error message, using `{:#}` will print it with colors
and `{}` will print it normally.

Cargo.lock

@@ -2,6 +2,8 @@
 name = "just"
 version = "0.2.16"
 dependencies = [
+ "ansi_term 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "atty 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "brev 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "clap 2.17.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "itertools 0.5.5 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -23,6 +25,16 @@ name = "ansi_term"
 version = "0.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "atty"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.16 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "bitflags"
 version = "0.7.0"
@@ -195,6 +207,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 [metadata]
 "checksum aho-corasick 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)" = "ca972c2ea5f742bfce5687b9aef75506a764f61d37f8f649047846a9686ddb66"
 "checksum ansi_term 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "23ac7c30002a5accbf7e8987d0632fa6de155b7c3d39d0067317a391e00a2ef6"
+"checksum atty 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "d7b4cb091c727ebec026331c1b7092981c9cdde34d8df109fa36f29a37532026"
 "checksum bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "aad18937a628ec6abcd26d1489012cc0e18c21798210f491af69ded9b881106d"
 "checksum brev 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "79571b60a8aa293f43b46370d8ba96fed28a5bee1303ea0e015d175ed0c63b40"
 "checksum clap 2.17.1 (registry+https://github.com/rust-lang/crates.io-index)" = "27dac76762fb56019b04aed3ccb43a770a18f80f9c2eb62ee1a18d9fb4ea2430"

Cargo.toml

@@ -7,6 +7,8 @@ license     = "WTFPL/MIT/Apache-2.0"
 homepage    = "https://github.com/casey/just"
 
 [dependencies]
+ansi_term   = "^0.9.0"
+atty        = "^0.2.1"
 brev        = "^0.1.6"
 clap        = "^2.0.0"
 itertools   = "^0.5.5"

justfile

@@ -42,8 +42,14 @@ install-nightly:
 sloc:
 	@cat src/*.rs | wc -l
 
+long:
+	! grep --color -n '.\{100\}' src/*.rs
+
 nop:
 
+fail:
+	exit 1
+
 # make a quine, compile it, and verify it
 quine: create
 	cc tmp/gen0.c -o tmp/gen0

notes

@@ -1,2 +1,2 @@
 todo
-----
+====

src/app.rs

@@ -1,5 +1,6 @@
 extern crate clap;
 extern crate regex;
+extern crate atty;
 
 use std::{io, fs, env, process};
 use std::collections::BTreeMap;
@@ -21,6 +22,32 @@ macro_rules! die {
   }};
 }
 
+#[derive(Copy, Clone)]
+enum UseColor {
+  Auto,
+  Always,
+  Never,
+}
+
+impl UseColor {
+  fn from_argument(use_color: &str) -> UseColor {
+    match use_color {
+      "auto"   => UseColor::Auto,
+      "always" => UseColor::Always,
+      "never"  => UseColor::Never,
+      _        => panic!("Invalid argument to --color. This is a bug in just."),
+    }
+  }
+
+  fn should_color_stream(self, stream: atty::Stream) -> bool {
+    match self {
+      UseColor::Auto   => atty::is(stream),
+      UseColor::Always => true,
+      UseColor::Never  => true,
+    }
+  }
+}
+
 pub fn app() {
   let matches = App::new("just")
     .version(concat!("v", env!("CARGO_PKG_VERSION")))
@@ -41,6 +68,12 @@ pub fn app() {
     .arg(Arg::with_name("evaluate")
          .long("evaluate")
          .help("Print evaluated variables"))
+    .arg(Arg::with_name("color")
+         .long("color")
+         .takes_value(true)
+         .possible_values(&["auto", "always", "never"])
+         .default_value("auto")
+         .help("Print colorful output"))
     .arg(Arg::with_name("show")
          .short("s")
          .long("show")
@@ -79,6 +112,9 @@ pub fn app() {
     die!("--dry-run and --quiet may not be used together");
   }
 
+  let use_color_argument = matches.value_of("color").expect("--color had no value");
+  let use_color = UseColor::from_argument(use_color_argument);
+
   let justfile_option = matches.value_of("justfile");
   let working_directory_option = matches.value_of("working-directory");
 
@@ -125,7 +161,13 @@ pub fn app() {
       .unwrap_or_else(|error| die!("Error reading justfile: {}", error));
   }
 
-  let justfile = super::parse(&text).unwrap_or_else(|error| die!("{}", error));
+  let justfile = super::parse(&text).unwrap_or_else(|error|
+    if use_color.should_color_stream(atty::Stream::Stderr) {
+      die!("{:#}", error);
+    } else {
+      die!("{}", error);
+    }
+  );
 
   if matches.is_present("list") {
     if justfile.count() == 0 {
@@ -185,8 +227,12 @@ pub fn app() {
 
   if let Err(run_error) = justfile.run(&arguments, &options) {
     if !options.quiet {
+      if use_color.should_color_stream(atty::Stream::Stderr) {
+        warn!("{:#}", run_error);
+      } else {
         warn!("{}", run_error);
       }
+    }
     match run_error {
       RunError::Code{code, .. } | RunError::BacktickCode{code, ..} => process::exit(code),
       _ => process::exit(-1),

src/integration.rs

@@ -13,7 +13,8 @@ fn integration_test(
   expected_stderr: &str,
 ) {
   let tmp = TempDir::new("just-integration")
-    .unwrap_or_else(|err| panic!("integration test: failed to create temporary directory: {}", err));
+    .unwrap_or_else(
+      |err| panic!("integration test: failed to create temporary directory: {}", err));
   let mut path = tmp.path().to_path_buf();
   path.push("justfile");
   brev::dump(path, justfile);
@@ -300,7 +301,7 @@ recipe:
     text,
     100,
     "",
-    "Recipe \"recipe\" failed with exit code 100\n",
+    "error: Recipe `recipe` failed with exit code 100\n",
   );
 }
 
@@ -348,7 +349,7 @@ fn backtick_code_assignment() {
     "b = a\na = `exit 100`\nbar:\n echo '{{`exit 200`}}'",
     100,
     "",
-    "backtick failed with exit code 100
+    "error: backtick failed with exit code 100
   |
 2 | a = `exit 100`
   |     ^^^^^^^^^^
@@ -363,7 +364,7 @@ fn backtick_code_interpolation() {
     "b = a\na = `echo hello`\nbar:\n echo '{{`exit 200`}}'",
     200,
     "",
-    "backtick failed with exit code 200
+    "error: backtick failed with exit code 200
   |
 4 |  echo '{{`exit 200`}}'
   |          ^^^^^^^^^^
@@ -378,7 +379,7 @@ fn backtick_code_long() {
     "\n\n\n\n\n\nb = a\na = `echo hello`\nbar:\n echo '{{`exit 200`}}'",
     200,
     "",
-    "backtick failed with exit code 200
+    "error: backtick failed with exit code 200
    |
 10 |  echo '{{`exit 200`}}'
    |          ^^^^^^^^^^
@@ -396,7 +397,7 @@ fn shebang_backtick_failure() {
  echo {{`exit 123`}}",
     123,
     "",
-    "backtick failed with exit code 123
+    "error: backtick failed with exit code 123
   |
 4 |  echo {{`exit 123`}}
   |         ^^^^^^^^^^
@@ -413,7 +414,7 @@ fn command_backtick_failure() {
  echo {{`exit 123`}}",
     123,
     "hello\n",
-    "echo hello\nbacktick failed with exit code 123
+    "echo hello\nerror: backtick failed with exit code 123
   |
 3 |  echo {{`exit 123`}}
   |         ^^^^^^^^^^
@@ -431,7 +432,7 @@ fn assignment_backtick_failure() {
 a = `exit 222`",
     222,
     "",
-    "backtick failed with exit code 222
+    "error: backtick failed with exit code 222
   |
 4 | a = `exit 222`
   |     ^^^^^^^^^^
@@ -449,7 +450,7 @@ fn unknown_override_options() {
 a = `exit 222`",
     255,
     "",
-    "Variables `baz` and `foo` overridden on the command line but not present in justfile\n",
+    "error: Variables `baz` and `foo` overridden on the command line but not present in justfile\n",
   );
 }
 
@@ -463,7 +464,7 @@ fn unknown_override_args() {
 a = `exit 222`",
     255,
     "",
-    "Variables `baz` and `foo` overridden on the command line but not present in justfile\n",
+    "error: Variables `baz` and `foo` overridden on the command line but not present in justfile\n",
   );
 }
 
@@ -477,7 +478,7 @@ fn unknown_override_arg() {
 a = `exit 222`",
     255,
     "",
-    "Variable `foo` overridden on the command line but not present in justfile\n",
+    "error: Variable `foo` overridden on the command line but not present in justfile\n",
   );
 }
 
@@ -786,10 +787,9 @@ foo A B:
     ",
     255,
     "",
-    "Recipe `foo` got 3 arguments but only takes 2\n"
+    "error: Recipe `foo` got 3 arguments but only takes 2\n",
   );
 }
-
 #[test]
 fn argument_mismatch_fewer() {
   integration_test(
@@ -800,7 +800,7 @@ foo A B:
     ",
     255,
     "",
-    "Recipe `foo` got 1 argument but takes 2\n"
+    "error: Recipe `foo` got 1 argument but takes 2\n"
   );
 }
 
@@ -811,7 +811,7 @@ fn unknown_recipe() {
     "hello:",
     255,
     "",
-    "Justfile does not contain recipe `foo`\n",
+    "error: Justfile does not contain recipe `foo`\n",
   );
 }
 
@@ -822,6 +822,32 @@ fn unknown_recipes() {
     "hello:",
     255,
     "",
-    "Justfile does not contain recipes `foo` or `bar`\n",
+    "error: Justfile does not contain recipes `foo` or `bar`\n",
   );
 }
+
+#[test]
+fn colors_with_context() {
+  integration_test(
+    &["--color", "always"],
+    "b = a\na = `exit 100`\nbar:\n echo '{{`exit 200`}}'",
+    100,
+    "",
+    "\u{1b}[1;31merror:\u{1b}[0m \u{1b}[1mbacktick failed with exit code 100\n\u{1b}[0m  |\n2 | a = `exit 100`\n  |     \u{1b}[1;31m^^^^^^^^^^\u{1b}[0m\n",
+  );
+}
+
+#[test]
+fn colors_no_context() {
+  let text ="
+recipe:
+ @exit 100";
+  integration_test(
+    &["--color=always"],
+    text,
+    100,
+    "",
+    "\u{1b}[1;31merror:\u{1b}[0m \u{1b}[1mRecipe `recipe` failed with exit code 100\u{1b}[0m\n",
+  );
+}
+

src/lib.rs

@@ -13,6 +13,7 @@ extern crate lazy_static;
 extern crate regex;
 extern crate tempdir;
 extern crate itertools;
+extern crate ansi_term;
 
 use std::io::prelude::*;
 
@@ -136,17 +137,23 @@ fn error_from_signal(recipe: &str, exit_status: process::ExitStatus) -> RunError
 }
 
 #[cfg(unix)]
-fn backtick_error_from_signal(exit_status: process::ExitStatus) -> RunError<'static> {
+fn backtick_error_from_signal<'a>(
+  token:       &Token<'a>,
+  exit_status: process::ExitStatus
+) -> RunError<'a> {
   use std::os::unix::process::ExitStatusExt;
   match exit_status.signal() {
-    Some(signal) => RunError::BacktickSignal{signal: signal},
+    Some(signal) => RunError::BacktickSignal{token: token.clone(), signal: signal},
-    None => RunError::BacktickUnknownFailure,
+    None => RunError::BacktickUnknownFailure{token: token.clone()},
   }
 }
 
 #[cfg(windows)]
-fn backtick_error_from_signal(exit_status: process::ExitStatus) -> RunError<'static> {
+fn backtick_error_from_signal<'a>(
-  RunError::BacktickUnknownFailure
+  token:       &Token<'a>,
+  exit_status: process::ExitStatus
+) -> RunError<'a> {
+  RunError::BacktickUnknownFailure{token: token.clone()}
 }
 
 fn export_env<'a>(
@@ -197,10 +204,10 @@ fn run_backtick<'a>(
           });
         }
       } else {
-        return Err(backtick_error_from_signal(output.status));
+        return Err(backtick_error_from_signal(token, output.status));
       }
       match std::str::from_utf8(&output.stdout) {
-        Err(error) => Err(RunError::BacktickUtf8Error{utf8_error: error}),
+        Err(error) => Err(RunError::BacktickUtf8Error{token: token.clone(), utf8_error: error}),
         Ok(utf8) => {
           Ok(if utf8.ends_with('\n') {
             &utf8[0..utf8.len()-1]
@@ -212,7 +219,7 @@ fn run_backtick<'a>(
         }
       }
     }
-    Err(error) => Err(RunError::BacktickIoError{io_error: error}),
+    Err(error) => Err(RunError::BacktickIoError{token: token.clone(), io_error: error}),
   }
 }
 
@@ -289,7 +296,8 @@ impl<'a> Recipe<'a> {
       // make the script executable
       let current_mode = perms.mode();
       perms.set_mode(current_mode | 0o100);
-      try!(fs::set_permissions(&path, perms).map_err(|error| RunError::TmpdirIoError{recipe: self.name, io_error: error}));
+      try!(fs::set_permissions(&path, perms)
+           .map_err(|error| RunError::TmpdirIoError{recipe: self.name, io_error: error}));
 
       // run it!
       let mut command = process::Command::new(path);
@@ -373,7 +381,8 @@ impl<'a> Display for Recipe<'a> {
         }
         match *piece {
           Fragment::Text{ref text} => try!(write!(f, "{}", text.lexeme)),
-          Fragment::Expression{ref expression, ..} => try!(write!(f, "{}{}{}", "{{", expression, "}}")),
+          Fragment::Expression{ref expression, ..} => 
+            try!(write!(f, "{}{}{}", "{{", expression, "}}")),
         }
       }
       if i + 1 < self.lines.len() {
@@ -765,27 +774,87 @@ fn conjoin<T: Display>(
     Ok(())
 }
 
+fn write_error_context(
+  f:      &mut fmt::Formatter,
+  text:   &str,
+  index:  usize,
+  line:   usize,
+  column: usize,
+  width:  Option<usize>,
+) -> Result<(), fmt::Error> {
+  let line_number = line + 1;
+  let red = maybe_red(f.alternate());
+  match text.lines().nth(line) {
+    Some(line) => {
+      let line_number_width = line_number.to_string().len();
+      try!(write!(f, "{0:1$} |\n", "", line_number_width));
+      try!(write!(f, "{} | {}\n", line_number, line));
+      try!(write!(f, "{0:1$} |", "", line_number_width));
+      try!(write!(f, " {0:1$}{2}{3:^<4$}{5}", "", column,
+                  red.prefix(), "", width.unwrap_or(1), red.suffix()));
+    },
+    None => if index != text.len() {
+      try!(write!(f, "internal error: Error has invalid line number: {}", line_number))
+    },
+  }
+  Ok(())
+}
+
+fn write_token_error_context(f: &mut fmt::Formatter, token: &Token) -> Result<(), fmt::Error> {
+  write_error_context(
+    f,
+    token.text,
+    token.index,
+    token.line,
+    token.column + token.prefix.len(),
+    Some(token.lexeme.len())
+  )
+}
+
+fn maybe_red(colors: bool) -> ansi_term::Style {
+  if colors {
+    ansi_term::Style::new().fg(ansi_term::Color::Red).bold()
+  } else {
+    ansi_term::Style::default()
+  }
+}
+
+fn maybe_bold(colors: bool) -> ansi_term::Style {
+  if colors {
+    ansi_term::Style::new().bold()
+  } else {
+    ansi_term::Style::default()
+  }
+}
+
 impl<'a> Display for Error<'a> {
   fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-    try!(write!(f, "error: "));
+    let red  = maybe_red(f.alternate());
+    let bold = maybe_bold(f.alternate());
+
+    try!(write!(f, "{} {}", red.paint("error:"), bold.prefix()));
     
     match self.kind {
       ErrorKind::CircularRecipeDependency{recipe, ref circle} => {
         if circle.len() == 2 {
           try!(write!(f, "recipe `{}` depends on itself", recipe));
         } else {
-          try!(writeln!(f, "recipe `{}` has circular dependency `{}`", recipe, circle.join(" -> ")));
+          try!(writeln!(f, "recipe `{}` has circular dependency `{}`",
+                        recipe, circle.join(" -> ")));
         }
       }
       ErrorKind::CircularVariableDependency{variable, ref circle} => {
         if circle.len() == 2 {
-          try!(writeln!(f, "variable `{}` depends on its own value: `{}`", variable, circle.join(" -> ")));
+          try!(writeln!(f, "variable `{}` depends on its own value: `{}`",
+                        variable, circle.join(" -> ")));
         } else {
-          try!(writeln!(f, "variable `{}` depends on its own value: `{}`", variable, circle.join(" -> ")));
+          try!(writeln!(f, "variable `{}` depends on its own value: `{}`",
+                        variable, circle.join(" -> ")));
         }
       }
       ErrorKind::InvalidEscapeSequence{character} => {
-        try!(writeln!(f, "`\\{}` is not a valid escape sequence", character.escape_default().collect::<String>()));
+        try!(writeln!(f, "`\\{}` is not a valid escape sequence",
+                      character.escape_default().collect::<String>()));
       }
       ErrorKind::DuplicateParameter{recipe, parameter} => {
         try!(writeln!(f, "recipe `{}` has duplicate parameter `{}`", recipe, parameter));
@@ -804,14 +873,16 @@ impl<'a> Display for Error<'a> {
                     recipe, first, self.line));
       }
       ErrorKind::DependencyHasParameters{recipe, dependency} => {
-        try!(writeln!(f, "recipe `{}` depends on `{}` which requires arguments. dependencies may not require arguments", recipe, dependency));
+        try!(writeln!(f, "recipe `{}` depends on `{}` which requires arguments. \
+                      dependencies may not require arguments", recipe, dependency));
       }
       ErrorKind::ParameterShadowsVariable{parameter} => {
         try!(writeln!(f, "parameter `{}` shadows variable of the same name", parameter));
       }
       ErrorKind::MixedLeadingWhitespace{whitespace} => {
         try!(writeln!(f,
-          "found a mix of tabs and spaces in leading whitespace: `{}`\n leading whitespace may consist of tabs or spaces, but not both",
+          "found a mix of tabs and spaces in leading whitespace: `{}`\n\
+          leading whitespace may consist of tabs or spaces, but not both",
           show_whitespace(whitespace)
         ));
       }
@@ -840,23 +911,15 @@ impl<'a> Display for Error<'a> {
         try!(writeln!(f, "unterminated string"));
       }
       ErrorKind::InternalError{ref message} => {
-        try!(writeln!(f, "internal error, this may indicate a bug in just: {}\n consider filing an issue: https://github.com/casey/just/issues/new", message));
+        try!(writeln!(f, "internal error, this may indicate a bug in just: {}\n\
+                          consider filing an issue: https://github.com/casey/just/issues/new",
+                          message));
       }
     }
 
-    match self.text.lines().nth(self.line) {
+    try!(write!(f, "{}", bold.suffix()));
-      Some(line) => {
+
-        let displayed_line = self.line + 1;
+    try!(write_error_context(f, self.text, self.index, self.line, self.column, self.width));
-        let line_number_width = displayed_line.to_string().len();
-        try!(write!(f, "{0:1$} |\n", "", line_number_width));
-        try!(write!(f, "{} | {}\n", displayed_line, line));
-        try!(write!(f, "{0:1$} |", "", line_number_width));
-        try!(write!(f, " {0:1$}{2:^<3$}", "", self.column, "", self.width.unwrap_or(1)));
-      },
-      None => if self.index != self.text.len() {
-        try!(write!(f, "internal error: Error has invalid line number: {}", self.line + 1))
-      },
-    };
 
     Ok(())
   }
@@ -1018,15 +1081,18 @@ enum RunError<'a> {
   UnknownFailure{recipe: &'a str},
   UnknownRecipes{recipes: Vec<&'a str>},
   UnknownOverrides{overrides: Vec<&'a str>},
-  BacktickCode{code: i32, token: Token<'a>},
+  BacktickCode{token: Token<'a>, code: i32},
-  BacktickIoError{io_error: io::Error},
+  BacktickIoError{token: Token<'a>, io_error: io::Error},
-  BacktickSignal{signal: i32},
+  BacktickSignal{token: Token<'a>, signal: i32},
-  BacktickUtf8Error{utf8_error: std::str::Utf8Error},
+  BacktickUtf8Error{token: Token<'a>, utf8_error: std::str::Utf8Error},
-  BacktickUnknownFailure,
+  BacktickUnknownFailure{token: Token<'a>},
 }
 
 impl<'a> Display for RunError<'a> {
   fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+    let red = maybe_red(f.alternate());
+    try!(write!(f, "{} ", red.paint("error:")));
+
     match *self {
       RunError::UnknownRecipes{ref recipes} => {
         try!(write!(f, "Justfile does not contain recipe{} {}",
@@ -1039,7 +1105,8 @@ impl<'a> Display for RunError<'a> {
                     And(&overrides.iter().map(Tick).collect::<Vec<_>>())))
       },
       RunError::NonLeadingRecipeWithParameters{recipe} => {
-        try!(write!(f, "Recipe `{}` takes arguments and so must be the first and only recipe specified on the command line", recipe));
+        try!(write!(f, "Recipe `{}` takes arguments and so must be the first and only recipe \
+                        specified on the command line", recipe));
       },
       RunError::ArgumentCountMismatch{recipe, found, expected} => {
         try!(write!(f, "Recipe `{}` got {} argument{} but {}takes {}",
@@ -1047,58 +1114,61 @@ impl<'a> Display for RunError<'a> {
                     if expected < found { "only " } else { "" }, expected));
       },
       RunError::Code{recipe, code} => {
-        try!(write!(f, "Recipe \"{}\" failed with exit code {}", recipe, code));
+        try!(write!(f, "Recipe `{}` failed with exit code {}", recipe, code));
       },
       RunError::Signal{recipe, signal} => {
-        try!(write!(f, "Recipe \"{}\" wast terminated by signal {}", recipe, signal));
+        try!(write!(f, "Recipe `{}` wast terminated by signal {}", recipe, signal));
       }
       RunError::UnknownFailure{recipe} => {
-        try!(write!(f, "Recipe \"{}\" failed for an unknown reason", recipe));
+        try!(write!(f, "Recipe `{}` failed for an unknown reason", recipe));
       },
       RunError::IoError{recipe, ref io_error} => {
         try!(match io_error.kind() {
-          io::ErrorKind::NotFound => write!(f, "Recipe \"{}\" could not be run because just could not find `sh` the command:\n{}", recipe, io_error),
+          io::ErrorKind::NotFound => write!(f,
-          io::ErrorKind::PermissionDenied => write!(f, "Recipe \"{}\" could not be run because just could not run `sh`:\n{}", recipe, io_error),
+            "Recipe `{}` could not be run because just could not find `sh` the command:\n{}",
-          _ => write!(f, "Recipe \"{}\" could not be run because of an IO error while launching `sh`:\n{}", recipe, io_error),
+            recipe, io_error),
+          io::ErrorKind::PermissionDenied => write!(
+            f, "Recipe `{}` could not be run because just could not run `sh`:\n{}",
+            recipe, io_error),
+          _ => write!(f, "Recipe `{}` could not be run because of an IO error while \
+                      launching `sh`:\n{}", recipe, io_error),
         });
       },
       RunError::TmpdirIoError{recipe, ref io_error} =>
-        try!(write!(f, "Recipe \"{}\" could not be run because of an IO error while trying to create a temporary directory or write a file to that directory`:\n{}", recipe, io_error)),
+        try!(write!(f, "Recipe `{}` could not be run because of an IO error while trying \
+                    to create a temporary directory or write a file to that directory`:\n{}",
+                    recipe, io_error)),
       RunError::BacktickCode{code, ref token} => {
         try!(write!(f, "backtick failed with exit code {}\n", code));
-        match token.text.lines().nth(token.line) {
+        try!(write_token_error_context(f, token));
-          Some(line) => {
-            let displayed_line = token.line + 1;
-            let line_number_width = displayed_line.to_string().len();
-            try!(write!(f, "{0:1$} |\n", "", line_number_width));
-            try!(write!(f, "{} | {}\n", displayed_line, line));
-            try!(write!(f, "{0:1$} |", "", line_number_width));
-            try!(write!(f, " {0:1$}{2:^<3$}", "",
-                        token.column + token.prefix.len(), "", token.lexeme.len()));
-          },
-          None => if token.index != token.text.len() {
-            try!(write!(f, "internal error: Error has invalid line number: {}", token.line + 1))
-          },
       }
-      }
+      RunError::BacktickSignal{ref token, signal} => {
-      RunError::BacktickSignal{signal} => {
         try!(write!(f, "backtick was terminated by signal {}", signal));
+        try!(write_token_error_context(f, token));
       }
-      RunError::BacktickUnknownFailure => {
+      RunError::BacktickUnknownFailure{ref token} => {
         try!(write!(f, "backtick failed for an uknown reason"));
+        try!(write_token_error_context(f, token));
       }
-      RunError::BacktickIoError{ref io_error} => {
+      RunError::BacktickIoError{ref token, ref io_error} => {
         try!(match io_error.kind() {
-          io::ErrorKind::NotFound => write!(f, "backtick could not be run because just could not find `sh` the command:\n{}", io_error),
+          io::ErrorKind::NotFound => write!(
-          io::ErrorKind::PermissionDenied => write!(f, "backtick could not be run because just could not run `sh`:\n{}", io_error),
+            f, "backtick could not be run because just could not find `sh` the command:\n{}",
-          _ => write!(f, "backtick could not be run because of an IO error while launching `sh`:\n{}", io_error),
+            io_error),
+          io::ErrorKind::PermissionDenied => write!(
+            f, "backtick could not be run because just could not run `sh`:\n{}", io_error),
+          _ => write!(f, "backtick could not be run because of an IO \
+                          error while launching `sh`:\n{}", io_error),
         });
+        try!(write_token_error_context(f, token));
       }
-      RunError::BacktickUtf8Error{ref utf8_error} => {
+      RunError::BacktickUtf8Error{ref token, ref utf8_error} => {
         try!(write!(f, "backtick succeeded but stdout was not utf8: {}", utf8_error));
+        try!(write_token_error_context(f, token));
       }
       RunError::InternalError{ref message} => {
-        try!(write!(f, "internal error, this may indicate a bug in just: {}\n consider filing an issue: https://github.com/casey/just/issues/new", message));
+        try!(write!(f, "internal error, this may indicate a bug in just: {}
+consider filing an issue: https://github.com/casey/just/issues/new", message));
       }
     }
 
@@ -1303,7 +1373,8 @@ fn tokenize(text: &str) -> Result<Vec<Token>, Error> {
     }
 
     let (prefix, lexeme, kind) = 
-    if let (0, &State::Indent(indent), Some(captures)) = (column, state.last().unwrap(), LINE.captures(rest)) {
+    if let (0, &State::Indent(indent), Some(captures)) = 
+      (column, state.last().unwrap(), LINE.captures(rest)) {
       let line = captures.at(0).unwrap();
       if !line.starts_with(indent) {
         return error!(ErrorKind::InternalError{message: "unexpected indent".to_string()});