ADD: link following

Cargo.lock

···
 ]
 
 [[package]]
+name = "is-docker"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "928bae27f42bc99b60d9ac7334e3a21d10ad8f1835a4e12ec3ec0464765ed1b3"
+dependencies = [
+ "once_cell",
+]
+
+[[package]]
+name = "is-wsl"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "173609498df190136aa7dea1a91db051746d339e18476eed5ca40521f02d7aa5"
+dependencies = [
+ "is-docker",
+ "once_cell",
+]
+
+[[package]]
 name = "is_terminal_polyfill"
 version = "1.70.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 version = "1.20.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1261fe7e33c73b354eab43b1273a57c8f967d0391e80353e51f764ac02cf6775"
+
+[[package]]
+name = "open"
+version = "5.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "61a877bf6abd716642a53ef1b89fb498923a4afca5c754f9050b4d081c05c4b3"
+dependencies = [
+ "is-wsl",
+ "libc",
+ "pathdiff",
+]
+
+[[package]]
+name = "pathdiff"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d61c5ce1153ab5b689d0c074c4e7fc613e942dfb7dd9eea5ab202d2ad91fe361"
 
 [[package]]
 name = "percent-encoding"
···
  "colored",
  "edit",
  "nix",
+ "open",
  "smallstr",
  "thiserror",
  "url",

Cargo.toml

···
 xattr = "1.3.1"
 colored = "2.1.0"
 smallstr = "0.3.0"
+open = "5.3.0"
 
 [build-dependencies]
 clap_mangen = "0.2.23"

src/main.rs

···
 use std::path::PathBuf;
 use std::process::exit;
 use std::{env::current_dir, io::Read};
+use task::ParsedLink;
 use workspace::{Id, TaskIdentifier, Workspace};
 
 //use smol;
···
         full_id: bool,
     },
 
-    /// Prints the contents of a task.
+    /// Prints the contents of a task, parsing the body as rich text and formatting it using ANSI
+    /// escape sequences.
     Show {
         /// Shows raw file attributes for the file
         #[arg(short = 'x', default_value_t = false)]
···
         task_id: TaskId,
     },
 
+    /// Follow a link that is parsed from a task body. It may be an internal or external link (ie.
+    /// a url or a wiki-style link using double square brackets). When using the `tsk show`
+    /// command, links that are successfully parsed get a numeric superscript that may be used to
+    /// address the link. That number should be supplied to the -l/link_index where it will be
+    /// subsequently followed opened or shown.
+    Follow {
+        /// The task whose body will be searched for links.
+        #[command(flatten)]
+        task_id: TaskId,
+        /// The index of the link to open. Must be supplied.
+        #[arg(short = 'l')]
+        link_index: usize,
+        /// When opening an internal link, whether to show or edit the addressed task.
+        #[arg(short = 'e', default_value_t = false)]
+        edit: bool,
+    },
+
     /// Drops the task on the top of the stack and archives it.
     Drop {
         /// The [TSK-]ID of the task to drop.
···
             task_id,
             show_attrs,
         } => command_show(dir, task_id, show_attrs),
+        Commands::Follow {
+            task_id,
+            link_index,
+            edit,
+        } => command_follow(dir, task_id, link_index, edit),
         Commands::Edit { task_id } => command_edit(dir, task_id),
         Commands::Completion { shell } => command_completion(shell),
         Commands::Drop { task_id } => command_drop(dir, task_id),
···
     }
 }
 
+fn taskid_from_tsk_id(tsk_id: Id) -> TaskId {
+    TaskId {
+        tsk_id: Some(tsk_id),
+        id: None,
+        relative_id: 0,
+        find: Find {
+            find: false,
+            args: FindArgs { search_body: false },
+        },
+    }
+}
+
 fn command_init(dir: PathBuf) -> Result<()> {
     Workspace::init(dir)
 }
···
     }
     Ok(())
 }
+
+fn command_follow(dir: PathBuf, task_id: TaskId, link_index: usize, edit: bool) -> Result<()> {
+    let task = Workspace::from_path(dir.clone())?.task(task_id.into())?;
+    if let Some(parsed_task) = task::parse(&task.to_string()) {
+        if link_index == 0 || link_index > parsed_task.links.len() {
+            eprintln!("Link index out of bounds.");
+            exit(1);
+        }
+        let link = &parsed_task.links[link_index - 1];
+        match link {
+            ParsedLink::External(url) => {
+                open::that_detached(url.as_str())?;
+                Ok(())
+            }
+            ParsedLink::Internal(id) => {
+                let taskid = taskid_from_tsk_id(*id);
+                if edit {
+                    command_edit(dir, taskid)
+                } else {
+                    command_show(dir, taskid, false)
+                }
+            }
+        }
+    } else {
+        eprintln!("Unable to parse any links from body.");
+        exit(1);
+    }
+}