Support parsing depends:.. in CLI

cli/src/argparse/args/colon.rs

@@ -1,4 +1,4 @@
-use super::{any, timestamp};
+use super::{any, id_list, timestamp, TaskId};
 use crate::argparse::NOW;
 use nom::bytes::complete::tag as nomtag;
 use nom::{branch::*, character::complete::*, combinator::*, sequence::*, IResult};
@@ -48,6 +48,17 @@ pub(crate) fn wait_colon(input: &str) -> IResult<&str, Option<DateTime<Utc>>> {
     )(input)
 }
 
+/// Recognizes `depends:<task>` to `(true, <task>)` and `depends:-<task>` to `(false, <task>)`.
+pub(crate) fn depends_colon(input: &str) -> IResult<&str, (bool, Vec<TaskId>)> {
+    fn to_bool(maybe_minus: Option<char>) -> Result<bool, ()> {
+        Ok(maybe_minus.is_none()) // None -> true, Some -> false
+    }
+    preceded(
+        nomtag("depends:"),
+        pair(map_res(opt(char('-')), to_bool), id_list),
+    )(input)
+}
+
 #[cfg(test)]
 mod test {
     use super::*;

cli/src/argparse/args/idlist.rs

@@ -2,7 +2,7 @@ use nom::{branch::*, character::complete::*, combinator::*, multi::*, sequence::
 use taskchampion::Uuid;
 
 /// A task identifier, as given in a filter command-line expression
-#[derive(Debug, PartialEq, Clone)]
+#[derive(Debug, PartialEq, Eq, Hash, Clone)]
 pub(crate) enum TaskId {
     /// A small integer identifying a working-set task
     WorkingSetId(usize),

cli/src/argparse/args/mod.rs

@@ -8,7 +8,7 @@ mod tags;
 mod time;
 
 pub(crate) use arg_matching::arg_matching;
-pub(crate) use colon::{status_colon, wait_colon};
+pub(crate) use colon::{depends_colon, status_colon, wait_colon};
 pub(crate) use idlist::{id_list, TaskId};
 pub(crate) use misc::{any, literal, report_name};
 pub(crate) use tags::{minus_tag, plus_tag};