From 91f927976f2c2aafd52153e3e99106573466c27f Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Thu, 26 Nov 2020 21:32:13 +0000
Subject: [PATCH] wip timestamp_abbreviate

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 Cargo.lock.example |  2 ++
 zcoord/Cargo.toml  |  2 ++
 zcoord/misc.rs     | 24 ++++++++++++++++++++++++
 zcoord/zcoord.rs   |  2 ++
 4 files changed, 30 insertions(+)
 create mode 100644 zcoord/misc.rs

diff --git a/Cargo.lock.example b/Cargo.lock.example
index 6b1e531d..89c6c15c 100644
--- a/Cargo.lock.example
+++ b/Cargo.lock.example
@@ -1186,8 +1186,10 @@ dependencies = [
 name = "otter-zcoord"
 version = "0.0.1"
 dependencies = [
+ "arrayvec",
  "derive_more",
  "fehler",
+ "if_chain",
  "serde",
  "serde_with",
  "thiserror",
diff --git a/zcoord/Cargo.toml b/zcoord/Cargo.toml
index 7a29c1f0..8fa43fa5 100644
--- a/zcoord/Cargo.toml
+++ b/zcoord/Cargo.toml
@@ -13,8 +13,10 @@ path = "zcoord.rs"
 
 [dependencies]
 
+arrayvec = "0"
 derive_more = "0.99"
 fehler = "1"
+if_chain = "1"
 thiserror = "1"
 serde = { version = "1", features = ["derive","rc"] }
 serde_with = "1"
diff --git a/zcoord/misc.rs b/zcoord/misc.rs
new file mode 100644
index 00000000..43531cc9
--- /dev/null
+++ b/zcoord/misc.rs
@@ -0,0 +1,24 @@
+// Copyright 2020 Ian Jackson
+// SPDX-License-Identifier: AGPL-3.0-or-later
+// There is NO WARRANTY.
+
+// This is in this crate for convenience, not because it's to do with
+// Z coordinates.
+
+use if_chain::if_chain;
+use arrayvec::ArrayVec;
+
+pub fn timesting_abbreviate<'x>(base: &str, this: &'x str) -> (&'x str, bool) {
+  fn split(s: &str) -> ArrayVec<[&str; 3]> {
+    s.splitn(3, ' ').collect()
+  }
+  let base3 = split(base);
+  let this3 = split(this);
+  let matches = |i| base3.get(i) == this3.get(i);
+  if_chain! {
+    if matches(0) && matches(2);
+    if let Some(abbrev) = this3.get(1);
+    then { (abbrev, true) }
+    else { (this, false) }
+  }
+}
diff --git a/zcoord/zcoord.rs b/zcoord/zcoord.rs
index 745e4ec9..bab9cfd0 100644
--- a/zcoord/zcoord.rs
+++ b/zcoord/zcoord.rs
@@ -79,6 +79,8 @@ use thiserror::Error;
 use serde_with::DeserializeFromStr;
 use serde_with::SerializeDisplay;
 
+mod misc;
+
 //---------- core definitions ----------
 
 pub type RangeCount = u32;
-- 
2.30.2