Initial support for DateTime types

examples/datetime_tests.nbt

@@ -0,0 +1,15 @@
+let epoch = parse_datetime("1970-01-01T00:00:00Z")
+assert_eq(to_unixtime(epoch), 0)
+
+assert_eq(to_unixtime(epoch + 1000 milliseconds + 2 seconds), 3)
+
+let x = parse_datetime("Wed, 20 Jul 2022 21:52:05 +0200")
+assert_eq(to_unixtime(x), 1658346725)
+
+assert_eq(to_unixtime(from_unixtime(1658346725)), 1658346725)
+
+# 2020 was a leap year
+let y = parse_datetime("2020-02-28T20:00:00Z")
+assert(format_datetime("%Y/%m/%d", y + 12 hours) == "2020/02/29")
+let z = parse_datetime("2021-02-28T20:00:00Z")
+assert(format_datetime("%Y/%m/%d", z + 12 hours) == "2021/03/01")

numbat-cli/Cargo.toml

@@ -22,6 +22,7 @@ itertools = "0.12"
 toml = { version = "0.8.8", features = ["parse"] }
 serde = { version = "1.0.195", features = ["derive"] }
 terminal_size = "0.3.0"
+chrono-tz = "0.8.5"
 
 [dependencies.clap]
 version = "4"

numbat-cli/src/completer.rs

@@ -9,6 +9,7 @@ use rustyline::{
 pub struct NumbatCompleter {
     pub context: Arc<Mutex<Context>>,
     pub modules: Vec<String>,
+    pub all_timezones: Vec<&'static str>,
 }
 
 impl Completer for NumbatCompleter {
@@ -73,6 +74,45 @@ impl Completer for NumbatCompleter {
             ));
         }
 
+        // does it look like we're tab-completing a timezone (via the conversion operator)?
+        let complete_tz = line
+            .find("->")
+            .or_else(|| line.find("→"))
+            .or_else(|| line.find("➞"))
+            .or_else(|| line.find(" to "))
+            .and_then(|convert_pos| {
+                if let Some(quote_pos) = line.rfind('"') {
+                    if quote_pos > convert_pos && pos > quote_pos {
+                        return Some(quote_pos + 1);
+                    }
+                }
+                None
+            });
+        if let Some(pos_word) = complete_tz {
+            let word_part = &line[pos_word..];
+            let matches = self
+                .all_timezones
+                .iter()
+                .filter(|tz| tz.starts_with(word_part))
+                .collect::<Vec<_>>();
+            let append_closing_quote = matches.len() <= 1;
+
+            return Ok((
+                pos_word,
+                matches
+                    .into_iter()
+                    .map(|tz| Pair {
+                        display: tz.to_string(),
+                        replacement: if append_closing_quote {
+                            format!("{tz}\"")
+                        } else {
+                            tz.to_string()
+                        },
+                    })
+                    .collect(),
+            ));
+        }
+
         let (pos_word, word_part) = extract_word(line, pos, None, |c| {
             // TODO: we could use is_identifier_char here potentially
             match c {

numbat-cli/src/main.rs

@@ -263,6 +263,11 @@ impl Cli {
             completer: NumbatCompleter {
                 context: self.context.clone(),
                 modules: self.context.lock().unwrap().list_modules().collect(),
+                all_timezones: {
+                    let mut all_tz: Vec<_> = chrono_tz::TZ_VARIANTS.map(|v| v.name()).into();
+                    all_tz.push("local");
+                    all_tz
+                },
             },
             highlighter: NumbatHighlighter {
                 context: self.context.clone(),