Separate jump behavior from increment/decrement (#4123)

increment/decrement (C-a/C-x) had some buggy behavior where selections
could be offset incorrectly or the editor could panic with some edits
that changed the number of characters in a number or date. These stemmed
from the automatic jumping behavior which attempted to find the next
date or integer to increment. The jumping behavior also complicated the
code quite a bit and made the behavior somewhat difficult to predict
when using many cursors.

This change removes the automatic jumping behavior and only increments
or decrements when the full text in a range of a selection is a number
or date. This simplifies the code and fixes the panics and buggy
behaviors from changing the number of characters.

4 files changed, 317 insertions, 758 deletions

diff --git a/helix-core/src/increment/date_time.rs b/helix-core/src/increment/date_time.rs
index 265242ce..2980bb58 100644
--- a/helix-core/src/increment/date_time.rs
+++ b/helix-core/src/increment/date_time.rs
@@ -1,114 +1,53 @@
-use chrono::{Datelike, Duration, NaiveDate, NaiveDateTime, NaiveTime, Timelike};
+use chrono::{Duration, NaiveDate, NaiveDateTime, NaiveTime};
 use once_cell::sync::Lazy;
 use regex::Regex;
-use ropey::RopeSlice;
-
-use std::borrow::Cow;
-use std::cmp;
 use std::fmt::Write;
 
-use super::Increment;
-use crate::{Range, Tendril};
+/// Increment a Date or DateTime
+///
+/// If just a Date is selected the day will be incremented.
+/// If a DateTime is selected the second will be incremented.
+pub fn increment(selected_text: &str, amount: i64) -> Option<String> {
+    if selected_text.is_empty() {
+        return None;
+    }
 
-#[derive(Debug, PartialEq, Eq)]
-pub struct DateTimeIncrementor {
-    date_time: NaiveDateTime,
-    range: Range,
-    fmt: &'static str,
-    field: DateField,
-}
+    FORMATS.iter().find_map(|format| {
+        let captures = format.regex.captures(selected_text)?;
+        if captures.len() - 1 != format.fields.len() {
+            return None;
+        }
 
-impl DateTimeIncrementor {
-    pub fn from_range(text: RopeSlice, range: Range) -> Option<DateTimeIncrementor> {
-        let range = if range.is_empty() {
-            if range.anchor < text.len_chars() {
-                // Treat empty range as a cursor range.
-                range.put_cursor(text, range.anchor + 1, true)
-            } else {
-                // The range is empty and at the end of the text.
-                return None;
+        let date_time = captures.get(0)?;
+        let has_date = format.fields.iter().any(|f| f.unit.is_date());
+        let has_time = format.fields.iter().any(|f| f.unit.is_time());
+        let date_time = &selected_text[date_time.start()..date_time.end()];
+        match (has_date, has_time) {
+            (true, true) => {
+                let date_time = NaiveDateTime::parse_from_str(date_time, format.fmt).ok()?;
+                Some(
+                    date_time
+                        .checked_add_signed(Duration::minutes(amount))?
+                        .format(format.fmt)
+                        .to_string(),
+                )
             }
-        } else {
-            range
-        };
-
-        FORMATS.iter().find_map(|format| {
-            let from = range.from().saturating_sub(format.max_len);
-            let to = (range.from() + format.max_len).min(text.len_chars());
-
-            let (from_in_text, to_in_text) = (range.from() - from, range.to() - from);
-            let text: Cow<str> = text.slice(from..to).into();
-
-            let captures = format.regex.captures(&text)?;
-            if captures.len() - 1 != format.fields.len() {
-                return None;
+            (true, false) => {
+                let date = NaiveDate::parse_from_str(date_time, format.fmt).ok()?;
+                Some(
+                    date.checked_add_signed(Duration::days(amount))?
+                        .format(format.fmt)
+                        .to_string(),
+                )
             }
-
-            let date_time = captures.get(0)?;
-            let offset = range.from() - from_in_text;
-            let range = Range::new(date_time.start() + offset, date_time.end() + offset);
-
-            let field = captures
-                .iter()
-                .skip(1)
-                .enumerate()
-                .find_map(|(i, capture)| {
-                    let capture = capture?;
-                    let capture_range = capture.range();
-
-                    if capture_range.contains(&from_in_text)
-                        && capture_range.contains(&(to_in_text - 1))
-                    {
-                        Some(format.fields[i])
-                    } else {
-                        None
-                    }
-                })?;
-
-            let has_date = format.fields.iter().any(|f| f.unit.is_date());
-            let has_time = format.fields.iter().any(|f| f.unit.is_time());
-
-            let date_time = &text[date_time.start()..date_time.end()];
-            let date_time = match (has_date, has_time) {
-                (true, true) => NaiveDateTime::parse_from_str(date_time, format.fmt).ok()?,
-                (true, false) => {
-                    let date = NaiveDate::parse_from_str(date_time, format.fmt).ok()?;
-
-                    date.and_hms_opt(0, 0, 0).unwrap()
-                }
-                (false, true) => {
-                    let time = NaiveTime::parse_from_str(date_time, format.fmt).ok()?;
-
-                    NaiveDate::from_ymd_opt(0, 1, 1).unwrap().and_time(time)
-                }
-                (false, false) => return None,
-            };
-
-            Some(DateTimeIncrementor {
-                date_time,
-                range,
-                fmt: format.fmt,
-                field,
-            })
-        })
-    }
-}
-
-impl Increment for DateTimeIncrementor {
-    fn increment(&self, amount: i64) -> (Range, Tendril) {
-        let date_time = match self.field.unit {
-            DateUnit::Years => add_years(self.date_time, amount),
-            DateUnit::Months => add_months(self.date_time, amount),
-            DateUnit::Days => add_duration(self.date_time, Duration::days(amount)),
-            DateUnit::Hours => add_duration(self.date_time, Duration::hours(amount)),
-            DateUnit::Minutes => add_duration(self.date_time, Duration::minutes(amount)),
-            DateUnit::Seconds => add_duration(self.date_time, Duration::seconds(amount)),
-            DateUnit::AmPm => toggle_am_pm(self.date_time),
+            (false, true) => {
+                let time = NaiveTime::parse_from_str(date_time, format.fmt).ok()?;
+                let (adjusted_time, _) = time.overflowing_add_signed(Duration::minutes(amount));
+                Some(adjusted_time.format(format.fmt).to_string())
+            }
+            (false, false) => None,
         }
-        .unwrap_or(self.date_time);
-
-        (self.range, date_time.format(self.fmt).to_string().into())
-    }
+    })
 }
 
 static FORMATS: Lazy<Vec<Format>> = Lazy::new(|| {
@@ -144,7 +83,7 @@ impl Format {
     fn new(fmt: &'static str) -> Self {
         let mut remaining = fmt;
         let mut fields = Vec::new();
-        let mut regex = String::new();
+        let mut regex = "^".to_string();
         let mut max_len = 0;
 
         while let Some(i) = remaining.find('%') {
@@ -166,6 +105,7 @@ impl Format {
             write!(regex, "({})", field.regex).unwrap();
             remaining = &after[spec_len..];
         }
+        regex += "$";
 
         let regex = Regex::new(&regex).unwrap();
 
@@ -305,155 +245,47 @@ impl DateUnit {
     }
 }
 
-fn ndays_in_month(year: i32, month: u32) -> u32 {
-    // The first day of the next month...
-    let (y, m) = if month == 12 {
-        (year + 1, 1)
-    } else {
-        (year, month + 1)
-    };
-    let d = NaiveDate::from_ymd_opt(y, m, 1).unwrap();
-
-    // ...is preceded by the last day of the original month.
-    d.pred_opt().unwrap().day()
-}
-
-fn add_months(date_time: NaiveDateTime, amount: i64) -> Option<NaiveDateTime> {
-    let month = (date_time.month0() as i64).checked_add(amount)?;
-    let year = date_time.year() + i32::try_from(month / 12).ok()?;
-    let year = if month.is_negative() { year - 1 } else { year };
-
-    // Normalize month
-    let month = month % 12;
-    let month = if month.is_negative() {
-        month + 12
-    } else {
-        month
-    } as u32
-        + 1;
-
-    let day = cmp::min(date_time.day(), ndays_in_month(year, month));
-
-    NaiveDate::from_ymd_opt(year, month, day).map(|date| date.and_time(date_time.time()))
-}
-
-fn add_years(date_time: NaiveDateTime, amount: i64) -> Option<NaiveDateTime> {
-    let year = i32::try_from((date_time.year() as i64).checked_add(amount)?).ok()?;
-    let ndays = ndays_in_month(year, date_time.month());
-
-    if date_time.day() > ndays {
-        NaiveDate::from_ymd_opt(year, date_time.month(), ndays)
-            .and_then(|date| date.succ_opt().map(|date| date.and_time(date_time.time())))
-    } else {
-        date_time.with_year(year)
-    }
-}
-
-fn add_duration(date_time: NaiveDateTime, duration: Duration) -> Option<NaiveDateTime> {
-    date_time.checked_add_signed(duration)
-}
-
-fn toggle_am_pm(date_time: NaiveDateTime) -> Option<NaiveDateTime> {
-    if date_time.hour() < 12 {
-        add_duration(date_time, Duration::hours(12))
-    } else {
-        add_duration(date_time, Duration::hours(-12))
-    }
-}
-
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::Rope;
 
     #[test]
     fn test_increment_date_times() {
         let tests = [
             // (original, cursor, amount, expected)
-            ("2020-02-28", 0, 1, "2021-02-28"),
-            ("2020-02-29", 0, 1, "2021-03-01"),
-            ("2020-01-31", 5, 1, "2020-02-29"),
-            ("2020-01-20", 5, 1, "2020-02-20"),
-            ("2021-01-01", 5, -1, "2020-12-01"),
-            ("2021-01-31", 5, -2, "2020-11-30"),
-            ("2020-02-28", 8, 1, "2020-02-29"),
-            ("2021-02-28", 8, 1, "2021-03-01"),
-            ("2021-02-28", 0, -1, "2020-02-28"),
-            ("2021-03-01", 0, -1, "2020-03-01"),
-            ("2020-02-29", 5, -1, "2020-01-29"),
-            ("2020-02-20", 5, -1, "2020-01-20"),
-            ("2020-02-29", 8, -1, "2020-02-28"),
-            ("2021-03-01", 8, -1, "2021-02-28"),
-            ("1980/12/21", 8, 100, "1981/03/31"),
-            ("1980/12/21", 8, -100, "1980/09/12"),
-            ("1980/12/21", 8, 1000, "1983/09/17"),
-            ("1980/12/21", 8, -1000, "1978/03/27"),
-            ("2021-11-24 07:12:23", 0, 1, "2022-11-24 07:12:23"),
-            ("2021-11-24 07:12:23", 5, 1, "2021-12-24 07:12:23"),
-            ("2021-11-24 07:12:23", 8, 1, "2021-11-25 07:12:23"),
-            ("2021-11-24 07:12:23", 11, 1, "2021-11-24 08:12:23"),
-            ("2021-11-24 07:12:23", 14, 1, "2021-11-24 07:13:23"),
-            ("2021-11-24 07:12:23", 17, 1, "2021-11-24 07:12:24"),
-            ("2021/11/24 07:12:23", 0, 1, "2022/11/24 07:12:23"),
-            ("2021/11/24 07:12:23", 5, 1, "2021/12/24 07:12:23"),
-            ("2021/11/24 07:12:23", 8, 1, "2021/11/25 07:12:23"),
-            ("2021/11/24 07:12:23", 11, 1, "2021/11/24 08:12:23"),
-            ("2021/11/24 07:12:23", 14, 1, "2021/11/24 07:13:23"),
-            ("2021/11/24 07:12:23", 17, 1, "2021/11/24 07:12:24"),
-            ("2021-11-24 07:12", 0, 1, "2022-11-24 07:12"),
-            ("2021-11-24 07:12", 5, 1, "2021-12-24 07:12"),
-            ("2021-11-24 07:12", 8, 1, "2021-11-25 07:12"),
-            ("2021-11-24 07:12", 11, 1, "2021-11-24 08:12"),
-            ("2021-11-24 07:12", 14, 1, "2021-11-24 07:13"),
-            ("2021/11/24 07:12", 0, 1, "2022/11/24 07:12"),
-            ("2021/11/24 07:12", 5, 1, "2021/12/24 07:12"),
-            ("2021/11/24 07:12", 8, 1, "2021/11/25 07:12"),
-            ("2021/11/24 07:12", 11, 1, "2021/11/24 08:12"),
-            ("2021/11/24 07:12", 14, 1, "2021/11/24 07:13"),
-            ("Wed Nov 24 2021", 0, 1, "Thu Nov 25 2021"),
-            ("Wed Nov 24 2021", 4, 1, "Fri Dec 24 2021"),
-            ("Wed Nov 24 2021", 8, 1, "Thu Nov 25 2021"),
-            ("Wed Nov 24 2021", 11, 1, "Thu Nov 24 2022"),
-            ("24-Nov-2021", 0, 1, "25-Nov-2021"),
-            ("24-Nov-2021", 3, 1, "24-Dec-2021"),
-            ("24-Nov-2021", 7, 1, "24-Nov-2022"),
-            ("2021 Nov 24", 0, 1, "2022 Nov 24"),
-            ("2021 Nov 24", 5, 1, "2021 Dec 24"),
-            ("2021 Nov 24", 9, 1, "2021 Nov 25"),
-            ("Nov 24, 2021", 0, 1, "Dec 24, 2021"),
-            ("Nov 24, 2021", 4, 1, "Nov 25, 2021"),
-            ("Nov 24, 2021", 8, 1, "Nov 24, 2022"),
-            ("7:21:53 am", 0, 1, "8:21:53 am"),
-            ("7:21:53 am", 3, 1, "7:22:53 am"),
-            ("7:21:53 am", 5, 1, "7:21:54 am"),
-            ("7:21:53 am", 8, 1, "7:21:53 pm"),
-            ("7:21:53 AM", 0, 1, "8:21:53 AM"),
-            ("7:21:53 AM", 3, 1, "7:22:53 AM"),
-            ("7:21:53 AM", 5, 1, "7:21:54 AM"),
-            ("7:21:53 AM", 8, 1, "7:21:53 PM"),
-            ("7:21 am", 0, 1, "8:21 am"),
-            ("7:21 am", 3, 1, "7:22 am"),
-            ("7:21 am", 5, 1, "7:21 pm"),
-            ("7:21 AM", 0, 1, "8:21 AM"),
-            ("7:21 AM", 3, 1, "7:22 AM"),
-            ("7:21 AM", 5, 1, "7:21 PM"),
-            ("23:24:23", 1, 1, "00:24:23"),
-            ("23:24:23", 3, 1, "23:25:23"),
-            ("23:24:23", 6, 1, "23:24:24"),
-            ("23:24", 1, 1, "00:24"),
-            ("23:24", 3, 1, "23:25"),
+            ("2020-02-28", 1, "2020-02-29"),
+            ("2020-02-29", 1, "2020-03-01"),
+            ("2020-01-31", 1, "2020-02-01"),
+            ("2020-01-20", 1, "2020-01-21"),
+            ("2021-01-01", -1, "2020-12-31"),
+            ("2021-01-31", -2, "2021-01-29"),
+            ("2020-02-28", 1, "2020-02-29"),
+            ("2021-02-28", 1, "2021-03-01"),
+            ("2021-03-01", -1, "2021-02-28"),
+            ("2020-02-29", -1, "2020-02-28"),
+            ("2020-02-20", -1, "2020-02-19"),
+            ("2021-03-01", -1, "2021-02-28"),
+            ("1980/12/21", 100, "1981/03/31"),
+            ("1980/12/21", -100, "1980/09/12"),
+            ("1980/12/21", 1000, "1983/09/17"),
+            ("1980/12/21", -1000, "1978/03/27"),
+            ("2021-11-24 07:12:23", 1, "2021-11-24 07:13:23"),
+            ("2021-11-24 07:12", 1, "2021-11-24 07:13"),
+            ("Wed Nov 24 2021", 1, "Thu Nov 25 2021"),
+            ("24-Nov-2021", 1, "25-Nov-2021"),
+            ("2021 Nov 24", 1, "2021 Nov 25"),
+            ("Nov 24, 2021", 1, "Nov 25, 2021"),
+            ("7:21:53 am", 1, "7:22:53 am"),
+            ("7:21:53 AM", 1, "7:22:53 AM"),
+            ("7:21 am", 1, "7:22 am"),
+            ("23:24:23", 1, "23:25:23"),
+            ("23:24", 1, "23:25"),
+            ("23:59", 1, "00:00"),
+            ("23:59:59", 1, "00:00:59"),
         ];
 
-        for (original, cursor, amount, expected) in tests {
-            let rope = Rope::from_str(original);
-            let range = Range::new(cursor, cursor + 1);
-            assert_eq!(
-                DateTimeIncrementor::from_range(rope.slice(..), range)
-                    .unwrap()
-                    .increment(amount)
-                    .1,
-                Tendril::from(expected)
-            );
+        for (original, amount, expected) in tests {
+            assert_eq!(increment(original, amount).unwrap(), expected);
         }
     }
 
@@ -482,10 +314,7 @@ mod test {
         ];
 
         for invalid in tests {
-            let rope = Rope::from_str(invalid);
-            let range = Range::new(0, 1);
-
-            assert_eq!(DateTimeIncrementor::from_range(rope.slice(..), range), None)
+            assert_eq!(increment(invalid, 1), None)
         }
     }
 }
diff --git a/helix-core/src/increment/integer.rs b/helix-core/src/increment/integer.rs
new file mode 100644
index 00000000..30803e17
--- /dev/null
+++ b/helix-core/src/increment/integer.rs
@@ -0,0 +1,235 @@
+const SEPARATOR: char = '_';
+
+/// Increment an integer.
+///
+/// Supported bases:
+///     2 with prefix 0b
+///     8 with prefix 0o
+///     10 with no prefix
+///     16 with prefix 0x
+///
+/// An integer can contain `_` as a separator but may not start or end with a separator.
+/// Base 10 integers can go negative, but bases 2, 8, and 16 cannot.
+/// All addition and subtraction is saturating.
+pub fn increment(selected_text: &str, amount: i64) -> Option<String> {
+    if selected_text.is_empty()
+        || selected_text.ends_with(SEPARATOR)
+        || selected_text.starts_with(SEPARATOR)
+    {
+        return None;
+    }
+
+    let radix = if selected_text.starts_with("0x") {
+        16
+    } else if selected_text.starts_with("0o") {
+        8
+    } else if selected_text.starts_with("0b") {
+        2
+    } else {
+        10
+    };
+
+    // Get separator indexes from right to left.
+    let separator_rtl_indexes: Vec<usize> = selected_text
+        .chars()
+        .rev()
+        .enumerate()
+        .filter_map(|(i, c)| if c == SEPARATOR { Some(i) } else { None })
+        .collect();
+
+    let word: String = selected_text.chars().filter(|&c| c != SEPARATOR).collect();
+
+    let mut new_text = if radix == 10 {
+        let number = &word;
+        let value = i128::from_str_radix(number, radix).ok()?;
+        let new_value = value.saturating_add(amount as i128);
+
+        let format_length = match (value.is_negative(), new_value.is_negative()) {
+            (true, false) => number.len() - 1,
+            (false, true) => number.len() + 1,
+            _ => number.len(),
+        } - separator_rtl_indexes.len();
+
+        if number.starts_with('0') || number.starts_with("-0") {
+            format!("{:01$}", new_value, format_length)
+        } else {
+            format!("{}", new_value)
+        }
+    } else {
+        let number = &word[2..];
+        let value = u128::from_str_radix(number, radix).ok()?;
+        let new_value = (value as i128).saturating_add(amount as i128);
+        let new_value = if new_value < 0 { 0 } else { new_value };
+        let format_length = selected_text.len() - 2 - separator_rtl_indexes.len();
+
+        match radix {
+            2 => format!("0b{:01$b}", new_value, format_length),
+            8 => format!("0o{:01$o}", new_value, format_length),
+            16 => {
+                let (lower_count, upper_count): (usize, usize) =
+                    number.chars().fold((0, 0), |(lower, upper), c| {
+                        (
+                            lower + c.is_ascii_lowercase().then(|| 1).unwrap_or(0),
+                            upper + c.is_ascii_uppercase().then(|| 1).unwrap_or(0),
+                        )
+                    });
+                if upper_count > lower_count {
+                    format!("0x{:01$X}", new_value, format_length)
+                } else {
+                    format!("0x{:01$x}", new_value, format_length)
+                }
+            }
+            _ => unimplemented!("radix not supported: {}", radix),
+        }
+    };
+
+    // Add separators from original number.
+    for &rtl_index in &separator_rtl_indexes {
+        if rtl_index < new_text.len() {
+            let new_index = new_text.len().saturating_sub(rtl_index);
+            if new_index > 0 {
+                new_text.insert(new_index, SEPARATOR);
+            }
+        }
+    }
+
+    // Add in additional separators if necessary.
+    if new_text.len() > selected_text.len() && !separator_rtl_indexes.is_empty() {
+        let spacing = match separator_rtl_indexes.as_slice() {
+            [.., b, a] => a - b - 1,
+            _ => separator_rtl_indexes[0],
+        };
+
+        let prefix_length = if radix == 10 { 0 } else { 2 };
+        if let Some(mut index) = new_text.find(SEPARATOR) {
+            while index - prefix_length > spacing {
+                index -= spacing;
+                new_text.insert(index, SEPARATOR);
+            }
+        }
+    }
+
+    Some(new_text)
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_increment_basic_decimal_numbers() {
+        let tests = [
+            ("100", 1, "101"),
+            ("100", -1, "99"),
+            ("99", 1, "100"),
+            ("100", 1000, "1100"),
+            ("100", -1000, "-900"),
+            ("-1", 1, "0"),
+            ("-1", 2, "1"),
+            ("1", -1, "0"),
+            ("1", -2, "-1"),
+        ];
+
+        for (original, amount, expected) in tests {
+            assert_eq!(increment(original, amount).unwrap(), expected);
+        }
+    }
+
+    #[test]
+    fn test_increment_basic_hexadecimal_numbers() {
+        let tests = [
+            ("0x0100", 1, "0x0101"),
+            ("0x0100", -1, "0x00ff"),
+            ("0x0001", -1, "0x0000"),
+            ("0x0000", -1, "0x0000"),
+            ("0xffffffffffffffff", 1, "0x10000000000000000"),
+            ("0xffffffffffffffff", 2, "0x10000000000000001"),
+            ("0xffffffffffffffff", -1, "0xfffffffffffffffe"),
+            ("0xABCDEF1234567890", 1, "0xABCDEF1234567891"),
+            ("0xabcdef1234567890", 1, "0xabcdef1234567891"),
+        ];
+
+        for (original, amount, expected) in tests {
+            assert_eq!(increment(original, amount).unwrap(), expected);
+        }
+    }
+
+    #[test]
+    fn test_increment_basic_octal_numbers() {
+        let tests = [
+            ("0o0107", 1, "0o0110"),
+            ("0o0110", -1, "0o0107"),
+            ("0o0001", -1, "0o0000"),
+            ("0o7777", 1, "0o10000"),
+            ("0o1000", -1, "0o0777"),
+            ("0o0107", 10, "0o0121"),
+            ("0o0000", -1, "0o0000"),
+            ("0o1777777777777777777777", 1, "0o2000000000000000000000"),
+            ("0o1777777777777777777777", 2, "0o2000000000000000000001"),
+            ("0o1777777777777777777777", -1, "0o1777777777777777777776"),
+        ];
+
+        for (original, amount, expected) in tests {
+            assert_eq!(increment(original, amount).unwrap(), expected);
+        }
+    }
+
+    #[test]
+    fn test_increment_basic_binary_numbers() {
+        let tests = [
+            ("0b00000100", 1, "0b00000101"),
+            ("0b00000100", -1, "0b00000011"),
+            ("0b00000100", 2, "0b00000110"),
+            ("0b00000100", -2, "0b00000010"),
+            ("0b00000001", -1, "0b00000000"),
+            ("0b00111111", 10, "0b01001001"),
+            ("0b11111111", 1, "0b100000000"),
+            ("0b10000000", -1, "0b01111111"),
+            ("0b0000", -1, "0b0000"),
+            (
+                "0b1111111111111111111111111111111111111111111111111111111111111111",
+                1,
+                "0b10000000000000000000000000000000000000000000000000000000000000000",
+            ),
+            (
+                "0b1111111111111111111111111111111111111111111111111111111111111111",
+                2,
+                "0b10000000000000000000000000000000000000000000000000000000000000001",
+            ),
+            (
+                "0b1111111111111111111111111111111111111111111111111111111111111111",
+                -1,
+                "0b1111111111111111111111111111111111111111111111111111111111111110",
+            ),
+        ];
+
+        for (original, amount, expected) in tests {
+            assert_eq!(increment(original, amount).unwrap(), expected);
+        }
+    }
+
+    #[test]
+    fn test_increment_with_separators() {
+        let tests = [
+            ("999_999", 1, "1_000_000"),
+            ("1_000_000", -1, "999_999"),
+            ("-999_999", -1, "-1_000_000"),
+            ("0x0000_0000_0001", 0x1_ffff_0000, "0x0001_ffff_0001"),
+            ("0x0000_0000", -1, "0x0000_0000"),
+            ("0x0000_0000_0000", -1, "0x0000_0000_0000"),
+            ("0b01111111_11111111", 1, "0b10000000_00000000"),
+            ("0b11111111_11111111", 1, "0b1_00000000_00000000"),
+        ];
+
+        for (original, amount, expected) in tests {
+            assert_eq!(increment(original, amount).unwrap(), expected);
+        }
+    }
+
+    #[test]
+    fn test_leading_and_trailing_separators_arent_a_match() {
+        assert_eq!(increment("9_", 1), None);
+        assert_eq!(increment("_9", 1), None);
+        assert_eq!(increment("_9_", 1), None);
+    }
+}
diff --git a/helix-core/src/increment/mod.rs b/helix-core/src/increment/mod.rs
index f5945774..f1978bde 100644
--- a/helix-core/src/increment/mod.rs
+++ b/helix-core/src/increment/mod.rs
@@ -1,8 +1,10 @@
-pub mod date_time;
-pub mod number;
+mod date_time;
+mod integer;
 
-use crate::{Range, Tendril};
+pub fn integer(selected_text: &str, amount: i64) -> Option<String> {
+    integer::increment(selected_text, amount)
+}
 
-pub trait Increment {
-    fn increment(&self, amount: i64) -> (Range, Tendril);
+pub fn date_time(selected_text: &str, amount: i64) -> Option<String> {
+    date_time::increment(selected_text, amount)
 }
diff --git a/helix-core/src/increment/number.rs b/helix-core/src/increment/number.rs
deleted file mode 100644
index 91268729..00000000
--- a/helix-core/src/increment/number.rs
+++ /dev/null
@@ -1,507 +0,0 @@
-use std::borrow::Cow;
-
-use ropey::RopeSlice;
-
-use super::Increment;
-
-use crate::{
-    textobject::{textobject_word, TextObject},
-    Range, Tendril,
-};
-
-#[derive(Debug, PartialEq, Eq)]
-pub struct NumberIncrementor<'a> {
-    value: i64,
-    radix: u32,
-    range: Range,
-
-    text: RopeSlice<'a>,
-}
-
-impl<'a> NumberIncrementor<'a> {
-    /// Return information about number under rang if there is one.
-    pub fn from_range(text: RopeSlice, range: Range) -> Option<NumberIncrementor> {
-        // If the cursor is on the minus sign of a number we want to get the word textobject to the
-        // right of it.
-        let range = if range.to() < text.len_chars()
-            && range.to() - range.from() <= 1
-            && text.char(range.from()) == '-'
-        {
-            Range::new(range.from() + 1, range.to() + 1)
-        } else {
-            range
-        };
-
-        let range = textobject_word(text, range, TextObject::Inside, 1, false);
-
-        // If there is a minus sign to the left of the word object, we want to include it in the range.
-        let range = if range.from() > 0 && text.char(range.from() - 1) == '-' {
-            range.extend(range.from() - 1, range.from())
-        } else {
-            range
-        };
-
-        let word: String = text
-            .slice(range.from()..range.to())
-            .chars()
-            .filter(|&c| c != '_')
-            .collect();
-        let (radix, prefixed) = if word.starts_with("0x") {
-            (16, true)
-        } else if word.starts_with("0o") {
-            (8, true)
-        } else if word.starts_with("0b") {
-            (2, true)
-        } else {
-            (10, false)
-        };
-
-        let number = if prefixed { &word[2..] } else { &word };
-
-        let value = i128::from_str_radix(number, radix).ok()?;
-        if (value.is_positive() && value.leading_zeros() < 64)
-            || (value.is_negative() && value.leading_ones() < 64)
-        {
-            return None;
-        }
-
-        let value = value as i64;
-        Some(NumberIncrementor {
-            range,
-            value,
-            radix,
-            text,
-        })
-    }
-}
-
-impl<'a> Increment for NumberIncrementor<'a> {
-    fn increment(&self, amount: i64) -> (Range, Tendril) {
-        let old_text: Cow<str> = self.text.slice(self.range.from()..self.range.to()).into();
-        let old_length = old_text.len();
-        let new_value = self.value.wrapping_add(amount);
-
-        // Get separator indexes from right to left.
-        let separator_rtl_indexes: Vec<usize> = old_text
-            .chars()
-            .rev()
-            .enumerate()
-            .filter_map(|(i, c)| if c == '_' { Some(i) } else { None })
-            .collect();
-
-        let format_length = if self.radix == 10 {
-            match (self.value.is_negative(), new_value.is_negative()) {
-                (true, false) => old_length - 1,
-                (false, true) => old_length + 1,
-                _ => old_text.len(),
-            }
-        } else {
-            old_text.len() - 2
-        } - separator_rtl_indexes.len();
-
-        let mut new_text = match self.radix {
-            2 => format!("0b{:01$b}", new_value, format_length),
-            8 => format!("0o{:01$o}", new_value, format_length),
-            10 if old_text.starts_with('0') || old_text.starts_with("-0") => {
-                format!("{:01$}", new_value, format_length)
-            }
-            10 => format!("{}", new_value),
-            16 => {
-                let (lower_count, upper_count): (usize, usize) =
-                    old_text.chars().skip(2).fold((0, 0), |(lower, upper), c| {
-                        (
-                            lower + usize::from(c.is_ascii_lowercase()),
-                            upper + usize::from(c.is_ascii_uppercase()),
-                        )
-                    });
-                if upper_count > lower_count {
-                    format!("0x{:01$X}", new_value, format_length)
-                } else {
-                    format!("0x{:01$x}", new_value, format_length)
-                }
-            }
-            _ => unimplemented!("radix not supported: {}", self.radix),
-        };
-
-        // Add separators from original number.
-        for &rtl_index in &separator_rtl_indexes {
-            if rtl_index < new_text.len() {
-                let new_index = new_text.len() - rtl_index;
-                new_text.insert(new_index, '_');
-            }
-        }
-
-        // Add in additional separators if necessary.
-        if new_text.len() > old_length && !separator_rtl_indexes.is_empty() {
-            let spacing = match separator_rtl_indexes.as_slice() {
-                [.., b, a] => a - b - 1,
-                _ => separator_rtl_indexes[0],
-            };
-
-            let prefix_length = if self.radix == 10 { 0 } else { 2 };
-            if let Some(mut index) = new_text.find('_') {
-                while index - prefix_length > spacing {
-                    index -= spacing;
-                    new_text.insert(index, '_');
-                }
-            }
-        }
-
-        (self.range, new_text.into())
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-    use crate::Rope;
-
-    #[test]
-    fn test_decimal_at_point() {
-        let rope = Rope::from_str("Test text 12345 more text.");
-        let range = Range::point(12);
-        assert_eq!(
-            NumberIncrementor::from_range(rope.slice(..), range),
-            Some(NumberIncrementor {
-                range: Range::new(10, 15),
-                value: 12345,
-                radix: 10,
-                text: rope.slice(..),
-            })
-        );
-    }
-
-    #[test]
-    fn test_uppercase_hexadecimal_at_point() {
-        let rope = Rope::from_str("Test text 0x123ABCDEF more text.");
-        let range = Range::point(12);
-        assert_eq!(
-            NumberIncrementor::from_range(rope.slice(..), range),
-            Some(NumberIncrementor {
-                range: Range::new(10, 21),
-                value: 0x123ABCDEF,
-                radix: 16,
-                text: rope.slice(..),
-            })
-        );
-    }
-
-    #[test]
-    fn test_lowercase_hexadecimal_at_point() {
-        let rope = Rope::from_str("Test text 0xfa3b4e more text.");
-        let range = Range::point(12);
-        assert_eq!(
-            NumberIncrementor::from_range(rope.slice(..), range),
-            Some(NumberIncrementor {
-                range: Range::new(10, 18),
-                value: 0xfa3b4e,
-                radix: 16,
-                text: rope.slice(..),
-            })
-        );
-    }
-
-    #[test]
-    fn test_octal_at_point() {
-        let rope = Rope::from_str("Test text 0o1074312 more text.");
-        let range = Range::point(12);
-        assert_eq!(
-            NumberIncrementor::from_range(rope.slice(..), range),
-            Some(NumberIncrementor {
-                range: Range::new(10, 19),
-                value: 0o1074312,
-                radix: 8,
-                text: rope.slice(..),
-            })
-        );
-    }
-
-    #[test]
-    fn test_binary_at_point() {
-        let rope = Rope::from_str("Test text 0b10111010010101 more text.");
-        let range = Range::point(12);
-        assert_eq!(
-            NumberIncrementor::from_range(rope.slice(..), range),
-            Some(NumberIncrementor {
-                range: Range::new(10, 26),
-                value: 0b10111010010101,
-                radix: 2,
-                text: rope.slice(..),
-            })
-        );
-    }
-
-    #[test]
-    fn test_negative_decimal_at_point() {
-        let rope = Rope::from_str("Test text -54321 more text.");
-        let range = Range::point(12);
-        assert_eq!(
-            NumberIncrementor::from_range(rope.slice(..), range),
-            Some(NumberIncrementor {
-                range: Range::new(10, 16),
-                value: -54321,
-                radix: 10,
-                text: rope.slice(..),
-            })
-        );
-    }
-
-    #[test]
-    fn test_decimal_with_leading_zeroes_at_point() {
-        let rope = Rope::from_str("Test text 000045326 more text.");
-        let range = Range::point(12);
-        assert_eq!(
-            NumberIncrementor::from_range(rope.slice(..), range),
-            Some(NumberIncrementor {
-                range: Range::new(10, 19),
-                value: 45326,
-                radix: 10,
-                text: rope.slice(..),
-            })
-        );
-    }
-
-    #[test]
-    fn test_negative_decimal_cursor_on_minus_sign() {
-        let rope = Rope::from_str("Test text -54321 more text.");
-        let range = Range::point(10);
-        assert_eq!(
-            NumberIncrementor::from_range(rope.slice(..), range),
-            Some(NumberIncrementor {
-                range: Range::new(10, 16),
-                value: -54321,
-                radix: 10,
-                text: rope.slice(..),
-            })
-        );
-    }
-
-    #[test]
-    fn test_number_under_range_start_of_rope() {
-        let rope = Rope::from_str("100");
-        let range = Range::point(0);
-        assert_eq!(
-            NumberIncrementor::from_range(rope.slice(..), range),
-            Some(NumberIncrementor {
-                range: Range::new(0, 3),
-                value: 100,
-                radix: 10,
-                text: rope.slice(..),
-            })
-        );
-    }
-
-    #[test]
-    fn test_number_under_range_end_of_rope() {
-        let rope = Rope::from_str("100");
-        let range = Range::point(2);
-        assert_eq!(
-            NumberIncrementor::from_range(rope.slice(..), range),
-            Some(NumberIncrementor {
-                range: Range::new(0, 3),
-                value: 100,
-                radix: 10,
-                text: rope.slice(..),
-            })
-        );
-    }
-
-    #[test]
-    fn test_number_surrounded_by_punctuation() {
-        let rope = Rope::from_str(",100;");
-        let range = Range::point(1);
-        assert_eq!(
-            NumberIncrementor::from_range(rope.slice(..), range),
-            Some(NumberIncrementor {
-                range: Range::new(1, 4),
-                value: 100,
-                radix: 10,
-                text: rope.slice(..),
-            })
-        );
-    }
-
-    #[test]
-    fn test_not_a_number_point() {
-        let rope = Rope::from_str("Test text 45326 more text.");
-        let range = Range::point(6);
-        assert_eq!(NumberIncrementor::from_range(rope.slice(..), range), None);
-    }
-
-    #[test]
-    fn test_number_too_large_at_point() {
-        let rope = Rope::from_str("Test text 0xFFFFFFFFFFFFFFFFF more text.");
-        let range = Range::point(12);
-        assert_eq!(NumberIncrementor::from_range(rope.slice(..), range), None);
-    }
-
-    #[test]
-    fn test_number_cursor_one_right_of_number() {
-        let rope = Rope::from_str("100 ");
-        let range = Range::point(3);
-        assert_eq!(NumberIncrementor::from_range(rope.slice(..), range), None);
-    }
-
-    #[test]
-    fn test_number_cursor_one_left_of_number() {
-        let rope = Rope::from_str(" 100");
-        let range = Range::point(0);
-        assert_eq!(NumberIncrementor::from_range(rope.slice(..), range), None);
-    }
-
-    #[test]
-    fn test_increment_basic_decimal_numbers() {
-        let tests = [
-            ("100", 1, "101"),
-            ("100", -1, "99"),
-            ("99", 1, "100"),
-            ("100", 1000, "1100"),
-            ("100", -1000, "-900"),
-            ("-1", 1, "0"),
-            ("-1", 2, "1"),
-            ("1", -1, "0"),
-            ("1", -2, "-1"),
-        ];
-
-        for (original, amount, expected) in tests {
-            let rope = Rope::from_str(original);
-            let range = Range::point(0);
-            assert_eq!(
-                NumberIncrementor::from_range(rope.slice(..), range)
-                    .unwrap()
-                    .increment(amount)
-                    .1,
-                Tendril::from(expected)
-            );
-        }
-    }
-
-    #[test]
-    fn test_increment_basic_hexadecimal_numbers() {
-        let tests = [
-            ("0x0100", 1, "0x0101"),
-            ("0x0100", -1, "0x00ff"),
-            ("0x0001", -1, "0x0000"),
-            ("0x0000", -1, "0xffffffffffffffff"),
-            ("0xffffffffffffffff", 1, "0x0000000000000000"),
-            ("0xffffffffffffffff", 2, "0x0000000000000001"),
-            ("0xffffffffffffffff", -1, "0xfffffffffffffffe"),
-            ("0xABCDEF1234567890", 1, "0xABCDEF1234567891"),
-            ("0xabcdef1234567890", 1, "0xabcdef1234567891"),
-        ];
-
-        for (original, amount, expected) in tests {
-            let rope = Rope::from_str(original);
-            let range = Range::point(0);
-            assert_eq!(
-                NumberIncrementor::from_range(rope.slice(..), range)
-                    .unwrap()
-                    .increment(amount)
-                    .1,
-                Tendril::from(expected)
-            );
-        }
-    }
-
-    #[test]
-    fn test_increment_basic_octal_numbers() {
-        let tests = [
-            ("0o0107", 1, "0o0110"),
-            ("0o0110", -1, "0o0107"),
-            ("0o0001", -1, "0o0000"),
-            ("0o7777", 1, "0o10000"),
-            ("0o1000", -1, "0o0777"),
-            ("0o0107", 10, "0o0121"),
-            ("0o0000", -1, "0o1777777777777777777777"),
-            ("0o1777777777777777777777", 1, "0o0000000000000000000000"),
-            ("0o1777777777777777777777", 2, "0o0000000000000000000001"),
-            ("0o1777777777777777777777", -1, "0o1777777777777777777776"),
-        ];
-
-        for (original, amount, expected) in tests {
-            let rope = Rope::from_str(original);
-            let range = Range::point(0);
-            assert_eq!(
-                NumberIncrementor::from_range(rope.slice(..), range)
-                    .unwrap()
-                    .increment(amount)
-                    .1,
-                Tendril::from(expected)
-            );
-        }
-    }
-
-    #[test]
-    fn test_increment_basic_binary_numbers() {
-        let tests = [
-            ("0b00000100", 1, "0b00000101"),
-            ("0b00000100", -1, "0b00000011"),
-            ("0b00000100", 2, "0b00000110"),
-            ("0b00000100", -2, "0b00000010"),
-            ("0b00000001", -1, "0b00000000"),
-            ("0b00111111", 10, "0b01001001"),
-            ("0b11111111", 1, "0b100000000"),
-            ("0b10000000", -1, "0b01111111"),
-            (
-                "0b0000",
-                -1,
-                "0b1111111111111111111111111111111111111111111111111111111111111111",
-            ),
-            (
-                "0b1111111111111111111111111111111111111111111111111111111111111111",
-                1,
-                "0b0000000000000000000000000000000000000000000000000000000000000000",
-            ),
-            (
-                "0b1111111111111111111111111111111111111111111111111111111111111111",
-                2,
-                "0b0000000000000000000000000000000000000000000000000000000000000001",
-            ),
-            (
-                "0b1111111111111111111111111111111111111111111111111111111111111111",
-                -1,
-                "0b1111111111111111111111111111111111111111111111111111111111111110",
-            ),
-        ];
-
-        for (original, amount, expected) in tests {
-            let rope = Rope::from_str(original);
-            let range = Range::point(0);
-            assert_eq!(
-                NumberIncrementor::from_range(rope.slice(..), range)
-                    .unwrap()
-                    .increment(amount)
-                    .1,
-                Tendril::from(expected)
-            );
-        }
-    }
-
-    #[test]
-    fn test_increment_with_separators() {
-        let tests = [
-            ("999_999", 1, "1_000_000"),
-            ("1_000_000", -1, "999_999"),
-            ("-999_999", -1, "-1_000_000"),
-            ("0x0000_0000_0001", 0x1_ffff_0000, "0x0001_ffff_0001"),
-            ("0x0000_0000_0001", 0x1_ffff_0000, "0x0001_ffff_0001"),
-            ("0x0000_0000_0001", 0x1_ffff_0000, "0x0001_ffff_0001"),
-            ("0x0000_0000", -1, "0xffff_ffff_ffff_ffff"),
-            ("0x0000_0000_0000", -1, "0xffff_ffff_ffff_ffff"),
-            ("0b01111111_11111111", 1, "0b10000000_00000000"),
-            ("0b11111111_11111111", 1, "0b1_00000000_00000000"),
-        ];
-
-        for (original, amount, expected) in tests {
-            let rope = Rope::from_str(original);
-            let range = Range::point(0);
-            assert_eq!(
-                NumberIncrementor::from_range(rope.slice(..), range)
-                    .unwrap()
-                    .increment(amount)
-                    .1,
-                Tendril::from(expected)
-            );
-        }
-    }
-}