Fix scn extract

src/ext/fancy_regex.rs

@@ -0,0 +1,67 @@
+use anyhow::Result;
+use fancy_regex::Regex;
+
+pub trait FancyRegexExt {
+    /// Splits the input string by the regex pattern.
+    /// Like python's `re.split()`, but returns an iterator.
+    fn py_split<'a>(&'a self, input: &'a str) -> Result<PySplit<'a>>;
+}
+
+pub struct PySplit<'a> {
+    str: &'a str,
+    pos: Vec<(usize, usize)>,
+    start: usize,
+}
+
+impl<'a> Iterator for PySplit<'a> {
+    type Item = &'a str;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.start >= self.str.len() {
+            return None;
+        }
+        match self.pos.first().cloned() {
+            Some((start, end)) => {
+                if self.start < start {
+                    let result = &self.str[self.start..start];
+                    self.start = start;
+                    if start == end {
+                        self.pos.remove(0);
+                    }
+                    Some(result)
+                } else if self.start < end {
+                    let result = &self.str[self.start..end];
+                    self.start = end;
+                    self.pos.remove(0);
+                    Some(result)
+                } else {
+                    unreachable!();
+                }
+            }
+            None => {
+                if self.start < self.str.len() {
+                    let result = &self.str[self.start..];
+                    self.start = self.str.len();
+                    Some(result)
+                } else {
+                    None
+                }
+            }
+        }
+    }
+}
+
+impl FancyRegexExt for Regex {
+    fn py_split<'a>(&'a self, input: &'a str) -> Result<PySplit<'a>> {
+        let mut poss = Vec::new();
+        for pos in self.find_iter(input) {
+            let pos = pos?;
+            poss.push((pos.start(), pos.end()));
+        }
+        Ok(PySplit {
+            str: input,
+            pos: poss,
+            start: 0,
+        })
+    }
+}

src/ext/mod.rs

@@ -1,4 +1,6 @@
 pub mod atomic;
+#[cfg(feature = "fancy-regex")]
+pub mod fancy_regex;
 pub mod io;
 #[cfg(feature = "emote-psb")]
 pub mod psb;