+use std::collections::{HashMap, HashSet};
+use std::io::BufRead;
+use std::iter::Iterator;
+
+#[derive(Debug, PartialEq, Eq)]
+struct RowInput {
+ label: String,
+ entries: Vec<String>,
+}
+
+struct Reader<Input: Iterator<Item = Result<String, std::io::Error>>> {
+ input: std::iter::Enumerate<Input>,
+ row: Option<RowInput>,
+}
+impl<Input: Iterator<Item = Result<String, std::io::Error>>> Reader<Input> {
+ fn new(input: Input) -> Self {
+ Self {
+ input: input.enumerate(),
+ row: None,
+ }
+ }
+}
+impl<Input: Iterator<Item = Result<String, std::io::Error>>> Iterator for Reader<Input> {
+ type Item = Result<RowInput, std::io::Error>;
+ fn next(&mut self) -> Option<Self::Item> {
+ loop {
+ match self
+ .input
+ .next()
+ .map(|(n, r)| (n, r.map(|line| String::from(line.trim_end()))))
+ {
+ None => return Ok(std::mem::take(&mut self.row)).transpose(),
+ Some((_, Err(e))) => return Some(Err(e)),
+ Some((_, Ok(line))) if line.is_empty() && self.row.is_some() => {
+ return Ok(std::mem::take(&mut self.row)).transpose()
+ }
+ Some((_, Ok(line))) if line.is_empty() => {}
+ Some((n, Ok(line))) if line.starts_with(' ') => match &mut self.row {
+ None => {
+ return Some(Err(std::io::Error::other(format!(
+ "{}: Entry with no header",
+ n + 1
+ ))))
+ }
+ Some(ref mut row) => row.entries.push(String::from(line.trim())),
+ },
+ Some((_, Ok(line))) => {
+ let prev = std::mem::take(&mut self.row);
+ self.row = Some(RowInput {
+ label: line,
+ entries: vec![],
+ });
+ if prev.is_some() {
+ return Ok(prev).transpose();
+ }
+ }
+ }
+ }
+ }
+}
+
+fn read_rows(input: impl std::io::Read) -> impl Iterator<Item = Result<RowInput, std::io::Error>> {
+ Reader::new(std::io::BufReader::new(input).lines())
+}
+
+fn column_counts(rows: &[RowInput]) -> Vec<(usize, String)> {
+ let mut counts: Vec<_> = rows
+ .iter()
+ .flat_map(|r| r.entries.iter().collect::<HashSet<_>>().into_iter())
+ .fold(HashMap::new(), |mut cs, e| {
+ cs.entry(String::from(e))
+ .and_modify(|n| *n += 1)
+ .or_insert(1);
+ cs
+ })
+ .into_iter()
+ .map(|(col, n)| (n, col))
+ .collect();
+ counts.sort();
+ counts
+}
+
+/// # Errors
+///
+/// Will return `Err` if
+/// * there's an i/o error while reading `input`
+/// * the log has invalid syntax:
+/// * an indented line with no preceding non-indented line
+pub fn tablify(input: impl std::io::Read) -> Result<String, std::io::Error> {
+ let rows = read_rows(input).collect::<Result<Vec<_>, _>>()?;
+ let _columns = column_counts(&rows);
+ Ok(String::from("Hello, world!"))
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ #[test]
+ fn test_read_rows() {
+ assert_eq!(
+ read_rows(&b"foo"[..]).flatten().collect::<Vec<_>>(),
+ vec![RowInput {
+ label: String::from("foo"),
+ entries: vec![]
+ }]
+ );
+ assert_eq!(
+ read_rows(&b"bar"[..]).flatten().collect::<Vec<_>>(),
+ vec![RowInput {
+ label: String::from("bar"),
+ entries: vec![]
+ }]
+ );
+ assert_eq!(
+ read_rows(&b"foo\nbar\n"[..]).flatten().collect::<Vec<_>>(),
+ vec![
+ RowInput {
+ label: String::from("foo"),
+ entries: vec![]
+ },
+ RowInput {
+ label: String::from("bar"),
+ entries: vec![]
+ }
+ ]
+ );
+ assert_eq!(
+ read_rows(&b"foo\n bar\n"[..]).flatten().collect::<Vec<_>>(),
+ vec![RowInput {
+ label: String::from("foo"),
+ entries: vec![String::from("bar")]
+ }]
+ );
+ assert_eq!(
+ read_rows(&b"foo\n bar\n baz\n"[..])
+ .flatten()
+ .collect::<Vec<_>>(),
+ vec![RowInput {
+ label: String::from("foo"),
+ entries: vec![String::from("bar"), String::from("baz")]
+ }]
+ );
+ assert_eq!(
+ read_rows(&b"foo\n\nbar\n"[..])
+ .flatten()
+ .collect::<Vec<_>>(),
+ vec![
+ RowInput {
+ label: String::from("foo"),
+ entries: vec![]
+ },
+ RowInput {
+ label: String::from("bar"),
+ entries: vec![]
+ }
+ ]
+ );
+ assert_eq!(
+ read_rows(&b"foo\n \nbar\n"[..])
+ .flatten()
+ .collect::<Vec<_>>(),
+ vec![
+ RowInput {
+ label: String::from("foo"),
+ entries: vec![]
+ },
+ RowInput {
+ label: String::from("bar"),
+ entries: vec![]
+ }
+ ]
+ );
+ assert_eq!(
+ read_rows(&b"foo \n bar \n"[..])
+ .flatten()
+ .collect::<Vec<_>>(),
+ vec![RowInput {
+ label: String::from("foo"),
+ entries: vec![String::from("bar")]
+ }]
+ );
+
+ let bad = read_rows(&b" foo"[..]).next().unwrap();
+ assert!(bad.is_err());
+ assert!(format!("{bad:?}").contains("1: Entry with no header"));
+
+ let bad2 = read_rows(&b"foo\n\n bar"[..]).nth(1).unwrap();
+ assert!(bad2.is_err());
+ assert!(format!("{bad2:?}").contains("3: Entry with no header"));
+ }
+
+ #[test]
+ fn test_column_counts() {
+ assert_eq!(
+ column_counts(
+ &read_rows(&b"foo\n bar\n baz\n"[..])
+ .collect::<Result<Vec<_>, _>>()
+ .unwrap()
+ ),
+ vec![(1, String::from("bar")), (1, String::from("baz"))]
+ );
+ assert_eq!(
+ column_counts(
+ &read_rows(&b"foo\n bar\n baz\nquux\n baz"[..])
+ .collect::<Result<Vec<_>, _>>()
+ .unwrap()
+ ),
+ vec![(1, String::from("bar")), (2, String::from("baz"))]
+ );
+ assert_eq!(
+ column_counts(
+ &read_rows(&b"foo\n bar\n bar\n baz\n bar\nquux\n baz"[..])
+ .collect::<Result<Vec<_>, _>>()
+ .unwrap()
+ ),
+ vec![(1, String::from("bar")), (2, String::from("baz"))]
+ );
+ }
projects / tablify / blobdiff