git.scottworley.com Git - tablify/blob - src/lib.rs

   1 #[cfg(test)]
   2 use std::collections::HashMap;
   3 #[cfg(test)]
   4 use std::io::BufRead;
   5 #[cfg(test)]
   6 use std::iter::Iterator;
   7
   8 #[derive(Debug, PartialEq, Eq)]
   9 struct RowInput {
  10     label: String,
  11     entries: Vec<String>,
  12 }
  13
  14 struct Reader<Input: Iterator<Item = Result<String, std::io::Error>>> {
  15     input: std::iter::Enumerate<Input>,
  16     row: Option<RowInput>,
  17 }
  18 impl<Input: Iterator<Item = Result<String, std::io::Error>>> Reader<Input> {
  19     #[cfg(test)]
  20     fn new(input: Input) -> Self {
  21         Self {
  22             input: input.enumerate(),
  23             row: None,
  24         }
  25     }
  26 }
  27 impl<Input: Iterator<Item = Result<String, std::io::Error>>> Iterator for Reader<Input> {
  28     type Item = Result<RowInput, std::io::Error>;
  29     fn next(&mut self) -> Option<Self::Item> {
  30         loop {
  31             match self
  32                 .input
  33                 .next()
  34                 .map(|(n, r)| (n, r.map(|line| String::from(line.trim_end()))))
  35             {
  36                 None => return Ok(std::mem::take(&mut self.row)).transpose(),
  37                 Some((_, Err(e))) => return Some(Err(e)),
  38                 Some((_, Ok(line))) if line.is_empty() && self.row.is_some() => {
  39                     return Ok(std::mem::take(&mut self.row)).transpose()
  40                 }
  41                 Some((_, Ok(line))) if line.is_empty() => {}
  42                 Some((n, Ok(line))) if line.starts_with(' ') => match &mut self.row {
  43                     None => {
  44                         return Some(Err(std::io::Error::other(format!(
  45                             "{}: Entry with no header",
  46                             n + 1
  47                         ))))
  48                     }
  49                     Some(ref mut row) => row.entries.push(String::from(line.trim())),
  50                 },
  51                 Some((_, Ok(line))) => {
  52                     let prev = std::mem::take(&mut self.row);
  53                     self.row = Some(RowInput {
  54                         label: line,
  55                         entries: vec![],
  56                     });
  57                     if prev.is_some() {
  58                         return Ok(prev).transpose();
  59                     }
  60                 }
  61             }
  62         }
  63     }
  64 }
  65
  66 #[cfg(test)]
  67 fn read_rows(input: impl std::io::Read) -> impl Iterator<Item = Result<RowInput, std::io::Error>> {
  68     Reader::new(std::io::BufReader::new(input).lines())
  69 }
  70
  71 #[cfg(test)]
  72 fn column_counts(rows: &[RowInput]) -> HashMap<String, usize> {
  73     rows.iter()
  74         .flat_map(|r| r.entries.iter())
  75         .fold(HashMap::new(), |mut counts, e| {
  76             counts
  77                 .entry(String::from(e))
  78                 .and_modify(|c| *c += 1)
  79                 .or_insert(1);
  80             counts
  81         })
  82 }
  83
  84 pub fn tablify(_input: &impl std::io::Read) -> String {
  85     String::from("Hello, world!")
  86 }
  87
  88 #[cfg(test)]
  89 mod tests {
  90     use super::*;
  91
  92     #[test]
  93     fn test_read_rows() {
  94         assert_eq!(
  95             read_rows(&b"foo"[..]).flatten().collect::<Vec<_>>(),
  96             vec![RowInput {
  97                 label: String::from("foo"),
  98                 entries: vec![]
  99             }]
 100         );
 101         assert_eq!(
 102             read_rows(&b"bar"[..]).flatten().collect::<Vec<_>>(),
 103             vec![RowInput {
 104                 label: String::from("bar"),
 105                 entries: vec![]
 106             }]
 107         );
 108         assert_eq!(
 109             read_rows(&b"foo\nbar\n"[..]).flatten().collect::<Vec<_>>(),
 110             vec![
 111                 RowInput {
 112                     label: String::from("foo"),
 113                     entries: vec![]
 114                 },
 115                 RowInput {
 116                     label: String::from("bar"),
 117                     entries: vec![]
 118                 }
 119             ]
 120         );
 121         assert_eq!(
 122             read_rows(&b"foo\n bar\n"[..]).flatten().collect::<Vec<_>>(),
 123             vec![RowInput {
 124                 label: String::from("foo"),
 125                 entries: vec![String::from("bar")]
 126             }]
 127         );
 128         assert_eq!(
 129             read_rows(&b"foo\n bar\n baz\n"[..])
 130                 .flatten()
 131                 .collect::<Vec<_>>(),
 132             vec![RowInput {
 133                 label: String::from("foo"),
 134                 entries: vec![String::from("bar"), String::from("baz")]
 135             }]
 136         );
 137         assert_eq!(
 138             read_rows(&b"foo\n\nbar\n"[..])
 139                 .flatten()
 140                 .collect::<Vec<_>>(),
 141             vec![
 142                 RowInput {
 143                     label: String::from("foo"),
 144                     entries: vec![]
 145                 },
 146                 RowInput {
 147                     label: String::from("bar"),
 148                     entries: vec![]
 149                 }
 150             ]
 151         );
 152         assert_eq!(
 153             read_rows(&b"foo\n \nbar\n"[..])
 154                 .flatten()
 155                 .collect::<Vec<_>>(),
 156             vec![
 157                 RowInput {
 158                     label: String::from("foo"),
 159                     entries: vec![]
 160                 },
 161                 RowInput {
 162                     label: String::from("bar"),
 163                     entries: vec![]
 164                 }
 165             ]
 166         );
 167         assert_eq!(
 168             read_rows(&b"foo  \n bar  \n"[..])
 169                 .flatten()
 170                 .collect::<Vec<_>>(),
 171             vec![RowInput {
 172                 label: String::from("foo"),
 173                 entries: vec![String::from("bar")]
 174             }]
 175         );
 176
 177         let bad = read_rows(&b" foo"[..]).next().unwrap();
 178         assert!(bad.is_err());
 179         assert!(format!("{bad:?}").contains("1: Entry with no header"));
 180
 181         let bad2 = read_rows(&b"foo\n\n bar"[..]).nth(1).unwrap();
 182         assert!(bad2.is_err());
 183         assert!(format!("{bad2:?}").contains("3: Entry with no header"));
 184     }
 185
 186     #[test]
 187     fn test_column_counts() {
 188         assert_eq!(
 189             column_counts(
 190                 &read_rows(&b"foo\n bar\n baz\n"[..])
 191                     .collect::<Result<Vec<_>, _>>()
 192                     .unwrap()
 193             ),
 194             HashMap::from([(String::from("bar"), 1), (String::from("baz"), 1)])
 195         );
 196         assert_eq!(
 197             column_counts(
 198                 &read_rows(&b"foo\n bar\n baz\nquux\n baz"[..])
 199                     .collect::<Result<Vec<_>, _>>()
 200                     .unwrap()
 201             ),
 202             HashMap::from([(String::from("bar"), 1), (String::from("baz"), 2)])
 203         );
 204     }
 205 }