Start connecting stuff

[tablify] / src / lib.rs

diff --git a/src/lib.rs b/src/lib.rs
index b583c3eefb0b3e3f1ea74f0aae24556b711865a1..8d60eb8ba898b65d93f3e50c00d859206f11ba36 100644 (file)
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,6 +1,5 @@
-#[cfg(test)]
+use std::collections::{HashMap, HashSet};
 use std::io::BufRead;
-#[cfg(test)]
 use std::iter::Iterator;
 
 #[derive(Debug, PartialEq, Eq)]
@@ -10,31 +9,42 @@ struct RowInput {
 }
 
 struct Reader<Input: Iterator<Item = Result<String, std::io::Error>>> {
-    input: Input,
+    input: std::iter::Enumerate<Input>,
     row: Option<RowInput>,
 }
 impl<Input: Iterator<Item = Result<String, std::io::Error>>> Reader<Input> {
-    #[cfg(test)]
     fn new(input: Input) -> Self {
-        Self { input, row: None }
+        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() {
+            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() => {
+                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(Ok(line)) if line.starts_with(' ') => match &mut self.row {
-                    None => return Some(Err(std::io::Error::other("Entry with no header"))),
+                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)) => {
+                Some((_, Ok(line))) => {
                     let prev = std::mem::take(&mut self.row);
                     self.row = Some(RowInput {
                         label: line,
@@ -49,13 +59,37 @@ impl<Input: Iterator<Item = Result<String, std::io::Error>>> Iterator for Reader
     }
 }
 
-#[cfg(test)]
 fn read_rows(input: impl std::io::Read) -> impl Iterator<Item = Result<RowInput, std::io::Error>> {
     Reader::new(std::io::BufReader::new(input).lines())
 }
 
-pub fn tablify(_input: &impl std::io::Read) -> String {
-    String::from("Hello, world!")
+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)]
@@ -122,13 +156,65 @@ mod tests {
                 }
             ]
         );
+        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("Entry with no header"));
+        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("Entry with no header"));
+        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"))]
+        );
     }
 }