Start connecting stuff

[tablify] / src / lib.rs

diff --git a/src/lib.rs b/src/lib.rs
index 56a2b6ddec94a404a23d582bbf3b16fcc06bb5bc..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)]
@@ -14,7 +13,6 @@ struct Reader<Input: Iterator<Item = Result<String, std::io::Error>>> {
     row: Option<RowInput>,
 }
 impl<Input: Iterator<Item = Result<String, std::io::Error>>> Reader<Input> {
-    #[cfg(test)]
     fn new(input: Input) -> Self {
         Self {
             input: input.enumerate(),
@@ -61,13 +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)]
@@ -167,4 +189,32 @@ mod tests {
         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"))]
+        );
+    }
 }