Add a special query syntax for Pickers to select columns

Now that the picker is defined as a table, we need a way to provide
input for each field in the picker. We introduce a small query syntax
that supports multiple columns without being too verbose. Fields are
specified as `%field pattern`. The default column for a picker doesn't
need the `%field` prefix. The field name may be selected by a prefix
of the field, for example `%p foo.rs` rather than `%path foo.rs`.

Co-authored-by: ItsEthra <107059409+ItsEthra@users.noreply.github.com>

helix-term/src/ui/picker.rs

@@ -1,4 +1,5 @@
 mod handlers;
+mod query;
 
 use crate::{
     alt,
@@ -9,6 +10,7 @@
     ui::{
         self,
         document::{render_document, LineDecoration, LinePos, TextRenderer},
+        picker::query::PickerQuery,
         EditorView,
     },
 };
@@ -226,7 +228,7 @@ pub struct Picker<T: 'static + Send + Sync, D: 'static> {
 
     cursor: u32,
     prompt: Prompt,
-    previous_pattern: String,
+    query: PickerQuery,
 
     /// Whether to show the preview panel (default true)
     show_preview: bool,
@@ -331,6 +333,8 @@ fn with(
             .map(|column| Constraint::Length(column.name.chars().count() as u16))
             .collect();
 
+        let query = PickerQuery::new(columns.iter().map(|col| &col.name).cloned(), default_column);
+
         Self {
             columns,
             primary_column: default_column,
@@ -339,7 +343,7 @@ fn with(
             shutdown,
             cursor: 0,
             prompt,
-            previous_pattern: String::new(),
+            query,
             truncate_start: true,
             show_preview: true,
             callback_fn: Box::new(callback_fn),
@@ -441,6 +445,13 @@ pub fn selection(&self) -> Option<&T> {
             .map(|item| item.data)
     }
 
+    fn primary_query(&self) -> Arc<str> {
+        self.query
+            .get(&self.columns[self.primary_column].name)
+            .cloned()
+            .unwrap_or_else(|| "".into())
+    }
+
     fn header_height(&self) -> u16 {
         if self.columns.len() > 1 {
             1
@@ -461,16 +472,36 @@ fn prompt_handle_event(&mut self, event: &Event, cx: &mut Context) -> EventResul
     }
 
     fn handle_prompt_change(&mut self) {
-        let pattern = self.prompt.line();
         // TODO: better track how the pattern has changed
-        if pattern != &self.previous_pattern {
-            self.matcher.pattern.reparse(
-                0,
-                pattern,
-                CaseMatching::Smart,
-                pattern.starts_with(&self.previous_pattern),
-            );
-            self.previous_pattern = pattern.clone();
+        let line = self.prompt.line();
+        let old_query = self.query.parse(line);
+        if self.query == old_query {
+            return;
+        }
+        // Have nucleo reparse each changed column.
+        for (i, column) in self
+            .columns
+            .iter()
+            .filter(|column| column.filter)
+            .enumerate()
+        {
+            let pattern = self
+                .query
+                .get(&column.name)
+                .map(|f| &**f)
+                .unwrap_or_default();
+            let old_pattern = old_query
+                .get(&column.name)
+                .map(|f| &**f)
+                .unwrap_or_default();
+            // Fastlane: most columns will remain unchanged after each edit.
+            if pattern == old_pattern {
+                continue;
+            }
+            let is_append = pattern.starts_with(old_pattern);
+            self.matcher
+                .pattern
+                .reparse(i, pattern, CaseMatching::Smart, is_append);
         }
     }
 

helix-term/src/ui/picker/query.rs

@@ -0,0 +1,282 @@
+use std::{collections::HashMap, mem, sync::Arc};
+
+#[derive(Debug)]
+pub(super) struct PickerQuery {
+    /// The column names of the picker.
+    column_names: Box<[Arc<str>]>,
+    /// The index of the primary column in `column_names`.
+    /// The primary column is selected by default unless another
+    /// field is specified explicitly with `%fieldname`.
+    primary_column: usize,
+    /// The mapping between column names and input in the query
+    /// for those columns.
+    inner: HashMap<Arc<str>, Arc<str>>,
+}
+
+impl PartialEq<HashMap<Arc<str>, Arc<str>>> for PickerQuery {
+    fn eq(&self, other: &HashMap<Arc<str>, Arc<str>>) -> bool {
+        self.inner.eq(other)
+    }
+}
+
+impl PickerQuery {
+    pub(super) fn new<I: Iterator<Item = Arc<str>>>(
+        column_names: I,
+        primary_column: usize,
+    ) -> Self {
+        let column_names: Box<[_]> = column_names.collect();
+        let inner = HashMap::with_capacity(column_names.len());
+        Self {
+            column_names,
+            primary_column,
+            inner,
+        }
+    }
+
+    pub(super) fn get(&self, column: &str) -> Option<&Arc<str>> {
+        self.inner.get(column)
+    }
+
+    pub(super) fn parse(&mut self, input: &str) -> HashMap<Arc<str>, Arc<str>> {
+        let mut fields: HashMap<Arc<str>, String> = HashMap::new();
+        let primary_field = &self.column_names[self.primary_column];
+        let mut escaped = false;
+        let mut in_field = false;
+        let mut field = None;
+        let mut text = String::new();
+
+        macro_rules! finish_field {
+            () => {
+                let key = field.take().unwrap_or(primary_field);
+
+                if let Some(pattern) = fields.get_mut(key) {
+                    pattern.push(' ');
+                    pattern.push_str(text.trim());
+                } else {
+                    fields.insert(key.clone(), text.trim().to_string());
+                }
+                text.clear();
+            };
+        }
+
+        for ch in input.chars() {
+            match ch {
+                // Backslash escaping
+                _ if escaped => {
+                    // '%' is the only character that is special cased.
+                    // You can escape it to prevent parsing the text that
+                    // follows it as a field name.
+                    if ch != '%' {
+                        text.push('\\');
+                    }
+                    text.push(ch);
+                    escaped = false;
+                }
+                '\\' => escaped = !escaped,
+                '%' => {
+                    if !text.is_empty() {
+                        finish_field!();
+                    }
+                    in_field = true;
+                }
+                ' ' if in_field => {
+                    // Go over all columns and their indices, find all that starts with field key,
+                    // select a column that fits key the most.
+                    field = self
+                        .column_names
+                        .iter()
+                        .filter(|col| col.starts_with(&text))
+                        // select "fittest" column
+                        .min_by_key(|col| col.len());
+                    text.clear();
+                    in_field = false;
+                }
+                _ => text.push(ch),
+            }
+        }
+
+        if !in_field && !text.is_empty() {
+            finish_field!();
+        }
+
+        let new_inner: HashMap<_, _> = fields
+            .into_iter()
+            .map(|(field, query)| (field, query.as_str().into()))
+            .collect();
+
+        mem::replace(&mut self.inner, new_inner)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use helix_core::hashmap;
+
+    use super::*;
+
+    #[test]
+    fn parse_query_test() {
+        let mut query = PickerQuery::new(
+            [
+                "primary".into(),
+                "field1".into(),
+                "field2".into(),
+                "another".into(),
+                "anode".into(),
+            ]
+            .into_iter(),
+            0,
+        );
+
+        // Basic field splitting
+        query.parse("hello world");
+        assert_eq!(
+            query,
+            hashmap!(
+                "primary".into() => "hello world".into(),
+            )
+        );
+        query.parse("hello %field1 world %field2 !");
+        assert_eq!(
+            query,
+            hashmap!(
+                "primary".into() => "hello".into(),
+                "field1".into() => "world".into(),
+                "field2".into() => "!".into(),
+            )
+        );
+        query.parse("%field1 abc %field2 def xyz");
+        assert_eq!(
+            query,
+            hashmap!(
+                "field1".into() => "abc".into(),
+                "field2".into() => "def xyz".into(),
+            )
+        );
+
+        // Trailing space is trimmed
+        query.parse("hello ");
+        assert_eq!(
+            query,
+            hashmap!(
+                "primary".into() => "hello".into(),
+            )
+        );
+
+        // Unknown fields are trimmed.
+        query.parse("hello %foo");
+        assert_eq!(
+            query,
+            hashmap!(
+                "primary".into() => "hello".into(),
+            )
+        );
+
+        // Multiple words in a field
+        query.parse("hello %field1 a b c");
+        assert_eq!(
+            query,
+            hashmap!(
+                "primary".into() => "hello".into(),
+                "field1".into() => "a b c".into(),
+            )
+        );
+
+        // Escaping
+        query.parse(r#"hello\ world"#);
+        assert_eq!(
+            query,
+            hashmap!(
+                "primary".into() => r#"hello\ world"#.into(),
+            )
+        );
+        query.parse(r#"hello \%field1 world"#);
+        assert_eq!(
+            query,
+            hashmap!(
+                "primary".into() => "hello %field1 world".into(),
+            )
+        );
+        query.parse(r#"%field1 hello\ world"#);
+        assert_eq!(
+            query,
+            hashmap!(
+                "field1".into() => r#"hello\ world"#.into(),
+            )
+        );
+        query.parse(r#"hello %field1 a\"b"#);
+        assert_eq!(
+            query,
+            hashmap!(
+                "primary".into() => "hello".into(),
+                "field1".into() => r#"a\"b"#.into(),
+            )
+        );
+        query.parse(r#"%field1 hello\ world"#);
+        assert_eq!(
+            query,
+            hashmap!(
+                "field1".into() => r#"hello\ world"#.into(),
+            )
+        );
+        query.parse(r#"\bfoo\b"#);
+        assert_eq!(
+            query,
+            hashmap!(
+                "primary".into() => r#"\bfoo\b"#.into(),
+            )
+        );
+        query.parse(r#"\\n"#);
+        assert_eq!(
+            query,
+            hashmap!(
+                "primary".into() => r#"\\n"#.into(),
+            )
+        );
+
+        // Only the prefix of a field is required.
+        query.parse("hello %anot abc");
+        assert_eq!(
+            query,
+            hashmap!(
+                "primary".into() => "hello".into(),
+                "another".into() => "abc".into(),
+            )
+        );
+        // The shortest matching the prefix is selected.
+        query.parse("hello %ano abc");
+        assert_eq!(
+            query,
+            hashmap!(
+                "primary".into() => "hello".into(),
+                "anode".into() => "abc".into()
+            )
+        );
+        // Multiple uses of a column are concatenated with space separators.
+        query.parse("hello %field1 xyz %fie abc");
+        assert_eq!(
+            query,
+            hashmap!(
+                "primary".into() => "hello".into(),
+                "field1".into() => "xyz abc".into()
+            )
+        );
+        query.parse("hello %fie abc");
+        assert_eq!(
+            query,
+            hashmap!(
+                "primary".into() => "hello".into(),
+                "field1".into() => "abc".into()
+            )
+        );
+        // The primary column can be explicitly qualified.
+        query.parse("hello %fie abc %prim world");
+        assert_eq!(
+            query,
+            hashmap!(
+                "primary".into() => "hello world".into(),
+                "field1".into() => "abc".into()
+            )
+        );
+    }
+}