Allow specifying file start position (#445)

Like helix-term/src/commands.rs:3426:15

helix-core/src/position.rs

@@ -109,7 +109,10 @@ pub fn visual_coords_at_pos(text: RopeSlice, pos: usize, tab_width: usize) -> Po
 /// TODO: this should be changed to work in terms of visual row/column, not
 /// graphemes.
 pub fn pos_at_coords(text: RopeSlice, coords: Position, limit_before_line_ending: bool) -> usize {
-    let Position { row, col } = coords;
+    let Position { mut row, col } = coords;
+    if limit_before_line_ending {
+        row = row.min(text.len_lines() - 1);
+    };
     let line_start = text.line_to_char(row);
     let line_end = if limit_before_line_ending {
         line_end_char_index(&text, row)
@@ -290,5 +293,12 @@ fn test_pos_at_coords() {
         assert_eq!(pos_at_coords(slice, (0, 0).into(), false), 0);
         assert_eq!(pos_at_coords(slice, (0, 1).into(), false), 1);
         assert_eq!(pos_at_coords(slice, (0, 2).into(), false), 2);
+
+        // Test out of bounds.
+        let text = Rope::new();
+        let slice = text.slice(..);
+        assert_eq!(pos_at_coords(slice, (10, 0).into(), true), 0);
+        assert_eq!(pos_at_coords(slice, (0, 10).into(), true), 0);
+        assert_eq!(pos_at_coords(slice, (10, 10).into(), true), 0);
     }
 }

helix-term/src/application.rs

@@ -1,10 +1,14 @@
-use helix_core::{merge_toml_values, syntax};
+use helix_core::{merge_toml_values, pos_at_coords, syntax, Selection};
 use helix_lsp::{lsp, util::lsp_pos_to_pos, LspProgressMap};
 use helix_view::{theme, Editor};
 use serde_json::json;
 
 use crate::{
-    args::Args, commands::apply_workspace_edit, compositor::Compositor, config::Config, job::Jobs,
+    args::Args,
+    commands::{align_view, apply_workspace_edit, Align},
+    compositor::Compositor,
+    config::Config,
+    job::Jobs,
     ui,
 };
 
@@ -130,7 +134,7 @@ pub fn new(args: Args, mut config: Config) -> Result<Self, Error> {
             // Unset path to prevent accidentally saving to the original tutor file.
             doc_mut!(editor).set_path(None)?;
         } else if !args.files.is_empty() {
-            let first = &args.files[0]; // we know it's not empty
+            let first = &args.files[0].0; // we know it's not empty
             if first.is_dir() {
                 std::env::set_current_dir(&first)?;
                 editor.new_file(Action::VerticalSplit);
@@ -138,16 +142,25 @@ pub fn new(args: Args, mut config: Config) -> Result<Self, Error> {
             } else {
                 let nr_of_files = args.files.len();
                 editor.open(first.to_path_buf(), Action::VerticalSplit)?;
-                for file in args.files {
+                for (file, pos) in args.files {
                     if file.is_dir() {
                         return Err(anyhow::anyhow!(
                             "expected a path to file, found a directory. (to open a directory pass it as first argument)"
                         ));
                     } else {
-                        editor.open(file.to_path_buf(), Action::Load)?;
+                        let doc_id = editor.open(file, Action::Load)?;
+                        // with Action::Load all documents have the same view
+                        let view_id = editor.tree.focus;
+                        let doc = editor.document_mut(doc_id).unwrap();
+                        let pos = Selection::point(pos_at_coords(doc.text().slice(..), pos, true));
+                        doc.set_selection(view_id, pos);
                     }
                 }
                 editor.set_status(format!("Loaded {} files.", nr_of_files));
+                // align the view to center after all files are loaded,
+                // does not affect views without pos since it is at the top
+                let (view, doc) = current!(editor);
+                align_view(doc, view, Align::Center);
             }
         } else if stdin().is_tty() {
             editor.new_file(Action::VerticalSplit);

helix-term/src/args.rs

@@ -1,5 +1,6 @@
 use anyhow::{Error, Result};
-use std::path::PathBuf;
+use helix_core::Position;
+use std::path::{Path, PathBuf};
 
 #[derive(Default)]
 pub struct Args {
@@ -7,7 +8,7 @@ pub struct Args {
     pub display_version: bool,
     pub load_tutor: bool,
     pub verbosity: u64,
-    pub files: Vec<PathBuf>,
+    pub files: Vec<(PathBuf, Position)>,
 }
 
 impl Args {
@@ -41,15 +42,49 @@ pub fn parse_args() -> Result<Args> {
                         }
                     }
                 }
-                arg => args.files.push(PathBuf::from(arg)),
+                arg => args.files.push(parse_file(arg)),
             }
         }
 
         // push the remaining args, if any to the files
-        for filename in iter {
-            args.files.push(PathBuf::from(filename));
+        for arg in iter {
+            args.files.push(parse_file(arg));
         }
 
         Ok(args)
     }
 }
+
+/// Parse arg into [`PathBuf`] and position.
+pub(crate) fn parse_file(s: &str) -> (PathBuf, Position) {
+    let def = || (PathBuf::from(s), Position::default());
+    if Path::new(s).exists() {
+        return def();
+    }
+    split_path_row_col(s)
+        .or_else(|| split_path_row(s))
+        .unwrap_or_else(def)
+}
+
+/// Split file.rs:10:2 into [`PathBuf`], row and col.
+///
+/// Does not validate if file.rs is a file or directory.
+fn split_path_row_col(s: &str) -> Option<(PathBuf, Position)> {
+    let mut s = s.rsplitn(3, ':');
+    let col: usize = s.next()?.parse().ok()?;
+    let row: usize = s.next()?.parse().ok()?;
+    let path = s.next()?.into();
+    let pos = Position::new(row.saturating_sub(1), col.saturating_sub(1));
+    Some((path, pos))
+}
+
+/// Split file.rs:10 into [`PathBuf`] and row.
+///
+/// Does not validate if file.rs is a file or directory.
+fn split_path_row(s: &str) -> Option<(PathBuf, Position)> {
+    let (row, path) = s.rsplit_once(':')?;
+    let row: usize = row.parse().ok()?;
+    let path = path.into();
+    let pos = Position::new(row.saturating_sub(1), 0);
+    Some((path, pos))
+}

helix-term/src/commands.rs

@@ -37,6 +37,7 @@
 use movement::Movement;
 
 use crate::{
+    args,
     compositor::{self, Component, Compositor},
     ui::{self, FilePicker, Picker, Popup, Prompt, PromptEvent},
 };
@@ -113,13 +114,13 @@ pub fn count(&self) -> usize {
     }
 }
 
-enum Align {
+pub(crate) enum Align {
     Top,
     Center,
     Bottom,
 }
 
-fn align_view(doc: &Document, view: &mut View, align: Align) {
+pub(crate) fn align_view(doc: &Document, view: &mut View, align: Align) {
     let pos = doc
         .selection(view.id)
         .primary()
@@ -2028,7 +2029,13 @@ fn open(
     ) -> anyhow::Result<()> {
         ensure!(!args.is_empty(), "wrong argument count");
         for arg in args {
-            let _ = cx.editor.open(arg.as_ref().into(), Action::Replace)?;
+            let (path, pos) = args::parse_file(arg);
+            let _ = cx.editor.open(path, Action::Replace)?;
+            let (view, doc) = current!(cx.editor);
+            let pos = Selection::point(pos_at_coords(doc.text().slice(..), pos, true));
+            doc.set_selection(view.id, pos);
+            // does not affect opening a buffer without pos
+            align_view(doc, view, Align::Center);
         }
         Ok(())
     }

helix-term/src/main.rs

@@ -56,7 +56,7 @@ async fn main_impl() -> Result<i32> {
     hx [FLAGS] [files]...
 
 ARGS:
-    <files>...    Sets the input file to use
+    <files>...    Sets the input file to use, position can also be specified via file[:row[:col]]
 
 FLAGS:
     -h, --help       Prints help information