View tree implementation: render multiple split views.

Cursors are still a bit buggy and we should render in focus statusbar
differently than in the other pane.

9 files changed, 238 insertions, 207 deletions

diff --git a/Cargo.lock b/Cargo.lock
index fc0d9e5a..eb38e755 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -11,9 +11,9 @@ dependencies = [
 
 [[package]]
 name = "anyhow"
-version = "1.0.37"
+version = "1.0.38"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ee67c11feeac938fae061b232e38e0b6d94f97a9df10e6271319325ac4c56a86"
+checksum = "afddf7f520a80dbf76e6f50a35bca42a2331ef227a28b3b6dc5c2e2338d114b1"
 
 [[package]]
 name = "async-channel"
@@ -321,9 +321,9 @@ dependencies = [
 
 [[package]]
 name = "dirs-sys-next"
-version = "0.1.1"
+version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "99de365f605554ae33f115102a02057d4fc18b01f3284d6870be0938743cfe7d"
+checksum = "4ebda144c4fe02d1f7ea1a7d9641b6fc6b580adcfa024ae48797ecdeb6825b4d"
 dependencies = [
  "libc",
  "redox_users",
@@ -388,9 +388,9 @@ dependencies = [
 
 [[package]]
 name = "futures"
-version = "0.3.9"
+version = "0.3.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c70be434c505aee38639abccb918163b63158a4b4bb791b45b7023044bdc3c9c"
+checksum = "da9052a1a50244d8d5aa9bf55cbc2fb6f357c86cc52e46c62ed390a7180cf150"
 dependencies = [
  "futures-channel",
  "futures-core",
@@ -403,9 +403,9 @@ dependencies = [
 
 [[package]]
 name = "futures-channel"
-version = "0.3.9"
+version = "0.3.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f01c61843314e95f96cc9245702248733a3a3d744e43e2e755e3c7af8348a0a9"
+checksum = "f2d31b7ec7efab6eefc7c57233bb10b847986139d88cc2f5a02a1ae6871a1846"
 dependencies = [
  "futures-core",
  "futures-sink",
@@ -413,15 +413,15 @@ dependencies = [
 
 [[package]]
 name = "futures-core"
-version = "0.3.9"
+version = "0.3.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "db8d3b0917ff63a2a96173133c02818fac4a746b0a57569d3baca9ec0e945e08"
+checksum = "79e5145dde8da7d1b3892dad07a9c98fc04bc39892b1ecc9692cf53e2b780a65"
 
 [[package]]
 name = "futures-executor"
-version = "0.3.9"
+version = "0.3.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9ee9ca2f7eb4475772cf39dd1cd06208dce2670ad38f4d9c7262b3e15f127068"
+checksum = "e9e59fdc009a4b3096bf94f740a0f2424c082521f20a9b08c5c07c48d90fd9b9"
 dependencies = [
  "futures-core",
  "futures-task",
@@ -430,9 +430,9 @@ dependencies = [
 
 [[package]]
 name = "futures-io"
-version = "0.3.9"
+version = "0.3.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e37c1a51b037b80922864b8eed90692c5cd8abd4c71ce49b77146caa47f3253b"
+checksum = "28be053525281ad8259d47e4de5de657b25e7bac113458555bb4b70bc6870500"
 
 [[package]]
 name = "futures-lite"
@@ -445,15 +445,15 @@ dependencies = [
  "futures-io",
  "memchr",
  "parking",
- "pin-project-lite 0.2.1",
+ "pin-project-lite 0.2.4",
  "waker-fn",
 ]
 
 [[package]]
 name = "futures-macro"
-version = "0.3.9"
+version = "0.3.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0f8719ca0e1f3c5e34f3efe4570ef2c0610ca6da85ae7990d472e9cbfba13664"
+checksum = "c287d25add322d9f9abdcdc5927ca398917996600182178774032e9f8258fedd"
 dependencies = [
  "proc-macro-hack",
  "proc-macro2",
@@ -463,24 +463,24 @@ dependencies = [
 
 [[package]]
 name = "futures-sink"
-version = "0.3.9"
+version = "0.3.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f6adabac1290109cfa089f79192fb6244ad2c3f1cc2281f3e1dd987592b71feb"
+checksum = "caf5c69029bda2e743fddd0582d1083951d65cc9539aebf8812f36c3491342d6"
 
 [[package]]
 name = "futures-task"
-version = "0.3.9"
+version = "0.3.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a92a0843a2ff66823a8f7c77bffe9a09be2b64e533562c412d63075643ec0038"
+checksum = "13de07eb8ea81ae445aca7b69f5f7bf15d7bf4912d8ca37d6645c77ae8a58d86"
 dependencies = [
  "once_cell",
 ]
 
 [[package]]
 name = "futures-util"
-version = "0.3.9"
+version = "0.3.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "036a2107cdeb57f6d7322f1b6c363dad67cd63ca3b7d1b925bdf75bd5d96cda9"
+checksum = "632a8cd0f2a4b3fdea1657f08bde063848c3bd00f9bbf6e256b8be78802e624b"
 dependencies = [
  "futures-channel",
  "futures-core",
@@ -489,7 +489,7 @@ dependencies = [
  "futures-sink",
  "futures-task",
  "memchr",
- "pin-project-lite 0.2.1",
+ "pin-project-lite 0.2.4",
  "pin-utils",
  "proc-macro-hack",
  "proc-macro-nested",
@@ -507,13 +507,13 @@ dependencies = [
 
 [[package]]
 name = "getrandom"
-version = "0.1.16"
+version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8fc3cb4d91f53b50155bdcfd23f6a4c39ae1969c2ae85982b135750cccaf5fce"
+checksum = "c9495705279e7140bf035dde1f6e750c162df8b625267cd52cc44e0b156732c8"
 dependencies = [
  "cfg-if 1.0.0",
  "libc",
- "wasi 0.9.0+wasi-snapshot-preview1",
+ "wasi",
 ]
 
 [[package]]
@@ -621,6 +621,7 @@ dependencies = [
  "helix-core",
  "helix-lsp",
  "once_cell",
+ "slotmap",
  "smol",
  "tui",
  "url",
@@ -628,9 +629,9 @@ dependencies = [
 
 [[package]]
 name = "hermit-abi"
-version = "0.1.17"
+version = "0.1.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5aca5565f760fb5b220e499d72710ed156fdb74e631659e99377d9ebfbd13ae8"
+checksum = "322f4de77956e22ed0e5032c359a0f1273f1f7f0d79bfa3b8ffbc730d7fbcc5c"
 dependencies = [
  "libc",
 ]
@@ -719,9 +720,9 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "libc"
-version = "0.2.82"
+version = "0.2.85"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "89203f3fba0a3795506acaad8ebce3c80c0af93f994d5a1d7a0b1eeb23271929"
+checksum = "7ccac4b00700875e6a07c6cde370d44d32fa01c5a65cdd2fca6858c479d28bb3"
 
 [[package]]
 name = "lock_api"
@@ -734,11 +735,11 @@ dependencies = [
 
 [[package]]
 name = "log"
-version = "0.4.11"
+version = "0.4.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4fabed175da42fed1fa0746b0ea71f412aa9d35e76e95e59b192c64b9dc2bf8b"
+checksum = "51b9bbe6c47d51fc3e1a9b945965946b4c44142ab8792c50835a980d362c2710"
 dependencies = [
- "cfg-if 0.1.10",
+ "cfg-if 1.0.0",
 ]
 
 [[package]]
@@ -897,7 +898,7 @@ dependencies = [
  "cfg-if 1.0.0",
  "instant",
  "libc",
- "redox_syscall",
+ "redox_syscall 0.1.57",
  "smallvec",
  "winapi",
 ]
@@ -922,9 +923,9 @@ checksum = "c917123afa01924fc84bb20c4c03f004d9c38e5127e3c039bbf7f4b9c76a2f6b"
 
 [[package]]
 name = "pin-project-lite"
-version = "0.2.1"
+version = "0.2.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e36743d754ccdf9954c2e352ce2d4b106e024c814f6499c2dadff80da9a442d8"
+checksum = "439697af366c49a6d0a010c56a0d97685bc140ce0d377b13a2ea2aa42d64a827"
 
 [[package]]
 name = "pin-utils"
@@ -953,9 +954,9 @@ checksum = "dbf0c48bc1d91375ae5c3cd81e3722dff1abcf81a30960240640d223f59fe0e5"
 
 [[package]]
 name = "proc-macro-nested"
-version = "0.1.6"
+version = "0.1.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "eba180dafb9038b050a4c280019bbedf9f2467b61e5d892dcad585bb57aadc5a"
+checksum = "bc881b2c22681370c6a780e47af9840ef841837bc98118431d4e1868bd0c1086"
 
 [[package]]
 name = "proc-macro2"
@@ -1007,20 +1008,29 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "41cc0f7e4d5d4544e8861606a285bb08d3e70712ccc7d2b84d7c0ccfaf4b05ce"
 
 [[package]]
+name = "redox_syscall"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "05ec8ca9416c5ea37062b502703cd7fcb207736bc294f6e0cf367ac6fc234570"
+dependencies = [
+ "bitflags",
+]
+
+[[package]]
 name = "redox_users"
-version = "0.3.5"
+version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "de0737333e7a9502c789a36d7c7fa6092a49895d4faa31ca5df163857ded2e9d"
+checksum = "528532f3d801c87aec9def2add9ca802fe569e44a544afe633765267840abe64"
 dependencies = [
  "getrandom",
- "redox_syscall",
+ "redox_syscall 0.2.4",
 ]
 
 [[package]]
 name = "regex"
-version = "1.4.2"
+version = "1.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "38cf2c13ed4745de91a5eb834e11c00bcc3709e773173b2ce4c56c9fbde04b9c"
+checksum = "d9251239e129e16308e70d853559389de218ac275b515068abc96829d05b948a"
 dependencies = [
  "aho-corasick",
  "memchr",
@@ -1030,9 +1040,9 @@ dependencies = [
 
 [[package]]
 name = "regex-syntax"
-version = "0.6.21"
+version = "0.6.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3b181ba2dcf07aaccad5448e8ead58db5b742cf85dfe035e2227f137a539a189"
+checksum = "b5eb417147ba9860a96cfe72a0b93bf88fee1744b5636ec99ab20c1aa9376581"
 
 [[package]]
 name = "ropey"
@@ -1066,18 +1076,18 @@ checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
 
 [[package]]
 name = "serde"
-version = "1.0.118"
+version = "1.0.123"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "06c64263859d87aa2eb554587e2d23183398d617427327cf2b3d0ed8c69e4800"
+checksum = "92d5161132722baa40d802cc70b15262b98258453e85e5d1d365c757c73869ae"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.118"
+version = "1.0.123"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c84d3526699cd55261af4b941e4e725444df67aa4f9e6a3564f18030d12672df"
+checksum = "9391c295d64fc0abb2c556bad848f33cb8296276b1ad2677d1ae1ace4f258f31"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1142,10 +1152,19 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c111b5bd5695e56cffe5129854aa230b39c93a305372fdbb2668ca2394eea9f8"
 
 [[package]]
+name = "slotmap"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ab3003725ae562cf995f3dc82bb99e70926e09000396816765bb6d7adbe740b1"
+dependencies = [
+ "version_check",
+]
+
+[[package]]
 name = "smallvec"
-version = "1.6.0"
+version = "1.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1a55ca5f3b68e41c979bf8c46a6f1da892ca4db8f94023ce0bd32407573b1ac0"
+checksum = "fe0f37c9e8f3c5a4a66ad655a93c74daac4ad00c441533bf5c6e7990bb42604e"
 
 [[package]]
 name = "smol"
@@ -1188,9 +1207,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.58"
+version = "1.0.60"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cc60a3d73ea6594cd712d830cc1f0390fd71542d8c8cd24e70cc54cdfd5e05d5"
+checksum = "c700597eca8a5a762beb35753ef6b94df201c81cca676604f547495a0d7f0081"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1199,8 +1218,8 @@ dependencies = [
 
 [[package]]
 name = "tendril"
-version = "0.4.1"
-source = "git+https://github.com/servo/tendril#9532724c32a0bf5e65acb56209373d97223bc530"
+version = "0.4.2"
+source = "git+https://github.com/servo/tendril#548cfaab79a3db13f350621d5b18a81d351463ba"
 dependencies = [
  "futf",
  "mac",
@@ -1238,29 +1257,28 @@ dependencies = [
 
 [[package]]
 name = "thread_local"
-version = "1.1.0"
+version = "1.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bb9bc092d0d51e76b2b19d9d85534ffc9ec2db959a2523cdae0697e2972cd447"
+checksum = "d8208a331e1cb318dd5bd76951d2b8fc48ca38a69f5f4e4af1b6a9f8c6236915"
 dependencies = [
- "lazy_static",
+ "once_cell",
 ]
 
 [[package]]
 name = "time"
-version = "0.1.44"
+version = "0.1.43"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6db9e6914ab8b1ae1c260a4ae7a49b6c5611b40328a735b21862567685e73255"
+checksum = "ca8a50ef2360fbd1eeb0ecd46795a87a19024eb4b53c5dc916ca1fd95fe62438"
 dependencies = [
  "libc",
- "wasi 0.10.0+wasi-snapshot-preview1",
  "winapi",
 ]
 
 [[package]]
 name = "tinyvec"
-version = "1.1.0"
+version = "1.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ccf8dbc19eb42fba10e8feaaec282fb50e2c14b2726d6301dbfeed0f73306a6f"
+checksum = "317cca572a0e89c3ce0ca1f1bdc9369547fe318a683418e42ac8f59d14701023"
 dependencies = [
  "tinyvec_macros",
 ]
@@ -1361,6 +1379,12 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f1bddf1187be692e79c5ffeab891132dfb0f236ed36a43c7ed39f1165ee20191"
 
 [[package]]
+name = "version_check"
+version = "0.9.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b5a972e5669d67ba988ce3dc826706fb0a8b01471c088cb0b6110b805cc36aed"
+
+[[package]]
 name = "waker-fn"
 version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -1379,15 +1403,9 @@ dependencies = [
 
 [[package]]
 name = "wasi"
-version = "0.9.0+wasi-snapshot-preview1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
-
-[[package]]
-name = "wasi"
-version = "0.10.0+wasi-snapshot-preview1"
+version = "0.10.2+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1a143597ca7c7793eff794def352d41792a93c481eb1042423ff7ff72ba2c31f"
+checksum = "fd6fbd9a79829dd1ad0cc20627bf1ed606756a7f77edff7b66b7064f9cb327c6"
 
 [[package]]
 name = "wepoll-sys"
diff --git a/helix-term/src/application.rs b/helix-term/src/application.rs
index f32db3b3..6e000534 100644
--- a/helix-term/src/application.rs
+++ b/helix-term/src/application.rs
@@ -39,11 +39,12 @@ impl Application {
     pub fn new(mut args: Args, executor: &'static smol::Executor<'static>) -> Result<Self, Error> {
         let backend = CrosstermBackend::new(stdout());
         let mut terminal = Terminal::new(backend)?;
-        let mut editor = Editor::new();
         let size = terminal.size()?;
+        let mut editor = Editor::new(size);
 
-        if let Some(file) = args.values_of_t::<PathBuf>("files").unwrap().pop() {
-            editor.open(file, (size.width, size.height), executor)?;
+        let files = args.values_of_t::<PathBuf>("files").unwrap();
+        for file in files {
+            editor.open(file, executor)?;
         }
 
         let mut compositor = Compositor::new();
@@ -132,11 +133,13 @@ impl Application {
                     Notification::PublishDiagnostics(params) => {
                         let path = Some(params.uri.to_file_path().unwrap());
 
-                        let view = self
-                            .editor
-                            .views
-                            .iter_mut()
-                            .find(|view| view.doc.path == path);
+                        let view: Option<&mut View> = None;
+                        // TODO
+                        // let view = self
+                        //     .editor
+                        //     .views
+                        //     .iter_mut()
+                        //     .find(|view| view.doc.path == path);
 
                         if let Some(view) = view {
                             let doc = view.doc.text().slice(..);
diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index ff8704d8..be43159d 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -183,7 +183,7 @@ pub fn check_cursor_in_view(view: &View) -> bool {
     let doc = &view.doc;
     let cursor = doc.selection().cursor();
     let line = doc.text().char_to_line(cursor);
-    let document_end = view.first_line + view.size.1.saturating_sub(1) as usize;
+    let document_end = view.first_line + view.area.height.saturating_sub(1) as usize;
 
     if (line > document_end.saturating_sub(PADDING)) | (line < view.first_line + PADDING) {
         return false;
@@ -197,7 +197,7 @@ pub fn page_up(cx: &mut Context) {
         return;
     }
 
-    view.first_line = view.first_line.saturating_sub(view.size.1 as usize);
+    view.first_line = view.first_line.saturating_sub(view.area.height as usize);
 
     if !check_cursor_in_view(view) {
         let text = view.doc.text();
@@ -208,7 +208,7 @@ pub fn page_up(cx: &mut Context) {
 
 pub fn page_down(cx: &mut Context) {
     let view = cx.view();
-    view.first_line += view.size.1 as usize + PADDING;
+    view.first_line += view.area.height as usize + PADDING;
 
     if view.first_line < view.doc.text().len_lines() {
         let text = view.doc.text();
@@ -223,7 +223,9 @@ pub fn half_page_up(cx: &mut Context) {
         return;
     }
 
-    view.first_line = view.first_line.saturating_sub(view.size.1 as usize / 2);
+    view.first_line = view
+        .first_line
+        .saturating_sub(view.area.height as usize / 2);
 
     if !check_cursor_in_view(view) {
         let text = &view.doc.text();
@@ -235,8 +237,8 @@ pub fn half_page_up(cx: &mut Context) {
 pub fn half_page_down(cx: &mut Context) {
     let view = cx.view();
     let lines = view.doc.text().len_lines();
-    if view.first_line < lines.saturating_sub(view.size.1 as usize) {
-        view.first_line += view.size.1 as usize / 2;
+    if view.first_line < lines.saturating_sub(view.area.height as usize) {
+        view.first_line += view.area.height as usize / 2;
     }
     if !check_cursor_in_view(view) {
         let text = view.doc.text();
@@ -367,8 +369,7 @@ pub fn change_selection(cx: &mut Context) {
 
 pub fn collapse_selection(cx: &mut Context) {
     let selection = cx
-        .view()
-        .doc
+        .doc()
         .selection()
         .transform(|range| Range::new(range.head, range.head));
 
@@ -377,8 +378,7 @@ pub fn collapse_selection(cx: &mut Context) {
 
 pub fn flip_selections(cx: &mut Context) {
     let selection = cx
-        .view()
-        .doc
+        .doc()
         .selection()
         .transform(|range| Range::new(range.head, range.anchor));
 
@@ -396,8 +396,7 @@ pub fn insert_mode(cx: &mut Context) {
     enter_insert_mode(cx);
 
     let selection = cx
-        .view()
-        .doc
+        .doc()
         .selection()
         .transform(|range| Range::new(range.to(), range.from()));
     cx.doc().set_selection(selection);
@@ -431,37 +430,40 @@ pub fn command_mode(cx: &mut Context) {
                 |_input: &str| {
                     // TODO: i need this duplicate list right now to avoid borrow checker issues
                     let command_list = vec![
-                    String::from("q"),
-                    String::from("aaa"),
-                    String::from("bbb"),
-                    String::from("ccc"),
-                    String::from("ddd"),
-                    String::from("eee"),
-                    String::from("averylongcommandaverylongcommandaverylongcommandaverylongcommandaverylongcommand"),
-                    String::from("q"),
-                    String::from("aaa"),
-                    String::from("bbb"),
-                    String::from("ccc"),
-                    String::from("ddd"),
-                    String::from("eee"),
-                    String::from("q"),
-                    String::from("aaa"),
-                    String::from("bbb"),
-                    String::from("ccc"),
-                    String::from("ddd"),
-                    String::from("eee"),
-                    String::from("q"),
-                    String::from("aaa"),
-                    String::from("bbb"),
-                    String::from("ccc"),
-                    String::from("ddd"),
-                    String::from("eee"),
-                    String::from("q"),
-                    String::from("aaa"),
-                    String::from("bbb"),
-                    String::from("ccc"),
-                    String::from("ddd"),
-                    String::from("eee"),
+                        "q".to_string(),
+                        "o".to_string(),
+                        "w".to_string(),
+                        // String::from("q"),
+                        // String::from("aaa"),
+                        // String::from("bbb"),
+                        // String::from("ccc"),
+                        // String::from("ddd"),
+                        // String::from("eee"),
+                        // String::from("averylongcommandaverylongcommandaverylongcommandaverylongcommandaverylongcommand"),
+                        // String::from("q"),
+                        // String::from("aaa"),
+                        // String::from("bbb"),
+                        // String::from("ccc"),
+                        // String::from("ddd"),
+                        // String::from("eee"),
+                        // String::from("q"),
+                        // String::from("aaa"),
+                        // String::from("bbb"),
+                        // String::from("ccc"),
+                        // String::from("ddd"),
+                        // String::from("eee"),
+                        // String::from("q"),
+                        // String::from("aaa"),
+                        // String::from("bbb"),
+                        // String::from("ccc"),
+                        // String::from("ddd"),
+                        // String::from("eee"),
+                        // String::from("q"),
+                        // String::from("aaa"),
+                        // String::from("bbb"),
+                        // String::from("ccc"),
+                        // String::from("ddd"),
+                        // String::from("eee"),
                     ];
                     command_list
                         .into_iter()
@@ -478,8 +480,7 @@ pub fn command_mode(cx: &mut Context) {
                     match *parts.as_slice() {
                         ["q"] => editor.should_close = true,
                         ["o", path] => {
-                            let size = editor.view().size;
-                            editor.open(path.into(), size, executor);
+                            editor.open(path.into(), executor);
                         }
                         _ => (),
                     }
@@ -499,12 +500,13 @@ pub fn file_picker(cx: &mut Context) {
 }
 
 pub fn buffer_picker(cx: &mut Context) {
-    cx.callback = Some(Box::new(
-        |compositor: &mut Compositor, editor: &mut Editor| {
-            let picker = ui::buffer_picker(&editor.views, editor.focus);
-            compositor.push(Box::new(picker));
-        },
-    ));
+    unimplemented!()
+    // cx.callback = Some(Box::new(
+    //     |compositor: &mut Compositor, editor: &mut Editor| {
+    //         let picker = ui::buffer_picker(&editor.views, editor.focus);
+    //         compositor.push(Box::new(picker));
+    //     },
+    // ));
 }
 
 // calculate line numbers for each selection range
@@ -617,12 +619,7 @@ fn append_changes_to_history(cx: &mut Context) {
     // TODO: trigger lsp/documentDidChange with changes
 
     // HAXX: we need to reconstruct the state as it was before the changes..
-    let old_state = cx
-        .view()
-        .doc
-        .old_state
-        .take()
-        .expect("no old_state available");
+    let old_state = cx.doc().old_state.take().expect("no old_state available");
 
     // TODO: take transaction by value?
     cx.doc().history.commit_revision(&transaction, &old_state);
diff --git a/helix-term/src/ui/editor.rs b/helix-term/src/ui/editor.rs
index a97ee713..721dccc0 100644
--- a/helix-term/src/ui/editor.rs
+++ b/helix-term/src/ui/editor.rs
@@ -37,15 +37,20 @@ impl EditorView {
         surface: &mut Surface,
         theme: &Theme,
     ) {
-        let area = Rect::new(OFFSET, 0, viewport.width - OFFSET, viewport.height - 2); // - 2 for statusline and prompt
+        let area = Rect::new(
+            viewport.x + OFFSET,
+            viewport.y,
+            viewport.width - OFFSET,
+            viewport.height - 2,
+        ); // - 2 for statusline and prompt
         self.render_buffer(view, area, surface, theme);
 
         // clear with background color
         // TODO: this seems to prevent setting style later
         // surface.set_style(viewport, theme.get("ui.background"));
 
-        let area = Rect::new(0, viewport.height - 2, viewport.width, 1);
-        self.render_statusline(view, area, surface, theme);
+        let area = Rect::new(viewport.x, viewport.height - 2, viewport.width, 1);
+        self.render_statusline(&view.doc, area, surface, theme);
     }
 
     // TODO: ideally not &mut View but highlights require it because of cursor cache
@@ -203,34 +208,46 @@ impl EditorView {
         let last_line = view.last_line();
         for (i, line) in (view.first_line..last_line).enumerate() {
             if view.doc.diagnostics.iter().any(|d| d.line == line) {
-                surface.set_stringn(0, i as u16, "●", 1, warning);
+                surface.set_stringn(
+                    viewport.x + 0 - OFFSET,
+                    viewport.y + i as u16,
+                    "●",
+                    1,
+                    warning,
+                );
             }
 
-            surface.set_stringn(1, i as u16, format!("{:>5}", line + 1), 5, style);
+            surface.set_stringn(
+                viewport.x + 1 - OFFSET,
+                viewport.y + i as u16,
+                format!("{:>5}", line + 1),
+                5,
+                style,
+            );
         }
     }
 
     pub fn render_statusline(
         &self,
-        view: &View,
+        doc: &Document,
         viewport: Rect,
         surface: &mut Surface,
         theme: &Theme,
     ) {
         let text_color = text_color();
-        let mode = match view.doc.mode() {
+        let mode = match doc.mode() {
             Mode::Insert => "INS",
             Mode::Normal => "NOR",
             Mode::Goto => "GOTO",
         };
         // statusline
         surface.set_style(
-            Rect::new(0, viewport.y, viewport.width, 1),
+            Rect::new(viewport.x, viewport.y, viewport.width, 1),
             theme.get("ui.statusline"),
         );
-        surface.set_string(1, viewport.y, mode, text_color);
+        surface.set_string(viewport.x + 1, viewport.y, mode, text_color);
 
-        if let Some(path) = view.doc.relative_path() {
+        if let Some(path) = doc.relative_path() {
             let path = path.to_string_lossy();
             surface.set_string(6, viewport.y, path, text_color);
             // TODO: append [+] if modified
@@ -239,7 +256,7 @@ impl EditorView {
         surface.set_string(
             viewport.width - 10,
             viewport.y,
-            format!("{}", view.doc.diagnostics.len()),
+            format!("{}", doc.diagnostics.len()),
             text_color,
         );
     }
@@ -251,9 +268,8 @@ impl Component for EditorView {
             Event::Resize(width, height) => {
                 // TODO: simplistic ensure cursor in view for now
                 // TODO: loop over views
-                let view = cx.editor.view_mut();
-                view.size = (width, height);
-                view.ensure_cursor_in_view();
+                cx.editor.tree.resize(Rect::new(0, 0, width, height));
+                // TODO: restore view.ensure_cursor_in_view();
                 EventResult::Consumed(None)
             }
             Event::Key(event) => {
@@ -306,8 +322,10 @@ impl Component for EditorView {
         // SAFETY: we cheat around the view_mut() borrow because it doesn't allow us to also borrow
         // theme. Theme is immutable mutating view won't disrupt theme_ref.
         let theme_ref = unsafe { &*(&cx.editor.theme as *const Theme) };
-        let view = cx.editor.view_mut();
-        self.render_view(view, area, surface, theme_ref);
+        for view in cx.editor.tree.views() {
+            // TODO: use parent area
+            self.render_view(view, view.area, surface, theme_ref);
+        }
 
         // TODO: drop unwrap
     }
diff --git a/helix-term/src/ui/mod.rs b/helix-term/src/ui/mod.rs
index bd40b249..7c12b918 100644
--- a/helix-term/src/ui/mod.rs
+++ b/helix-term/src/ui/mod.rs
@@ -82,38 +82,38 @@ pub fn file_picker(root: &str, ex: &'static smol::Executor) -> Picker<PathBuf> {
             path.strip_prefix("./").unwrap().to_str().unwrap().into()
         },
         move |editor: &mut Editor, path: &PathBuf| {
-            let size = editor.view().size;
-            editor.open(path.into(), size, ex);
+            editor.open(path.into(), ex);
         },
     )
 }
 
 use helix_view::View;
 pub fn buffer_picker(views: &[View], current: usize) -> Picker<(Option<PathBuf>, usize)> {
-    use helix_view::Editor;
-    Picker::new(
-        views
-            .iter()
-            .enumerate()
-            .map(|(i, view)| (view.doc.relative_path().map(Path::to_path_buf), i))
-            .collect(),
-        move |(path, index): &(Option<PathBuf>, usize)| {
-            // format_fn
-            match path {
-                Some(path) => {
-                    if *index == current {
-                        format!("{} (*)", path.to_str().unwrap()).into()
-                    } else {
-                        path.to_str().unwrap().into()
-                    }
-                }
-                None => "[NEW]".into(),
-            }
-        },
-        |editor: &mut Editor, &(_, index): &(Option<PathBuf>, usize)| {
-            if index < editor.views.len() {
-                editor.focus = index;
-            }
-        },
-    )
+    unimplemented!();
+    // use helix_view::Editor;
+    // Picker::new(
+    //     views
+    //         .iter()
+    //         .enumerate()
+    //         .map(|(i, view)| (view.doc.relative_path().map(Path::to_path_buf), i))
+    //         .collect(),
+    //     move |(path, index): &(Option<PathBuf>, usize)| {
+    //         // format_fn
+    //         match path {
+    //             Some(path) => {
+    //                 if *index == current {
+    //                     format!("{} (*)", path.to_str().unwrap()).into()
+    //                 } else {
+    //                     path.to_str().unwrap().into()
+    //                 }
+    //             }
+    //             None => "[NEW]".into(),
+    //         }
+    //     },
+    //     |editor: &mut Editor, &(_, index): &(Option<PathBuf>, usize)| {
+    //         if index < editor.views.len() {
+    //             editor.focus = index;
+    //         }
+    //     },
+    // )
 }
diff --git a/helix-view/Cargo.toml b/helix-view/Cargo.toml
index 0a435811..938f35e5 100644
--- a/helix-view/Cargo.toml
+++ b/helix-view/Cargo.toml
@@ -24,3 +24,5 @@ url = "2"
 
 smol = "1"
 futures-util = "0.3"
+
+slotmap = "1"
diff --git a/helix-view/src/editor.rs b/helix-view/src/editor.rs
index 54a098f9..eb745066 100644
--- a/helix-view/src/editor.rs
+++ b/helix-view/src/editor.rs
@@ -1,45 +1,36 @@
 use crate::theme::Theme;
+use crate::tree::Tree;
 use crate::{Document, View};
+use slotmap::DefaultKey as Key;
 
 use std::path::PathBuf;
 
 use anyhow::Error;
 
 pub struct Editor {
-    pub views: Vec<View>,
-    pub focus: usize,
+    pub tree: Tree,
+    // pub documents: Vec<Document>,
+    pub focus: Key,
     pub should_close: bool,
     pub theme: Theme, // TODO: share one instance
     pub language_servers: helix_lsp::Registry,
 }
 
-impl Default for Editor {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
 impl Editor {
-    pub fn new() -> Self {
+    pub fn new(area: tui::layout::Rect) -> Self {
         let theme = Theme::default();
         let language_servers = helix_lsp::Registry::new();
 
         Self {
-            views: Vec::new(),
-            focus: 0,
+            tree: Tree::new(area),
+            focus: Key::default(),
             should_close: false,
             theme,
             language_servers,
         }
     }
 
-    pub fn open(
-        &mut self,
-        path: PathBuf,
-        size: (u16, u16),
-        executor: &smol::Executor,
-    ) -> Result<(), Error> {
-        let pos = self.views.len();
+    pub fn open(&mut self, path: PathBuf, executor: &smol::Executor) -> Result<(), Error> {
         let mut doc = Document::load(path, self.theme.scopes())?;
 
         // try to find a language server based on the language name
@@ -60,16 +51,17 @@ impl Editor {
             .unwrap();
         }
 
-        self.views.push(View::new(doc, size)?);
+        let view = View::new(doc)?;
+        let pos = self.tree.insert(view);
         self.focus = pos;
         Ok(())
     }
 
     pub fn view(&self) -> &View {
-        self.views.get(self.focus).unwrap()
+        self.tree.get(self.focus)
     }
 
     pub fn view_mut(&mut self) -> &mut View {
-        self.views.get_mut(self.focus).unwrap()
+        self.tree.get_mut(self.focus)
     }
 }
diff --git a/helix-view/src/lib.rs b/helix-view/src/lib.rs
index f28c8116..05de7e9f 100644
--- a/helix-view/src/lib.rs
+++ b/helix-view/src/lib.rs
@@ -1,6 +1,7 @@
 pub mod document;
 pub mod editor;
 pub mod theme;
+pub mod tree;
 pub mod view;
 
 pub use document::Document;
diff --git a/helix-view/src/view.rs b/helix-view/src/view.rs
index df41e3ae..24b50d81 100644
--- a/helix-view/src/view.rs
+++ b/helix-view/src/view.rs
@@ -17,15 +17,15 @@ pub const PADDING: usize = 5;
 pub struct View {
     pub doc: Document,
     pub first_line: usize,
-    pub size: (u16, u16),
+    pub area: Rect,
 }
 
 impl View {
-    pub fn new(doc: Document, size: (u16, u16)) -> Result<Self, Error> {
+    pub fn new(doc: Document) -> Result<Self, Error> {
         let view = Self {
             doc,
             first_line: 0,
-            size,
+            area: Rect::default(), // will get calculated upon inserting into tree
         };
 
         Ok(view)
@@ -34,7 +34,7 @@ impl View {
     pub fn ensure_cursor_in_view(&mut self) {
         let cursor = self.doc.state.selection().cursor();
         let line = self.doc.text().char_to_line(cursor);
-        let document_end = self.first_line + (self.size.1 as usize).saturating_sub(2);
+        let document_end = self.first_line + (self.area.height as usize).saturating_sub(2);
 
         // TODO: side scroll
 
@@ -50,7 +50,7 @@ impl View {
     /// Calculates the last visible line on screen
     #[inline]
     pub fn last_line(&self) -> usize {
-        let viewport = Rect::new(6, 0, self.size.0, self.size.1 - 2); // - 2 for statusline and prompt
+        let viewport = Rect::new(6, 0, self.area.width, self.area.height - 2); // - 2 for statusline and prompt
         std::cmp::min(
             self.first_line + (viewport.height as usize),
             self.doc.text().len_lines() - 1,