Better use of source locations

.github/workflows/telomare-ci.yml

@@ -93,7 +93,7 @@ jobs:
           extraPullNames: nix-community
       - name: hlint linting
         run: |
-          output=$(nix develop -c hlint "--ignore=Parse error" app/Evaluare.hs . --no-exit-code)
+          output=$(nix develop -c hlint . --no-exit-code)
           if [ "$output" = "No hints" ]; then
               echo "Success! No Hlint suggestions."
           else

Prelude.tel

@@ -143,44 +143,19 @@ gcd = \a b ->
 lcm = \a b -> dDiv (dTimes a b) (gcd a b)
 
 [Rational, fromRational, toRational, rPlus, rTimes, rMinus, rDiv] = \h ->
-  [ \n d -> if dEqual d 0
-            then abort "Denominator cannot be zero"
-            else
-              let g   = gcd n d
-                  num = dDiv n g
-                  den = dDiv d g
-              in (h, (num, den))
-  , \i -> Rational i
-  , \a b ->
-      let n1 = left (right a)
-          d1 = right (right a)
-          n2 = left (right b)
-          d2 = right (right b)
-          num = dPlus (dTimes n1 d2) (dTimes n2 d1)
-          den = dTimes d1 d2
-      in fromRational num den
-  , \a b ->
-      let n1 = left (right a)
-          d1 = right (right a)
-          n2 = left (right b)
-          d2 = right (right b)
-          num = dTimes n1 n2
-          den = dTimes d1 d2
-      in fromRational num den
-  , \a b ->
-      let n1 = left (right a)
-          d1 = right (right a)
-          n2 = left (right b)
-          d2 = right (right b)
-          num = dMinus (dTimes n1 d2) (dTimes n2 d1)
-          den = dTimes d1 d2
-      in fromRational num den
-  , \a b ->
-      let n1 = left (right a)
-          d1 = right (right a)
-          n2 = left (right b)
-          d2 = right (right b)
-          num = dTimes n1 d2
-          den = dTimes d1 n2
-      in fromRational num den
-  ]
+  let rNum = \x -> left (right x)
+      rDen = \x -> right (right x)
+  in [ \n d -> if dEqual d 0
+               then abort "Denominator cannot be zero"
+               else let g = gcd n d
+                    in (h, (dDiv n g, dDiv d g))
+     , Rational
+     , \a b -> fromRational (dPlus (dTimes (rNum a) (rDen b)) (dTimes (rNum b) (rDen a)))
+                            (dTimes (rDen a) (rDen b))
+     , \a b -> fromRational (dTimes (rNum a) (rNum b))
+                            (dTimes (rDen a) (rDen b))
+     , \a b -> fromRational (dMinus (dTimes (rNum a) (rDen b)) (dTimes (rNum b) (rDen a)))
+                            (dTimes (rDen a) (rDen b))
+     , \a b -> fromRational (dTimes (rNum a) (rDen b))
+                            (dTimes (rDen a) (rNum b))
+     ]

README.md

@@ -53,7 +53,136 @@ This project is in active development. Do expect bugs and general trouble, and p
    $ cabal run telomare-repl -- --haskell # or nix run .#repl
    ```
 2. Profit!
-
+
+## Editor Support (LSP)
+
+Telomare ships a language server (`telomare-lsp`) and an Emacs major mode
+under [`emacs-telomare-mode/`](emacs-telomare-mode/), with variants for
+Spacemacs, Doom, and vanilla Emacs.
+
+### LSP capabilities
+
+The language server provides:
+
+- **Diagnostics** — on every document open and edit it reports parse
+  errors, missing imported modules, undefined variable references, and
+  resolver errors. Diagnostics are cleared when the document is closed.
+- **Go to definition** — jumps to local `let`, lambda, and case-pattern
+  binders, to top-level definitions, and to definitions in qualified
+  imported modules.
+- **Find references** — lists every reference to a symbol, optionally
+  including its declaration.
+- **Semantic-token highlighting** — keywords, comments, strings,
+  numbers, and operators, for the whole file or a requested range.
+- **Code action** — *Partially evaluate*: select an expression and the
+  server evaluates it, reporting the result in an editor popup.
+- **Workspace commands**:
+  - `telomare.version` — reports the server version as a UTC timestamp.
+  - `telomare.partialEval` — evaluates a given expression; this backs
+    the partial-evaluation code action.
+
+Document sync is full-text (whole-document). Hover and rename are not
+implemented yet.
+
+### Installing the Emacs mode
+
+The recommended Spacemacs setup is to load Telomare's Emacs mode from the
+same Telomare flake input that provides the language server. Do not point
+Spacemacs at a random checkout unless you are actively developing the mode;
+make the editor use the same pinned source that NixOS or Home Manager builds.
+
+For a NixOS/Home Manager Spacemacs config, add Telomare as a flake input and
+load the mode file from that input:
+
+```elisp
+(load "${telomare}/emacs-telomare-mode/telomare-mode-spacemacs.el")
+```
+
+The mode auto-detects the surrounding flake source path and starts the LSP with
+`nix run path:<telomare-source>#lsp --`. This matters for Nix store paths:
+`nix run /nix/store/...-source#lsp --` is parsed incorrectly by Nix, while
+`nix run path:/nix/store/...-source#lsp --` is the intended absolute-path flake
+form.
+
+For a manual checkout-based setup, load the mode from this repository and set
+`TELOMARE_ROOT` only if auto-detection cannot find `flake.nix`:
+
+```elisp
+(load "/path/to/telomare/emacs-telomare-mode/telomare-mode-spacemacs.el")
+```
+
+For Doom and vanilla Emacs setup, see
+[`emacs-telomare-mode/README.md`](emacs-telomare-mode/README.md).
+
+### Keybindings
+
+The mode binds only features the server implements. Some entries below
+come from `lsp-mode` rather than Telomare's mode — these are marked
+*(lsp-mode)*. Spacemacs exposes the major-mode leader as `SPC m` in Evil
+state and as `M-m m` in holy-mode; the leader entries are otherwise the
+same bindings.
+
+**Spacemacs — Evil mode** (`SPC m` major-mode leader):
+
+| Key | Action |
+|-----|--------|
+| `SPC m g` | Go to definition |
+| `SPC m G` | Find references |
+| `SPC m a` | Execute code action (partial evaluation) |
+| `SPC m v` | Show Telomare LSP version |
+| `C-c C-v` | Show Telomare LSP version |
+| `g d` | Go to definition *(lsp-mode / Evil default)* |
+
+**Spacemacs — holy mode** (`M-m m` major-mode leader):
+
+| Key | Action |
+|-----|--------|
+| `M-m m g` | Go to definition |
+| `M-m m G` | Find references |
+| `M-m m a` | Execute code action (partial evaluation) |
+| `M-m m v` | Show Telomare LSP version |
+| `C-c C-v` | Show Telomare LSP version |
+| `M-.` | Go to definition *(lsp-mode)* |
+| `M-?` | Find references *(lsp-mode)* |
+| `M-,` | Jump back *(xref)* |
+
+Vanilla Emacs binds `M-.`, `M-?`, `C-c a`, and `C-c C-v`.
+
+### Troubleshooting
+
+If navigation does not work, check the active LSP session with
+`M-x lsp-describe-session`, restart it with `M-x lsp-workspace-restart`, and
+confirm the server command with:
+
+```elisp
+M-: (telomare--lsp-command)
+```
+
+The expected command shape is:
+
+```elisp
+("nix" "run" "path:/nix/store/...-source#lsp" "--")
+```
+
+### LSP version command
+
+`C-c C-v` (or `SPC m v` / `M-m m v` in Spacemacs) reports the server
+version as a UTC timestamp truncated to minutes, using the parent commit
+timestamp when git history is available and the flake source timestamp
+when launched from a Nix store source without `.git`. It can also be
+invoked directly:
+
+```elisp
+(lsp-request "workspace/executeCommand"
+             `(:command "telomare.version" :arguments []))
+```
+
+The command shows an editor message such as:
+
+```text
+Telomare LSP version: 2026-05-22T10:14Z
+```
+
 ## Git Hooks
 
 You can setup your git configuration to automatically format and look for lint suggestions. Just run: