From 35a2508415866c376e6d2ba49ac7e81cea648f23 Mon Sep 17 00:00:00 2001
From: Marco Turchetto <marco.turchetto.mt@gmail.com>
Date: Thu, 25 Dec 2025 01:28:12 +0100
Subject: [PATCH 1/2] feat: haskell lsp support

---
 packages/opencode/src/lsp/server.ts | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/packages/opencode/src/lsp/server.ts b/packages/opencode/src/lsp/server.ts
index b432e5a5d0a..0610aa2d07e 100644
--- a/packages/opencode/src/lsp/server.ts
+++ b/packages/opencode/src/lsp/server.ts
@@ -1892,4 +1892,22 @@ export namespace LSPServer {
       }
     },
   }
+
+  export const HLS: Info = {
+    id: "haskell-language-server",
+    extensions: [".hs", ".lhs"],
+    root: NearestRoot(["stack.yaml", "cabal.project", "hie.yaml", "*.cabal"]),
+    async spawn(root) {
+      const bin = Bun.which("haskell-language-server-wrapper")
+      if (!bin) {
+        log.info("haskell-language-server-wrapper not found, please install haskell-language-server")
+        return
+      }
+      return {
+        process: spawn(bin, ["--lsp"], {
+          cwd: root,
+        }),
+      }
+    },
+  }
 }

From 896daf94372108fe84d257184ce02ebd720a8b40 Mon Sep 17 00:00:00 2001
From: Marco Turchetto <marco.turchetto.mt@gmail.com>
Date: Thu, 25 Dec 2025 19:13:32 +0100
Subject: [PATCH 2/2] fix: add .lhs haskell extension

---
 packages/opencode/src/lsp/language.ts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/opencode/src/lsp/language.ts b/packages/opencode/src/lsp/language.ts
index 620944a8e07..d279f7d64e7 100644
--- a/packages/opencode/src/lsp/language.ts
+++ b/packages/opencode/src/lsp/language.ts
@@ -39,6 +39,7 @@ export const LANGUAGE_EXTENSIONS: Record<string, string> = {
   ".hbs": "handlebars",
   ".handlebars": "handlebars",
   ".hs": "haskell",
+  ".lhs": "haskell",
   ".html": "html",
   ".htm": "html",
   ".ini": "ini",