add hover function

server/src/lsp_server.py

@@ -13,6 +13,7 @@ import sys
 import sysconfig
 import traceback
 from typing import Any, Optional, Sequence
+import re
 
 
 # **********************************************************
@@ -106,6 +107,72 @@ def on_completion(params: lsp.CompletionParams) -> list[lsp.CompletionItem]:
     return lsp.CompletionList(is_incomplete=False, items=items)
 
 
+@LSP_SERVER.feature(lsp.TEXT_DOCUMENT_HOVER)
+def hover(params: lsp.HoverParams) -> lsp.Hover:
+    pos = params.position
+    document_uri = params.text_document.uri
+    document = LSP_SERVER.workspace.get_text_document(document_uri)
+    col = params.position.character
+
+    try:
+        line = document.lines[pos.line]
+    except IndexError:
+        return None
+
+    for m in re.finditer(r"\b\w+\b", line):
+        if m.start() <= col <= m.end():
+            token = m.group(0)
+            break
+    else:
+        return None
+
+    command = token
+    data = standard_items.json_data
+
+    all_items = data.get("MOM_procs", []) + data.get("mom_variables", [])
+
+    match = next((item for item in all_items if item["label"] == command), None)
+    if not match:
+        return None
+
+    if not match.get("kind") == "function":
+        return None
+
+    label = match.get("label", "")
+
+    parameters = match.get("parameters", [])
+    param_lines = (
+        "\n".join(f"- `{p['name']}`: {p['desc']}" for p in parameters) or "_None_"
+    )
+
+    example_data = match.get("example", [])
+    example_md = "\n".join(f"{line}" for line in example_data)
+
+    returns_data = match.get("returns", ["None"])
+    returns_md = "\n".join(f"- {line}" for line in returns_data)
+
+    doc_md = f"""\
+### 📘 {label}
+
+**Purpose**  
+{match.get("description", "No description available.")}
+
+**Format**  
+`{match.get("format", label)}`
+
+**Parameters**  
+{param_lines}
+
+**Return value**  
+{returns_md}
+
+**Example**  
+```tcl
+{example_md}"""
+
+    return lsp.Hover(lsp.MarkupContent(kind=lsp.MarkupKind.Markdown, value=doc_md))
+
+
 # **********************************************************
 # Linting features end here
 # **********************************************************