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|
structure Lsp :> LSP = struct
fun trim (s: substring): substring =
Substring.dropr
(fn c => c = #" " orelse c = #"\n" orelse c = #"\r")
(Substring.dropl (fn c => c = #" " orelse c = #"\n" orelse c = #"\r") s)
fun readHeader (): (string * string) option =
let
val line = TextIO.inputLine TextIO.stdIn
in
case line of
NONE => OS.Process.exit OS.Process.success
| SOME str =>
let
val (key, value) = Substring.splitl (fn c => c <> #":") (Substring.full str)
in
if Substring.isEmpty (trim value)
then NONE
else SOME ( Substring.string (trim key)
, Substring.string (trim (Substring.dropl (fn c => c = #":") (trim value))))
end
end
fun readAllHeaders (l: (string * string) list): (string * string) list =
case readHeader () of
NONE => l
| SOME tup => tup :: readAllHeaders l
fun getJsonObjectValue (s: string) (l: (string * Json.json) list): Json.json option =
case List.find (fn tup => #1 tup = s ) l of
NONE => NONE
| SOME tup => SOME (#2 tup)
fun getJsonObjectValue' (s: string) (l: Json.json): Json.json =
case l of
Json.Obj l =>
(case getJsonObjectValue s l of
NONE => raise Fail ("Failed to find JSON object key " ^ s)
| SOME v => v)
| a => raise Fail ("Expected JSON object, got: " ^ Json.print a)
fun parseInt (j: Json.json): int =
case j of
Json.Int i => i
| _ => raise Fail ("Expected JSON int, got: " ^ Json.print j)
fun parseString (j: Json.json): string =
case j of
Json.String s => s
| _ => raise Fail ("Expected JSON string, got: " ^ Json.print j)
fun parseRequest (j: Json.json): {id: Json.json, method: string, params: Json.json} =
let
val id = getJsonObjectValue' "id" j
val method = parseString (getJsonObjectValue' "method" j)
val params = getJsonObjectValue' "params" j
in
{id = id, method = method, params = params}
end
type textDocumentIdentifier =
{ scheme: string
, authority: string
, path: string
, query: string
, fragment: string
}
fun parseTextDocumentIdentifier (j: Json.json): textDocumentIdentifier =
let
val str = Substring.full (parseString (getJsonObjectValue' "uri" j))
val (scheme, rest) = Substring.splitl (fn c => c <> #":") str
val (authority, rest) = Substring.splitl (fn c => c <> #"/") (Substring.triml 3 rest (* :// *))
val (path, rest) = Substring.splitl (fn c => c <> #"?" orelse c <> #"#") (Substring.triml 1 rest (* / *))
val (query, rest) = if Substring.first rest = SOME #"?"
then Substring.splitl (fn c => c <> #"#") (Substring.triml 1 rest (* ? *))
else (Substring.full "", rest)
val fragment = if Substring.first rest = SOME #"#"
then (Substring.triml 1 rest (* # *))
else Substring.full ""
in
{ scheme = Substring.string scheme
, authority = Substring.string authority
, path = Substring.string path
, query = Substring.string query
, fragment = Substring.string fragment
}
end
type position = { line: int
, character: int
}
fun parsePosition (j: Json.json) =
{ line = parseInt (getJsonObjectValue' "line" j)
, character = parseInt (getJsonObjectValue' "character" j)
}
datatype result = Success of Json.json
| Error of (int * string)
fun handleHover (params: Json.json): result =
let
val textDocument = parseTextDocumentIdentifier (getJsonObjectValue' "textDocument" params)
val position = parsePosition (getJsonObjectValue' "position" params)
val answer = ""
in
Success (Json.Obj (("contents", Json.String answer) :: []))
end
fun serverLoop () =
let
val headers = readAllHeaders []
val lengthO = List.find (fn (k,v) => k = "Content-Length") headers
val request = case lengthO of
NONE => raise Fail "No header with Content-Length found"
| SOME (k, v) =>
case Int.fromString v of
NONE => raise Fail ("Couldn't parse content-length from string: " ^ v)
| SOME i => TextIO.inputN (TextIO.stdIn, i)
(* val parsed = Json.parse (Substring.string (Substring.trimr 1 (Substring.full request))) (* Trimming last newline *) *)
val parsed = Json.parse request
val requestMessage = parseRequest parsed
fun fail (err: (int * string)) =
Json.print (Json.Obj (("id", #id requestMessage)
:: ("error", Json.Obj (("code", Json.Int (#1 err))
:: ("message", Json.String (#2 err))
:: []))
:: []
))
val result: result =
case #method requestMessage of
"initialize" => Success (Json.Obj (("capabilities", Json.Obj (("hoverProvider", Json.Bool true) :: [])) :: []))
| "textDocument/hover" => handleHover (#params requestMessage)
| "shutdown" => Success (Json.Null)
| "exit" => OS.Process.exit OS.Process.success
| method => Error (~32601, "Method not supported: " ^ method)
in
case result of
Success j => TextIO.output (TextIO.stdOut,
Json.print (Json.Obj (("id", #id requestMessage)
:: ("result", j)
:: [])))
| Error (i, err) =>
TextIO.output (TextIO.stdOut,
Json.print (Json.Obj (("id", #id requestMessage)
:: ("error", Json.Obj (("code", Json.Int i)
:: ("message", Json.String err)
:: []))
:: []
)))
end
fun startServer () =
while (1 < 2) do
serverLoop ()
end
|
