Implement signature help

src/JETLS.jl

@@ -98,6 +98,7 @@ end
 
 include("utils.jl")
 include("completions.jl")
+include("signature-help.jl")
 
 struct IncludeCallback <: Function
     file_cache::Dict{URI,FileInfo}
@@ -186,6 +187,8 @@ function _handle_message(state::ServerState, msg)
         return handle_CompletionRequest(state, msg)
     elseif msg isa CompletionResolveRequest
         return handle_CompletionResolveRequest(state, msg)
+    elseif msg isa SignatureHelpRequest
+        return handle_SignatureHelpRequest(state, msg)
     elseif JETLS_DEV_MODE
         @warn "Unhandled message" msg
     end
@@ -245,6 +248,9 @@ function initialize_result()
                 triggerCharacters = ["@"],
                 completionItem = (;
                     labelDetailsSupport = true)),
+            signatureHelpProvider = SignatureHelpOptions(;
+                triggerCharacters = ["(", ",", ";"],
+                retriggerCharacters = ["."]),
         ),
         serverInfo = (;
             name = "JETLS",

src/LSP/LSP.jl

@@ -16,6 +16,7 @@ include("lifecycle-messages/exit.jl")
 include("document-synchronization.jl")
 include("language-features/diagnostics.jl")
 include("language-features/completions.jl")
+include("language-features/signature-help.jl")
 include("workspace-features/workspace-folders.jl")
 include("workspace-features/files.jl")
 include("capabilities.jl")

src/LSP/capabilities.jl

@@ -28,6 +28,8 @@
 
     completionProvider::Union{CompletionOptions, Nothing} = nothing
 
+    signatureHelpProvider::Union{SignatureHelpOptions, Nothing} = nothing
+
     "Workspace specific server capabilities"
     workspace::Union{Nothing, @interface begin
         """

src/LSP/language-features/signature-help.jl

@@ -0,0 +1,251 @@
+@interface SignatureHelpClientCapabilities begin
+    """
+    Whether signature help supports dynamic registration.
+    """
+    dynamicRegistration::Union{Nothing, Bool} = nothing
+
+    """
+    The client supports the following `SignatureInformation`
+    specific properties.
+    """
+    signatureInformation::Union{Nothing, @interface begin
+        """
+        Client supports the follow content formats for the documentation
+        property. The order describes the preferred format of the client.
+        """
+        documentationFormat::Union{Nothing, Vector{MarkupKind.Ty}} = nothing
+
+        """
+        Client capabilities specific to parameter information.
+        """
+        parameterInformation::Union{Nothing, @interface begin
+            """
+            The client supports processing label offsets instead of a
+            simple label string.
+
+            # Tags
+            - since - 3.14.0
+            """
+            labelOffsetSupport::Union{Nothing, Bool} = nothing
+        end} = nothing
+
+        """
+        The client supports the `activeParameter` property on
+        `SignatureInformation` literal.
+
+        # Tags
+        - since - 3.16.0
+        """
+        activeParameterSupport::Union{Nothing, Bool} = nothing
+    end} = nothing
+
+    """
+    The client supports to send additional context information for a
+    `textDocument/signatureHelp` request. A client that opts into
+    contextSupport will also support the `retriggerCharacters` on
+    `SignatureHelpOptions`.
+
+    # Tags
+    - since - 3.15.0
+    """
+    contextSupport::Union{Nothing, Bool} = nothing
+end
+
+@interface SignatureHelpOptions @extends WorkDoneProgressOptions begin
+    """
+    The characters that trigger signature help
+    automatically.
+    """
+    triggerCharacters::Union{Nothing, Vector{String}} = nothing
+
+    """
+    List of characters that re-trigger signature help.
+
+    These trigger characters are only active when signature help is already
+    showing. All trigger characters are also counted as re-trigger
+    characters.
+
+    # Tags
+    - since - 3.15.0
+    """
+    retriggerCharacters::Union{Nothing, Vector{String}} = nothing
+end
+
+@interface SignatureHelpRegistrationOptions @extends TextDocumentRegistrationOptions, SignatureHelpOptions begin
+end
+
+"""
+How a signature help was triggered.
+
+# Tags
+- since - 3.15.0
+"""
+@namespace SignatureHelpTriggerKind::Int begin
+    """
+    Signature help was invoked manually by the user or by a command.
+    """
+    Invoked = 1
+    """
+    Signature help was triggered by a trigger character.
+    """
+    TriggerCharacter = 2
+    """
+    Signature help was triggered by the cursor moving or by the document
+    content changing.
+    """
+    ContentChange = 3
+end
+
+"""
+Represents a parameter of a callable-signature. A parameter can
+have a label and a doc-comment.
+"""
+@interface ParameterInformation begin
+
+    """
+    The label of this parameter information.
+
+    Either a string or an inclusive start and exclusive end offsets within
+    its containing signature label. (see SignatureInformation.label). The
+    offsets are based on a UTF-16 string representation as `Position` and
+    `Range` does.
+
+    *Note*: a label of type string should be a substring of its containing
+    signature label. Its intended use case is to highlight the parameter
+    label part in the `SignatureInformation.label`.
+    """
+    label::Union{String, Vector{UInt}} # vector should have length 2
+
+    """
+    The human-readable doc-comment of this parameter. Will be shown
+    in the UI but can be omitted.
+    """
+    documentation::Union{Nothing, String, MarkupContent} = nothing
+end
+
+"""
+Represents the signature of something callable. A signature
+can have a label, like a function-name, a doc-comment, and
+a set of parameters.
+"""
+@interface SignatureInformation begin
+    """
+    The label of this signature. Will be shown in
+    the UI.
+    """
+    label::String
+
+    """
+    The human-readable doc-comment of this signature. Will be shown
+    in the UI but can be omitted.
+    """
+    documentation::Union{Nothing, String, MarkupContent} = nothing
+
+    """
+    The parameters of this signature.
+    """
+    parameters::Union{Nothing, Vector{ParameterInformation}} = nothing
+
+    """
+    The index of the active parameter.
+
+    If provided, this is used in place of `SignatureHelp.activeParameter`.
+
+     # Tags
+    - since - 3.16.0
+    """
+    activeParameter::Union{Nothing, UInt} = nothing
+end
+
+"""
+Signature help represents the signature of something
+callable. There can be multiple signature but only one
+active and only one active parameter.
+"""
+@interface SignatureHelp begin
+    """
+    One or more signatures. If no signatures are available the signature help
+    request should return `null`.
+    """
+    signatures::Vector{SignatureInformation}
+
+    """
+    The active signature. If omitted or the value lies outside the
+    range of `signatures` the value defaults to zero or is ignore if
+    the `SignatureHelp` as no signatures.
+
+    Whenever possible implementors should make an active decision about
+    the active signature and shouldn't rely on a default value.
+
+    In future version of the protocol this property might become
+    mandatory to better express this.
+    """
+    activeSignature::Union{Nothing, UInt} = nothing
+
+    """
+    The active parameter of the active signature. If omitted or the value
+    lies outside the range of `signatures[activeSignature].parameters`
+    defaults to 0 if the active signature has parameters. If
+    the active signature has no parameters it is ignored.
+    In future version of the protocol this property might become
+    mandatory to better express the active parameter if the
+    active signature does have any.
+    """
+    activeParameter::Union{Nothing, UInt} = nothing
+end
+
+"""
+Additional information about the context in which a signature help request
+was triggered.
+
+# Tags
+- since - 3.15.0
+"""
+@interface SignatureHelpContext begin
+    """
+    Action that caused signature help to be triggered.
+    """
+    triggerKind::SignatureHelpTriggerKind.Ty
+
+    """
+    Character that caused signature help to be triggered.
+
+    This is undefined when triggerKind !==
+    SignatureHelpTriggerKind.TriggerCharacter
+    """
+    triggerCharacter::Union{Nothing, String} = nothing
+
+    """
+    `true` if signature help was already showing when it was triggered.
+
+    Retriggers occur when the signature help is already active and can be
+    caused by actions such as typing a trigger character, a cursor move, or
+    document content changes.
+    """
+    isRetrigger::Bool
+
+    """
+    The currently active `SignatureHelp`.
+
+    The `activeSignatureHelp` has its `SignatureHelp.activeSignature` field
+    updated based on the user navigating through available signatures.
+    """
+    activeSignatureHelp::Union{Nothing, SignatureHelp} = nothing
+end
+
+@interface SignatureHelpParams @extends TextDocumentPositionParams, WorkDoneProgressParams begin
+    """
+    The signature help context. This is only available if the client
+    specifies to send this using the client capability
+    `textDocument.signatureHelp.contextSupport === true`
+
+    # Tags
+    - since - 3.15.0
+    """
+    context::Union{Nothing, SignatureHelpContext} = nothing
+end
+
+@interface SignatureHelpRequest @extends RequestMessage begin
+    method::String = "textDocument/signatureHelp"
+    params::SignatureHelpParams
+end

src/completions.jl

@@ -32,53 +32,6 @@ end
 # local completions
 # =================
 
-"""
-Like `Base.unique`, but over node ids, and with this comment promising that the
-lowest-index copy of each node is kept.
-"""
-function deduplicate_syntaxlist(sl::JL.SyntaxList)
-    sl2 = JL.SyntaxList(sl.graph)
-    seen = Set{JL.NodeId}()
-    for st in sl
-        if !(st._id in seen)
-            push!(sl2, st._id)
-            push!(seen, st._id)
-        end
-    end
-    return sl2
-end
-
-"""
-    byte_ancestors(st::JL.SyntaxTree, rng::UnitRange{Int})
-    byte_ancestors(st::JL.SyntaxTree, byte::Int)
-
-Get a list of `SyntaxTree`s containing certain bytes.
-Output should be topologically sorted, children first.
-
-If we know that parent ranges contain all child ranges, and that siblings don't
-have overlapping ranges (this is not true after lowering, but appear to be true
-after parsing), each tree in the result will be a child of the next.
-"""
-function byte_ancestors(st::JL.SyntaxTree, rng::UnitRange{Int})
-    sl = JL.SyntaxList(st._graph, [st._id])
-    stack = [st]
-    while !isempty(stack)
-        st = pop!(stack)
-        if JS.numchildren(st) === 0
-            continue
-        end
-        for ci in JS.children(st)
-            if rng ⊆ JS.byte_range(ci)
-                push!(sl, ci)
-            end
-            push!(stack, ci)
-        end
-    end
-    # delete later duplicates when sorted parent->child
-    return reverse!(deduplicate_syntaxlist(sl))
-end
-byte_ancestors(st::JL.SyntaxTree, byte::Int) = byte_ancestors(st, byte:byte)
-
 """
 Find any largest lowerable tree containing the cursor and the cursor's position
 within it.  For local completions; something like least_unlowerable would be
@@ -301,33 +254,6 @@ end
 # global completions
 # ==================
 
-function find_file_module!(state::ServerState, uri::URI, pos::Position)
-    mod = find_file_module(state, uri, pos)
-    state.completion_module[] = mod
-    return mod
-end
-function find_file_module(state::ServerState, uri::URI, pos::Position)
-    haskey(state.contexts, uri) || return Main
-    contexts = state.contexts[uri]
-    context = first(contexts)
-    for ctx in contexts
-        # prioritize `PackageSourceAnalysisEntry` if exists
-        if isa(context.entry, PackageSourceAnalysisEntry)
-            context = ctx
-            break
-        end
-    end
-    safi = successfully_analyzed_file_info(context, uri)
-    isnothing(safi) && return Main
-    curline = Int(pos.line) + 1
-    curmod = Main
-    for (range, mod) in safi.module_range_infos
-        curline in range || continue
-        curmod = mod
-    end
-    return curmod
-end
-
 function global_completions!(items::Dict{String, CompletionItem}, state::ServerState, uri::URI, params::CompletionParams)
     pos = params.position
     is_macro_invoke = let context = params.context