Merge #1110

1110: Introduce display module and implement new FunctionSignature for CallInfo's r=matklad a=vipentti

This introduces a new module `display` in `ra_ide_api` that contains UI-related things, in addition this refactors CallInfo's function signatures into a new `FunctionSignature` type, which implements `Display` and can be converted into `lsp_types::SignatureInformation` in the `conv` layer. 

Currently only `CallInfo` uses the `FunctionSignature` directly, but `function_label` now uses the same signature and returns it as a string, using the `Display` implementation.

This also fixes #960 

I think this similar structure could be applied to other UI-displayable items, so instead of the `ra_ide_api` returning `Strings` we could return some intermediate structures that can be converted into a UI-displayable `String` easily, but that could also provide some additional information.

Co-authored-by: Ville Penttinen <[email protected]>

2 files changed, 27 insertions, 18 deletions

diff --git a/crates/ra_lsp_server/src/conv.rs b/crates/ra_lsp_server/src/conv.rs
index 74e91c236..4d6ede316 100644
--- a/crates/ra_lsp_server/src/conv.rs
+++ b/crates/ra_lsp_server/src/conv.rs
@@ -174,6 +174,28 @@ impl Conv for ra_ide_api::Documentation {
     }
 }
 
+impl Conv for ra_ide_api::FunctionSignature {
+    type Output = lsp_types::SignatureInformation;
+    fn conv(self) -> Self::Output {
+        use lsp_types::{ParameterInformation, ParameterLabel, SignatureInformation};
+
+        let label = self.to_string();
+
+        let documentation = self.doc.map(|it| it.conv());
+
+        let parameters: Vec<ParameterInformation> = self
+            .parameters
+            .into_iter()
+            .map(|param| ParameterInformation {
+                label: ParameterLabel::Simple(param),
+                documentation: None,
+            })
+            .collect();
+
+        SignatureInformation { label, documentation, parameters: Some(parameters) }
+    }
+}
+
 impl ConvWith for TextEdit {
     type Ctx = LineIndex;
     type Output = Vec<lsp_types::TextEdit>;
diff --git a/crates/ra_lsp_server/src/main_loop/handlers.rs b/crates/ra_lsp_server/src/main_loop/handlers.rs
index 89e96a33a..b96deb061 100644
--- a/crates/ra_lsp_server/src/main_loop/handlers.rs
+++ b/crates/ra_lsp_server/src/main_loop/handlers.rs
@@ -3,8 +3,8 @@ use lsp_types::{
     CodeActionResponse, CodeLens, Command, Diagnostic, DiagnosticSeverity, CodeAction,
     DocumentFormattingParams, DocumentHighlight, DocumentSymbol, FoldingRange,
     FoldingRangeKind, FoldingRangeParams, Hover, HoverContents, Location, MarkupContent,
-    MarkupKind, ParameterInformation, ParameterLabel, Position, PrepareRenameResponse, Range,
-    RenameParams, SignatureInformation, SymbolInformation, TextDocumentIdentifier, TextEdit,
+    MarkupKind, Position, PrepareRenameResponse, Range,
+    RenameParams,SymbolInformation, TextDocumentIdentifier, TextEdit,
     WorkspaceEdit,
 };
 use ra_ide_api::{
@@ -403,26 +403,13 @@ pub fn handle_signature_help(
 ) -> Result<Option<req::SignatureHelp>> {
     let position = params.try_conv_with(&world)?;
     if let Some(call_info) = world.analysis().call_info(position)? {
-        let parameters: Vec<ParameterInformation> = call_info
-            .parameters
-            .into_iter()
-            .map(|param| ParameterInformation {
-                label: ParameterLabel::Simple(param.clone()),
-                documentation: None,
-            })
-            .collect();
+        let active_parameter = call_info.active_parameter.map(|it| it as i64);
+        let sig_info = call_info.signature.conv();
 
-        let documentation = call_info.doc.map(|it| it.conv());
-
-        let sig_info = SignatureInformation {
-            label: call_info.label,
-            documentation,
-            parameters: Some(parameters),
-        };
         Ok(Some(req::SignatureHelp {
             signatures: vec![sig_info],
             active_signature: Some(0),
-            active_parameter: call_info.active_parameter.map(|it| it as i64),
+            active_parameter,
         }))
     } else {
         Ok(None)