allow cycling through function signatures/overloads (#9974)

implement handle_event to cycle through the function signatures.

To change the signature press alt+p/n .

Signed-off-by: Ben Fekih, Hichem <hichem.f@live.de>

helix-term/src/handlers/signature_help.rs

@@ -5,7 +5,7 @@ use helix_core::syntax::LanguageServerFeature;
 use helix_event::{
     cancelable_future, cancelation, register_hook, send_blocking, CancelRx, CancelTx,
 };
-use helix_lsp::lsp;
+use helix_lsp::lsp::{self, SignatureInformation};
 use helix_stdx::rope::RopeSliceExt;
 use helix_view::document::Mode;
 use helix_view::events::{DocumentDidChange, SelectionDidChange};
@@ -18,7 +18,7 @@ use crate::commands::Open;
 use crate::compositor::Compositor;
 use crate::events::{OnModeSwitch, PostInsertChar};
 use crate::handlers::Handlers;
-use crate::ui::lsp::SignatureHelp;
+use crate::ui::lsp::{Signature, SignatureHelp};
 use crate::ui::Popup;
 use crate::{job, ui};
 
@@ -82,6 +82,7 @@ impl helix_event::AsyncHook for SignatureHelpHandler {
                     }
                 }
                 self.state = if open { State::Open } else { State::Closed };
+
                 return timeout;
             }
         }
@@ -138,6 +139,31 @@ pub fn request_signature_help(
     });
 }
 
+fn active_param_range(
+    signature: &SignatureInformation,
+    response_active_parameter: Option<u32>,
+) -> Option<(usize, usize)> {
+    let param_idx = signature
+        .active_parameter
+        .or(response_active_parameter)
+        .unwrap_or(0) as usize;
+    let param = signature.parameters.as_ref()?.get(param_idx)?;
+    match &param.label {
+        lsp::ParameterLabel::Simple(string) => {
+            let start = signature.label.find(string.as_str())?;
+            Some((start, start + string.len()))
+        }
+        lsp::ParameterLabel::LabelOffsets([start, end]) => {
+            // LS sends offsets based on utf-16 based string representation
+            // but highlighting in helix is done using byte offset.
+            use helix_core::str_utils::char_to_byte_idx;
+            let from = char_to_byte_idx(&signature.label, *start as usize);
+            let to = char_to_byte_idx(&signature.label, *end as usize);
+            Some((from, to))
+        }
+    }
+}
+
 pub fn show_signature_help(
     editor: &mut Editor,
     compositor: &mut Compositor,
@@ -184,54 +210,50 @@ pub fn show_signature_help(
     let doc = doc!(editor);
     let language = doc.language_name().unwrap_or("");
 
-    let signature = match response
+    if response.signatures.is_empty() {
+        return;
+    }
+
+    let signatures: Vec<Signature> = response
         .signatures
-        .get(response.active_signature.unwrap_or(0) as usize)
+        .into_iter()
-    {
+        .map(|s| {
-        Some(s) => s,
+            let active_param_range = active_param_range(&s, response.active_parameter);
-        None => return,
-    };
-    let mut contents = SignatureHelp::new(
-        signature.label.clone(),
-        language.to_string(),
-        Arc::clone(&editor.syn_loader),
-    );
 
-    let signature_doc = if config.lsp.display_signature_help_docs {
+            let signature_doc = if config.lsp.display_signature_help_docs {
-        signature.documentation.as_ref().map(|doc| match doc {
+                s.documentation.map(|doc| match doc {
-            lsp::Documentation::String(s) => s.clone(),
+                    lsp::Documentation::String(s) => s,
-            lsp::Documentation::MarkupContent(markup) => markup.value.clone(),
+                    lsp::Documentation::MarkupContent(markup) => markup.value,
+                })
+            } else {
+                None
+            };
+
+            Signature {
+                signature: s.label,
+                signature_doc,
+                active_param_range,
+            }
         })
-    } else {
+        .collect();
-        None
-    };
-
-    contents.set_signature_doc(signature_doc);
-
-    let active_param_range = || -> Option<(usize, usize)> {
-        let param_idx = signature
-            .active_parameter
-            .or(response.active_parameter)
-            .unwrap_or(0) as usize;
-        let param = signature.parameters.as_ref()?.get(param_idx)?;
-        match &param.label {
-            lsp::ParameterLabel::Simple(string) => {
-                let start = signature.label.find(string.as_str())?;
-                Some((start, start + string.len()))
-            }
-            lsp::ParameterLabel::LabelOffsets([start, end]) => {
-                // LS sends offsets based on utf-16 based string representation
-                // but highlighting in helix is done using byte offset.
-                use helix_core::str_utils::char_to_byte_idx;
-                let from = char_to_byte_idx(&signature.label, *start as usize);
-                let to = char_to_byte_idx(&signature.label, *end as usize);
-                Some((from, to))
-            }
-        }
-    };
-    contents.set_active_param_range(active_param_range());
 
     let old_popup = compositor.find_id::<Popup<SignatureHelp>>(SignatureHelp::ID);
+    let mut active_signature = old_popup
+        .as_ref()
+        .map(|popup| popup.contents().active_signature())
+        .unwrap_or_else(|| response.active_signature.unwrap_or_default() as usize);
+
+    if active_signature >= signatures.len() {
+        active_signature = signatures.len() - 1;
+    }
+
+    let contents = SignatureHelp::new(
+        language.to_string(),
+        Arc::clone(&editor.syn_loader),
+        active_signature,
+        signatures,
+    );
+
     let mut popup = Popup::new(SignatureHelp::ID, contents)
         .position(old_popup.and_then(|p| p.get_position()))
         .position_bias(Open::Above)

helix-term/src/ui/lsp.rs

@@ -3,60 +3,95 @@ use std::sync::Arc;
 use arc_swap::ArcSwap;
 use helix_core::syntax;
 use helix_view::graphics::{Margin, Rect, Style};
+use helix_view::input::Event;
 use tui::buffer::Buffer;
+use tui::layout::Alignment;
+use tui::text::Text;
 use tui::widgets::{BorderType, Paragraph, Widget, Wrap};
 
-use crate::compositor::{Component, Compositor, Context};
+use crate::compositor::{Component, Compositor, Context, EventResult};
 
+use crate::alt;
 use crate::ui::Markdown;
 
 use super::Popup;
 
-pub struct SignatureHelp {
+pub struct Signature {
-    signature: String,
+    pub signature: String,
-    signature_doc: Option<String>,
+    pub signature_doc: Option<String>,
     /// Part of signature text
-    active_param_range: Option<(usize, usize)>,
+    pub active_param_range: Option<(usize, usize)>,
+}
 
+pub struct SignatureHelp {
     language: String,
     config_loader: Arc<ArcSwap<syntax::Loader>>,
+    active_signature: usize,
+    signatures: Vec<Signature>,
 }
 
 impl SignatureHelp {
     pub const ID: &'static str = "signature-help";
 
     pub fn new(
-        signature: String,
         language: String,
         config_loader: Arc<ArcSwap<syntax::Loader>>,
+        active_signature: usize,
+        signatures: Vec<Signature>,
     ) -> Self {
         Self {
-            signature,
-            signature_doc: None,
-            active_param_range: None,
             language,
             config_loader,
+            active_signature,
+            signatures,
         }
     }
 
-    pub fn set_signature_doc(&mut self, signature_doc: Option<String>) {
+    pub fn active_signature(&self) -> usize {
-        self.signature_doc = signature_doc;
+        self.active_signature
-    }
-
-    pub fn set_active_param_range(&mut self, offset: Option<(usize, usize)>) {
-        self.active_param_range = offset;
     }
 
     pub fn visible_popup(compositor: &mut Compositor) -> Option<&mut Popup<Self>> {
         compositor.find_id::<Popup<Self>>(Self::ID)
     }
+
+    fn signature_index(&self) -> String {
+        format!("({}/{})", self.active_signature + 1, self.signatures.len())
+    }
 }
 
 impl Component for SignatureHelp {
+    fn handle_event(&mut self, event: &Event, _cx: &mut Context) -> EventResult {
+        let Event::Key(event) = event else {
+            return EventResult::Ignored(None);
+        };
+
+        if self.signatures.len() <= 1 {
+            return EventResult::Ignored(None);
+        }
+
+        match event {
+            alt!('p') => {
+                self.active_signature = self
+                    .active_signature
+                    .checked_sub(1)
+                    .unwrap_or(self.signatures.len() - 1);
+                EventResult::Consumed(None)
+            }
+            alt!('n') => {
+                self.active_signature = (self.active_signature + 1) % self.signatures.len();
+                EventResult::Consumed(None)
+            }
+            _ => EventResult::Ignored(None),
+        }
+    }
+
     fn render(&mut self, area: Rect, surface: &mut Buffer, cx: &mut Context) {
         let margin = Margin::horizontal(1);
 
-        let active_param_span = self.active_param_range.map(|(start, end)| {
+        let signature = &self.signatures[self.active_signature];
+
+        let active_param_span = signature.active_param_range.map(|(start, end)| {
             vec![(
                 cx.editor
                     .theme
@@ -66,21 +101,29 @@ impl Component for SignatureHelp {
             )]
         });
 
+        let sig = &self.signatures[self.active_signature];
         let sig_text = crate::ui::markdown::highlighted_code_block(
-            &self.signature,
+            sig.signature.as_str(),
             &self.language,
             Some(&cx.editor.theme),
             Arc::clone(&self.config_loader),
             active_param_span,
         );
 
+        if self.signatures.len() > 1 {
+            let signature_index = self.signature_index();
+            let text = Text::from(signature_index);
+            let paragraph = Paragraph::new(&text).alignment(Alignment::Right);
+            paragraph.render(area.clip_top(1).with_height(1).clip_right(1), surface);
+        }
+
         let (_, sig_text_height) = crate::ui::text::required_size(&sig_text, area.width);
         let sig_text_area = area.clip_top(1).with_height(sig_text_height);
         let sig_text_area = sig_text_area.inner(&margin).intersection(surface.area);
         let sig_text_para = Paragraph::new(&sig_text).wrap(Wrap { trim: false });
         sig_text_para.render(sig_text_area, surface);
 
-        if self.signature_doc.is_none() {
+        if sig.signature_doc.is_none() {
             return;
         }
 
@@ -92,7 +135,7 @@ impl Component for SignatureHelp {
             }
         }
 
-        let sig_doc = match &self.signature_doc {
+        let sig_doc = match &sig.signature_doc {
             None => return,
             Some(doc) => Markdown::new(doc.clone(), Arc::clone(&self.config_loader)),
         };
@@ -110,13 +153,15 @@ impl Component for SignatureHelp {
         const PADDING: u16 = 2;
         const SEPARATOR_HEIGHT: u16 = 1;
 
+        let sig = &self.signatures[self.active_signature];
+
         if PADDING >= viewport.1 || PADDING >= viewport.0 {
             return None;
         }
         let max_text_width = (viewport.0 - PADDING).min(120);
 
         let signature_text = crate::ui::markdown::highlighted_code_block(
-            &self.signature,
+            sig.signature.as_str(),
             &self.language,
             None,
             Arc::clone(&self.config_loader),
@@ -125,7 +170,7 @@ impl Component for SignatureHelp {
         let (sig_width, sig_height) =
             crate::ui::text::required_size(&signature_text, max_text_width);
 
-        let (width, height) = match self.signature_doc {
+        let (width, height) = match sig.signature_doc {
             Some(ref doc) => {
                 let doc_md = Markdown::new(doc.clone(), Arc::clone(&self.config_loader));
                 let doc_text = doc_md.parse(None);
@@ -139,6 +184,12 @@ impl Component for SignatureHelp {
             None => (sig_width, sig_height),
         };
 
-        Some((width + PADDING, height + PADDING))
+        let sig_index_width = if self.signatures.len() > 1 {
+            self.signature_index().len() + 1
+        } else {
+            0
+        };
+
+        Some((width + PADDING + sig_index_width as u16, height + PADDING))
     }
 }