dev: insert commas in arg context for completing before identifiers (#251)

crates/tinymist-query/src/completion.rs

@@ -99,6 +99,7 @@ impl StatefulRequest for CompletionRequest {
 
         let mut match_ident = None;
         let mut completion_result = None;
+        let is_callee = matches!(deref_target, Some(DerefTarget::Callee(..)));
         match deref_target {
             Some(DerefTarget::Callee(v) | DerefTarget::VarAccess(v)) => {
                 if v.is::<ast::Ident>() {
@@ -152,10 +153,9 @@ impl StatefulRequest for CompletionRequest {
             let replace_range;
             if match_ident.as_ref().is_some_and(|i| i.offset() == offset) {
                 let match_ident = match_ident.unwrap();
-                let rng = match_ident.range();
-                replace_range = ctx.to_lsp_range(match_ident.range(), &source);
-
+                let mut rng = match_ident.range();
                 let ident_prefix = source.text()[rng.start..cursor].to_string();
+
                 completions.retain(|c| {
                     // c.label
                     let mut prefix_matcher = c.label.chars();
@@ -171,6 +171,29 @@ impl StatefulRequest for CompletionRequest {
 
                     true
                 });
+
+                // if modifying some arguments, we need to truncate and add a comma
+                if !is_callee && cursor != rng.end && is_arg_like_context(&match_ident) {
+                    // extend comma
+                    for c in completions.iter_mut() {
+                        let apply = match &mut c.apply {
+                            Some(w) => w,
+                            None => {
+                                c.apply = Some(c.label.clone());
+                                c.apply.as_mut().unwrap()
+                            }
+                        };
+                        if apply.trim_end().ends_with(',') {
+                            continue;
+                        }
+                        apply.push_str(", ");
+                    }
+
+                    // Truncate
+                    rng.end = cursor;
+                }
+
+                replace_range = ctx.to_lsp_range(rng, &source);
             } else {
                 let lsp_start_position = ctx.to_lsp_pos(offset, &source);
                 replace_range = LspRange::new(lsp_start_position, self.position);
@@ -198,6 +221,28 @@ impl StatefulRequest for CompletionRequest {
     }
 }
 
+fn is_arg_like_context(mut matching: &LinkedNode) -> bool {
+    while let Some(parent) = matching.parent() {
+        use SyntaxKind::*;
+        // if parent.kind() == SyntaxKind::Markup | SyntaxKind::Markup |
+        // SyntaxKind::Markup {     return true;
+        // }
+        // if parent.kind() == SyntaxKind::Args {
+        //     return true;
+        // }
+
+        // todo: contextual
+        match parent.kind() {
+            ContentBlock | Equation | CodeBlock | Markup | Math | Code => return false,
+            Args | Params | Destructuring | Array | Dict => return true,
+            _ => {}
+        }
+
+        matching = parent;
+    }
+    false
+}
+
 #[cfg(test)]
 mod tests {
     use std::collections::HashSet;

crates/tinymist-query/src/fixtures/completion/func_args_after.typ

@@ -0,0 +1,17 @@
+// contains: content,authors,font,class
+
+#let tmpl(content, authors: (), font: none, class: "article") = {
+  if class != "article" and class != "letter" {
+    panic("")
+  }
+
+  set document(author: authors)
+  set text(font: font)
+
+  set page(paper: "a4") if class == "article"
+  set page(paper: "us-letter") if class == "letter"
+
+  content
+}
+
+#tmpl(/* range after 1..2 */authors: (),)

crates/tinymist-query/src/fixtures/completion/snaps/test@func_args_after.typ.snap

@@ -0,0 +1,31 @@
+---
+source: crates/tinymist-query/src/completion.rs
+description: Completion on u (371..372)
+expression: "JsonRepr::new_pure(results)"
+input_file: crates/tinymist-query/src/fixtures/completion/func_args_after.typ
+---
+[
+ {
+  "isIncomplete": false,
+  "items": [
+   {
+    "kind": 6,
+    "label": "class",
+    "sortText": "000",
+    "textEdit": {
+     "newText": "class: ${1:}, ",
+     "range": {
+      "end": {
+       "character": 29,
+       "line": 16
+      },
+      "start": {
+       "character": 28,
+       "line": 16
+      }
+     }
+    }
+   }
+  ]
+ }
+]

crates/tinymist-query/src/tests.rs

@@ -158,18 +158,28 @@ pub fn run_with_sources<T>(source: &str, f: impl FnOnce(&mut TypstSystemWorld, P
 
 pub fn find_test_range(s: &Source) -> Range<usize> {
     // /* range -3..-1 */
-    let re = s.text().find("/* range ").unwrap();
-    let re_base = re;
-    let re = re + "/* range ".len();
-    let re = re..s.text().find(" */").unwrap();
-    let re = &s.text()[re];
+    fn find_prefix(s: &str, sub: &str, left: bool) -> Option<(usize, usize, bool)> {
+        Some((s.find(sub)?, sub.len(), left))
+    }
+    let (re_base, re_len, is_after) = find_prefix(s.text(), "/* range after ", true)
+        .or_else(|| find_prefix(s.text(), "/* range ", false))
+        .unwrap();
+    let re_end = re_base + re_len;
+    let range_rng = re_end..(s.text()[re_end..].find(" */").unwrap() + re_end);
+    let range_base = if is_after {
+        range_rng.end + " */".len()
+    } else {
+        re_base
+    };
+    let range = &s.text()[range_rng];
     // split by ".."
-    let mut re = re.split("..");
+    let mut bounds = range.split("..");
     // parse the range
-    let start: isize = re.next().unwrap().parse().unwrap();
-    let end: isize = re.next().unwrap().parse().unwrap();
-    let start = start + re_base as isize;
-    let end = end + re_base as isize;
+    let start: isize = bounds.next().unwrap().parse().unwrap();
+    let end: isize = bounds.next().unwrap().parse().unwrap();
+
+    let start = start + range_base as isize;
+    let end = end + range_base as isize;
     start as usize..end as usize
 }