add keyword snippets for autocomplete

src/Server.zig

@@ -16,9 +16,11 @@ const shared = @import("shared.zig");
 const Ast = std.zig.Ast;
 const tracy = @import("tracy.zig");
 const uri_utils = @import("uri.zig");
-const data = @import("data/data.zig");
 const diff = @import("diff.zig");
 
+const data = @import("data/data.zig");
+const snipped_data = @import("data/snippets.zig");
+
 const log = std.log.scoped(.server);
 
 // Server fields
@@ -1160,6 +1162,30 @@ fn populateBuiltinCompletions(builtin_completions: *std.ArrayListUnmanaged(types
     truncateCompletions(builtin_completions.items, config.max_detail_length);
 }
 
+fn populateSnippedCompletions(
+    allocator: std.mem.Allocator,
+    completions: *std.ArrayListUnmanaged(types.CompletionItem),
+    snippets: []const snipped_data.Snipped,
+    config: Config,
+    start_with: ?[]const u8,
+) error{OutOfMemory}!void {
+    try completions.ensureUnusedCapacity(allocator, snippets.len);
+
+    for (snippets) |snipped| {
+        if (start_with) |needle| {
+            if (!std.mem.startsWith(u8, snipped.label, needle)) continue;
+        }
+
+        completions.appendAssumeCapacity(.{
+            .label = snipped.label,
+            .kind = snipped.kind,
+            .detail = if (config.enable_snippets) snipped.text else null,
+            .insertText = if (config.enable_snippets) snipped.text else null,
+            .insertTextFormat = if (config.enable_snippets and snipped.text != null) .Snippet else .PlainText,
+        });
+    }
+}
+
 fn completeBuiltin(server: *Server, writer: anytype, id: types.RequestId) !void {
     const tracy_zone = tracy.trace(@src());
     defer tracy_zone.end();
@@ -1192,6 +1218,7 @@ fn completeGlobal(server: *Server, writer: anytype, id: types.RequestId, pos_ind
         .orig_handle = handle,
     };
     try analysis.iterateSymbolsGlobal(&server.document_store, &server.arena, handle, pos_index, declToCompletion, context);
+    try populateSnippedCompletions(server.arena.allocator(), &completions, &snipped_data.generic, server.config.*, null);
     sortCompletionItems(completions.items, server.arena.allocator());
     truncateCompletions(completions.items, server.config.max_detail_length);
 
@@ -1437,7 +1464,7 @@ fn kindToSortScore(kind: types.CompletionItem.Kind) []const u8 {
         .Field => "3_",
         .Function => "4_",
 
-        .Keyword, .EnumMember => "5_",
+        .Keyword, .Snippet, .EnumMember => "5_",
 
         .Class,
         .Interface,
@@ -1770,8 +1797,17 @@ fn completionHandler(server: *Server, writer: anytype, id: types.RequestId, req:
         return try respondGeneric(writer, id, no_completions_response);
     };
 
-    if (req.params.position.character == 0)
+    if (req.params.position.character == 0) {
-        return try respondGeneric(writer, id, no_completions_response);
+        var completions = std.ArrayListUnmanaged(types.CompletionItem){};
+        try populateSnippedCompletions(server.arena.allocator(), &completions, &snipped_data.top_level_decl_data, server.config.*, null);
+
+        return try send(writer, server.arena.allocator(), types.Response{
+            .id = id,
+            .result = .{
+                .CompletionList = .{ .isIncomplete = false, .items = completions.items },
+            },
+        });
+    }
 
     const source_index = offsets.positionToIndex(handle.document.text, req.params.position, server.offset_encoding);
     const pos_context = try analysis.getPositionContext(server.arena.allocator(), handle.document, source_index);

src/data/snippets.zig

@@ -0,0 +1,79 @@
+const types = @import("../types.zig");
+
+pub const Snipped = struct {
+    label: []const u8,
+    kind: types.CompletionItem.Kind,
+    text: ?[]const u8 = null,
+};
+
+pub const top_level_decl_data = [_]Snipped{
+    .{ .label = "fn", .kind = .Snippet, .text = "fn ${1:name}($2) ${3:!void} {$0}" },
+    .{ .label = "pub fn", .kind = .Snippet, .text = "pub fn ${1:name}($2) ${3:!void} {$0}" },
+    .{ .label = "struct", .kind = .Snippet, .text = "const $1 = struct {$0}" },
+    .{ .label = "error set", .kind = .Snippet, .text = "const ${1:Error} = error {$0}" },
+    .{ .label = "enum", .kind = .Snippet, .text = "const $1 = enum {$0}" },
+    .{ .label = "union", .kind = .Snippet, .text = "const $1 = union {$0}" },
+    .{ .label = "union tagged", .kind = .Snippet, .text = "const $1 = union(${2:enum}) {$0}" },
+    .{ .label = "test", .kind = .Snippet, .text = "test \"$1\" {$0}" },
+};
+
+pub const generic = [_]Snipped{
+    // keywords
+    .{ .label = "align", .kind = .Keyword },
+    .{ .label = "allowzero", .kind = .Keyword },
+    .{ .label = "and", .kind = .Keyword },
+    .{ .label = "anyframe", .kind = .Keyword },
+    .{ .label = "anytype", .kind = .Keyword },
+    .{ .label = "asm", .kind = .Keyword },
+    .{ .label = "async", .kind = .Keyword },
+    .{ .label = "await", .kind = .Keyword },
+    .{ .label = "break", .kind = .Keyword },
+    .{ .label = "callconv", .kind = .Keyword, .text = "callconv($0)" },
+    .{ .label = "catch", .kind = .Keyword },
+    .{ .label = "comptime", .kind = .Keyword },
+    .{ .label = "const", .kind = .Keyword },
+    .{ .label = "continue", .kind = .Keyword },
+    .{ .label = "defer", .kind = .Keyword },
+    .{ .label = "else", .kind = .Keyword, .text = "else {$0}" },
+    .{ .label = "enum", .kind = .Keyword, .text = "enum {$0}" },
+    .{ .label = "errdefer", .kind = .Keyword },
+    .{ .label = "error", .kind = .Keyword },
+    .{ .label = "export", .kind = .Keyword },
+    .{ .label = "extern", .kind = .Keyword },
+    .{ .label = "fn", .kind = .Keyword, .text = "fn ${1:name}($2) ${3:!void} {$0}" },
+    .{ .label = "for", .kind = .Keyword, .text = "for ($1) {$0}" },
+    .{ .label = "if", .kind = .Keyword, .text = "if ($1) {$0}" },
+    .{ .label = "inline", .kind = .Keyword },
+    .{ .label = "noalias", .kind = .Keyword },
+    .{ .label = "nosuspend", .kind = .Keyword },
+    .{ .label = "noinline", .kind = .Keyword },
+    .{ .label = "opaque", .kind = .Keyword },
+    .{ .label = "or", .kind = .Keyword },
+    .{ .label = "orelse", .kind = .Keyword },
+    .{ .label = "packed", .kind = .Keyword },
+    .{ .label = "pub", .kind = .Keyword },
+    .{ .label = "resume", .kind = .Keyword },
+    .{ .label = "return", .kind = .Keyword },
+    .{ .label = "linksection", .kind = .Keyword },
+    .{ .label = "struct", .kind = .Keyword, .text = "struct {$0}" },
+    .{ .label = "suspend", .kind = .Keyword },
+    .{ .label = "switch", .kind = .Keyword, .text = "switch ($1) {$0}" },
+    .{ .label = "test", .kind = .Keyword, .text = "test \"$1\" {$0}" },
+    .{ .label = "threadlocal", .kind = .Keyword },
+    .{ .label = "try", .kind = .Keyword },
+    .{ .label = "union", .kind = .Keyword },
+    .{ .label = "unreachable", .kind = .Keyword },
+    .{ .label = "usingnamespace", .kind = .Keyword },
+    .{ .label = "var", .kind = .Keyword },
+    .{ .label = "volatile", .kind = .Keyword },
+    .{ .label = "while", .kind = .Keyword, .text = "while ($1) {$0}" },
+
+    // keyword snippets
+    .{ .label = "asmv", .kind = .Snippet, .text = "asm volatile (${1:input}, ${0:input})" },
+    .{ .label = "pub fn", .kind = .Snippet, .text = "pub fn ${1:name}($2) ${3:!void} {$0}" },
+    .{ .label = "forv", .kind = .Snippet, .text = "for ($1) |${2:value}| {$0}" },
+    .{ .label = "fori", .kind = .Snippet, .text = "for ($1) |_, ${2:i}| {$0}" },
+    .{ .label = "forvi", .kind = .Snippet, .text = "for ($1) |${2:value},${3:i}| {$0}" },
+    .{ .label = "if else", .kind = .Snippet, .text = "if ($1) {$2} else {$0}" },
+    .{ .label = "catch switch", .kind = .Snippet, .text = "catch |${1:err}| switch(${1:err}) {$0}" },
+};