change use to usingnamespace

See #2014

`use` syntax is still accepted for now. `zig fmt` automatically
updates code. After a release cycle the old syntax will be removed.

doc/docgen.zig

@@ -788,7 +788,7 @@ fn tokenizeAndPrintRaw(docgen_tokenizer: *Tokenizer, out: var, source_token: Tok
             std.zig.Token.Id.Keyword_try,
             std.zig.Token.Id.Keyword_union,
             std.zig.Token.Id.Keyword_unreachable,
-            std.zig.Token.Id.Keyword_use,
+            std.zig.Token.Id.Keyword_usingnamespace,
             std.zig.Token.Id.Keyword_var,
             std.zig.Token.Id.Keyword_volatile,
             std.zig.Token.Id.Keyword_allowzero,

doc/langref.html.in

@@ -9918,7 +9918,7 @@ KEYWORD_try         <- 'try'         end_of_word
 KEYWORD_undefined   <- 'undefined'   end_of_word
 KEYWORD_union       <- 'union'       end_of_word
 KEYWORD_unreachable <- 'unreachable' end_of_word
-KEYWORD_use         <- 'use'         end_of_word
+KEYWORD_usingnamespace <- 'usingnamespace' end_of_word
 KEYWORD_var         <- 'var'         end_of_word
 KEYWORD_volatile    <- 'volatile'    end_of_word
 KEYWORD_while       <- 'while'       end_of_word
@@ -9935,7 +9935,7 @@ keyword <- KEYWORD_align / KEYWORD_and / KEYWORD_allowzero / KEYWORD_anyerror
          / KEYWORD_stdcallcc / KEYWORD_struct / KEYWORD_suspend
          / KEYWORD_switch / KEYWORD_test / KEYWORD_threadlocal / KEYWORD_true / KEYWORD_try
          / KEYWORD_undefined / KEYWORD_union / KEYWORD_unreachable
-         / KEYWORD_use / KEYWORD_var / KEYWORD_volatile / KEYWORD_while</code></pre>
+         / KEYWORD_usingnamespace / KEYWORD_var / KEYWORD_volatile / KEYWORD_while</code></pre>
       {#header_close#}
       {#header_open|Zen#}
       <ul>

src/parser.cpp

@@ -668,7 +668,7 @@ static AstNode *ast_parse_top_level_decl(ParseContext *pc, VisibMod visib_mod) {
         return res;
     }
 
-    Token *use = eat_token_if(pc, TokenIdKeywordUse);
+    Token *use = eat_token_if(pc, TokenIdKeywordUsingNamespace);
     if (use != nullptr) {
         AstNode *expr = ast_expect(pc, ast_parse_expr);
         expect_token(pc, TokenIdSemicolon);

src/tokenizer.cpp

@@ -153,7 +153,8 @@ static const struct ZigKeyword zig_keywords[] = {
     {"undefined", TokenIdKeywordUndefined},
     {"union", TokenIdKeywordUnion},
     {"unreachable", TokenIdKeywordUnreachable},
-    {"use", TokenIdKeywordUse},
+    {"use", TokenIdKeywordUsingNamespace},
+    {"usingnamespace", TokenIdKeywordUsingNamespace},
     {"var", TokenIdKeywordVar},
     {"volatile", TokenIdKeywordVolatile},
     {"while", TokenIdKeywordWhile},
@@ -1546,7 +1547,7 @@ const char * token_name(TokenId id) {
         case TokenIdKeywordUndefined: return "undefined";
         case TokenIdKeywordUnion: return "union";
         case TokenIdKeywordUnreachable: return "unreachable";
-        case TokenIdKeywordUse: return "use";
+        case TokenIdKeywordUsingNamespace: return "usingnamespace";
         case TokenIdKeywordVar: return "var";
         case TokenIdKeywordVolatile: return "volatile";
         case TokenIdKeywordWhile: return "while";

src/tokenizer.hpp

@@ -96,7 +96,7 @@ enum TokenId {
     TokenIdKeywordUndefined,
     TokenIdKeywordUnion,
     TokenIdKeywordUnreachable,
-    TokenIdKeywordUse,
+    TokenIdKeywordUsingNamespace,
     TokenIdKeywordVar,
     TokenIdKeywordVolatile,
     TokenIdKeywordWhile,

std/zig/parse.zig

@@ -203,7 +203,7 @@ fn parseTopLevelComptime(arena: *Allocator, it: *TokenIterator, tree: *Tree) !?*
 /// TopLevelDecl
 ///     <- (KEYWORD_export / KEYWORD_extern STRINGLITERAL? / KEYWORD_inline)? FnProto (SEMICOLON / Block)
 ///      / (KEYWORD_export / KEYWORD_extern STRINGLITERAL?)? KEYWORD_threadlocal? VarDecl
-///      / KEYWORD_use Expr SEMICOLON
+///      / KEYWORD_usingnamespace Expr SEMICOLON
 fn parseTopLevelDecl(arena: *Allocator, it: *TokenIterator, tree: *Tree) !?*Node {
     var lib_name: ?*Node = null;
     const extern_export_inline_token = blk: {
@@ -2809,7 +2809,7 @@ fn parseTry(arena: *Allocator, it: *TokenIterator, tree: *Tree) !?*Node {
 }
 
 fn parseUse(arena: *Allocator, it: *TokenIterator, tree: *Tree) !?*Node {
-    const token = eatToken(it, .Keyword_use) orelse return null;
+    const token = eatToken(it, .Keyword_usingnamespace) orelse return null;
     const node = try arena.create(Node.Use);
     node.* = Node.Use{
         .base = Node{ .id = .Use },

std/zig/parser_test.zig

@@ -1,3 +1,13 @@
+// TODO remove `use` keyword eventually
+test "zig fmt: change use to usingnamespace" {
+    try testTransform(
+        \\use @import("std");
+    ,
+        \\usingnamespace @import("std");
+        \\
+    );
+}
+
 test "zig fmt: allowzero pointer" {
     try testCanonical(
         \\const T = [*]allowzero const u8;
@@ -2090,8 +2100,8 @@ test "zig fmt: Block after if" {
 
 test "zig fmt: use" {
     try testCanonical(
-        \\use @import("std");
-        \\pub use @import("std");
+        \\usingnamespace @import("std");
+        \\pub usingnamespace @import("std");
         \\
     );
 }

std/zig/render.zig

@@ -168,7 +168,9 @@ fn renderTopLevelDecl(allocator: *mem.Allocator, stream: var, tree: *ast.Tree, i
             if (use_decl.visib_token) |visib_token| {
                 try renderToken(tree, stream, visib_token, indent, start_col, Space.Space); // pub
             }
-            try renderToken(tree, stream, use_decl.use_token, indent, start_col, Space.Space); // use
+            // TODO after depracating use, go back to this:
+            //try renderToken(tree, stream, use_decl.use_token, indent, start_col, Space.Space); // usingnamespace
+            try stream.write("usingnamespace ");
             try renderExpression(allocator, stream, tree, indent, start_col, use_decl.expr, Space.None);
             try renderToken(tree, stream, use_decl.semicolon_token, indent, start_col, Space.Newline); // ;
         },

std/zig/tokenizer.zig

@@ -59,7 +59,8 @@ pub const Token = struct {
         Keyword{ .bytes = "undefined", .id = Id.Keyword_undefined },
         Keyword{ .bytes = "union", .id = Id.Keyword_union },
         Keyword{ .bytes = "unreachable", .id = Id.Keyword_unreachable },
-        Keyword{ .bytes = "use", .id = Id.Keyword_use },
+        Keyword{ .bytes = "use", .id = Id.Keyword_usingnamespace },
+        Keyword{ .bytes = "usingnamespace", .id = Id.Keyword_usingnamespace },
         Keyword{ .bytes = "var", .id = Id.Keyword_var },
         Keyword{ .bytes = "volatile", .id = Id.Keyword_volatile },
         Keyword{ .bytes = "while", .id = Id.Keyword_while },
@@ -190,7 +191,7 @@ pub const Token = struct {
         Keyword_undefined,
         Keyword_union,
         Keyword_unreachable,
-        Keyword_use,
+        Keyword_usingnamespace,
         Keyword_var,
         Keyword_volatile,
         Keyword_while,