Determine if simple command names are declaration utilities

builtin.c

@@ -1,6 +1,6 @@
 /* Yash: yet another shell */
 /* builtin.c: built-in commands */
-/* (C) 2007-2022 magicant */
+/* (C) 2007-2025 magicant */
 
 /* This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -77,16 +77,28 @@ void init_builtin(void)
     ht_initwithcapacity(&builtins, hashstr, htstrcmp, 53);
 
 #if YASH_ENABLE_HELP
-# define DEFBUILTIN(name,func,type,help,syntax,options) \
-    do {                                                                      \
-        static const builtin_T bi = { func, type, help, syntax, options, };   \
-        ht_set(&builtins, name, &bi);                                         \
+# define DEFBUILTIN(name,func,type,help,syntax,options)      \
+    do {                                                     \
+        static const builtin_T bi =                          \
+            { func, type, false, help, syntax, options, };   \
+        ht_set(&builtins, name, &bi);                        \
+    } while (0)
+# define DEFDECLUTIL(name,func,type,help,syntax,options)     \
+    do {                                                     \
+        static const builtin_T bi =                          \
+            { func, type, true, help, syntax, options, };    \
+        ht_set(&builtins, name, &bi);                        \
     } while (0)
 #else
-# define DEFBUILTIN(name,func,type,help,syntax,options) \
-    do {                                                                      \
-        static const builtin_T bi = { func, type, };                          \
-        ht_set(&builtins, name, &bi);                                         \
+# define DEFBUILTIN(name,func,type,help,syntax,options)      \
+    do {                                                     \
+        static const builtin_T bi = { func, type, false, };  \
+        ht_set(&builtins, name, &bi);                        \
+    } while (0)
+# define DEFDECLUTIL(name,func,type,help,syntax,options)     \
+    do {                                                     \
+        static const builtin_T bi = { func, type, true, };   \
+        ht_set(&builtins, name, &bi);                        \
     } while (0)
 #endif
 
@@ -121,13 +133,13 @@ void init_builtin(void)
             unalias_syntax, all_help_options);
 
     /* defined in "variable.c" */
-    DEFBUILTIN("typeset", typeset_builtin, BI_ELECTIVE, typeset_help,
+    DEFDECLUTIL("typeset", typeset_builtin, BI_ELECTIVE, typeset_help,
             typeset_syntax, typeset_options);
-    DEFBUILTIN("export", typeset_builtin, BI_SPECIAL, export_help,
+    DEFDECLUTIL("export", typeset_builtin, BI_SPECIAL, export_help,
             export_syntax, typeset_options);
-    DEFBUILTIN("local", typeset_builtin, BI_ELECTIVE, local_help,
+    DEFDECLUTIL("local", typeset_builtin, BI_ELECTIVE, local_help,
             local_syntax, local_options);
-    DEFBUILTIN("readonly", typeset_builtin, BI_SPECIAL, readonly_help,
+    DEFDECLUTIL("readonly", typeset_builtin, BI_SPECIAL, readonly_help,
             readonly_syntax, typeset_options);
 #if YASH_ENABLE_ARRAY
     DEFBUILTIN("array", array_builtin, BI_EXTENSION, array_help, array_syntax,

builtin.h

@@ -1,6 +1,6 @@
 /* Yash: yet another shell */
 /* builtin.h: built-in commands */
-/* (C) 2007-2022 magicant */
+/* (C) 2007-2025 magicant */
 
 /* This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -36,6 +36,7 @@ typedef enum builtintype_T {
 typedef struct builtin_T {
     main_T *body;
     builtintype_T type;
+    _Bool isdeclutil;
 #if YASH_ENABLE_HELP
     const char *help_text, *syntax_text;
     const struct xgetopt_T *options;

parser.c

@@ -34,6 +34,7 @@
 #include <wchar.h>
 #include <wctype.h>
 #include "alias.h"
+#include "builtin.h"
 #include "expand.h"
 #include "input.h"
 #include "option.h"
@@ -663,6 +664,8 @@ static redir_T *tryparse_redirect(parsestate_T *ps)
     __attribute__((nonnull,malloc,warn_unused_result));
 static void validate_redir_operand(parsestate_T *ps)
     __attribute__((nonnull));
+static bool is_declaration_utility(void *const *words)
+    __attribute__((nonnull,pure,warn_unused_result));
 static command_T *parse_compound_command(parsestate_T *ps)
     __attribute__((nonnull,malloc,warn_unused_result));
 static command_T *parse_group(parsestate_T *ps)
@@ -2098,7 +2101,7 @@ command_T *parse_command(parsestate_T *ps)
     result->c_redirs = NULL;
     result->c_words = parse_simple_command_tokens(
             ps, &result->c_assigns, &result->c_redirs);
-    result->c_isdeclutil = false; // TODO FIXME
+    result->c_isdeclutil = is_declaration_utility(result->c_words);
 
     if (result->c_words[0] == NULL && result->c_assigns == NULL &&
             result->c_redirs == NULL) {
@@ -2386,6 +2389,29 @@ void validate_redir_operand(parsestate_T *ps)
     } while (psubstitute_alias(ps, 0));
 }
 
+/* Determines if the command name is a declaration utility.
+ * `words` must point to a NULL-terminated array of pointers to `wordunit_T's.
+ * This function usually examines only the first word, but may scan remaining
+ * words if a word delegates to the next one. */
+bool is_declaration_utility(void *const *words)
+{
+    for (; *words != NULL; words++) {
+        const wordunit_T *w = *words;
+        if (!is_single_string_word(w))
+            return false;
+        if (wcscmp(w->wu_string, L"command") == 0)
+            continue;
+
+        char *name = malloc_wcstombs(w->wu_string);
+        if (name == NULL)
+            return false;
+        const builtin_T *bi = get_builtin(name);
+        free(name);
+        return bi != NULL && bi->isdeclutil;
+    }
+    return false;
+}
+
 /* Parses a compound command.
  * `command' is the name of the command to parse such as "(" and "if".
  * Returns NULL iff the current token does not start a compound command. */