Tweaks to MULTI_FUNC_DEF

Output multiple function definitions using "function" form.

Note exceptions to errors with NO_MULTI_FUNC_DEF

ChangeLog

@@ -1,3 +1,9 @@
+2022-06-07  Peter Stephenson  <p.stephenson@samsung.com>
+
+	* 50339: Doc/Zsh/options.yo, Src/text.c, Test/C04funcdef.ztst:
+	Make multiple function output safer with NO_MULTI_FUNC_DEF and
+	document exceptions to errors raised by MULTI_FUNC_DEF.
+
 2022-06-04  Bart Schaefer  <schaefer@zsh.org>
 
 	* 50323: Completion/Base/Utility/_shadow (new file),

Doc/Zsh/options.yo

@@ -1884,6 +1884,11 @@ fn2)var(...)tt(LPAR()RPAR())'; if the option is not set, this causes
 a parse error.  Definition of multiple functions with the tt(function)
 keyword is always allowed.  Multiple function definitions are not often
 used and can cause obscure errors.
+
+Note that no error is raised if multiple functions are defined as a
+result of a set of names that were originally read as a single word on
+the command line, for example `tt(TRAP{INT,QUIT})'.  Although there are
+no plans to change this behaviour at present, it is not guaranteed.
 )
 pindex(MULTIOS)
 pindex(NO_MULTIOS)

Src/text.c

@@ -578,11 +578,16 @@ gettext2(Estate state)
 		Wordcode end = p + WC_FUNCDEF_SKIP(code);
 		int nargs = *state->pc++;
 
+		if (nargs > 1)
+		    taddstr("function ");
 		taddlist(state, nargs);
 		if (nargs)
 		    taddstr(" ");
 		if (tjob) {
-		    taddstr("() { ... }");
+		    if (nargs > 1)
+			taddstr("{ ... }");
+		    else
+			taddstr("() { ... }");
 		    state->pc = end;
 		    if (!nargs) {
 			/*
@@ -594,7 +599,10 @@ gettext2(Estate state)
 		    }
 		    stack = 1;
 		} else {
-		    taddstr("() {");
+		    if (nargs > 1)
+			taddstr("{");
+		    else
+			taddstr("() {");
 		    tindent++;
 		    taddnl(1);
 		    n = tpush(code, 1);

Test/C04funcdef.ztst

@@ -53,6 +53,26 @@
 >b: redirection
 >a: redirection
 
+  define_multiple() {
+    fn1 fn2 fn3() {
+      print This is $0
+    }
+  }
+  which -x2 define_multiple
+  define_multiple
+  fn1
+  fn2
+  fn3
+0: Safe output of multiple function definitions
+>define_multiple () {
+>  function fn1 fn2 fn3 {
+>    print This is $0
+>  }
+>}
+>This is fn1
+>This is fn2
+>This is fn3
+
   functions -M m1
   m1() { (( $# )) }
   print $(( m1() ))