New variable: *args-eff*.

* txr.c (txr_main): As arguments are processed, collect
them into a list called the effective arg list,
which is eventually visible as the *args-eff* variable.
This is the argument list which reflects the expansions
that have been applied by --args or --eargs.
Those two options take special care to remove themselves
from that list.

* txr.1: Documented *args-eff*.

2 files changed, 52 insertions, 10 deletions

diff --git a/txr.1 b/txr.1
index 49957259..09b1b172 100644
--- a/txr.1
+++ b/txr.1
@@ -45935,18 +45935,44 @@ Note that environment variable names, their values, and command line
 arguments are all regarded as being externally encoded in UTF-8. \*(TX performs
 the encoding and decoding automatically.
 
-.coNP Special variables @ *args* and @ *args-full*
+.coNP Special variables @, *args-full* @ *args-eff* @ *args*
 .desc
 The
-.code *args*
-variable holds a list of strings representing the remaining
-arguments which follow any options processed by the \*(TX executable,
-and the script name.
+.code *args-full*
+variable holds the original, complete list of arguments passed
+from the operating system, including the program executable
+name.
+
+During command line option processing, \*(TX may transform the
+argument list. The hash bang mechanism, and the
+.code --args
+and
+.code --eargs
+options can inject new command line arguments, as can code
+which is executed during argument processing via the
+.code -e
+options and others.
 
 The
+.code *args-eff*
+variable holds the list of
+.I "effective arguments" ,
+which is the argument list after these transformations are applied.
+This variable is established and set to the same value as
 .code *args-full*
-variable holds the original, complete list of arguments passed
-from the operating system.
+prior to command line processing, but is not updated with its final
+value until after command line processing.
+
+The
+.code *args*
+variable holds a list of strings representing the remaining
+arguments which follow any options processed by the \*(TX executable,
+and the script name. This list is a suffix of
+.codn *args-eff* .
+Thus, the arguments before
+.code *args*
+can be calculated using the expression
+.codn "(ldiff *args-eff* *args*)" .
 
 The
 .code *args*
diff --git a/txr.c b/txr.c
index 743530c3..3fdb18c0 100644
--- a/txr.c
+++ b/txr.c
@@ -488,8 +488,9 @@ int txr_main(int argc, char **argv)
   val self_path_s = intern(lit("self-path"), user_package);
   val compat_var = lit("TXR_COMPAT");
   val compat_val = getenv_wrap(compat_var);
-  val orig_args = nil;
+  val orig_args = nil, ref_arg_list = nil;
   list_collect_decl(arg_list, arg_tail);
+  list_collect_decl(eff_arg_list, eff_arg_tail);
 
   static char alt_args_buf[128 + 7] = "@(txr):", *alt_args = alt_args_buf + 7;
 
@@ -516,8 +517,12 @@ int txr_main(int argc, char **argv)
   reg_varl(intern(lit("compat"), system_package), zero);
   reg_var(intern(lit("*full-args*"), user_package), arg_list);
   reg_var(intern(lit("*args-full*"), user_package), arg_list);
+  reg_var(intern(lit("*args-eff*"), user_package), eff_arg_list);
 
-  arg_list = cdr(arg_list);
+  if (arg_list) {
+    eff_arg_tail = list_collect(eff_arg_tail, car(arg_list));
+    arg_list = cdr(arg_list);
+  }
 
   if (*alt_args) {
     orig_args = arg_list;
@@ -533,10 +538,12 @@ int txr_main(int argc, char **argv)
 #endif
   }
 
-  for (arg = upop(&arg_list, &arg_undo);
+  for (ref_arg_list = arg_list, arg = upop(&arg_list, &arg_undo);
        arg && car(arg) == chr('-');
        arg = upop(&arg_list, &arg_undo))
   {
+    eff_arg_tail = list_collect(eff_arg_tail, arg);
+
     if (equal(arg, lit("--")))
       break;
 
@@ -549,6 +556,7 @@ int txr_main(int argc, char **argv)
       val sep = sub_str(arg, num(6), num(7));
       arg = sub_str(arg, num(7), nil);
       arg_list = append2(split_str(arg, sep), arg_list);
+      set(eff_arg_tail, butlastn(one, deref(eff_arg_tail)));
       continue;
     }
 
@@ -570,6 +578,7 @@ int txr_main(int argc, char **argv)
                                             arg2),
                                 split_str(arg, sep)),
                          arg_list);
+      set(eff_arg_tail, butlastn(one, deref(eff_arg_tail)));
       continue;
     }
 
@@ -741,6 +750,8 @@ int txr_main(int argc, char **argv)
 
       arg = upop(&arg_list, &arg_undo);
 
+      eff_arg_tail = list_collect(eff_arg_tail, arg);
+
       switch (c_chr(opt)) {
       case 'a':
         if (!do_fixnum_opt(array_dim, opt, arg))
@@ -907,6 +918,11 @@ int txr_main(int argc, char **argv)
     }
   }
 
+  eff_arg_tail = list_collect_nconc(eff_arg_tail, arg_list);
+
+  if (!equal(cdr(eff_arg_list), ref_arg_list))
+    reg_var(intern(lit("*args-eff*"), user_package), eff_arg_list);
+
   if (specstring && spec_file) {
     drop_privilege();
     format(std_error, lit("~a: cannot specify both -f and -c\n"),