From c91af9a17b0533c6df846ff712e7ade306c7b38a Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Tue, 30 May 2017 23:04:31 -0700
Subject: command line: --eargs semantics change.

The --eargs mechanism won't perform a blind substring
replacement of {} with the following argument. Only
arguments which match {} exactly are replaced.

* eval.c (retf): Static function becomes extern.

* eval.h (retf): Declared.

* txr.c (txr_main): Replace the filtering logic on the
split eargs argument list to just look for items
equal to the string "{}" and replace with the following
argument.

* txr.1: Updated --eargs documentation.
---
 eval.c |  2 +-
 eval.h |  1 +
 txr.1  | 36 ++++++++++++++++++++++++++----------
 txr.c  |  5 ++---
 4 files changed, 30 insertions(+), 14 deletions(-)

diff --git a/eval.c b/eval.c
index 4e6766d0..220355b3 100644
--- a/eval.c
+++ b/eval.c
@@ -5246,7 +5246,7 @@ static val do_retf(val ret, struct args *args)
   return ret;
 }
 
-static val retf(val ret)
+val retf(val ret)
 {
   return func_f0v(ret, do_retf);
 }
diff --git a/eval.h b/eval.h
index 69391879..75cf2c75 100644
--- a/eval.h
+++ b/eval.h
@@ -80,6 +80,7 @@ val mapcarv(val fun, struct args *lists);
 val mapcarl(val fun, val list_of_lists);
 val lazy_mapcar(val fun, val list);
 val generate(val while_pred, val gen_fun);
+val retf(val ret);
 val prinl(val obj, val stream);
 val pprinl(val obj, val stream);
 val tprint(val obj, val out);
diff --git a/txr.1 b/txr.1
index 09b1b172..26a66dbb 100644
--- a/txr.1
+++ b/txr.1
@@ -769,10 +769,10 @@ option (extended
 .codn --args )
 is like
 .code --args
-but must be followed by an argument. The argument is substituted
-in place of occurrences of
+but must be followed by an argument. The argument is removed from
+the argument list and substituted in place of occurrences of
 .code {}
-in the
+among the arguments expanded from the
 .code --eargs
 syntax.
 
@@ -1136,11 +1136,17 @@ The
 mechanism allows an additional flexibility. An
 .code --eargs
 argument must be followed by one more argument.
-Occurrences of the two-character sequence
+
+After
+.code --eargs
+performs the argument splitting in the same manner as
+.codn --args ,
+any of the arguments which it produces which are the
+two-character sequence
 .code {}
-in the encoded argument string are replaced with that
-following argument. This replacement occurs after
-the argument splitting.
+are replaced with that following argument. Whether
+or not the replacement occurs, that following argument
+is then removed.
 
 Example:
 
@@ -1172,9 +1178,11 @@ processing takes place, firstly the argument sequence
   -B {} --foo 42
 .cble
 
-is produced. Then, all occurrences of
+is produced by splitting into four fields using the
+.code :
+character as the separator.  Then, within these four fields, all occurrences of
 .code {}
-are replaced with
+are replaced with the following argument
 .codn script.txr ,
 resulting in:
 
@@ -1182,7 +1190,15 @@ resulting in:
   -B script.txr --foo 42
 .cble
 
-The resulting \*(TX invocation is
+Furthermore, that
+.code script.txr
+argument is removed from the remaining argument list.
+
+The four arguments are then substituted in place of the original
+.code --eargs:-B:{}:--foo:42
+syntax.
+
+The resulting \*(TX invocation is, therefore:
 
 .cblk
   /usr/bin/txr -B script.txr --foo 42 a b c
diff --git a/txr.c b/txr.c
index 3fdb18c0..ca80c2ca 100644
--- a/txr.c
+++ b/txr.c
@@ -573,9 +573,8 @@ int txr_main(int argc, char **argv)
       }
       arg = sub_str(arg, num(8), nil);
       arg2 = upop(&arg_list, &arg_undo);
-      arg_list = append2(mapcar(curry_123_3(func_n3(regsub),
-                                            regex_compile(lit("{}"), nil),
-                                            arg2),
+      arg_list = append2(mapcar(iffi(curry_12_2(equal_f, lit("{}")),
+                                     retf(arg2), nil),
                                 split_str(arg, sep)),
                          arg_list);
       set(eff_arg_tail, butlastn(one, deref(eff_arg_tail)));
-- 
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