Refactoring hash bang support; hash bang null hack.

The hash bang mechanism is handled in one place,
and disentangled from all parsing logic.
It is also endowed with special powers.

* eval.c (load): Pass one less argument to read_eval_stream.

* match.c (v_load): Likewise.

* parser.c (read_eval_stream): hash_bang_support Boolean
argument removed. Hash bang logic removed.
(load_rcfile): Pass only two arguments to read_eval_stream.

* parser.h (read_eval_stream): Declaration updated.

* txr.c (remove_hash_bang_line): Function removed.
(check_hash_bang): New static function.
(txr_main): Recognize the script file name while still
inside the argument processing loop. Open the file,
and check for a hash bang line, doing the special
processing which can generate more arguments from material
after a null byte in the hash bang line. The parse_stream
variable is now initialized to nil and doubles as a Boolean
indicating whether a stream has been opened. After the
loop, we remove the script file from the arguments, if we
have an open stream and the spec_file_str matches.
read_eval_stream is called only with two arguments.

* txr.1: Revised existing documentation and described
new features.

1 files changed, 2 insertions, 12 deletions

diff --git a/parser.c b/parser.c
index 5c22ac3a..11bf27f7 100644
--- a/parser.c
+++ b/parser.c
@@ -577,21 +577,11 @@ val iread(val source_in, val error_stream, val error_return_val,
                          name_in, lineno);
 }
 
-val read_eval_stream(val stream, val error_stream, val hash_bang_support)
+val read_eval_stream(val stream, val error_stream)
 {
   val error_val = gensym(nil);
   val name = stream_get_prop(stream, name_k);
 
-  if (hash_bang_support) {
-    val firstline = get_line(stream);
-
-    if (firstline && !match_str(firstline, lit("#!"), nil)) {
-      val flwnl = scat(nil, firstline, lit("\n"), nao);
-      val string_stream = make_string_byte_input_stream(flwnl);
-      stream = make_catenated_stream(list(string_stream, stream, nao));
-    }
-  }
-
   for (;;) {
     val form = lisp_parse(stream, error_stream, error_val, name, colon_k);
     val parser = get_parser(stream);
@@ -639,7 +629,7 @@ static void load_rcfile(val name)
     } else {
       val saved_dyn_env = set_dyn_env(make_env(nil, nil, dyn_env));
       env_vbind(dyn_env, load_path_s, resolved_name);
-      read_eval_stream(stream, std_output, nil);
+      read_eval_stream(stream, std_output);
       dyn_env = saved_dyn_env;
     }
   }