Stream-seeking functionality.

Bugfix in stdio_flush: check FILE * handle for null.

Minor cleanups.

* eval.c (eval_init): Register seek_stream as intrinsic.

* stream.c (from_start_k, from_current_k, from_end_k): New symbol
variables.
(strm_whence): New enum.
(strm_ops): New member, seek.
(stdio_maybe_write_error): Renamed to stdio_maybe_error; takes
new string argument to describe action.
(stdio_put_string, stdio_put_char, stdio_put_byte): Updated call to
stdio_maybe_error.
(stdio_flush): Updated call to stdio_maybe_error. Check
handle for null.
(stdio_seek): New static function.
(stdio_ops): Added stdio_seek.
(pipe_ops, string_in_ops, byte_in_ops, string_out_ops,
strlist_out_ops, dir_ops): Added explicit zero entries and comments for
unimplemented functions.
(seek_stream): New function.
(stream_init): New keyword symbols interned.

* stream.h (from_start_k, from_current_k, from_end_k): New
variables declared.
(dev_k, ino_k, mode_k, nlink_k, uid_k, gid_k, rdev_k, size_k,
blksize_k, blocks_k, atime_k, mtime_k, ctime_k, s_ifmt, s_iflnk,
s_ifreg, s_ifblk, s_ifdir, s_ifchr, s_ififo, s_isuid, s_isgid, s_isvtx,
s_irwxu, s_irusr, s_iwusr, s_ixusr, s_irwxg, s_irgrp,
s_iwgrp): Existing extern variables declared.
(seek_stream): New function declared.

* txr.1: Documented seek-stream.

1 files changed, 6 insertions, 0 deletions

diff --git a/stream.h b/stream.h
index bf516b2f..1cf0281d 100644
--- a/stream.h
+++ b/stream.h
@@ -27,6 +27,11 @@
 extern val std_input, std_output, std_debug, std_error;
 extern val output_produced;
 
+extern val dev_k, ino_k, mode_k, nlink_k, uid_k;
+extern val gid_k, rdev_k, size_k, blksize_k, blocks_k;
+extern val atime_k, mtime_k, ctime_k;
+extern val from_start_k, from_current_k, from_end_k;
+
 extern val s_ifmt, s_iflnk, s_ifreg, s_ifblk, s_ifdir;
 extern val s_ifchr, s_ififo, s_isuid, s_isgid, s_isvtx, s_irwxu;
 extern val s_irusr, s_iwusr, s_ixusr, s_irwxg, s_irgrp, s_iwgrp;
@@ -55,6 +60,7 @@ val put_line(val string, val stream);
 val put_char(val ch, val stream);
 val put_byte(val byte, val stream);
 val flush_stream(val stream);
+val seek_stream(val stream, val offset, val whence);
 val statf(val path);
 val open_directory(val path);
 val open_file(val path, val mode_str);