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Diffstat (limited to 'ChangeLog')
| -rw-r--r-- | ChangeLog | 50 |
1 files changed, 50 insertions, 0 deletions
@@ -1,3 +1,53 @@ +2013-12-01 Kaz Kylheku <kaz@kylheku.com> + + Steps toward fixing an issue: lazy list readahead. + The problem is that accurate lazy lists are not suitable for + real time use, where we want the TXR program to respond immediately + to matching some datum. + + I'm implementing a simple, naive variant of lazy stream lists + which simply populates the lazy cons by reading from the stream when + the car or cdr fields are accessed. This type of stream can never + be nil (empty list) even if the file is empty; in that case + it will be (nil) and in general, it will have a spurious nil + item at the end instead of ending in a string. + (An adjustment was made in match.c to detect this; more + will be needed.) + + I'm adding attributes to streams so streams can now have a + "real-time" attribute. When a lazy string list is constructed over + a real-time stream, the simple implementation is used. + File streams are automatically real-time if (on Unix) they are tied + to tty streams. Tail streams are also real-time. + + More work is needed to achieve the goal of this change, + but this is a big step in the right direction. + + * configure: Detect isatty function. + + * lib.c (simple_lazy_stream_func): New static function. + (lazy_stream_cons): Use simple implementation for real-time streams. + + * match.c (match_files): Do not call match_line_completely + with a data line that is nil (as a result of simple lazy list + over a real-time stream). A nil item in a lazy list of strings + is treated as eof. + + * stream.c (real_time_k): New symbol variable. + (struct strm_ops): New members: get_prop, set_prop. + (struct stdio_handle): New member: is_real_time. + (stdio_get_prop, stdio_set_prop): New static function. + (stdio_ops, tail_ops, pipe_ops): stdio_get_prop and + stdio_set_prop funtions wired in. + (make_stdio_stream_common): Attribute streams as real-time + if they are tty devices. + (make_tail_stream): Tail streams are real-time attributed. + (stream_set_prop, real_time_stream_p): New functions. + (stream_init): Initialize real_time_k. + + * stream.h (real_time_k): Declared. + (real_time_stream_p, stream_set_prop): Likewise. + 2013-11-29 Kaz Kylheku <kaz@kylheku.com> * eval.c (eval_init): New functions countqual, countql, countq |