21 Jul
2025
21 Jul
'25
7:40 p.m.
Dan is spot on, almost, see below.
On Mon, Jul 21, 2025 at 02:37:04PM -0400, Dan Cross wrote:
On Mon, Jul 21, 2025 at 1:32???PM Douglas McIlroy
<douglas.mcilroy(a)dartmouth.edu> wrote:
It's a general purpose output language for stuff contained in BitKeeper.
:WHATEVER: digs the current graph nodes n->whatever.
The json dspec is an example of that language being told to emit JSON,
but you can write dspecs for anything.
Think git log --dspec-file=/path/to/dspec
and now you can have any output format you like.
I sort of mislead people when I said it was like awk, it sort of is,
but each awk line is a revision in the graph you are looking at.
So the dspec runs on each revsision.
--
---
Larry McVoy Retired to fishing http://www.mcvoy.com/lm/boat
Larry McVoy wrote
I do not believe Larry is referring (directly) to M4 with this
comment, but rather, referring to the language he used for the example
he posted earlier, at:
http://mcvoy.com/lm/bkdocs/dspec-changes-json-v.txt
That language is, if I understand correctly, an invention of Larry's,
that drew inspiration from awk, and that he saw as an improvement over
M4 for the purpose of making bitkeeper emit JSON. Well, we had begin and end blocks. And other
than that, the whole thing
is a wad that is called per line. That was definitely awk inspired.
The way I have used m4, a program is executed just once from top to bottom.
[snip]