I've been saying for a while[1][2][3] that adding extra abstractions makes
things harder for newcomers, and adding new notations doubly so. And then
I notice this DSL in my own backyard. Makes me feel like a hypocrite.
[1] https://news.ycombinator.com/item?id=13565743#13570092
[2] https://lobste.rs/s/to8wpr/configuration_files_are_canary_warning
[3] https://lobste.rs/s/mdmcdi/little_languages_by_jon_bentley_1986#c_3miuf2
The implementation of the DSL was also highly hacky:
a) It was happening in the tangle/ tool, but was utterly unrelated to tangling
layers.
b) There were several persnickety constraints on the different kinds of
lines and the specific order they were expected in. I kept finding bugs
where the translator would silently do the wrong thing. Or the error messages
sucked, and readers may be stuck looking at the generated code to figure
out what happened. Fixing error messages would require a lot more code,
which is one of my arguments against DSLs in the first place: they may
be easy to implement, but they're hard to design to go with the grain of
the underlying platform. They require lots of iteration. Is that effort
worth prioritizing in this project?
On the other hand, the DSL did make at least some readers' life easier,
the ones who weren't immediately put off by having to learn a strange syntax.
There were fewer quotes to parse, fewer backslash escapes.
Anyway, since there are also people who dislike having to put up with strange
syntaxes, we'll call that consideration a wash and tear this DSL out.
---
This commit was sheer drudgery. Hopefully it won't need to be redone with
a new DSL because I grow sick of backslashes.
I've extracted it into a separate binary, independent of my Mu prototype.
I also cleaned up my tracing layer to be a little nicer. Major improvements:
- Realized that incremental tracing really ought to be the default.
And to minimize printing traces to screen.
- Finally figured out how to combine layers and call stack frames in a
single dimension of depth. The answer: optimize for the experience of
`browse_trace`. Instructions occupy a range of depths based on their call
stack frame, and minor details of an instruction lie one level deeper
in each case.
Other than that, I spent some time adjusting levels everywhere to make
`browse_trace` useful.
Experimental: kinda support $print in console mode.
It's not perfect and probably will never be, because 'cout' buffers
differently from termbox primitives, which can cause console-aware
newlines to show up before other (console-oblivious) prints, like in
this example program:
def main [
open-console
$print [abc], 10/newline
$print [def], 10/newline
wait-for-some-interaction
close-console
]
And then there's the problem that there's no way for cout to update
Display_column. So mixing $print and print will be confusing.
Perhaps we should just not mess with Display_* variables inside $print?
But then we'll only ever be able to see a single line of $print at a
time.
Always show instruction before any transforms in error messages.
This is likely going to make some errors unclear because they *need* to
show the original instruction. But if we don't have tests for those
situations did they ever really work?
I'd been toying with this idea for some time now given how large the
repo had been growing. The final straw was noticing that people cloning
the repo were having to wait *5 minutes*! That's not good, particularly
for a project with 'tiny' in its description. After purging .traces/
clone time drops to 7 seconds in my tests.
Major issue: some commits refer to .traces/ but don't really change
anything there. That could get confusing :/
Minor issues:
a) I've linked inside commits on GitHub like a half-dozen times online
or over email. Those links are now liable to eventually break. (I seem
to recall GitHub keeps them around as long as they get used at least
once every 60 days, or something like that.)
b) Numbering of commits is messed up because some commits only had
changes to the .traces/ sub-directory.
Standardize quotes around reagents in error messages.
I'm still sure there's issues. For example, the messages when
type-checking 'copy'. I'm not putting quotes around them because in
layer 60 I end up creating dilated reagents, and then it's a bit much to
have quotes and (two kinds of) brackets. But I'm sure I'm doing that
somewhere..
More consistent labeling of waypoints. Use types only when you need to
distinguish between function overloadings. Otherwise just use variable
names unless it's truly not apparent what they are (like that the result
is a recipe in "End Rewrite Instruction").
I'm dropping all mention of 'recipe' terminology from the Readme. That
way I hope to avoid further bike-shedding discussions while I very
slowly decide on the right terminology with my students.
I could be smarter in my error messages and use 'recipe' when code uses
it and 'function' otherwise. But what about other words like ingredient?
It would all add complexity that I'm not yet sure is worthwhile. But I
do want separate experiences for veteran programmers reading about Mu on
github and for people learning programming using Mu.
Stack of plans for cleaning up replace_type_ingredients() and a couple
of other things, from main problem to subproblems:
include type names in the type_tree rather than in the separate properties vector
make type_tree and string_tree real cons cells, with separate leaf nodes
redo the vocabulary for dumping various objects:
do we really need to_string and debug_string?
can we have a version with *all* information?
can we have to_string not call debug_string?
This commit nibbles at the edges of the final task, switching from
member method syntax to global function like almost everything else. I'm
mostly using methods just for STL in this project.
If you restore 2 sandboxes, the first render was setting
response-starting-row-on-screen on both, without ever rendering a
response. If the lower sandbox contained a print and rendered the screen
instead of the response, the original response-starting-row-on-screen
was never reset. If the process of running the sandboxes caused the
lower sandbox's title bar to move below the now-stale
response-starting-row-on-screen[1], editing the lower sandbox no longer
works.
[1] (Either because the upper sandbox prints to screen as well (causing
the first F4 to move the lower sandbox down by several lines), or
because a fresh sandbox is created with several lines before the first
F4 is hit.)
Current solution: never set response-starting-row-on-screen during
reload (or otherwise when there's no response).
This is hard to test right now because 'restore' is not a tested
interface, and I can't come up with another situation where the
response-starting-row-on-screen goes stale. So I'm now trying to keep
all changes to response-starting-row-on-screen close together. Another
idea is to add a check that the click row lies below the
response-starting row *and* above the start of the next sandbox. (But
what if there's no next sandbox?)
(This bug is really a regression, introduced last Sep in 2163.)
- notes
bug in edit/ triggers in immutable but not master branch
bug triggered by changes to layer 059: we're finding an unspecialized call to 'length' in 'append_6'
hard to debug because trace isn't complete
just bring out the big hammer: use a new log file
length_2 from recipes.mu is not being deleted (bug #1)
so reload doesn't switch length to length_2 when variant_already_exists (bug #2)
so we end up saving in Recipe for a primitive ordinal
so no valid specialization is found for 'length' (bug #3)
why doesn't it trigger in a non-interactive scenario?
argh, wasn't checking for an empty line at end. ok, confidence restored.
I'm still seeing all sorts of failures in turning on layer 11 of edit/,
so I'm backing away and nailing down every culprit I run into. First up:
stop accidentally inserting empty objects into maps during lookups.
Commands run:
$ sed -i 's/\(Recipe_ordinal\|Recipe\|Type_ordinal\|Type\|Memory\)\[\([^]]*\)\] = \(.*\);/put(\1, \2, \3);/' 0[1-9]*
$ vi 075scenario_console.cc # manually fix up Memory[Memory[CONSOLE]]
$ sed -i 's/\(Memory\)\[\([^]]*\)\]/get_or_insert(\1, \2)/' 0[1-9]*
$ sed -i 's/\(Recipe_ordinal\|Type_ordinal\)\[\([^]]*\)\]/get(\1, \2)/' 0[1-9]*
$ sed -i 's/\(Recipe\|Type\)\[\([^]]*\)\]/get(\1, \2)/' 0[1-9]*
Now mu dies pretty quickly because of all the places I try to lookup a
missing value.
There were several places where we push a call on to a routine without
incrementing call-stack depth, which was used to compute the depth at
which to trace an instruction. So sometimes you ended up one depth lower
than you started a call with. Do this enough times and instructions that
should be traced at level 100 end up at level 0 and pop up as errors.
Solution: since call-stack depth is only used for tracing, include it in
the trace stream and make sure we reset it along with the trace stream.
Then catch all places where we forget to increment call-stack depth and
make sure we catch such places in the future.
When I first ran into this with Caleb I thought there must be some way
that we're writing some output into the warnings result. I didn't
recognize that the spurious output as part of the trace, just at the
wrong level.
At the lowest level I'm reluctantly starting to see the need for errors
that stop the program in its tracks. Only way to avoid memory corruption
and security issues. But beyond that core I still want to be as lenient
as possible at higher levels of abstraction.
Always show recipe name where error occurred. But don't show internal
'interactive' name for sandboxes, that's just confusing.
What started out as warnings are now ossifying into errors that halt all
execution. Is this how things went with C and Unix as well?
Turns out the default format for printing floating point numbers is
neither 'scientific' nor 'fixed' even though those are the only two
options offered. Reading the C++ standard I found out that the default
(modulo locale changes) is basically the same as the printf "%g" format.
And "%g" is basically the shorter of:
a) %f with trailing zeros trimmed
b) %e
So we'll just do %f and trim trailing zeros.
Finally terminate the experiment of keeping debug prints around. I'm
also going to give up on maintaining counts.
What we really need is two kinds of tracing:
a) For tests, just the domain-specific facts, organized by labels.
b) For debugging, just transient dumps to stdout.
b) only works if stdout is clean by default.
Hmm, I think this means 'stash' should be the transient kind of trace.
Kartik Agaram