Stop naming 'jump' instructions in their errors since they're so often
rewritten from 'break' or 'loop' instructions.
Thanks Lakshman Swaminathan for running into this issue.
The drawback of this is that we forget to initialize old_name when we
create instructions out of whole cloth in a few places. But this problem
already existed..
More consistent definitions for jump targets and waypoints.
1. A label is a word starting with something other than a letter or
digit or '$'.
2. A waypoint is a label that starts with '<' and ends with '>'. It has
no restrictions. A recipe can define any number of waypoints, and
recipes can have duplicate waypoints.
3. The special labels '{' and '}' can also be duplicated any number of
times in a recipe. The only constraint on them is that they have to
balance in any recipe. Every '{' must be followed by a matching '}'.
4. All other labels are 'jump targets'. You can't have duplicate jump
targets in a recipe; that would make jumps ambiguous.
Drop a few debug prints. Hopefully now we need never duplicate trace
statements and can instead just dump them to screen.
I'll soon need the ability to selectively dump traces for a specific
label.
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..
Be more consistent that 'return' is the name of the instruction, and
'reply' just a synonym. Maybe I should take it out. It wouldn't affect
the recipe/ingredient terminology while I teach..
This was an interaction between two transforms. The first turned:
return-if ...
into:
jump-unless ..., 1:offset # skip next instruction
return ...
The second added an unconditional return at the end of the recipe if it
didn't already exist (so that functions always end with a return).
However, it was getting confused by the return instructions generated
above, which look unconditional but sometimes get skipped.
To fix this, conditional returns are now transformed into this:
{
break-unless ...
return ...
}
Since the final instruction is now no longer a reply (but rather the '}'
label), the second transform triggers and adds the unconditional return
after it.
This commit removes the final place marked 'BUG:' in the codebase
yesterday (see commit 2870).
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.
I really have only one warning left: when somebody redefines a function.
I think I'm going to just turn that into an error as well and drop the
notion of warnings altogether. Anytime we find something wrong we stop
running the program. This is a place where hygiene is justified.
All my attempts at staging this change failed with this humongous commit
that took all day and involved debugging three monstrous bugs. Two of
the bugs had to do with forgetting to check the type name in the
implementation of shape-shifting recipes. Bug #2 in particular would
cause core tests in layer 59 to fail -- only when I loaded up edit/! It
got me to just hack directly on mu.cc until I figured out the cause
(snapshot saved in mu.cc.modified). The problem turned out to be that I
accidentally saved a type ingredient in the Type table during
specialization. Now I know that that can be very bad.
I've checked the traces for any stray type numbers (rather than names).
I also found what might be a bug from last November (labeled TODO), but
we'll verify after this commit.
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.
More flailing around trying to come up with the right phase ordering.
I've tried to narrow down each transform's constraints wrt transforms in
previous layers.
One issue that keeps biting me is the Type map containing empty records
because of stray [] operations. That's gotta be important.
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.
More verbose, but it saves trouble when debugging; there's never
something you thought should be traced but just never came out the other
end.
Also got rid of fatal errors entirely. Everything's a warning now, and
code after a warning isn't guaranteed to run.
Don't die on unbalanced '{'.
I won't bother adding more tests for warnings. Suffice it to say that we
need to gradually eliminate all asserts that check for illegal mu code.
Kartik Agaram