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* 5001 - drop the :(scenario) DSLKartik Agaram2019-03-121-42/+70
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
* 4987 - support `browse_trace` tool in SubXKartik Agaram2019-02-251-1/+1
| | | | | | | | | | | | | | | | | | 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.
* 4266 - space for alloc-id in heap allocationsKartik Agaram2018-06-241-33/+17
| | | | This has taken me almost 6 weeks :(
* 4265Kartik Agaram2018-06-171-5/+5
| | | | Standardize use of type ingredients some more.
* 4263Kartik Agaram2018-06-171-7/+1
| | | | | Implement literal constants before type abbreviations, reducing some unnecessary tangling.
* 4262 - literal 'null'Kartik Agaram2018-06-171-2/+6
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* 4261 - start using literals for 'true' and 'false'Kartik Agaram2018-06-171-18/+1
| | | | | | | | | They uncovered one bug: in edit/003-shortcuts.mu <scroll-down> was returning 0 for an address in one place where I thought it was returning 0 for a boolean. Now we've eliminated this bad interaction between tangling and punning literals.
* 4260 - make address coercions explicitKartik Agaram2018-06-161-9/+0
| | | | | 'deaddress' is a terrible name. Hopefully I'll come up with something better.
* 4258 - undo 4257Kartik Agaram2018-06-151-18/+7
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* 4257 - abortive attempt at safe fat pointersKartik Agaram2018-06-151-7/+18
| | | | | | | | | | | | | | | | I've been working on this slowly over several weeks, but it's too hard to support 0 as the null value for addresses. I constantly have to add exceptions for scalar value corresponding to an address type (now occupying 2 locations). The final straw is the test for 'reload': x:num <- reload text 'reload' returns an address. But there's no way to know that for arbitrary instructions. New plan: let's put this off for a bit and first create support for literals. Then use 'null' instead of '0' for addresses everywhere. Then it'll be easy to just change what 'null' means.
* 4243Kartik Agaram2018-05-121-8/+7
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* 4120Kartik K. Agaram2017-11-101-0/+8
| | | | Support explicit conversions from number to character.
* 3963Kartik K. Agaram2017-07-081-7/+18
| | | | | | | | Narrow the scope of implicit type conversions. Now only numbers can be freely converted to from other scalars (booleans, characters). We want in particular to make this an error: x:character <- new [abc]
* 3877Kartik K. Agaram2017-05-261-1/+1
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* 3836Kartik K. Agaram2017-04-191-0/+2
| | | | Fix CI.
* 3833Kartik K. Agaram2017-04-181-1/+16
| | | | Loosen type-checking slightly to accomodate type abbreviations.
* 3812Kartik K. Agaram2017-04-041-3/+3
| | | | Fix CI.
* 3811Kartik K. Agaram2017-04-041-2/+2
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* 3752 - fix a couple of segfaultsKartik K. Agaram2017-03-021-0/+1
| | | | Thanks Ella Couch for running into these.
* 3707Kartik K. Agaram2016-12-121-2/+1
| | | | | | | | | | | | | | | | | | Be more disciplined about tagging 2 different concepts in the codebase: a) Use the phrase "later layers" to highlight places where a layer doesn't have the simplest possible self-contained implementation. b) Use the word "hook" to point out functions that exist purely to provide waypoints for extension by future layers. Since both these only make sense in the pre-tangled representation of the codebase, using '//:' and '#:' comments to get them stripped out of tangled output. (Though '#:' comments still make it to tangled output at the moment. Let's see if we use it enough to be worth supporting. Scenarios are pretty unreadable in tangled output anyway.)
* 3663 - fix a refcounting bug: '(type)' != 'type'Kartik K. Agaram2016-11-101-4/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This was a large commit, and most of it is a follow-up to commit 3309, undoing what is probably the final ill-considered optimization I added to s-expressions in Mu: I was always representing (a b c) as (a b . c), etc. That is now gone. Why did I need to take it out? The key problem was the error silently ignored in layer 30. That was causing size_of("(type)") to silently return garbage rather than loudly complain (assuming 'type' was a simple type). But to take it out I had to modify types_strictly_match (layer 21) to actually strictly match and not just do a prefix match. In the process of removing the prefix match, I had to make extracting recipe types from recipe headers more robust. So far it only matched the first element of each ingredient's type; these matched: (recipe address:number -> address:number) (recipe address -> address) I didn't notice because the dotted notation optimization was actually representing this as: (recipe address:number -> address number) --- One final little thing in this commit: I added an alias for 'assert' called 'assert_for_now', to indicate that I'm not sure something's really an invariant, that it might be triggered by (invalid) user programs, and so require more thought on error handling down the road. But this may well be an ill-posed distinction. It may be overwhelmingly uneconomic to continually distinguish between model invariants and error states for input. I'm starting to grow sympathetic to Google Analytics's recent approach of just banning assertions altogether. We'll see..
* 3653Kartik K. Agaram2016-11-081-2/+8
| | | | | | | | | Don't crash on bad types. I need to be more careful in distinguishing between the two causes of constraint violations: bad input and internal bugs. Maybe I should create a second assert() to indicate "this shouldn't really be an assert, but I'm too lazy to think about it right now."
* 3522Kartik K. Agaram2016-10-191-2/+2
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* 3381Kartik K. Agaram2016-09-171-3/+3
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* 3380Kartik K. Agaram2016-09-171-13/+13
| | | | | One more place we were missing expanding type abbreviations: inside container definitions.
* 3378Kartik K. Agaram2016-09-171-3/+2
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* 3309Kartik K. Agaram2016-09-091-29/+47
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rip out everything to fix one failing unit test (commit 3290; type abbreviations). This commit does several things at once that I couldn't come up with a clean way to unpack: A. It moves to a new representation for type trees without changing the actual definition of the `type_tree` struct. B. It adds unit tests for our type metadata precomputation, so that errors there show up early and in a simpler setting rather than dying when we try to load Mu code. C. It fixes a bug, guarding against infinite loops when precomputing metadata for recursive shape-shifting containers. To do this it uses a dumb way of comparing type_trees, comparing their string representations instead. That is likely incredibly inefficient. Perhaps due to C, this commit has made Mu incredibly slow. Running all tests for the core and the edit/ app now takes 6.5 minutes rather than 3.5 minutes. == more notes and details I've been struggling for the past week now to back out of a bad design decision, a premature optimization from the early days: storing atoms directly in the 'value' slot of a cons cell rather than creating a special 'atom' cons cell and storing it on the 'left' slot. In other words, if a cons cell looks like this: o / | \ left val right ..then the type_tree (a b c) used to look like this (before this commit): o | \ a o | \ b o | \ c null ..rather than like this 'classic' approach to s-expressions which never mixes val and right (which is what we now have): o / \ o o | / \ a o o | / \ b o null | c The old approach made several operations more complicated, most recently the act of replacing a (possibly atom/leaf) sub-tree with another. That was the final straw that got me to realize the contortions I was going through to save a few type_tree nodes (cons cells). Switching to the new approach was hard partly because I've been using the old approach for so long and type_tree manipulations had pervaded everything. Another issue I ran into was the realization that my layers were not cleanly separated. Key parts of early layers (precomputing type metadata) existed purely for far later ones (shape-shifting types). Layers I got repeatedly stuck at: 1. the transform for precomputing type sizes (layer 30) 2. type-checks on merge instructions (layer 31) 3. the transform for precomputing address offsets in types (layer 36) 4. replace operations in supporting shape-shifting recipes (layer 55) After much thrashing I finally noticed that it wasn't the entirety of these layers that was giving me trouble, but just the type metadata precomputation, which had bugs that weren't manifesting until 30 layers later. Or, worse, when loading .mu files before any tests had had a chance to run. A common failure mode was running into types at run time that I hadn't precomputed metadata for at transform time. Digging into these bugs got me to realize that what I had before wasn't really very good, but a half-assed heuristic approach that did a whole lot of extra work precomputing metadata for utterly meaningless types like `((address number) 3)` which just happened to be part of a larger type like `(array (address number) 3)`. So, I redid it all. I switched the representation of types (because the old representation made unit tests difficult to retrofit) and added unit tests to the metadata precomputation. I also made layer 30 only do the minimal metadata precomputation it needs for the concepts introduced until then. In the process, I also made the precomputation more correct than before, and added hooks in the right place so that I could augment the logic when I introduced shape-shifting containers. == lessons learned There's several levels of hygiene when it comes to layers: 1. Every layer introduces precisely what it needs and in the simplest way possible. If I was building an app until just that layer, nothing would seem over-engineered. 2. Some layers are fore-shadowing features in future layers. Sometimes this is ok. For example, layer 10 foreshadows containers and arrays and so on without actually supporting them. That is a net win because it lets me lay out the core of Mu's data structures out in one place. But if the fore-shadowing gets too complex things get nasty. Not least because it can be hard to write unit tests for features before you provide the plumbing to visualize and manipulate them. 3. A layer is introducing features that are tested only in later layers. 4. A layer is introducing features with tests that are invalidated in later layers. (This I knew from early on to be an obviously horrendous idea.) Summary: avoid Level 2 (foreshadowing layers) as much as possible. Tolerate it indefinitely for small things where the code stays simple over time, but become strict again when things start to get more complex. Level 3 is mostly a net lose, but sometimes it can be expedient (a real case of the usually grossly over-applied term "technical debt"), and it's better than the conventional baseline of no layers and no scenarios. Just clean it up as soon as possible. Definitely avoid layer 4 at any time. == minor lessons Avoid unit tests for trivial things, write scenarios in context as much as possible. But within those margins unit tests are fine. Just introduce them before any scenarios (commit 3297). Reorganizing layers can be easy. Just merge layers for starters! Punt on resplitting them in some new way until you've gotten them to work. This is the wisdom of Refactoring: small steps. What made it hard was not wanting to merge *everything* between layer 30 and 55. The eventual insight was realizing I just need to move those two full-strength transforms and nothing else.
* 3210 - new primitive: character-to-codeKartik K. Agaram2016-08-171-0/+7
| | | | Thanks Ella Couch; this was long overdue.
* 3120Kartik K. Agaram2016-07-211-1/+1
| | | | | | | | 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?
* 3097Kartik K. Agaram2016-07-031-2/+2
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* 2991Kartik K. Agaram2016-05-201-4/+4
| | | | | Never mind, always quote direct quotes from code in error messages. Dilated reagents are the uncommon case.
* 2931 - be explicit about making copiesKartik K. Agaram2016-05-061-7/+12
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* 2929 - fix a bug in static dispatchKartik K. Agaram2016-05-051-9/+0
| | | | | | Thanks Caleb for finding this. We'd been using sandboxes for so long, I hadn't tried a null/0 screen/console in a while and somewhere down the road Mu stopped matching 0 against concrete addresses.
* 2836 - arcane bug in generic functionsKartik K. Agaram2016-04-151-0/+13
| | | | Thanks Caleb Couch for finding and reporting this.
* 2803Kartik K. Agaram2016-03-211-2/+1
| | | | | Show more thorough information about instructions in the trace, but keep the original form in error messages.
* 2773 - switch to 'int'Kartik K. Agaram2016-03-131-2/+2
| | | | This should eradicate the issue of 2771.
* 2735 - define recipes using 'def'Kartik K. Agaram2016-03-081-7/+7
| | | | | | | | | | | | 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.
* 2712Kartik K. Agaram2016-02-261-2/+2
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* 2711 - permit boolean<-number conversionsKartik K. Agaram2016-02-251-0/+9
| | | | | | | | | | | I might change my mind on this, but it's worth a try after watching Ella run up against it today. I got her to build the recipe 'odd?', but then it failed to run because she couldn't convert a numeric remainder to a number without a conditional (which I haven't taught her yet). For now I don't change the value in the boolean, so booleans can store arbitrary bit patterns like in C. We just say that 0 is false and anything else is true. I *think* that doesn't break the type system..
* 2709Kartik K. Agaram2016-02-251-2/+0
| | | | | Only Hide_errors when strictly necessary. In other places let test failures directly show the unexpected error.
* 2681 - drop reagent types from reagent propertiesKartik K. Agaram2016-02-211-3/+3
| | | | | | | | | | | | | | | | | 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.
* 2678Kartik K. Agaram2016-02-201-3/+3
| | | | | | | Start using type names from the type tree rather than the property tree in most places. Hopefully the only occurrences of 'properties.at(0).second' left are ones where we're managing it. Next we can stop writing to it.
* 2685Kartik K. Agaram2016-02-191-1/+1
| | | | | | | | | | | | | | | | 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.
* 2646 - redo static dispatch algorithmKartik K. Agaram2016-02-111-0/+9
| | | | | | | | The old approach of ad hoc boosts and penalties based on various features was repeatedly running into exceptions and bugs. New organization: multiple tiered scores interleaved with tie-breaks. The moment one tier yields one or more candidates, we stop scanning further tiers. Just break ties and return.
* 2620Kartik K. Agaram2016-01-301-27/+27
| | | | | I was finding it hard to wrap around the directionality of calls with 'lhs' and 'rhs'. Seems to work better with 'to' and 'from'. Let's see.
* 2619 - actually allow coercing booleans to numbersKartik K. Agaram2016-01-301-3/+19
| | | | | This uncovered a bug where I've been forgetting the directionality of arguments to types_coercible().
* 2578Kartik K. Agaram2016-01-201-4/+0
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* 2549Kartik K. Agaram2015-12-281-1/+3
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* 2607 - resolve some edge cases in static dispatchKartik K. Agaram2015-11-291-9/+16
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* 2494Kartik K. Agaram2015-11-281-1/+1
| | | | | Some more structure to transforms, and flattening of dependencies between them.