about summary refs log tree commit diff stats
path: root/056shape_shifting_recipe.cc
Commit message (Collapse)AuthorAgeFilesLines
* 5001 - drop the :(scenario) DSLKartik Agaram2019-03-121-605/+758
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 Agaram2019-02-251-23/+23
| | | | | | | | | | | | | | | | | | 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.
* 4413Kartik Agaram2018-07-251-2/+2
| | | | | Never mind, let's drop unused/vestigial altogether. Use absence of names to signal unused arguments.
* 4412Kartik Agaram2018-07-251-2/+2
| | | | Drop names of unused arguments.
* 4275Kartik Agaram2018-06-251-0/+1
| | | | Fix CI.
* 4266 - space for alloc-id in heap allocationsKartik Agaram2018-06-241-17/+17
| | | | This has taken me almost 6 weeks :(
* 4262 - literal 'null'Kartik Agaram2018-06-171-6/+6
|
* 4261 - start using literals for 'true' and 'false'Kartik Agaram2018-06-171-6/+2
| | | | | | | | | 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.
* 4235 - fix a build issue for Apple clang 900.0.38Kartik K. Agaram2018-04-201-2/+2
| | | | | | | The trouble with rewriting 'unused' to '__attribute__(unused)' is that if we happen to deliberately introduce '__attribute__(unused)' somehow, say in the standard headers, then it gets expanded twice to '__attribute__(__attribute__(unused))'. So we switch to a synonym.
* 4152Kartik K. Agaram2017-12-071-1/+1
|
* 4145 - specializing recipe literals in `call`Kartik K. Agaram2017-12-071-0/+1
|
* 4143Kartik K. Agaram2017-12-071-22/+24
|
* 4142Kartik K. Agaram2017-12-051-8/+6
|
* 4141Kartik K. Agaram2017-12-051-20/+21
| | | | | Cleaner way to redo commit 2479 from just over two years ago, fixing scenario specialize_recursive_shape_shifting_recipe.
* 4098Kartik K. Agaram2017-10-301-5/+56
| | | | | | | | | Finally, make the seemingly-trivial change to buffer methods that I was envisioning 2 days ago. I still have zero confidence in our heuristic for picking the generic method to specialize for a call-site. Waiting for issues to reveal themselves.
* 4097Kartik K. Agaram2017-10-301-21/+34
| | | | | | | Don't silently ignore ties we failed to break when matching generic functions to calls. Now we can start working on the bug that triggered commits 4092-4097.
* 4096Kartik K. Agaram2017-10-301-6/+6
|
* 4095Kartik K. Agaram2017-10-301-1/+1
|
* 4094Kartik K. Agaram2017-10-301-3/+7
|
* 4093Kartik K. Agaram2017-10-301-6/+2
|
* 4092Kartik K. Agaram2017-10-301-2/+3
| | | | Some cleanup as I remind myself of how generic functions work in Mu.
* 4086 - back to cleaning up delimited continuationsKartik K. Agaram2017-10-181-1/+1
|
* 3877Kartik K. Agaram2017-05-261-4/+4
|
* 3841Kartik K. Agaram2017-04-271-2/+2
| | | | | Use the real original instruction in error messages. Thanks Ella Couch.
* 3840Kartik K. Agaram2017-04-201-9/+0
| | | | | | | | Fix CI. Our previous approach was breaking because a test was generating different results depending on what layer you stopped at. Turns out we rename instructions in layer 54. So let's save the original_name in the same layer.
* 3839Kartik K. Agaram2017-04-201-0/+2
| | | | | | Fix CI. In the process I also fixed a bug in the tangle/ utility.
* 3791Kartik K. Agaram2017-03-121-6/+3
| | | | Simpler way to do commit 2929.
* 3663 - fix a refcounting bug: '(type)' != 'type'Kartik K. Agaram2016-11-101-0/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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..
* 3661Kartik K. Agaram2016-11-101-22/+24
| | | | Another place I missed in commit 3309.
* 3658Kartik K. Agaram2016-11-101-23/+23
|
* 3577Kartik K. Agaram2016-10-231-0/+1
|
* 3561Kartik K. Agaram2016-10-221-2/+2
|
* 3522Kartik K. Agaram2016-10-191-31/+31
|
* 3434Kartik K. Agaram2016-10-041-2/+2
|
* 3422Kartik K. Agaram2016-09-271-10/+2
| | | | | | | | | | Stop checking the number of ingredients and products when picking shape-shifting recipes. That's more consistent with how we handle regular recipes, and we still get errors in all the examples I can think of: reverse # no ingredients or products n:num <- length # no ingredients; products don't provide type
* 3421Kartik K. Agaram2016-09-271-4/+0
|
* 3392Kartik K. Agaram2016-09-171-2/+23
| | | | Bugfix for the "remaining bug" mentioned in commit 3391.
* 3390Kartik K. Agaram2016-09-171-4/+4
|
* 3389Kartik K. Agaram2016-09-171-31/+31
|
* 3385Kartik K. Agaram2016-09-171-66/+66
|
* 3379Kartik K. Agaram2016-09-171-3/+3
| | | | Can't use type abbreviations inside 'memory-should-contain'.
* 3376 - start maximally using all type abbreviationsKartik K. Agaram2016-09-171-4/+4
| | | | | | It might be too much, particularly if students start peeking inside .mu files early. But worth a shot for not just to iron out the kinks in the abbreviation system.
* 3346Kartik K. Agaram2016-09-131-1/+6
| | | | Process type abbreviations in *shape-shifting* function headers.
* 3311Kartik K. Agaram2016-09-101-1/+0
|
* 3309Kartik K. Agaram2016-09-091-91/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
* 3279Kartik K. Agaram2016-08-291-1/+1
| | | | | Stop inlining functions because that will complicate separate compilation. It also simplifies the code without impacting performance.
* 3259Kartik K. Agaram2016-08-261-1/+1
| | | | | | | | | | | Prefer preincrement operators wherever possible. Old versions of compilers used to be better at optimizing them. Even if we don't care about performance it's useful to make unary operators look like unary operators wherever possible, and to distinguish the 'statement form' which doesn't care about the value of the expression from the postincrement which usually increments as a side-effect in some larger computation (and so is worth avoiding except for some common idioms, or perhaps even there).
* 3120Kartik K. Agaram2016-07-211-2/+2
| | | | | | | | 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?
* 3108Kartik K. Agaram2016-07-101-1/+1
|
* 3101 - purge .traces/ dir from repo historyKartik K. Agaram2016-07-051-2/+0
| | | | | | | | | | | | | | | | | | | | | 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.