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* 4266 - space for alloc-id in heap allocationsKartik Agaram2018-06-241-69/+32
| | | | This has taken me almost 6 weeks :(
* 4265Kartik Agaram2018-06-171-2/+2
| | | | Standardize use of type ingredients some more.
* 4264Kartik Agaram2018-06-171-0/+575
| | | | Undo the relayout of 4259.
* 4259Kartik Agaram2018-06-161-575/+0
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* 4258 - undo 4257Kartik Agaram2018-06-151-36/+32
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* 4257 - abortive attempt at safe fat pointersKartik Agaram2018-06-151-32/+36
| | | | | | | | | | | | | | | | 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.
* 4256 - get rid of container metadata entirelyKartik Agaram2018-06-091-80/+0
| | | | | We have some ugly duplication in computing size_of on containers between layers 30/33 and 55.
* 4243Kartik Agaram2018-05-121-3/+3
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* 4223Kartik K. Agaram2018-03-141-6/+3
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* 4104Kartik K. Agaram2017-11-031-2/+2
| | | | | Stop hardcoding Max_depth everywhere; we had a default value for a reason but then we forgot all about it.
* 3970Kartik K. Agaram2017-08-191-2/+1
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* 3887 - clean up early exits in interpreter loopKartik K. Agaram2017-05-281-2/+4
| | | | | | | | | | It's always confusing when `break` refers to a `switch` but `continue` refers to the loop around the `switch`. But we've done ugly things like this and `goto` for expedience. However, we're starting to run into cases where we now need to insert code at every `continue` or `continue`-mimicking `goto` inside the core interpreter loop. Better to make the loop single-entry-single-exit. Common things to run after every instruction will now happen inside the `finish_instruction` function rather than at the `finish_instruction` label.
* 3877Kartik K. Agaram2017-05-261-11/+11
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* 3863Kartik K. Agaram2017-05-191-0/+11
| | | | Thanks Lakshman Swaminathan for running into this bug.
* 3841Kartik K. Agaram2017-04-271-5/+5
| | | | | Use the real original instruction in error messages. Thanks Ella Couch.
* 3663 - fix a refcounting bug: '(type)' != 'type'Kartik K. Agaram2016-11-101-10/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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..
* 3652Kartik K. Agaram2016-11-081-0/+13
| | | | | size_of(type_tree*) is a mess; clean it up with an eye to the final tangled version.
* 3647Kartik K. Agaram2016-11-081-2/+3
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* 3646Kartik K. Agaram2016-11-071-22/+22
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* 3645Kartik K. Agaram2016-11-071-26/+17
| | | | | | Extract a helper to compute the element type of an array. As a side effect, the hack for disambiguating array:address:number and array:number:3 is now in just one place.
* 3644Kartik K. Agaram2016-11-071-0/+80
| | | | Eject some array-related code out of the container layer.
* 3643Kartik K. Agaram2016-11-071-3/+3
| | | | | Standardize on calling literate waypoints "Special-cases" rather than "Cases". Invariably there's a default path already present.
* 3625 - gracefully handle fractional array indexKartik K. Agaram2016-11-051-0/+11
| | | | | Follow-up to commit 3622. Even though there's no code change that's just a happy accident; we hadn't at all considered this constraint thus far.
* 3621Kartik K. Agaram2016-11-041-1/+1
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* 3522Kartik K. Agaram2016-10-191-2/+2
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* 3380Kartik K. Agaram2016-09-171-89/+89
| | | | | One more place we were missing expanding type abbreviations: inside container definitions.
* 3364Kartik K. Agaram2016-09-151-1/+1
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* 3309Kartik K. Agaram2016-09-091-16/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
* 3260Kartik K. Agaram2016-08-261-1/+1
| | | | | array length = number of elements array size = in locations
* 3221Kartik K. Agaram2016-08-181-3/+3
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* 3209Kartik K. Agaram2016-08-171-1/+1
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* 3120Kartik K. Agaram2016-07-211-6/+6
| | | | | | | | 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?
* 3119Kartik K. Agaram2016-07-211-1/+3
| | | | | | | Warn if 'put' or 'put-index' has a mismatch in the type of the product, not just the name. It won't do any harm, but could be misleading to a later reader. In both instructions, the product is just for documentation.
* 3110 - better support static arrays in containersKartik K. Agaram2016-07-111-1/+20
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* 3064 - improve an error messageKartik K. Agaram2016-06-231-3/+3
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* 3061Kartik K. Agaram2016-06-171-0/+1
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* 3059Kartik K. Agaram2016-06-171-1/+11
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* 2992Kartik K. Agaram2016-05-201-0/+14
| | | | | Raise an error if a 'put' or 'put-index' doesn't match ingredient and product. That wouldn't do what you would expect.
* 2990Kartik K. Agaram2016-05-201-15/+15
| | | | | | | | | | 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..
* 2932Kartik K. Agaram2016-05-061-1/+1
| | | | | | | 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").
* 2931 - be explicit about making copiesKartik K. Agaram2016-05-061-14/+14
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* 2899Kartik K. Agaram2016-05-041-1/+13
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* 2898 - start filling in missing refcountsKartik K. Agaram2016-05-031-3/+5
| | | | | | | This commit covers instructions 'put', 'put-index' and 'maybe-convert'. Next up are the harder ones: 'copy' and 'merge'. In these cases there's a non-scalar being copied, and we need to figure out which locations within it need to update their refcount.
* 2893Kartik K. Agaram2016-05-031-0/+456
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* 2863Kartik K. Agaram2016-04-241-467/+0
| | | | | Finally after much massaging, the 'address' and 'new' layers are adjacent.
* 2862Kartik K. Agaram2016-04-241-14/+0
| | | | | Layers 0-29 are now a complete rudimentary platform except for pointers and indirection.
* 2860 - rename 'index-address' to 'put-index'Kartik K. Agaram2016-04-231-45/+38
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* 2847Kartik K. Agaram2016-04-201-4/+5
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* 2846Kartik K. Agaram2016-04-201-4/+4
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* 2831 - bugfix in static arraysKartik K. Agaram2016-04-131-10/+23
| | | | | | | | | | | I'd started using size_of() in transforms at some point, but not gotten around to actually updating it to support arrays before run-time. Wish there was a way I could statically enforce that something is only called at transform time vs runtime. Thanks Ella and Caleb Couch for finding this issue. Static arrays are likely still half-baked, but should get a thorough working-over in coming weeks.