about summary refs log tree commit diff stats
path: root/020run.cc
Commit message (Collapse)AuthorAgeFilesLines
* 3335Kartik K. Agaram2016-09-111-2/+6
| | | | | | | | Clean up rest of long-standing bit of ugliness. I'm growing more confident now that I can use layers to cleanly add any functionality I want. All I need is hook functions. No need to ever put '{' on their own line, or add arguments to calls.
* 3334Kartik K. Agaram2016-09-111-2/+1
| | | | Clean up one long-standing bit of ugliness.
* 3309Kartik K. Agaram2016-09-091-4/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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. Agaram2016-08-291-8/+8
| | | | | Stop inlining functions because that will complicate separate compilation. It also simplifies the code without impacting performance.
* 3263Kartik K. Agaram2016-08-271-1/+1
| | | | Commit 3171 which added '--trace' broke 'Save_trace'.
* 3259Kartik K. Agaram2016-08-261-2/+2
| | | | | | | | | | | 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).
* 3246Kartik K. Agaram2016-08-251-1/+1
|
* 3245 - refuse to run programs with errorsKartik K. Agaram2016-08-221-0/+1
| | | | | | | | | | | | | | I started out incredibly lax about running past errors (I even used to call them 'warnings' when I started Mu), but I've been gradually seeing the wisdom of Go and Racket in refusing to run code if it doesn't pass basic integrity checks (such as using a literal as an address). Go is right to have no warnings, only errors. But where Go goes wrong is in even caring about unused variables. Racket and other languages perform more aggressive integrity checks so that the can optimize more aggressively, and I'm starting to realize I don't know enough to disagree with them.
* 3223Kartik K. Agaram2016-08-181-1/+4
|
* 3201Kartik K. Agaram2016-08-161-1/+1
|
* 3200Kartik K. Agaram2016-08-161-1/+1
|
* 3199Kartik K. Agaram2016-08-161-2/+5
| | | | | | | | | Never mind, just close your nose and replace that function parameter with a global variable. This may not always be the solution for the problem of layers being unable to add parameters and arguments, but here it works well and it's unclear what problems the global might cause.
* 3197Kartik K. Agaram2016-08-161-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Replace an integer with a boolean across two layers of function calls. It has long been one of the ugliest consequences of my approach with layers that functions might need to be introduced with unnecessary arguments simply because we have no clean way to add parameters to a function definition after the fact -- or to add the default argument corresponding to that parameter in calls. This problem is exacerbated by the redundant argument having to be passed in through multiple layers of functions. In this instance: In layer 20 we define write_memory with an argument called 'saving_instruction_products' which isn't used yet. In layer 36 we reveal that we use this argument in a call to should_update_refcounts_in_write_memory() -- where it is again not used yet. Layer 43 finally clarifies what we're shooting for: a) In general when we need to update some memory, we always want to update refcounts. b) The only exception is when we're reclaiming locals in a function that set up its stack frame using 'local-scope' (signalling that it wants immediate reclamation). At that point we avoid decrementing refcounts of 'escaping' addresses that are being returned, and we also avoid incrementing refcounts of products in the caller instruction. The latter case is basically why we need this boolean and its dance across 3 layers. In summary, write_memory() needs to update refcounts except if: we're writing products for an instruction, the instruction is not a primitive, and the (callee) recipe for the instruction starts with 'local-scope'.
* 3196Kartik K. Agaram2016-08-161-1/+1
|
* 3171 - new commandline flag: --traceKartik K. Agaram2016-08-121-2/+11
| | | | | | | | The edit/ app without tracing turned on takes 22s to load up a reasonably complex file and run 12 scenarios. Turn on tracing, and it takes 68s. Turn on tracing just for app-level stashes, and it still takes 40s. That's too much overhead, so let's keep it turned off by default but give students an option to enable it at the commandline.
* 3137Kartik K. Agaram2016-07-221-2/+2
| | | | | | | | | | | | | | | | | | Complicated logic to not run core tests. I only want to disable core tests if: a) I'm changing CFLAGS on the commandline (usually to disable optimizations, causing tests to run slower in a debug cycle) b) I'm not printing a help message (either with just 'mu' or 'mu --help') c) I'm loading other files besides just the core. Under these circumstances I only want to run tests in the files explicitly loaded at the commandline. This is all pretty hairy, in spite of my attempts to document it in four different places. I might end up taking it all out the first time I need to run core tests under all these conditions.
* 3110 - better support static arrays in containersKartik K. Agaram2016-07-111-1/+1
|
* 3101 - purge .traces/ dir from repo historyKartik K. Agaram2016-07-051-4/+4
| | | | | | | | | | | | | | | | | | | | | 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.
* 3060Kartik K. Agaram2016-06-171-3/+3
|
* 3051Kartik K. Agaram2016-06-121-0/+2
|
* 3027Kartik K. Agaram2016-06-021-2/+2
|
* 2990Kartik K. Agaram2016-05-201-3/+3
| | | | | | | | | | 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..
* 2973 - reclaim refcounts for local scopes againKartik K. Agaram2016-05-181-4/+3
| | | | | | More thorough redo of commit 2767 (Mar 12), which was undone in commit 2810 (Mar 24). It's been a long slog. Next step: write a bunch of mu code in the edit/ app in search of bugs.
* 2932Kartik K. Agaram2016-05-061-6/+6
| | | | | | | 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. Agaram2016-05-061-4/+6
|
* 2882 - warn if programmer overuses transform_all()Kartik K. Agaram2016-04-281-0/+1
| | | | | | | | | | | | | | | | | | | | This continues a line of thought sparked in commit 2831. I spent a while trying to avoid calling size_of() at transform-time, but there's no getting around the fact that translating names to addresses requires knowing how much space they need. This raised the question of what happens if the size of a container changes after a recipe using it is already transformed. I could go down the road of trying to detect such situations and redoing work, but that massively goes against the grain of my original design, which assumed that recipes don't get repeatedly transformed. Even though we call transform_all() in every test, in a non-testing run we should be loading all code and calling transform_all() just once to 'freeze-dry' everything. But even if we don't want to support multiple transforms it's worth checking that they don't occur. This commit does so in just one situation. There are likely others.
* 2864 - replace all address:shared with just addressKartik K. Agaram2016-04-241-1/+1
| | | | | | | Now that we no longer have non-shared addresses, we can just always track refcounts for all addresses. Phew!
* 2862Kartik K. Agaram2016-04-241-1/+1
| | | | | Layers 0-29 are now a complete rudimentary platform except for pointers and indirection.
* 2827 - start replacing 'get-address' with 'put'Kartik K. Agaram2016-04-101-0/+1
| | | | | | | Current plan: - get rid of get-address and index-address, and therefore any address that is not address:shared - rename address:shared to just 'shared'
* 2816Kartik K. Agaram2016-03-271-1/+0
| | | | Move all bounds checks for types and recipes to one place.
* 2803Kartik K. Agaram2016-03-211-11/+7
| | | | | Show more thorough information about instructions in the trace, but keep the original form in error messages.
* 2800 - remove a gotcha when writing testsKartik K. Agaram2016-03-201-1/+6
| | | | | | | | | Several times now I've wasted time tracking down a failing test only to eventually remember that order of definition matters in tests even though it doesn't elsewhere -- I've been having tests implicitly start running the first function defined in them. Now I stop doing that if a test defines a function called 'main', and just start the test at main instead.
* 2799 - new approach to undoing changes in testsKartik K. Agaram2016-03-201-11/+8
| | | | | | | | As outlined at the end of 2797. This worked out surprisingly well. Now the snapshotting code touches fewer layers, and it's much better behaved, with less need for special-case logic, particularly inside run_interactive(). 30% slower, but should hopefully not cause any more bugs.
* 2797 - bugfix: transform can create recipesKartik K. Agaram2016-03-191-2/+2
| | | | | | | | | | | | | | | | | | | | | When I started to make channels generic in 2784, I introduced an infinite loop when running until just layer 72. This happens because transform_all() can create new recipes while specializing, and these were getting added to Recently_added_recipes and then deleted. I didn't notice until now because layer 91 was clearing Recently_added_recipes soon after. Solution: make calls to transform_all after calls to load_permanently also clear Recently_added_recipes like load_permanently does. No transforms yet create new types. If they do we'll need to start handling the other Recently_added_* variables as well. I should rethink this whole approach of tracking changes to global state while running tests, and undoing such changes. Ideally I wouldn't need to manually track changes for each global. I should just encapsulate all global state in an object, copy it for each test and delete the copy when I'm done.
* 2792Kartik K. Agaram2016-03-191-0/+1
|
* 2773 - switch to 'int'Kartik K. Agaram2016-03-131-16/+16
| | | | This should eradicate the issue of 2771.
* 2772 - fix all layersKartik K. Agaram2016-03-131-0/+5
|
* 2765Kartik K. Agaram2016-03-121-9/+9
| | | | | Get rid of a local variable that was only serving to render unreadable the code for reclaiming allocated memory.
* 2762Kartik K. Agaram2016-03-121-1/+1
|
* 2735 - define recipes using 'def'Kartik K. Agaram2016-03-081-10/+10
| | | | | | | | | | | | 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. Agaram2016-02-261-5/+5
|
* 2707Kartik K. Agaram2016-02-251-1/+0
|
* 2691Kartik K. Agaram2016-02-231-2/+0
|
* 2690 - one more memory leakKartik K. Agaram2016-02-221-2/+2
| | | | | | | This is the easy one. The remaining ones are like phantoms popping up and dying at random. One thing I know is that they all have to do with tangling. Always implicated is the line in the tangle layer where instructions are loaded and inserted into After_fragments.
* 2685Kartik K. Agaram2016-02-191-4/+4
| | | | | | | | | | | | | | | | 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.
* 2663Kartik K. Agaram2016-02-161-6/+1
|
* 2649Kartik K. Agaram2016-02-111-0/+2
| | | | More tweaks to the trace after all my debugging.
* 2610 - warn when recipes don't use default-spaceKartik K. Agaram2016-01-271-0/+2
| | | | Somehow this never transferred over from the Arc version until now.
* 2609 - reuse test-recipe variables in sandbox/ testsKartik K. Agaram2016-01-271-0/+1
| | | | | | | | I'd feared that the refcount errors in the previous commit meant there was a bug in my ref-counting, so I temporarily used new variables rather than reusing existing ones. But it turns out the one remaining place memory corruption can happen is when recipes don't use default-scope and so end up sharing memory. Don't I have a warning for this?
* 2583 - start maintaining refcountsKartik K. Agaram2016-01-211-1/+3
| | | | | | | | | | | | Also start auto-abandoning addresses when their refcount returns to 0. I'm mixing this auto-abandon support with my earlier/hackier support for automatically abandoning default-space created by 'local-scope'. We need to flesh out the story for automatically reclaiming memory using C++-style destructors. But that's a value-add. Memory corruption is far more important to avoid than memory *leaks*.