5485 - promote SubX to top-level

1 files changed, 4 insertions, 306 deletions

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@@ -8,314 +8,12 @@ Is it a language, or an operating system, or a virtual machine?
 Mu.
 </div>
 
-Read these first: <b><a href='http://akkartik.name/about'>problem statement</a></b>,
-<b><a href='http://github.com/akkartik/mu#readme'>trying out Mu</a></b>.
-(Mu requires minimal dependencies.)
+<b><a href='http://akkartik.name/about'>Problem statement.</a></b>
 
-<p>
-Mu's code looks quite alien, requiring editors to be specially configured to
-colorize it in a sane manner. So this page provides links to the source files
-showing how it currently looks in my <a href='https://github.com/akkartik/mu/blob/master/mu.vim'>custom setup</a>.
-
-<p>Whetting your appetite, some example programs:
-
-<ul>
-<li><a href='html/x.mu.html'>x.mu</a>: a simple program to add two numbers
-together. Shows that at bottom Mu is a simple VM bytecode designed to convert
-directly to machine code.
-<li><a href='html/factorial.mu.html'>factorial.mu</a>: everyone's favorite
-example, showing how Mu supports conditionals and loops without any special
-syntax, using the special labels '{' and '}'.
-<li><a href='html/tangle.mu.html'>tangle.mu</a>: another (contrived) version
-of factorial showing Mu's ability to 'tangle' code from multiple places into a
-single function or <em>recipe</em>.
-<li>simple examples showing off support for concurrency: <a href='html/fork.mu.html'>fork.mu</a>,
-<a href='html/channel.mu.html'>channel.mu</a>
-<li>simple examples showing off hardware control: <a href='html/display.mu.html'>display.mu</a>,
-<a href='html/console.mu.html'>console.mu</a>.
-<li><a href='html/screen.mu.html'>screen.mu</a>: example program showing
-print primitives that inject a 'screen' <em>dependency</em> which can be faked
-for testing.
-<li><a href='html/filesystem.mu.html'>filesystem.mu</a>: example program
-showing file primitives that inject a 'filesystem' dependency which can be
-faked for testing.
-<li><a href='html/http-client.mu.html'>http-client.mu</a> and <a href='html/http-server.mu.html'>http-server.mu</a>,
-examples of Mu's testable high-level interfaces to the network.
-<li><a href='html/static-dispatch.mu.html'>static-dispatch.mu</a>: example
-program showing Mu's ability to define recipes with headers, and thereby to
-allow functions with the same name but arguments of different types to
-coexist.
-<li><a href='html/counters.mu.html'>counters.mu</a>: lexical scope
-<li><a href='html/chessboard.mu.html'>chessboard.mu</a>: a little program for
-2 people to play chess, with thorough tests of its behavior including both
-screen and keyboard handling.
-<li><a href='html/nqueens.mu.html'>nqueens.mu</a>: a solution to the <a href='http://rosettacode.org/wiki/N-queens_problem'>N queens problem</a>.
-<li>Example programs using delimited continuations:
-  <a href='html/continuation1.mu.html'>1</a>,
-  <a href='html/continuation2.mu.html'>2</a>,
-  <a href='html/continuation3.mu.html'>3</a>,
-  <a href='html/continuation4.mu.html'>4</a>,
-  <a href='html/continuation5.mu.html'>5</a>.
-<li>A code essay: <a href='http://akkartik.name/coroutines-in-mu'>&ldquo;Coroutines in Mu&rdquo;</a>
-<li><a href='html/same-fringe.mu.html'>same-fringe.mu</a>: a solution to the
-  <a href='http://wiki.c2.com/?SameFringeProblem'>&lsquo;same fringe&rsquo;</a>
-  problem, demonstrating Mu's coroutines and generic functions.
-<li>Two klunky ways to build exceptions out of continuations in Mu:
-    <a href='html/exception1.mu.html'>1</a>,
-    <a href='html/exception2.mu.html'>2</a>.
-Since Mu is statically typed, there's no way to implement a <tt>try</tt>
-primitive that can wrap arbitrary functions.
-</ul>
-
-Now a listing of every layer in Mu. Recall that you can <a href='http://akkartik.name/post/wart-layers'>stop
-loading at any layer and get a valid program to run with a subset of features,
-that passes all its tests</a>.
-
-<p><b>Part I</b>: basic infrastructure
-
-<p/><a href='html/000organization.cc.html'>000organization.cc</a>: the basic
-skeleton program. Compiles and runs but doesn't do much. Later <em>layers</em>
-hook into this skeleton to add functionality. Mu's guarantee: you can <a href='http://youtube.com/watch?v=c8N72t7aScY'>load
-features</a> up until any layer, and it will compile and pass all tests until
-that point. <a href='http://akkartik.name/post/wart-layers'>More details &rarr;</a>
-<br/><a href='html/001help.cc.html'>001help.cc</a>: just a simple test layer
-to show how to hook into the skeleton. Also summarizes how to invoke Mu,
-behaviors that later layers will be providing.
-<br/><a href='html/002test.cc.html'>002test.cc</a>: Mu's minimalist test
-harness, relying on a couple of one-liners in the <tt>build</tt> script to
-auto-generate lists of tests to run.
-<br/><a href='html/003trace.cc.html'>003trace.cc</a>: support for logging
-facts about our program, and for <a href='http://akkartik.name/post/tracing-tests'>checking the facts logged in tests</a>.
-(<a href='html/003trace.test.cc.html'>tests for the tracing system</a>)
-
-<p><b>Part II</b>: the core Mu virtual machine, designed to compile easily to
-machine language.
-
-<p/><a href='html/010vm.cc.html'>010vm.cc</a>: core data structures:
-recipes, instructions and <em>reagents</em> (operands).
-<br/><a href='html/011load.cc.html'>011load.cc</a>: the textual representation
-of recipes and how it's turned into the data structures.
-<br/><a href='html/012transform.cc.html'>012transform.cc</a>: after Mu
-programs are loaded but before they are run they can be transformed in an
-extensible manner akin to lisp macros. Think of this as the core of Mu's
-&lsquo;compiler&rsquo; for providing high-level features atop the core.
-<br/><a href='html/013update_operation.cc.html'>013update_operation.cc</a>:
-our first transform: check for unknown recipes before the program runs.
-<br/><a href='html/014literal_string.cc.html'>014literal_string.cc</a>: extend
-the loader to support literal strings in various instructions.
-<br/><a href='html/015literal_noninteger.cc.html'>015literal_noninteger.cc</a>:
-extend the loader to support non-integer numbers.
-<br/><a href='html/016dilated_reagent.cc.html'>016dilated_reagent.cc</a>:
-allowing whitespace in reagents.
-<br/><a href='html/017parse_tree.cc.html'>017parse_tree.cc</a>: a new syntax
-for representing complex types as trees using whitespace and parentheses
-(s-expressions).
-<br/><a href='html/019type_abbreviations.cc.html'>019type_abbreviations.cc</a>:
-the core types of Mu are designed to be fully explicit and familiar to
-non-programmers at the cost of some verbosity: <tt>number</tt>,
-<tt>character</tt>, <tt>boolean</tt>, etc. Once learners get acclimatized,
-we can teach them abbreviated forms that are familiar to veteran programmers:
-<tt>num</tt>, <tt>char</tt>, <tt>bool</tt>. Mu's facility for type
-abbreviations is extensible: learners can abbreviate <tt>number</tt> to
-<tt>n</tt> if they so choose, thereby exploring such trade-offs. You can also
-create abbreviations suitable for a specific program, like abbreviating
-<tt>address:array:address:array:character</tt> to <tt>board</tt> for say a
-tic-tac-toe or chess program. Think C's <tt>typedef</tt> statement.
-<br/><a href='html/020run.cc.html'>020run.cc</a>: executing Mu recipes by
-executing the list of instructions they contain. Future layers will define
-more primitive operations that can be used in instructions.
-<br/><a href='html/021check_instruction.cc.html'>021check_instruction.cc</a>:
-harness for adding per-primitive checks to run before running a program.
-
-<p/>Various primitive operations: on <a href='html/022arithmetic.cc.html'>numbers</a>,
-<a href='html/023boolean.cc.html'>booleans</a>, for <a href='html/024jump.cc.html'>control flow</a>,
-and <a href='html/025compare.cc.html'>comparing values</a>.
-
-<p/>Support for <a href='html/026call.cc.html'>defining new recipes</a>. In
-Mu calls to functions look just like primitive operations, with the ability to 
-<a href='html/027call_ingredient.cc.html'>pass in ingredients</a>, and to 
-<a href='html/028call_return.cc.html'>return products</a>. In particular, Mu
-supports returning multiple values, and uses this ability far more pervasively
-than high-level languages can.
-
-<p/>Support for various data structures: heterogeneous compound types called
-<a href='html/030container.cc.html'><em>containers</em></a>, akin to records
-or structs, homogeneous <a href='html/032array.cc.html'>arrays</a> of a single
-type of value (type <tt>array</tt> conventionally abbreviated as <tt>@</tt>),
-and <a href='html/033exclusive_container.cc.html'><em>exclusive containers</em></a>,
-akin to C unions but with a tag so each value knows its &lsquo;kind&rsquo;.
-Out of these primitive types, Mu builds the usual and growing menagerie of
-data structures: <a href='html/064list.mu.html'>linked lists</a> permitting
-fast insertion and deletion and unidirectional scanning but slow search;
-<a href='html/065duplex_list.mu.html'><em>duplex lists</em></a> that permit
-bidirectional scanning; <a href='html/070table.mu.html'>associative arrays or <em>tables</em></a>
-for fast insertion, deletion and search using <a href='html/069hash.cc.html'>hash</a>
-functions; <a href='html/066stream.mu.html'><em>streams</em></a> for scanning
-through strings incrementally; and <a href='html/061text.mu.html'><em>buffers</em></a>
-for gradually constructing long strings in a piecemeal fashion.
-
-<p/>Dynamic memory management: Mu supports <a href='html/034address.cc.html'>allocating</a>
-space at run-time as pointers or <em>addresses</em>. All Mu instructions can
-dereference or <a href='html/035lookup.cc.html'><em>lookup</em></a> addresses
-of values in addition to operating on regular values. These addresses are
-manually managed like C, and can be reclaimed using the <a href='html/037abandon.cc.html'><tt>abandon</tt></a>
-instruction. To ensure that stale addresses aren't used after being
-abandoned/reused, each allocation gets a unique <em>alloc id</em> that is also
-stored in the address returned. The lookup operation ensures that the alloc id
-of an address matches that of its payload. This eliminates a whole class of
-undefined behavior and security vulnerabilities that plague C. Compared to
-Rust, Mu pays some additional runtime cost in exchange for C-like flexibility
-(you can copy addresses around all you like, and write from any copy of an
-address) and simpler implementation (no static analysis). Mu by convention
-abbreviates type <tt>address</tt> to <tt>&amp;</tt>.
-
-<p/>Support for higher-order recipes that can pass <a href='html/072recipe.cc.html'>recipes</a>
-around like any other value.
-
-<p/>Support for running multiple functions concurrently using <a href='html/073scheduler.cc.html'><em>routines</em></a>,
-for communicating between routines using <a href='html/075channel.mu.html'><em>channels</em></a>,
-and for <a href='html/074wait.cc.html'>synchronizing</a> between routines.
-Channels are Mu's only synchronization primitive, queues that can cause the
-routine reading or writing from them to stall without taking up CPU resources.
-Mu provides safe concurrency by forbidding routines from sharing addresses;
-writing to a channel always performs a <a href='html/071deep_copy.cc.html'>deep copy</a>
-that preserves all internal aliasing.
-
-<p/>Support for <a href='html/076continuation.cc.html'>delimited continuations</a>
-that let one pause and resume sub-computations.
-
-<p><b>Part III</b>: transforms to make Mu a little more expressive, and give
-it some of the benefits of a high-level language.
-
-<p/><a href='html/040brace.cc.html'>040brace.cc</a> and
-<a href='html/041jump_target.cc.html'>041jump_target.cc</a>: how Mu provides
-structured goto-less programming without introducing the syntax of
-conditionals and loops other languages require.
-<br/><a href='html/042name.cc.html'>042name.cc</a>: how Mu transforms variable
-names to raw memory addresses.
-<br/><a href='html/043space.cc.html'>043space.cc</a>: how variables in
-different routines are isolated from each other using <em>spaces</em>. Mu
-&lsquo;local variables&rsquo; are allocated on the heap.
-<br/><a href='html/044space_surround.cc.html'>044space_surround.cc</a>:
-Chaining spaces together to accomodate variables with varying lifetimes and
-ownership properties.
-<br/><a href='html/045closure_name.cc.html'>045closure_name.cc</a>: how spaces
-can implement lexical scope.
-<br/><a href='html/046check_type_by_name.cc.html'>046check_type_by_name.cc</a>:
-a transform to deduce missing types in instructions on the basis of
-previous instructions in the same function.
-<br/><a href='html/050scenario.cc.html'>050scenario.cc</a>: Mu's first syntax
-&mdash; not for code but for tests. (<a href='html/051scenario_test.mu.html'>example</a>)
-<br/><a href='html/052tangle.cc.html'>052tangle.cc</a>: support for layers in
-Mu programs. They've been so good to us.
-<br/><a href='html/053recipe_header.cc.html'>053recipe_header.cc</a>:
-a new syntax for summarizing the number and types of ingredients and products
-a function expects at the top next to its name, in a <em>header</em>.
-<br/><a href='html/054static_dispatch.cc.html'>054static_dispatch.cc</a>:
-allowing multiple variants of a function to coexist as long as each has a
-unique header.
-<br/>Support for generic or <em>shape-shifting</em> <a href='html/055shape_shifting_container.cc.html'>data structures</a>
-and <a href='html/056shape_shifting_recipe.cc.html'>recipes</a>, containing
-wildcard type ingredients that start with an &lsquo;_&rsquo;. Everytime you
-use a shape-shifting recipe with a new set of &lsquo;concrete&rsquo; types
-for its type ingredients, it creates a new variant of the recipe for you
-matching those types.
-<br/><a href='html/057immutable.cc.html'>057immutable.cc</a>, a static analysis to
-ensure that functions never modify anything but their products.
-
-<p><b>Part IV</b>: Miscellaneous.
-
-<p/><a href='html/061text.mu.html'>061text.mu</a>: strings in Mu are
-bounds-checked rather than null-terminated. They're also unicode-aware (code
-points only; no control characters, no combining characters, no
-normalization). Mu recipes that take strings can take literal strings thanks
-to a <a href='html/060rewrite_literal_string.cc.html'>transform</a> that
-allocates them on the heap.
-<br/><a href='html/062convert_ingredients_to_text.cc.html'>062convert_ingredients_to_text.cc</a>:
-a convenience transform primarily intended to provide the illusion of dynamic
-typing when adding to the trace. The <span style='font-family:courier,fixed'>stash</span>
-command can print any number of ingredients of any type into the trace. Its
-default output format is fairly simplistic, but it can be overridden for
-arbitrary types by defining a variant of the <a href='html/058to_text.cc.html'><span style='font-family:courier,fixed'>to-text</span></a>
-function with an ingredient of the appropriate type. For example, see
-<a href='html/064list.mu.html'>064list.mu</a> which defines how we trace
-lists.
-<br/><a href='html/067random.cc.html'>067random.cc</a>: a random-number
-generator with a <a href='html/068random.mu.html'>testable</a> interface.
-
-<p><b>Part V</b>: Primitives for interfacing with hardware.
-
-<p/><a href='html/080display.cc.html'>080display.cc</a>: primitives for
-accessing the keyboard and screen.
-<br/><a href='html/081print.mu.html'>081print.mu</a>: helpers that can swap
-the real screen with fake ones for testing.
-<br/><a href='html/082scenario_screen.cc.html'>082scenario_screen.cc</a>:
-writing tests that check what is printed to screen.
-(<a href='html/083scenario_screen_test.mu.html'>examples</a>)
-<br/><a href='html/084console.mu.html'>084console.mu</a>: helpers that can
-swap the real keyboard and mouse with fake ones for testing.
-<br/><a href='html/085scenario_console.cc.html'>085scenario_console.cc</a>:
-writing tests for keyboard and mouse using the fakes.
-(<a href='html/086scenario_console_test.mu.html'>examples</a>)
-<br/><a href='html/087file.cc.html'>087file.cc</a>: primitives for accessing
-the file system.
-<br/><a href='html/088file.mu.html'>088file.mu</a>: helpers that permit
-swapping a fake filesystem or <tt>resources</tt> object for testing.
-<br/><a href='html/089scenario_filesystem.cc.html'>089scenario_filesystem.cc</a>:
-writing tests for filesystem using the fakes.
-(<a href='html/090scenario_filesystem_test.mu.html'>examples</a>)
-<br/><a href='html/091socket.cc.html'>091socket.cc</a>: primitives for
-accessing the network.
-<br/><a href='html/092socket.mu.html'>092socket.mu</a>: helpers for the
-network. In Mu you create a fake network &lsquo;neighborhood&rsquo; the same
-way you create a fake local file system.
-
-<p/><a href='html/029tools.cc.html'>029tools.cc</a>: various primitive
-operations to help with testing and debugging.
-<br/><a href='html/100trace_browser.cc.html'>100trace_browser.cc</a>: a
-zoomable UI for inspecting traces generated by Mu programs. Allows both
-scanning a high-level view and drilling down into selective details.
-
-<p><b>Part VI</b>: An environment that watches programmers as they
-manually test their code, and turns these interactive sessions into reproducible
-test scenarios. The <a href='https://github.com/akkartik/mu/blob/master/edit/Readme.md'>readme for the app</a>
-contains instructions for running it. Stop loading after each of these layers
-to get a working version with just fewer features. 
+<b><a href='http://github.com/akkartik/mu'>Solution.</a></b>
 
-<p/><a href='html/edit/001-editor.mu.html'>edit/001-editor.mu</a>: data
-structures for a text editor widget. Load just this layer to see just the
-rendering and line-wrapping at work.
-<br/><a href='html/edit/002-typing.mu.html'>edit/002-typing.mu</a>: support
-for moving the cursor anywhere with the mouse and typing text in there.
-<br/><a href='html/edit/003-shortcuts.mu.html'>edit/003-shortcuts.mu</a>:
-support for various keyboard shortcuts for manipulating text you've typed in.
-<br/><a href='html/edit/004-programming-environment.mu.html'>edit/004-programming-environment.mu</a>:
-combining two text editor widgets, one on the left, one on the right.
-<br/><a href='html/edit/005-sandbox.mu.html'>edit/005-sandbox.mu</a>: support
-for running Mu code in the right-hand widget using code from the left, and
-displaying results in a <em>sandbox</em> below on the right. You can have
-multiple sandboxes, and hit F4 to rerun them all at any time with the latest
-version of the code on the left side.
-<br/><a href='html/edit/006-sandbox-copy.mu.html'>edit/006-sandbox-edit.mu</a>:
-click on the 'copy' button in each sandbox to duplicate its contents.
-<br/><a href='html/edit/007-sandbox-delete.mu.html'>edit/007-sandbox-delete.mu</a>:
-support for the 'delete' button in each sandbox.
-<br/><a href='html/edit/008-sandbox-edit.mu.html'>edit/008-sandbox-edit.mu</a>:
-click on the 'edit' button of each sandbox to pop its back into the sandbox
-editor. Basically like copying and then deleting a sandbox.
-<br/><a href='html/edit/009-sandbox-test.mu.html'>edit/009-sandbox-test.mu</a>:
-click on the results of a sandbox to turn them green and save the output as
-golden/expected. Any future changes to the output will then be flagged in red.
-<br/><a href='html/edit/010-sandbox-trace.mu.html'>edit/010-sandbox-trace.mu</a>:
-click on code in a sandbox to open up a drawer containing its trace. The trace
-can be added to using the <span style='font-family:courier,fixed'>stash</span>
-command, which can be extended to render arbitrary data structures by creating
-new variants of the <span style='font-family:courier,fixed'>to-text</span>
-recipe for the appropriate types.
-<br/><a href='html/edit/011-errors.mu.html'>edit/011-errors.mu</a>:
-support for rendering errors on both the left and in each sandbox.
-<br/><a href='html/edit/012-editor-undo.mu.html'>edit/012-editor-undo.mu</a>:
-support for undo in the editor widget.
+<p>For an earlier prototype, a high-level statement-oriented language with a
+tree-walking interpreter, see <a href='http://akkartik.github.io/mu1'>mu1</a>.
 
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