Initial docs

Makefile

+.SILENT:
+
+.PHONY: docs docs-server docs-watch docs-sync-server
+
+_invalid:
+	echo "Specify a target name to execute"
+
+docs:
+	sphinx-build -b html \
+		docs \
+		_build/docs \
+		-Wqaj8
+	echo "Docs generated to _build/docs"
+
+docs-server: docs
+	echo "Docs are visible on http://localhost:9794/"
+	cd _build/docs && \
+		python -m http.server 9794
+
+docs-watch: docs
+	+sh tools/docs-watch.sh
+
+docs-sync-server: docs
+	cd _build/docs && \
+	browser-sync start --server \
+		--reload-delay 300 \
+		--watch **/*.html

docs/conf.py

+# -*- coding: utf-8 -*-
+# Refer: http://www.sphinx-doc.org/en/master/config
+
+# -- Project information -----------------------------------------------------
+project = 'dds'
+copyright = '2019, vector-of-bool'
+author = 'vector-of-bool'
+
+# The short X.Y version
+version = ''
+# The full version, including alpha/beta/rc tags
+release = '0.1.0'
+
+# -- General configuration ---------------------------------------------------
+extensions = []
+templates_path = ['_templates']
+source_suffix = '.rst'
+master_doc = 'index'
+language = None
+exclude_patterns = ['_build', 'Thumbs.db', '.DS_Store']
+pygments_style = None
+
+# -- Options for HTML output -------------------------------------------------
+html_theme = 'pyramid'
+html_theme_options = {}
+html_static_path = []
+html_sidebars = {}

docs/guide/design.rst

+``dds`` Design and Rationale
+############################
+
+``dds`` has been designed from the very beginning as an extremely opinionated
+hybrid *build system* and *package manager*. Unlike most build systems however,
+``dds`` has a hyper-specific focus on a particular aspect of software
+development: C++ libraries.
+
+This may sound pointless, right? Libraries are useless unless we can use them
+to build applications!
+
+Indeed, applications *are* essential, but that is "not our job."
+
+Another design decision is that ``dds`` is built to be driven by automated
+tools as well as humans. ``dds`` will not build your AAA console game, nor will
+it compile an OS kernel. Instead, the build system of your AAA console game or
+OS kernel can *use* ``dds``.
+
+
+Background
+**********
+
+I'm going to say something somewhat controversial: C++ doesn't need "package
+management." At least, not *generalize* "package management." C++ needs
+*library* "package management."
+
+The C and C++ compilation model is inherently *more complex* than almost any
+other language in use today. This isn't to say "bad," but rather than it is
+built to meet extremely high and strange demands. It also comes with a large
+burden of *legacy*. Meeting both of these requirements simultaneously presents
+incredible implementation challenges.
+
+Despite the vast amount of work put into build systems and tooling, virtually
+all developers are using them *incorrectly* and/or *dangerously* without
+realizing it. Despite this work, we seem to be a great distance from a unified
+library package distribution and consumption mechanism.
+
+
+Tabula Rasa
+***********
+
+``dds`` attempts to break from the pattern of legacy demands and strange usage
+demands in a few ways. The major differences between ``dds`` and other build
+systems like CMake, Meson, build2, SCons, MSBuild, etc. is that of *tradeoffs*.
+If you opt-in to have your library built by ``dds``, you forgoe
+*customizability* in favor of *simplicity* and *ease*.
+
+``dds`` takes a look at what is needed to build and develop *libraries* and
+hyper-optimizes for that use case. It is also built with a very strong, very
+opinionated idea of *how* libraries should be constructed and used. These
+prescriptions are not at all arbitrary, though. They are built upon the
+observations of the strengths and weaknesses of build systems in use throughout
+industry and community.
+
+There is some ambiguity on the term "build system." It can mean one of two
+things:
+
+1. A *proper noun* "Build System," such as CMake, Meson, Autotools, or even
+   Gulp, WebPack, and Mix. These are specific tools that have been developed
+   for the implementation of the second definition:
+2. A general noun "build system" refers to the particular start-to-finish
+   process through which a specific piece of software is mapped from its raw
+   *inputs* (source code, resource libraries, toolchains) to the outputs
+   (applications, appliances, libraries, or web sites).
+
+For example, LLVM and Blender both use the CMake "Build System," but their
+"build system" is not the same. The "build system" for each is wildly
+different, despite both using the same underlying "Build System."
+
+``dds`` takes a massive divergence at this point. One project using ``dds`` as
+their build system has an identical build process to every other project using
+``dds``. Simply running :code:`dds -F` is enough to build *any* ``dds``
+project.
+
+In order to reach this uniformity and simplicity, ``dds`` drops almost all
+aspects of project-by-project customizability. Instead, ``dds`` affords the
+developer a contract:
+
+    If you play by my rules, you get to play in my space.
+
+
+.. _design.rules:
+
+The Rules
+*********
+
+We've talked an awful lot about the "rules" and "restrictions" that ``dds``
+imposes, but what are they?
+
+
+.. _design.rules.not-apps:
+
+``dds`` Is not Made for Complex Applications
+===============================================
+
+Alright, this one isn't a "rule" as much as a recommendation: If you are
+building an application that *needs* some build process functionality that
+``dds`` does not provide, ``dds`` is only open to changes that do not
+violate any of the other existing rules.
+
+.. note::
+    **However:** If you are a *library* author and you find that ``dds``
+    cannot correctly build your library without violating other rules, we may
+    have to take a look. This is certainly not to say it will allow arbitrary
+    customization features to permit the rules to be bent arbitrarily: Read
+    on.
+
+``dds`` contains a minimal amount of functionality for building simple
+applications, but it is certainly not its primary purpose (See the ``--apps``
+flag).
+
+
+.. _design.rules.change:
+
+*Your* Code Should Be Changed Before ``dds`` Should Be Changed
+=================================================================
+
+The wording of this rule means that the onus is on the library developer to
+meet the expectations that ``dds`` prescribes in order to make the build
+work.
+
+If your library meets all the requirements outlined in this document but you
+still find trouble in making your build work, this is grounds for change in
+``dds``, either in clarifying the rules or tweaking ``dds`` functionality.
+
+
+.. _design.rules.layout:
+
+Library Projects Must Meet the Layout Requirements
+==================================================
+
+This is a very concrete requirement. ``dds`` prescribes a particular project
+structure layout with minimal differing options. ``dds`` prescribes the
+`Pitchfork`_ layout requirements.
+
+.. note::
+    These prescriptions are not as draconian as they may sound upon first
+    reading. Refer to the :doc:`layout` page for more information.
+
+.. _Pitchfork: https://api.csswg.org/bikeshed/?force=1&url=https://raw.githubusercontent.com/vector-of-bool/pitchfork/develop/data/spec.bs
+
+
+.. _design.rules.no-cond-compile:
+
+A Library Build Must Successfully Compile All Source Files
+==========================================================
+
+Almost all Build Systems have a concept of *conditionally* adding a source file
+to a build. ``dds`` elides this feature in place of relying on in-source
+conditional compilation.
+
+
+.. _design.rules.no-lazy-code-gen:
+
+All Code Must Be in Place Before Building
+=========================================
+
+``dds`` does not provide code-generation functionality. Instead, any
+generated code should be generated and committed to the repository to be only
+ever modified through such generation scripts.
+
+
+.. _design.rules.one-binary-per-src:
+
+All Compilable Files in a ``src/`` Directory Must Link Together
+===============================================================
+
+As part of the prescribed project layout, the ``src/`` project directory
+contains source files. ``dds`` requires that *all* source files in a given
+``src/`` directory should link together cleanly. Practically, this means that
+every ``src/`` directory must correspond to *exactly* one library.
+
+
+.. _design.rules.include:
+
+No Arbitrary ``#include`` Directories
+=====================================
+
+Only ``src/`` and ``include/`` will ever be used as the basis for header
+resolution while building a library, so all ``#include`` directives should be
+relative to those directories. Refer to :ref:`guide.layout.include`.
+
+
+.. _design.rules.uniform-compile:
+
+All Files Compile with the Same Options
+=======================================
+
+When DDS compiles a library, every source file will be compiled with an
+identical set of options. Additionally, when DDS compiles a dependency tree,
+every library in that dependency tree will be compiled with an identical set of
+options. Refer to the :doc:`toolchains` page for more information.

docs/guide/index.rst

+.. _guide:
+
+User Guide
+##########
+
+.. toctree::
+    :maxdepth: 2
+
+    design
+    layout
+    toolchains

docs/guide/layout.rst

+Project Layout
+##############
+
+The layout expected by ``dds`` is based on the `Pitchfork layout`_ (PFL).
+``dds`` does not make use of every provision of the layout document, but the
+features it does have are based on PFL.
+
+.. _Pitchfork layout: https://api.csswg.org/bikeshed/?force=1&url=https://raw.githubusercontent.com/vector-of-bool/pitchfork/develop/data/spec.bs
+
+In particular, the following directories are used:
+
+- ``src/``
+- ``include/``
+- ``libs/``
+- ``_build/`` (the default build output directory used by ``dds``).
+
+Note that the ``libs/*/`` directories can contain their own ``src/`` and
+``include/`` directories, the purposes and behaviors of which match those of
+their top-level counterparts.
+
+
+.. _guide.layout.include:
+
+Include Directories and Header Resolution
+*****************************************
+
+A compiler's "include path" is the list of directories in which it will attempt
+to resolve ``#include`` directives.
+
+The layout prescriptions permit either ``src/``, ``include/``, or both. In the
+presence of both, the ``include/`` directory is used as the *public* include
+directory, and ``src/`` is used as the *private* include directory. When only
+one of either is present, that directory will be treated as the *public*
+include directory (and there will be no *private* include directory).
+
+
+.. _guide.layout.sources:
+
+Source Files
+************
+
+``dds`` distinguishes between *headers* and *compilable* sources. The heuristic
+used is based on common file extensions:
+
+The following are considered to be *header* source files:
+
+- ``.h``
+- ``.hpp``
+- ``.hxx``
+- ``.inl``
+- ``.h++``
+
+While the following are considered to be *compilable* source files:
+
+- ``.c``
+- ``.cpp``
+- ``.cc``
+- ``.cxx``
+- ``.c++``
+
+``dds`` will compile every compilable source file that appears in the ``src/``
+directory. ``dds`` will not compile compilable source files that appear in the
+``include/`` directory and will issue a warning on each file found.
+
+
+.. _guide.layout.apps-tests:
+
+Applications and Tests
+**********************
+
+``dds`` will recognize certain compilable source files as belonging to
+applications and tests. If a compilable source file stem ends with ``.main`` or
+``.test``, that source file is assumed to correspond to an executable to
+generate. The filename stem before the ``.main`` or ``.test`` will be used as
+the name of the generated executable. For example:
+
+- ``foo.main.cpp`` will generate an executable named ``foo``.
+- ``bar.test.cpp`` will generate an executable named ``bar``.
+- ``cat-meow.main.cpp`` will generate an executable named ``cat-meow``.
+- ``cats.musical.test.cpp`` will generate an executable named ``cats.musical``.
+
+.. note::
+    ``dds`` will automatically append the appropriate filename extension to the
+    generated executables based on the host and toolchain.
+
+If the inner extension is ``.main``, then ``dds`` will assume the corresponding
+executable to be an *application*. If the inner extension is ``.test``, ``dds``
+will assume the executable to be a test.
+
+The building of tests and applications can be controlled when running
+``dds build``. If tests are built, ``dds`` will automatically execute those
+tests in parallel once the executables have been generated.
+
+In any case, the executables are associated with a *library*, and, when those
+executables are linked, the associated library (and its dependencies) will be
+linked into the final executable. There is no need to manually specify this
+linking behavior.
+
+
+.. _guide.layout.libraries:
+
+Libraries
+*********
+
+The *library* is a fundamental unit of consumable code, and ``dds`` is
+specifically built to work with them. When you are in ``dds``, the library is
+the center of everything.
+
+A *source root* is a directory that contains the ``src/`` and/or ``include/``
+directories. The ``src/`` and ``include/`` directories are themselves
+*source directories*. A single *source root* will always correspond to exactly
+one library. If the library has any compilable sources then ``dds`` will use
+those sources to generate a static library file that is linked into runtime
+binaries. If a library contains only headers then ``dds`` will not generate an
+archive to be included in downstream binaries, but it will still generate link
+rules for the dependencies of a header-only library.
+
+In the previous section, :ref:`guide.layout.apps-tests`, it was noted that
+applications and tests are associated with a library. This association is
+purely based on being collocated within the same source root.
+
+When an executable is built within the context of a library, that library (and
+all of its dependencies) will be linked into that executable.

docs/guide/toolchains.rst

+Toolchains
+##########
+
+One of the core components of ``dds`` is that of the *toolchain*. A toolchain
+encompasses the environment used to build and link source code, including, but
+not limited to:
+
+#. The executable binaries that constitute the language implementation:
+   Compilers, linkers, and archive managers.
+#. The configuration of those tools, including most options given to those
+   tools when they are invoked.
+#. The set of preprocessor macros and language features that are active during
+   compilation.
+
+When a build is run, every file in the entire tree (including dependencies)
+will be compiled, archived, and linked using the same toolchain.
+
+This page provides an introduction on how one can make use of toolchains most
+effectively in your project.
+
+
+Passing a Toolchain
+*******************
+
+In ``dds``, the default format of a toolchain is that of a single file that
+describes the entire toolchain, and uses the extension ``.tc.dds`` by
+convention. When running a build for a project, the ``dds`` executable will
+look for a file named ``toolchain.tc.dds`` by default, and will error out if
+this file does not exist. A different toolchain can be provided by passing the
+toolchain file for the ``--toolchain`` (or ``-T``) option on the command line::
+
+    $ dds build -T my-toolchain.tc.dds
+
+Alternatively, you can pass the name of a built-in toolchain. See below.
+
+
+Built-in Toolchains
+*******************
+
+For convenience, ``dds`` includes several built-in toolchains that can be
+accessed in the ``--toolchain`` command-line option using a colon ``:``
+prefix::
+
+    $ dds build -T :gcc
+
+``dds`` will treat the leading colon (``:``) as a name for a built-in
+toolchain (this means that a toolchain's filepath may not begin with a colon).
+
+There are several built-in toolchains that may be specified:
+
+``:gcc``
+    Uses the default ``gcc`` and ``g++`` executables, linkers, and options
+    thereof.
+
+``:gcc-N`` (for some integer ``N``)
+    Equivalent to ``:gcc``, but uses the ``gcc-N`` and ``g++-N`` executables.
+
+``:clang``
+    Equivalent to ``:gcc``, but uses the ``clang`` and ``clang++`` executables.
+
+``:clang-N`` (for some integer ``N``)
+    Equivalent to ``:clang``, but uses the ``clang-N`` and ``clang++-N``
+    executables.
+
+``:msvc``
+    Compiles and links using the Visual C++ toolchain.
+
+The following pseudo-toolchains are also available:
+
+``:ccache:XYZ``
+    Uses built-in toolchain ``:XYZ``, but prefixes all compile commands with
+    ``ccache``.
+
+.. note::
+    **IMPORTANT**: ``dds`` will *not* automatically load the Visual C++
+    environment. To use Visual C++, ``dds`` must be executed from the
+    appropriate environment in order for the Visual C++ toolchain executables
+    and files to be available.
+
+

docs/index.rst

+DDS
+######
+
+**dds** is the Drop-Dead-Simple Build and Library Management Tool.
+
+dds is a hybrid build system and package manager with a unique twist.
+There's a lot to learn, but I'm glad you're here! I hope you find ``dds``
+useful to you and your projects.
+
+If you're completely new and have no idea what the project is about, check out
+the :doc:`guide/design` page to get started.
+
+.. toctree::
+    :maxdepth: 2
+
+    guide/index
+
+
+Indices and tables
+==================
+
+* :ref:`genindex`
+* :ref:`modindex`
+* :ref:`search`

tools/docs-watch.sh

+set -eu
+
+THIS_SCRIPT=$(readlink -m $0)
+HERE=$(dirname ${THIS_SCRIPT})
+ROOT=$(dirname ${HERE})
+
+while true; do
+    echo "Watching for changes..."
+    inotifywait -r ${ROOT}/docs/ -q \
+		-e modify 			\
+		-e close_write 		\
+		-e move 			\
+		-e delete 			\
+		-e create
+    make docs || :
+done