In the "Type Coercion" section, rename:
- Coercion Float to Int => Float to Int
- unions and enums => Unions and Enums
- tuples to arrays => Tuples to Arrays
In the "C Translation CLI" section, move the paragraph inside the p
element.
The current HTML is valid, but, as an example, a paragraph outside a p
element is not handled correctly by the browser Inspect tool.
In commit 3542dbf0ea (langref: add section numbers) I accidentally
added an extra closing curly bracket at the end of the style element.
Sorry for not validating the HTML file before creating the PR.
Update the genToc funtion to make the name required in the Code node,
and add an additional optional field for the expected error, to use with
test_err, test_safety and obj_err.
Update langref.html.in to ensure all code blocks have a name that
- is unique, so that a doctest can be identified by it
- is descriptive
For test, test_err and test_safefy, ensure that the doctest name starts
with "test_", excluding doctests in the "Zig Test" section and doctests
that are imported by other doctests.
Ensure that the indentation of code_begin and code_end blocks are
consistent.
Fix a typo in pointer_arthemtic.
In a syntax_block the code always start on a separate code, expect for
C, JavaScript, Peg and with Zig inline assembly.
Ensure that the code starts on a separate line, even in cases where
there is only one line.
Ensure that the end_syntax_block is always on a separate line and that
the indentation is consistent.
The current compiler ignores the UTF-8 BOM if it is at the start of the
file, and disallows it anywhere else. Document it in the Source Encoding
section.
Add the new addrspace keyword in the Keyword Reference section, without
documentation.
Move the linksection keyword in order to keep the keywords list sorted.
The deallocations of the process arguments are unnecessary, since the
memory will be deallocated by arena.deinit().
The deallocations are incorrect, since ArgIterator.next() returns a
slice pointing to the iterator's internal buffer, that should be
deallocated with args_it.deinit().
When reading a document with nested sections, it is not easy to discover
the depth of the current section.
Add support for nested section numbers, from the h2 to the h4 heading,
in the format "lv1. ", "lv1.lv2. ", "lv1.lv2.lv3. ". The "Zig Version"
and "Table of Content" sections are excluded.
The section numbers are implemented in CSS, with the CSS rules declared
inside a @media rule. Currently the @media rule targets all media.
This was a poor naming choice; these are parameters, not arguments.
Parameters specify what kind of arguments are expected, whereas the arguments are the actual values passed.
Add a missing ReleaseSmall when describing unreachable in the try
section and the unreachable entry in the Keyword Reference section.
Additionally, transform Debug, ReleaseSafe, ReleaseFast and ReleaseSmall
into links in the try section.
Co-authored-by: Andrew Kelley <andrew@ziglang.org>
Currently, the test_fn_reflection.zig doctest has an example of
.Fn.is_var_args. This example can confuse the reader, since there is no
documentation about variadic functions and is_var_args is mainly used in
the compiler.
Remove the example with .Fn.is_var_args and add instead examples with
.Fn.return_type and .Fn.is_generic.
In the slice_bounds.zig doctest, the code "const slice = array[2..4]" is
incorrect, since the actual type is a pointer to an array, instead of a
slice.
Use a runtime know value to slice the array.
In the slices.zig doctest, the code
`const all_together_slice = all_together[0..]` is incorrect, since the
actual type is a pointer to an array, instead of a slice.
Use a runtime-known value to slice the array.
In the next "slice pointer" test, clarify that slicing a slice to
produce a pointer to an array, requires comptime-known indexes, not just
constant indexes.
Split the original `defer.zig` doctest into 3 doctest:
1. Document the defer keyword
2. Document that the return statement is not allowed inside a defer
expression
3. Document the errdefer keyword
Replace "method" with "expression" in the text `defer method`.
Several <em> elements where added inside a shell node in the
Using--target-and--cflags section. Remove them, since they are not
supposed to be handled by codegen.
For the original commit, see
0c091feb5 (Improve HTML semantics and a11y of language reference).
Fixes#13846
This commit removes async/await/suspend/resume from the language
reference, as that feature does not yet work in the self-hosted
compiler.
We will be regressing this feature temporarily. Users of these language
features should stick with 0.10.x with the `-fstage1` flag until they
are restored.
See tracking issue #6025.
The packed struct example was mistakenly applying endianness where it
shouldn't have been. This wasn't being caught because we don't currently
test the examples on Big-endian systems.
I updated the test to remove the endianness where it didn't apply, and
added a new part of the test to demonstrate when it would apply.
* When a field starts at some bit offset within a byte you need to load
starting from that byte and shift, not starting from the next byte,
so a rounded-down divide is required here, not a rounded-up one.
* Remove paragraph from doc that no longer relates to anything.
Closes#12363
Storing defers this way has the benefits that the defer doesn't get
analyzed multiple times in AstGen, it takes up less space, and it
makes Sema aware of defers allowing for 'unreachable else prong'
error on error sets in generic code.
The disadvantage is that it is a bit more complex and errdefers with
payloads now emit a placeholder instruction (but those are rare).
Sema.zig before:
Total ZIR bytes: 3.7794370651245117MiB
Instructions: 238996 (2.051319122314453MiB)
String Table Bytes: 89.2802734375KiB
Extra Data Items: 430144 (1.640869140625MiB)
Sema.zig after:
Total ZIR bytes: 3.3344192504882812MiB
Instructions: 211829 (1.8181428909301758MiB)
String Table Bytes: 89.2802734375KiB
Extra Data Items: 374611 (1.4290275573730469MiB)
Before, native glibc and dynamic linker detection attempted to use the
executable's own binary if it was dynamically linked to answer both the
C ABI question and the dynamic linker question. However, this could be
problematic on a system that uses a RUNPATH for the compiler binary,
locking it to an older glibc version, while system binaries such as
/usr/bin/env use a newer glibc version. The problem is that libc.so.6
glibc version will match that of the system while the dynamic linker
will match that of the compiler binary. Executables with these versions
mismatching will fail to run.
Therefore, this commit changes the logic to be the same regardless of
whether the compiler binary is dynamically or statically linked. It
inspects `/usr/bin/env` as an ELF file to find the answer to these
questions, or if there is a shebang line, then it chases the referenced
file recursively. If that does not provide the answer, then the function
falls back to defaults.
This commit also solves a TODO to remove an Allocator parameter to the
detect() function.
saying []T is a pointer is confusing because zig docs say there are two types of pointers (*T and [*]T). It is more clear to say that []T is a slice type which contains a [*]T pointer and a length.
Co-authored-by: Philipp Lühmann <47984692+luehmann@users.noreply.github.com>
This reverts commit 7cbd586ace.
This is causing a fail to build from source:
```
./lib/std/fmt.zig:492:17: error: cannot format optional without a specifier (i.e. {?} or {any})
@compileError("cannot format optional without a specifier (i.e. {?} or {any})");
^
./src/link/MachO/Atom.zig:544:26: note: called from here
log.debug(" RELA({s}) @ {x} => %{d} in object({d})", .{
^
```
I looked at the code to fix it but none of those args are optionals.
The current phrasing is vague; it is unclear whether it is demonstrating an example of the type of permitted behavior, from which the rule set must be extrapolated, or it is stating that this restriction only applies to the relationship between integers and bare structs.
Rename all references of sparcv9 to sparc64, to make Zig align more with
other projects. Also, added new function to convert glibc arch name to Zig
arch name, since it refers to the architecture as sparcv9.
This is based on the suggestion by @kubkon in PR 11847.
(https://github.com/ziglang/zig/pull/11487#pullrequestreview-963761757)
stage2: change logic for detecting whether the main package is inside
the std package. Previously it relied on realpath() which is not portable.
This uses resolve() which is how imports already work.
* stage2: fix cleanup bug when creating Module
* flatten lib/std/special/* to lib/*
- this was motivated by making main_pkg_is_inside_std false for
compiler_rt & friends.
* rename "mini libc" to "universal libc"
The reason for having `@tan` is that we already have `@sin` and `@cos`
because some targets have machine code instructions for them, but in the
case that the implementation needs to go into compiler-rt, sin, cos, and
tan all share a common dependency which includes a table of data. To
avoid duplicating this table of data, we promote tan to become a builtin
alongside sin and cos.
ZIR: The tag enum is at capacity so this commit moves
`field_call_bind_named` to be `extended`. I measured this as one of
the least used tags in the zig codebase.
Fix libc math suffix for `f32` being wrong in both stage1 and stage2.
stage1: add missing libc prefix for float functions.
For those souls looking for a zig `size_t` equivalent, and not
lucky/educated enough (that was me yesterday) to know it's the same as
`uintptr_t`.
From a recent discussion on IRC.
Two major changes here:
1. We store the CWD as a simple `[]const u8` and lookup Preopens for
every absolute or CWD-referenced file operation, based on the
Preopen with the longest match (i.e. most specific path)
2. Preorders are normalized to POSIX absolute paths at init time.
Behavior depends on the "cwd_root" parameter of `initPreopensWasi`:
`cwd_root` is used for any Preopens that start with "."
For example:
"./foo/bar" - inits to -> "{cwd_root}/foo/bar"
"foo/bar" - inits to -> "/foo/bar"
"/foo/bar" - inits to -> "/foo/bar"
`cwd_root` must be an absolute path.
Using "/" as `cwd_root` gives behavior similar to wasi-libc.
* make it always return a fully qualified name. stage1 is inconsistent
about this.
* AstGen: fix anon_name_strategy to correctly be `func` when anon type
creation happens in the operand of the return expression.
* Sema: implement type names for the "function" naming strategy.
* Put "enum", "union", "opaque", or "struct" in place of "anon" when
creating respective anonymous Decl names.
* std.testing: add `expectStringStartsWith`. Didn't end up using it
after all.
Also this enables the real test runner for stage2 LLVM backend (sans
wasm32) since it works now.
I hit the "quotes in an RSP file" issue when trying to compile gRPC using
"zig cc". As a fun exercise, I decided to see if I could fix it myself.
I'm fully open to this code being flat-out rejected. Or I can take feedback
to fix it up.
This modifies (and renames) _ArgIteratorWindows_ in process.zig such that
it works with arbitrary strings (or the contents of an RSP file).
In main.zig, this new _ArgIteratorGeneral_ is used to address the "TODO"
listed in _ClangArgIterator_.
This change closes#4833.
**Pros:**
- It has the nice attribute of handling "RSP file" arguments in the same way it
handles "cmd_line" arguments.
- High Performance, minimal allocations
- Fixed bug in previous _ArgIteratorWindows_, where final trailing backslashes
in a command line were entirely dropped
- Added a test case for the above bug
- Harmonized the _ArgIteratorXxxx._initWithAllocator()_ and _next()_ interface
across Windows/Posix/Wasi (Moved Windows errors to _initWithAllocator()_
rather than _next()_)
- Likely perf benefit on Windows by doing _utf16leToUtf8AllocZ()_ only once
for the entire cmd_line
**Cons:**
- Breaking Change in std library on Windows: Call
_ArgIterator.initWithAllocator()_ instead of _ArgIterator.init()_
- PhaseMage is new with contributions to Zig, might need a lot of hand-holding
- PhaseMage is a Windows person, non-Windows stuff will need to be double-checked
**Testing Done:**
- Wrote a few new test cases in process.zig
- zig.exe build test -Dskip-release (no new failures seen)
- zig cc now builds gRPC without error
* Create Vector language documentation
Main changes to docs:
1. Create brief documentation on Zig vector types with code example
2. Get rid of the SIMD sub-heading under the main Vectors heading,
and update links accordingly
3. Add an example to the `@shuffle` docs
`getExternalExecutor` is moved from `std.zig.CrossTarget` to
`std.zig.system.NativeTargetInfo.getExternalExecutor`.
The function also now communicates a bit more information about *why*
the host is unable to execute a binary. The CLI is updated to report
this information in a useful manner.
`getExternalExecutor` is also improved to detect such patterns as:
* x86_64 is able to execute x86 binaries
* aarch64 is able to execute arm binaries
* etc.
Added qemu-hexagon support to `getExternalExecutor`.
`std.Target.canExecBinaries` of is removed; callers should use the more
powerful `getExternalExecutor` instead.
Now that `zig test` tries to run the resulting binary no matter what,
this commit has a follow-up change to the build system and docgen to
utilize the `getExternalExecutor` function and pass `--test-no-exec`
in some cases to avoid getting the error.
Additionally:
* refactor: extract NativePaths and NativeTargetInfo into their own
files named after the structs.
* small improvement to langref to reduce the complexity of the `callconv`
expression in a couple examples.
Updates the Language Reference sections: Comments, Values, and Zig Test.
Zig Test section moved down with the goal "make sure it can be read top to
bottom sensibly" in mind (issue #1524).
Comments and Values section examples changed test declarations to a main
function and expect statement to print statements.
A print statement was added to the "String Literals and Unicode Code Point"
section's example to demonstrate the "u" format specifier.
Zig Test Section:
* Addresses the question: "How does the syntax work?".
* Partially answers the question: "What can I do with the zig test tool?" but
should be sufficient to understand the examples in all of this document.
* Addresses the question: "How does a top-level test block differ from a function definition?"
* Provides a example to run multiple test.
Lacks clear definitions of containers, top-level, order independence, lazy
analysis, resolve, reference.
GitHub Issues: #8221, #8234
* Remove the builtins `@addWithSaturation`, `@subWithSaturation`,
`@mulWithSaturation`, and `@shlWithSaturation` now that we have
first-class syntax for saturating arithmetic.
* langref: Clarify the behavior of `@shlExact`.
* Ast: rename `bit_shift_left` to `shl` and `bit_shift_right` to `shr`
for consistency.
* Air: rename to include underscore separator with consistency with
the rest of the ops.
* Air: add shl_exact instruction
* Use non-extended tags for saturating arithmetic, to keep it
simple so that all the arithmetic operations can be done the same
way.
- Sema: unify analyzeArithmetic with analyzeSatArithmetic
- implement comptime `+|`, `-|`, and `*|`
- allow float operands to saturating arithmetic
* `<<|` allows any integer type for the RHS.
* C backend: fix rebase conflicts
* LLVM backend: reduce the amount of branching for arithmetic ops
* zig.h: fix magic number not matching actual size of C integer types
docgen HTML escapes characters inside of `syntax_block`s. This commit replaces the escaped
greater than with the `>` character. No other occurrences were found.
Fixes#9840
There were two things to resolve here:
* Snektron's branch edited Zir printing, but in master branch
I moved the printing code from Zir.zig to print_zir.zig. So that
just had to be moved over.
* In master branch I fleshed out coerceInMemory a bit more, which
caused one of Snektron's test cases to fail, so I had to add
addrspace awareness to that. Once I did that the tests passed again.
In a previous commit (f4d3d29), syntax checking for code blocks with the
`syntax` type was disabled due to a change in astgen now checking the existence of
identifiers. The change in astgen caused some code samples in the language
reference to cause compilation errors.
This commit updates the code samples in the language reference and
re-enables syntax checking. Some code samples have been changed to unchecked
syntax blocks using `{#syntax_block#}` when suitable.
This edit allows the reader to understand the syntax this section is talking about more quickly – they don’t have to read the whole code block and understand which part of it demonstrates the feature being described.
Affects https://ziglang.org/documentation/master/#Inferred-Error-Sets
* langref: add some more "see also" links for atomics
* Add the following AIR instructions
- atomic_load
- atomic_store_unordered
- atomic_store_monotonic
- atomic_store_release
- atomic_store_seq_cst
- atomic_rmw
* Implement those AIR instructions in LLVM and C backends.
* AstGen: make the `ty` result locations for `@atomicRmw`, `@atomicLoad`,
and `@atomicStore` be `coerced_ty` to avoid unnecessary ZIR
instructions when Sema will be doing the coercions redundantly.
* Sema for `@atomicLoad` and `@atomicRmw` is done, however Sema for
`@atomicStore` is not yet implemented.
- comptime eval for `@atomicRmw` is not yet implemented.
* Sema: flesh out `coerceInMemoryAllowed` a little bit more. It can now
handle pointers.
The language reference's HTML has been updated to be more semantically correct.
This also helps to improve the document's accessibility concerns.
* Document structure has single h1, other header sections start at h2, nav sections w/ aria labels, main section
* Zig's homepage is linked, Zig Standard Library section link to it
* Tables have caption and scoping rows and columns
* Code blocks are figures with figure captions citing source files
* Change line height 1.5 to include table of contents as well
* Luminosity contrast ratios have been adjusted to 7:1
* Dark mode colors adjusted to reduce eye strain
* Links have default browser underline with hover and focus effects
* Asides, definition lists, keyboard inputs, program outputs are represented semantically
Tools used to check:
WAVE plugin https://wave.webaim.org/
Firefox Accessibility Developer Tool
Lighthouse Accessibility Tool
- adds 1 simple behavior tests for each
which does integer and vector ops at
runtime and comptime
- adds bigint_*_sat() methods for each
- use CreateIntrinsic() which accepts a
variable number of arguments to pass
the scale parameter
* update langref
- added case to test/compile_errors.zig given floats
- explain upstream bug in llvm.smul.fix.sat and link to #9643 in langref and commented out test cases
* sat-arithmetic: skip mul tests if arch == .wasm32 because ci is erroring with 'LLVM ERROR: Unable to expand fixed point multiplication' when compiling for wasm32
This is a backwards-compatible language change.
Previously, `@intToEnum` coerced its integer operand to the integer tag
type of the destination enum type, often requiring the callsite to
additionally wrap the operand in an `@intCast`. Now, the `@intCast` is
implicit, and any integer operand can be passed to `@intToEnum`.
The same as before, it is illegal behavior to pass any integer which does
not have a corresponding enum tag.
The async/await documentation was somewhat hard for me to follow when first learning. Two particular sticking points were
1. The alphabet example constructing the string "abcdefghi" breaks the stated rule that every async has a matching await.
2. It was somewhat unclear to me what the rules for control flow were around async/await constructs.
I've tried to improve this documentation with some minimal explanatory edits, which are correct to the best of my beginner's understanding & experimentation.
* Make clearer inline code blocks in language reference paragraphs
This commit makes the inline code blocks within paragraphs standout against the
descriptive text. The code blocks within tables are left un-styled.
The line-height of the paragraphs has been set to 1.7 based on recommendations
from MDN Web Docs and W3C. The value is unitless based on the recommendation.
Closes#9316, #6313
* Make clearer inline code blocks in language reference paragraphs
Goal: To improve legibility of inline code blocks in the language reference.
This commit alters the styles of code HTML elements in paragraphs, unordered
lists, ordered lists, tables, and preformatted text elements.
Most of the changes here are taken from suggestions from @dbandstra on GitHub
in response to a code review.
* p, ul, ol, but not #toc are set to the same line-height
* p, ul, ol, and table have the same inline code styles
* The inline code background color set to match the preformatted code blocks in
the light theme and dark theme. The border colors are adjusted as well.
* The preformatted code block font size is set to default. The 12pt setting was removed.
The line-height of paragraphs is set to 1.5. This value is chosen based on
recommendations from W3C [1] via MDN Web Docs [2] and the contents of the
language reference.
The MDN Web Docs offers two recommendations:
1. Use a unitless number for line-height.
2. Use a minimum value of 1.5 for main paragraph content.
[1] https://www.w3.org/TR/WCAG21/#visual-presentation
[2] https://developer.mozilla.org/en-US/docs/Web/CSS/line-heightCloses#6313, #9316
* Set language reference line-height and pre code border color
This commit is an update to a group of commits with the goal of improving the
legibility of the language reference. In this commit, the line-height is now set
in the `#contents` ID and reset to normal for preformatted code blocks. This
change better separates lines of all main content text for legibility.
Closes: #9316, #6313
* Style the language reference code elements
This commit sets the style of the HTML code element. Since preformatted code
blocks have an overriding style, this is safe to set for all inline code elements.
@select(
comptime T: type,
pred: std.meta.Vector(len, bool),
a: std.meta.Vector(len, T),
b: std.meta.Vector(len, T)
) std.meta.Vector(len, T)
Constructs a vector from a & b, based on the values in the predicate vector. For indices where the predicate value is true, the corresponding
element from the a vector is selected, and otherwise from b.
* Added doc comments for `std.Target.ObjectFormat` enum
* `std.Target.oFileExt` is removed because it is incorrect for Plan-9
targets. Instead, use `std.Target.ObjectFormat.fileExt` and pass a
CPU architecture.
* Added `Compilation.Directory.joinZ` for when a null byte is desired.
* Improvements to `Compilation.create` logic for computing `use_llvm`
and reporting errors in contradictory flags. `-femit-llvm-ir` and
`-femit-llvm-bc` will now imply `-fLLVM`.
* Fix compilation when passing `.bc` files on the command line.
* Improvements to the stage2 LLVM backend:
- cleaned up error messages and error reporting. Properly bubble up
some errors rather than dumping to stderr; others turn into panics.
- properly call ZigLLVMCreateTargetMachine and
ZigLLVMTargetMachineEmitToFile and implement calculation of the
respective parameters (cpu features, code model, abi name, lto,
tsan, etc).
- LLVM module verification only runs in debug builds of the compiler
- use LLVMDumpModule rather than printToString because in the case
that we incorrectly pass a null pointer to LLVM it may crash during
dumping the module and having it partially printed is helpful in
this case.
- support -femit-asm, -fno-emit-bin, -femit-llvm-ir, -femit-llvm-bc
- Support LLVM backend when used with Mach-O and WASM linkers.
c_void is *not* simply `const c_void = opaque{};`. It has unique
semantics as any pointer type may coerce to `*c_void` which is not true
for an arbitrary `*opaque{}`.
The "Zig Test" section of the language reference has been moved between the
current "Hello World" section and the "Comments" section. This was done to
introduce the Zig test syntax before it is used in later sections.
The description of the Zig test feature has NOT been updated in this commit.
Closes#5837
* Remove parser error on double ampersand
* Add failing test for double ampersand case
* Add error when encountering double ampersand in AstGen
"Bit and" operator should not make sense when one of its operands
is an address.
* Check that 2 ampersands are adjacent to each other in source string
* Remove cases of unused variables in tests
This is for consistency with the documentation on sentinel-terminated
{arrays,slices,pointers} which already use `N` for a comptime-inferred
size rather than `X`.
Also adds a behavioral test to assert that a string literal is returned.
This was already the case, but the documentation failed to point out
that the returned value is of type `*const [N:0]u8`, i.e. that of a
string literal.
Also adds a behavioral test to assert that this is the case.
The Zig language specification will support identifiers and field access
in order to refer to which declaration to export with `@export`.
This commit implements the change in AstGen and updates the language
reference.
I want the language reference to be divorced from any particular
community. Also remove the call to action since the docs are
known to be incomplete and are not the current focus of the project.
Closes#9055
- hash/eql functions moved into a Context object
- *Context functions pass an explicit context
- *Adapted functions pass specialized keys and contexts
- new getPtr() function returns a pointer to value
- remove functions renamed to fetchRemove
- new remove functions return bool
- removeAssertDiscard deleted, use assert(remove(...)) instead
- Keys and values are stored in separate arrays
- Entry is now {*K, *V}, the new KV is {K, V}
- BufSet/BufMap functions renamed to match other set/map types
- fixed iterating-while-modifying bug in src/link/C.zig
This matches the behaviour for other targets in that
```
zig build-lib math.zig -target wasm32-freestanding
```
produces now `libmath.a` while
```
zig build-lib math.zig -dynamic -target wasm32-freestanding
```
is required to create a loadable Wasm module.
This matches the behaviour of other languages and leaves us
the ability to create actual static Wasm archives with
```
zig build-lib -static some.zig
```
which can then be combined with other Wasm object files and linked
into either a Wasm lib or executable using `wasm-ld`.
Update langref to reflect the fact we now ship WASI libc.
Conflicts:
* doc/langref.html.in
* lib/std/enums.zig
* lib/std/fmt.zig
* lib/std/hash/auto_hash.zig
* lib/std/math.zig
* lib/std/mem.zig
* lib/std/meta.zig
* test/behavior/alignof.zig
* test/behavior/bitcast.zig
* test/behavior/bugs/1421.zig
* test/behavior/cast.zig
* test/behavior/ptrcast.zig
* test/behavior/type_info.zig
* test/behavior/vector.zig
Master branch added `try` to a bunch of testing function calls, and some
lines also had changed how to refer to the native architecture and other
`@import("builtin")` stuff.
Conflicts:
lib/std/crypto/25519/field.zig
lib/std/crypto/poly1305.zig
I had resolved those by removing `comptime` but master branch decided to
make the parameters `comptime`.
This also pulls in the updated default `zig build` install directory.
* docs: document the nosuspend keyword
* Specify that resuming from suspend is allowed in nosuspend
* Fix the description of the requirements of nosuspend
* Make use of nosuspend in some example code.
This is mainly motivated by the incorrect claim that "there would be
no way to collect the return value of amain, if it were something
other than void".
This makes a few changes to the base64 codecs.
* The padding character is optional. The common "URL-safe" variant, in
particular, is generally not used with padding. This is also the case for
password hashes, so having this will avoid code duplication with bcrypt,
scrypt and other functions.
* The URL-safe variant is added. Instead of having individual constants
for each parameter of each variant, we are now grouping these in a
struct. So, `standard_pad_char` just becomes `standard.pad_char`.
* Types are not `snake_case`'d any more. So, `standard_encoder` becomes
`standard.Encoder`, as it is a type.
* Creating a decoder with ignored characters required the alphabet and
padding. Now, `standard.decoderWithIgnore(<ignored chars>)` returns a
decoder with the standard parameters and the set of ignored chars.
* Whatever applies to `standard.*` obviously also works with `url_safe.*`
* the `calcSize()` interface was inconsistent, taking a length in the
encoder, and a slice in the encoder. Rename the variant that takes a
slice to `calcSizeForSlice()`.
* In the decoder with ignored characters, add `calcSizeUpperBound()`,
which is more useful than the one that takes a slice in order to size
a fixed buffer before we have the data.
* Return `error.InvalidCharacter` when the input actually contains
characters that are neither padding nor part of the alphabet. If we
hit a padding issue (which includes extra bits at the end),
consistently return `error.InvalidPadding`.
* Don't keep the `char_in_alphabet` array permanently in a decoder;
it is only required for sanity checks during initialization.
* Tests are unchanged, but now cover both the standard (padded) and
the url-safe (non-padded) variants.
* Add an error set, rename `OutputTooSmallError` to `NoSpaceLeft`
to match the `hex2bin` equivalent.
