# Revision history for zeolite-lang
## 0.12.0.0 -- 2020-12-11
### Language
* **[breaking]** Several more fixes for named returns:
* **[new]** Allows *initialization* of named returns in `if`/`elif`/`while`
predicates. Although *setting* a named return in a predicate has always been
allowed, it previously did not count as an initialization for the purposes
of checking usage in subsequent statements.
* **[breaking]** Fixes a bug where named returns used in `if`/`elif`/`while`
predicates inside of `cleanup` blocks were not getting checked for
initialization. This turns a potential runtime error into a compile-time
error, which could break buggy code that was never going to be executed.
* **[fix]** Fixes a bug where a named return with a primitive type was not
getting set in an explicit `return` statement. This only affected code that
used primitive named returns inside of a `cleanup` block where the
corresponding `in` block used an explicit `return` statement.
```text
@type call () -> (Int)
call () (x) {
cleanup {
\ foo(x) // x was not getting set for this call
} in return 1 // 1 was still returned from the function as expected
}
```
This *did not* affect non-primitive types such as `String` and user-defined
`concrete` and `interface` categories.
* **[breaking]** Updates associativity of infix operators:
* **[breaking]** Makes infix `Bool` operators `&&` and `||`
*right-associative*. For example, `x && y && z` used to be parsed as
`(x && y) && z`, whereas now it is parsed as `x && (y && z)`. This better
reflects the intuition of side-effects happening in order, with respect to
short-circuiting. (No other operators currently short-circuit.)
* **[breaking]** Makes comparison operators (e.g., `<=`) *non-associative*.
This means that expressions such as `x < y == true` will no longer compile.
This is because an equivalent-looking expression `true == x < y` might have
a different interpretation. (Note that order operators such as `<` *are not*
defined for `Bool`, so something like `x < y < z` would have already failed
previously.)
All other infix operators (including infix function calls such as
``x `Math.pow` y``) remain *left-associative*.
### Libraries
* **[new]** Adds `Math.abs` for `Int` absolute value to `lib/math`.
## 0.11.0.0 -- 2020-12-09
### Compiler CLI
* **[breaking]** Switches from [`parsec`][parsec] to [`megaparsec`][megaparsec]
for parsing, to allow for better structuring of compile-time error messages.
This should not affect syntax acceptance, but it has additional transitive
dependencies that might prevent installation of `zeolite`.
### Language
* **[breaking]** Several `cleanup` fixes:
* **[fix]** Fixes a bug in `cleanup` that caused the `scoped` block to be
prepended to it when it was inlined in the `in` block.
* **[fix]** Fixes a bug where `cleanup` might use an uninitialized named
return when inlined at a `break` or `continue` statement in a `while` loop.
Such situations will now cause a compilation error. Previously, this could
have allowed an uninitialized value to be passed around, which would only be
noticed with a `Function called on null value` failure at some point.
* **[fix]** Fixes inlining of `cleanup` blocks when `continue` is used inside
of the `in` block. Previously, `cleanup` was skipped when `continue` was
used inside of the respective `in` block.
* **[breaking]** Disallows explicit `break` and `continue` inside of `cleanup`
blocks. Previously this was allowed (but `return` wasn't), which led to
ambiguity when the `in` block contained a `return`.
* **[new]** Allows `cleanup` to refer to variables created at the top level of
the `in` block.
```text
cleanup {
\ foo(bar) // bar is created below
} in Type bar <- Type.create() // cleanup is inlined after this
```
## 0.10.0.0 -- 2020-12-05
### Language
* **[breaking]** Major changes to `.0rt` syntax:
* **[breaking]** Removes the expression argument from `success` and `crash`
`testcase` types. Use one or more `unittest` (see next point) instead.
* **[new]** Adds `unittest` keyword to allow the user to define multiple
tests within a single `success` `testcase`.
```text
testcase "simple tests" {
success
}
unittest checkInvariant1 {
// this is a regular procedure with no return
}
unittest checkInvariant2 {
// this is a regular procedure with no return
}
```
This allows multiple tests to use the same setup, while still being able to
track multiple test failures. `error` and `crash` `testcase` types are still
available.
* **[breaking]** Allows `testcase` to statically set `Argv` (see `lib/util`)
using the `args` keyword. By default, only the program name is set.
Previously, `Argv` used whatever was passed to the test binary.
```text
testcase "with static Argv" {
success
args "arg1" "arg2"
}
unittest test {
// something that requires Argv.global()
}
```
Note that this *isn't* a
library change; this also affects C++ extensions that use `Argv` from
`base/logging.hpp`.
* **[new]** Adds `compiles` mode for `testcase`. This is like `success` except
nothing is executed. (`success` requires at least one `unittest`, whereas
`compiles` will not execute anything even if `unittest` are present.)
### Libraries
* **[new]** Adds the `lib/testing` library with basic helpers for unit tests.
### Compiler CLI
* **[new]** Updates parsing of `.zeolite-module` to allow any ordering of the
fields. Previously, the fields needed to be in a very specific order.
* **[fix]** Adds compile-time protection against self-referential expression
macros defined in `expression_map:` in `.zeolite-module`. Previously, the
result was infinite recursion that could exhaust system resources.
* **[breaking]** Adds an error when `root`/`path` in `.zeolite-module` differs
from the location of the respective `.zeolite-module`. This is to catch both
typos (e.g., copy-and-paste errors) and ambiguities.
## 0.9.0.0 -- 2020-11-23
### Compiler CLI
* **[breaking]** Major changes to C++ extensions:
* **[breaking]** Corrects hole in `$ModuleOnly$` visibility in C++ extensions.
Previously, C++ extensions could directly access categories defined in
`$ModuleOnly$` sources in dependencies.
* **[breaking]** Randomizes cache paths and `namespace`s for generated C++
code so that C++ extensions cannot use static `#include` paths to circumvent
the visibility rules of a dependency.
* **[breaking]** Makes `TypeInstance`s shared in generated C++ and in C++
extensions, to allow for better memory management of `@type`s in the future.
* **[breaking]** Adds guards to C++ headers for `$TestsOnly$` categories, to
prevent them from being used in non-`$TestsOnly$` C++ extensions.
* **[fix]** Fixes regression where calling `zeolite` with `-p` would overwrite
an existing `.zeolite-module`.
### Language
* **[breaking]** Syntax changes:
* **[breaking]** Changes the syntax for calling `@category` functions from
`$$` to `:`, e.g., `Foo:create()` instead of `Foo$$create()`. A new error
message (to be removed later) will remind the user to stop using `$$`.
* **[breaking]** Changes the syntax for calling `@type` functions from `$`
to `.`, e.g., `Foo.create()` instead of `Foo$create()`. A new error message
(to be removed later) will remind the user to stop using `$`.
* **[breaking]** Changes to param usage:
* **[breaking]** Updates param inference to be more accurate. The new
algorithm will infer a param type iff the best choice is unambiguous given
the expected and actual function arguments.
* **[breaking]** Disallows bounding a single param both above and below, e.g.,
having both `#x requires Foo` and `#x allows Bar`. This is primarily to
prevent cycles and contradictions in the type system.
Previously, the *best case* for such restrictions was that there are
extremely few choices for `#x`, and the *worst case* was that it implies
`Bar` converts to `Foo` when it isn't true, thus making `#x` unusable.
Having either of those requirements likely indicates a design flaw.
* **[breaking]** Prohibits having a `$TestsOnly$` definition for a
non-`$TestsOnly$` category. Previously, a `concrete` category declared in a
non-`$TestsOnly$` `.0rp` could be `define`d in a `$TestsOnly$` `.0rx`, which
creates a loophole that allows binaries to utilize `$TestsOnly$` code.
* **[fix]** Fixes a latent type-checking bug that could occur when attempting to
assign a value with an intersection type to a variable with a union type, if
one or both types has another nested type, e.g., `[A&B]`→`[[A&B]|C]` or
`[[A|B]&C]`→`[A|B]`. This change *shouldn't* cause new type-checking failures.
### Libraries
* **[fix]** Implements `subSequence` for `Argv` in `lib/util`. This is required
by `ReadPosition` but was forgotten. Calling it prior to this would cause a
failure.
## 0.8.0.0 -- 2020-08-07
### Language
* **[breaking]** Makes the semantics of `cleanup` more consistent:
* **[breaking]** Disallows statements that modify `return` values within
`cleanup` blocks, i.e., `return` with values and assigning named returns.
* **[new]** Allows `cleanup` to access named returns that are initialized
within the corresponding `in` statement. Previously, access required
initialization *before* the `in` statement.
* **[new]** An explicit *positional* return (e.g., `return 1, 2`) will assign
the values to the respective named returns, if applicable. This will make
the actual return values available within `cleanup`.
```text
@type get () -> (Int)
get () (foo) { // foo is the name of the return variable
cleanup {
\ bar(foo) // foo has been initialized by the time this is called
} in return 1 // 1 is assigned to foo here
}
```
* **[fix]** Adds unwinding of `cleanup` blocks when used with `break` and
`continue`, respecting loop boundaries. Previously, `cleanup` was ignored.
* **[breaking]** Skips compilation of unreachable statements. The target
use-case is temporary changes to code that circumvent parts of a procedure,
e.g., an early `return` for the purposes of debugging.
* **[breaking]** Marks statements following `break` and `continue` as
unreachable.
### Compiler CLI
* **[behavior]** Adds a compiler warning for `public_deps` that are not required
by public `.0rp` sources within the same module, since they are potentially
just cluttering the public namespace of the module.
## 0.7.1.0 -- 2020-07-13
### Language
* **[new]** Adds the `$SourceContext$` macro, which inserts a `String` with
info about source file and code location.
* **[fix]** Adds context to error messages related to inherited functions that
have not been overridden.
## 0.7.0.2 -- 2020-05-21
### Language
* **[fix]** Improves the likelihood of successful type inference when unions,
intersections, or filters are combined with inheritance and type nesting.
## 0.7.0.1 -- 2020-05-20
### Language
* **[fix]** Fixes an edge-case where type-inference can be influenced by a
param filter for a param with the same name in the scope that is calling the
function. (For example, having `#x requires Foo` in scope while calling a
function that also happens to have a param named `#x`.)
* **[fix]** Fixes an edge-case where parameter substitution at the type level
can clash with a type parameter scoped to a function. (Related to the above,
but actually a separate issue discovered while solving the former.)
* **[behavior]** Shows inferred-type assignments in error messages related to
expressions containing inferred types.
## 0.7.0.0 -- 2020-05-19
### Language
* **[new]** Adds limited inference of type parameters in function calls. The new
syntax is `call<?,Int>(foo,bar)`, where `?` designates that inference is
requested for the first position.
* **[behavior]** Reduces the memory cost of `$TraceCreation$` by avoiding
storing the entire trace text.
### Compiler CLI
* **[behavior]** Improves handling of I/O errors when calling `zeolite`, and
allows compilation to continue in `-r`/`-R` modes if compilation of one module
fails.
## 0.6.0.0 -- 2020-05-14
### Compiler CLI
* **[behavior]** Improves error messages for type mismatches and return-count
mismatches.
* **[behavior]** Improves the efficiency of loading metadata for dependencies.
* **[breaking]** Fixes module-staleness check when running tests (`-t`).
* **[breaking]** Prevents binaries from being created from main categories that
are defined in `$TestsOnly$` sources. (This was the original intention, but it
was missed the first time around.)
### Language
* **[new]** Allows `@category` members in `concrete` categories to refer to each
other during initialization.
* **[new]** Adds the `$ExprLookup[`*`MACRO_NAME`*`]$` pragma, which allows the
user to define expression substitutions in `.zeolite-module`.
* **[new]** Adds the `$NoTrace$` pragma, which skips generating stack-trace
information for specific functions. This is useful for deeply-recursive
functions whose full trace would not be useful.
* **[new]** Adds the `$TraceCreation$` pragma, which appends a trace for the
creation of a value when there is a crash in one of its functions. This is
useful when the crash stems from value initialization.
* **[fix]** Fixes parsing of the `'"'` `Char`-literal.
### Libraries
* **[new]** Adds the `ErrorOr<#x>` category to `lib/util`. This allows functions
to return either the expected type or an error message.
* **[new]** Adds the `Void` category to `lib/util`. This can be used to ignore
type parameters when a value still needs to be instantiated.
* **[new]** Adds the `readAll` function to `TextReader` (in `lib/util`) to
support reading an entire file at once.
* **[breaking]** Adds crashes when attempting to read `RawFileReader` or write
`RawFileWriter` if there is a preexisting file error.
## 0.5.0.0 -- 2020-05-12
* **[new]** Adds compiler support for pragmas, which will allow compiler
features that aren't a part of the language:
- **[new]** `$ModuleOnly$` pragma for `.0rp` files, which limits their
visibility to the modules that own them.
- **[new]** `$TestsOnly$` pragma for `.0rp` files, which limits their
visibility to `.0rt` files, and `.0rx` files that also use `$TestsOnly$`.
* **[new]** Adds support for global seach paths for dependencies via a
plain-text file at `$(zeolite --get-path)/global-paths`. This can be used to
set up a separate directory for general-use Zeolite modules.
* **[breaking]** Better handling of symbols from dependencies. This might break
code that inavertently relied on broken visibility. In particular, `..` in a
dependency path precludes it from resolving to a system module.
## 0.4.1.0 -- 2020-05-05
* **[new]** Adds a compiler mode (`--show-deps`) to display the symbolic
dependencies of a module.
* **[new]** Adds a compiler mode (`--fast`) to quickly compile a binary from a
single source file without needing to create a module.
* **[new]** Adds a compiler mode (`-R`) to recursively recompile modules.
* **[new]** Improves thread-safety of internal code so that thread support can
be safely added later. (Probably via a library.)
* **[new]** Adds the `Builder` interface to make `String` concatenation more
efficient.
* **[new]** Adds support for basic mathematical `Float` operations, such as
`sin`, `exp`, and `sqrt`.
* **[new]** Adds support for bitwise `Int` operations.
* **[fix]** Fixes broken `--templates` mode when builtin types are used.
## 0.4.0.0 -- 2020-05-05
* **[new]** Allows modules to specify custom linker flags and private include
paths in `.zeolite-module`. This lets categories written in C++ depend on
external libraries written in other languages.
* **[behavior]** Adds optimization of dependency inclusion for categories that
are defined in C++ sources. This should eliminate linking in object files that
are not needed by the binary.
* **[behavior]** Adds checks to prevent a module from defining a category that
was declared in another module.
* **[breaking]** Updates the `.zeolite-module` format to require associating
externally-defined categories with the source files that define them. This
allows finer-grained linking of binaries and tests.
## 0.3.0.0 -- 2020-05-03
* **[breaking]** Updates syntax for discarding all returns to use `\` instead of
`~`. This will allow `~` to be used for bitwise-not later on. (Not to mention
that `~` was kind of ugly in that context.)
* **[breaking]** Cleans up multiple-`return` syntax by removing `{}`. This
applies to *both* the `return` and the assignment.
## 0.2.0.0 -- 2020-05-03
* **[breaking]** Requires that `concrete` categories defined in `.cpp` files be
listed as `external` in `.zeolite-module`. This allows the compiler to ensure
that all categories have a definition, which helps avoid linker errors.
* **[breaking]** Gives `.zeolite-module` configs a proper file format.
* **[new]** Adds version checking to cached module data.
## 0.1.3.0 -- 2020-05-01
* **[new]** Adds support for more versions of GHC.
## 0.1.2.0 -- 2020-04-28
* **[fix]** Fixes a parser issue with empty `{}` blocks following `scoped`.
* **[behavior]** Updates `cleanup` procedures to allow setting named-return
values. Previously, initializing a named return in `cleanup` was not
sufficient.
* **[behavior]** Updates `zeolite-setup` to unconditionally rebuild supporting
libraries. Incidentally, this causes all existing user modules to be out of
date.
## 0.1.1.0 -- 2020-04-27
* **[behavior]** Set the default output path for binaries to the module's path
rather than the current directory.
* **[new]** Allows a base path (`-p`) with recompile mode (`-r`).
## 0.1.0.0 -- 2020-04-27
* First version. Released on an unsuspecting world.
[megaparsec]: https://hackage.haskell.org/package/megaparsec
[parsec]: https://hackage.haskell.org/package/parsec