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a5c2c211a1
This allows a function to be inlined for totality checking purposes only. So, for example, (>>=) might be a function, but if it evaluates to something constructor guarded in some context, then it might still be productive.
58 lines
2.5 KiB
Markdown
58 lines
2.5 KiB
Markdown
Changes since Idris 2 v0.1.0
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----------------------------
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The implementation is now self-hosted. To initialise the build, either use
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the [bootstrapping version of Idris2](https://github.com/edwinb/Idris2-boot)
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or build from the generated Scheme, using `make bootstrap`.
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Language changes:
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* `total`, `covering` and `partial` flags on functions now have an effect.
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* Fields of records can be accessed (and updated) using the dot syntax,
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such as `r.field1.field2` or `record { field1.field2 = 42 }`.
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For details, see https://idris2.readthedocs.io/en/latest/reference/records.html
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* New function flag `%tcinline` which means that the function should be
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inlined for the purposes of totality checking (but otherwise not inlined).
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This can be used as a hint for totality checking, to make the checker look
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inside functions that it otherwise might not.
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* %transform directive, for declaring transformation rules on runtime
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expressions. Transformation rules are automatically added for top level
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implementations of interfaces.
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* A %spec flag on functions which allows arguments to be marked for partial
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evaluation, following the rules from "Scrapping Your Inefficient Engine"
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(ICFP 2010, Brady & Hammond)
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Library additions:
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* Additional file management operations in `base`
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* New module in `base` for time (`System.Clock`)
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* New modules in `contrib` for JSON (`Language.JSON.*`); random numbers
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(`System.Random`)
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Compiler updates:
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* Data types with a single constructor, with a single unerased arguments,
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are translated to just that argument, to save repeated packing and unpacking.
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(c.f. `newtype` in Haskell)
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+ A data type can opt out of this behaviour by specifying `noNewtype` in its
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options list. `noNewtype` allows code generators to apply special handling
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to the generated constructor/deconstructor, for a newtype-like data type,
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that would otherwise be optimised away.
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* 0-multiplicity constructor arguments are now properly erased, not just
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given a placeholder null value.
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Other improvements:
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* Various performance improvements in the typechecker:
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+ Noting which metavariables are blocking unification constraints, so that
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they only get retried if those metavariables make progress.
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+ Evaluating `fromInteger` at compile time.
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* Extend Idris2's literate mode to support reading Markdown and OrgMode files.
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For more details see: https://idris2.readthedocs.io/en/latest/reference/literate.html
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Changes since Idris 1
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---------------------
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Everything :). For full details, see:
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https://idris2.readthedocs.io/en/latest/updates/updates.html
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