1.2.1

Fix the installation from crates.io via cargo install. This version is identical to 1.2.0 for any other installation method (Nix, cargo from source, etc.).

1.2.0

Version 1.2

Version 1.2 comes with several improvements on the LSP and other components of the Nickel tooling. The new customize mode of the CLI makes it possible to dynamically turn a configuration into a command-line interface, which you can interact with.

Several related long-standing issues and limitations when typechecking polymorphic functions are also finally fixed.

Core language

• Make the lexer accept scientific notation by @vkleen in #1456
• Improve polymorphism handling, bidirectional typechecking and fix unsound generalization by @yannham in #1372
• Error on serializing very large numbers by @vkleen in #1470
• Import YAML files containing multiple documents as arrays by @vkleen in #1497
• Normalize line endings in string literals during parsing (Windows compatiblity) by @vkleen in #1562
• Implement curried dot operator by @suimong in #1578
• Statically merge partial record definitions by @vkleen in #1599
• Disable recursive priorities by @yannham in #1600

Fixes

• Various fixes to the pretty-printer by @vkleen (#1411, #1412, #1410, #1417)
• Fix REPL panic on transitive imports by @Radvendii in #1474
• Fix contract application order in let bindings and annotations by @vkleen in #1544
• Fix cursor desyncing when using REPL by @deotimedev in #1546
• Fix handling of relative imports @jneem in #1489
• LSP Fix two issues with incomplete input by @jneem in #1550
• Fix incomplete check of record row constraints by @yannham in #1558
• Fix LSP regression on hovering by @yannham in #1583

Tooling

• Full vscode extension by @szlend and @yannham in (#1405, #1413, #1416)
• Invalidate importers in NLS (plus a couple other import-related issues) by @jneem in #1426
• Improve nickel query (and :query in the REPL) interface by @yannham in
  #1447
• Topiary integration (formatting) as nickel format by @vkleen in #1371
• LSP: various improvements to completion by @jneem (#1450, #1473)
• Improve doc extraction capabilities through nickel doc (evaluate terms before extracting documentation) by @vkleen in #1463
• LSP Fix persistent diagnostics by @jneem in #1478
• Restore --version for CLI, include git revision by @yannham in #1486
• Disable the colors when stdout isn't a tty by @thufschmitt in #1508
• Improve type variables name allocation when reporting type errors by @yannham in #1512
• LSP formatting without calling the topiary binary by @vkleen in #1526
• LSP Initial handling of incomplete input by @jneem in #1541
• LSP resolve imports for incomplete inputs also by @jneem in #1542
• Add multiline string support for VSCode autoclosing pairs by @deotimedev in #1553
• Display icon for nickel file in vscode explorer by @suimong in #1556
• New experimental customize mode CLI to interact with a configuration on the
  command line (see nickel help export) by @Radvendii and @yannham in
  #1475
• (LSP) Import completion by @deotimedev in #1561
• Get rid of uninformative generic notes for higher-order contract errors by @yannham in #1564
• Render hover documentation as Markdown in LSP by @deotimedev in #1559
• Exit with nonzero exit code on failure by @vkleen in #1576

Stdlib

• add std.contract.Sequence by @Radvendii in #1452

Documentation

• manual docs: fix mismatch between input command and its echo in the output by @foo-jin in #1421
• Add two examples: imports and foreach pattern by @mipmip in #1387
• Fix some leftover instances of the old enum syntax in the manual by @vkleen in #1548

New Contributors

• @szlend made their first contribution in #1405
• @foo-jin made their first contribution in #1421
• @nrhtr made their first contribution in #1454
• @deotimedev made their first contribution in #1547
• @suimong made their first contribution in #1556

Full Changelog: 1.1.1...1.2.0

1.1.1

This version mostly includes bugfixes and stdlib improvement since 1.0. 1.1.0 has been immediately followed by 1.1.1, because of a missing README issue on the new nickel-lang-cli crate published to crates.io. Because crates on crates.io are immutable, we had to bump the minor version.

IMPORTANT: The main crate nickel-lang has been split between nickel-lang-cli (the binary) and nickel-lang-core (the library). If you're using cargo to install Nickel, please uninstall the previous crate by running cargo uninstall nickel-lang, and from now one use cargo install nickel-lang-cli to install 1.1 and do further updates.

Stdlib

• Encode more pre-conditions of stdlib functions as additional contracts,
  replacing dynamic type errors with nice contract errors by @yannham in #1358
• ArraySliceFun incorrectly excluded the length of the array as the end index by @vkleen in #1396

Tooling

• Improve the pretty printing of terms in the CLI and within error messages @vkleen in #1262
• Fix LSP panic when importing JSON by @yannham in #1382
• Fix LSP hanging under certain conditions involving external imports by @yannham in #1390
• Better error message when contract makes certain rows illegal by @Radvendii in #1323
• Fix function params hovering in the LSP by @yannham in #1395
• Fix LSP infinite loop on hovering on external imports by @yannham in #1397

Fixes

• Fixes incorrect variable names in type mismatch errors by @vkleen in #1313
• Improve error messages for polymorphic tail parametricity violations by @matthew-healy in #1320
• Fix panic on duplicated top-level idents in record destructuring by @matthew-healy in #1324
• Prevent panic when parsing record type with field path by @matthew-healy in #1325
• Give a better error message when trying to query a non-record by @jneem in #1326
• Fix error position by @jneem in #1333
• Fix panic when interpolating fields in a record type by @jneem in #1332
• Fix type annotations not generating contracts by @yannham in #1379
• Fix typechecker looping by adding missing check for unifying equal type vars by @yannham in #1400
• Fix panic on function contract failure (position of arrow functions not set) by @yannham in #1407

1.0.0

Version 1.0

This is the 1.0 release! The syntax and the semantics of the core language have
been stabilized and shouldn't evolve as much in the future.

• The core semantics of the language have been reworked and stabilized, in
  particular (but not limited to) merging, types and contracts with the
  implementation of RFC005
• The stdlib has been augmented with many new functions
• Parts of the syntax and some builtin symobls (types, stdlib functions, and so
  on) have been improved and made consistent
• New features for the LSP, and in particular code completion

Breaking changes

• Various functions from the stdlib have been renamed for better discoverability,
  and the stdlib got a lot of new additions. Please refer to the documentation
  of the stdlib.
• String functions are now unicode-aware, and operate on the Unicode grapheme
  cluster abstraction instead of the character abstraction (string.length,
  string.is_match, etc.)
• The switch keyword has been replaced by match, and can now be used as a
  standalone function (doesn't need to be applied right away)
• The Num and Str builtin types have been renamed to Number and String by @yannham in #1164
• The num and str stdlib modules have been renamed to number and string
• The builtin.typeof function now returns 'Number, 'String, 'Function
  instead of respectively 'Num, 'Str, and 'Fun
• The builtin.is_num, builtin.is_str and builtin.to_str functions have been
  renamed to is_number, is_string and to_string
• The string.to_num and string.from_num functions have been renamed to
  to_number and from_number
• All the stdlib modules array, string, record, etc. have been put
  under a std namespace. They must now be accessed as std.array,
  std.string and so on.
• RFC005 was implemented, which changes the semantics of contract annotations
  and merging. See the RFC
  content
  for more details. Most notably, metadata annotation (default values,
  optional, documentation, etc.) can only appear next to a record field.
  Contract and type annotations can still appear anywhere. Documentation can
  still appear on let-bindings.
• Use static dictionary types for record.fields and record.values by @matthew-healy in #1024
• Make type annotations to not propagate through merging by @yannham in #1271
• Change to dictionary contracts and introduction of a separate dictionary contract (in addition to dictionary type):
  • Fix dictionary contract semantics by @vkleen in #1141
  • Introduce dictionary contracts by @yannham in #1272
• Stdlib string.Stringingable -> string.Stringable by @vkleen in #1180
• Fix the type of array.elem by @yannham in #1223
• Change the enum tag start delimiter from backtick to single-quote by @vkleen in #1279
• import is now a statement, import "foo.ncl" arg1 arg2 requires parenthesis now: (import "foo.ncl") arg1 arg2, see #1293

Language features

• Symbolic strings by @matthew-healy in #994
• [RFC005] Lazy propagation by @yannham in #1086
• Non-exported record fields by @vkleen in #1132
• Enrich label custom reporting data by @yannham in #1152
• Use type annotations in record patterns during typechecking by @matthew-healy in #1176
• Use arbitrary precision rationals as the underlying representation of numbers by @yannham in #1182
• Allow equal arrays to be merged in order to make merge idempotent by @yannham in #1229
• Use deterministic hashtables, making runtime errors and typechecking error deterministic by @yannham in #1235

Stdlib

• Add a %trace% primop (and std.trace function) by @vkleen in #1055
• Add std.contract.Equal contract to the stdlib by @yannham in #1203

Tooling

• Display meta information when providing completion in #966
• LSP completion for import terms by @ebresafegaga in #993
• Fix LSP server not giving completion when a non-contract meta-information is present in a declaration by @ebresafegaga in #991
• Fix LSP not giving completion when an identifier is prefixed by a delimiting character by @ebresafegaga in #1043
• Improve the "goto definition" feature of the LSP by making it work across multiple files by @ebresafegaga in #1029
• Add --color option to the CLI by @matthew-healy in #1033
• Make the "find references" feature of the LSP work across multiple files by @ebresafegaga in #1037
• Add support for LSP completion using the surrounding context by @ebresafegaga (context completion) in #1057
• Support completion for field names inside recursive records. by @ebresafegaga in #1088
• Improve contract violation error reporting by @ebresafegaga in #1139
• Add a JSON documentation export option by @vkleen in #1209
• Add support for formatting capabilities to the LSP by @ebresafegaga in #1216

0.3.1

Version 0.3.1 (2022-12-15)

Fixes

• Fix blame error when calling string.find by @euank in #988

0.3.0

Version 0.3 (2022-12-07)

Breaking changes

• Change switch to match and make it a proper function by @yannham in #970

Fixes

• Fix polymorphic contracts unduly changing semantics by @ebresafegaga in #802
• Fix typechecking and unification in presence of flat types (aka opaque types, aka contracts) by @yannham in #766
• Fix polarity for polymorphic contract failure by @ebresafegaga in #831
• Fix panic when a row mismatch occurs while unifying row tails by @matthew-healy in #847
• Fix type to term conversion causing unbound type variables errors by @francois-caddet in #854
• Fix bad lexing of enum tags by @matthew-healy in #874
• Fix multiple recursive overriding by @yannham in #940

Language features

• Optional fields by @yannham in #815
• Numeral merge priorities by @yannham in #829
• Recursive merge priorities (or push-priorities, or leafy priorities) by @yannham in #845

Stdlib

• Statically type string.join by @matthew-healy in #946

Tooling

• Add record completion in the LSP by @ebresafegaga in
  • #867
  • #909
  • #913
  • #914
• Add completion for Nickel's stdlib in the LSP by @ebresafegaga in #918

Performances

• Lazy array contracts by @fuzzypixelz in #809
• Array slices by @fuzzypixelz in #776
• String interning for identifiers by @Acaccia in #835

0.2.1

Remove printing statements in the LSP server that causes requests for information on hover to take an exceedingly long time.

0.2.0

Version 0.2 (2022-07-29)

Breaking changes

• Using a contract as part of a static type annotation will in most cases fail with an appropriate error message. This is a temporary limitation in order to fix previously unsound behavior in the typechecker. This restriction will likely be lifted in the upcoming 0.3.x release.
  For more details, see issues #701 and #724

Fixes

• Fix unnecessarily restricted record contract for record.update
• Fix wrong interpretation of long interpolation-like sequences %..%{ in strings
• Fix panic when evaluating a switch in specific cases
• Fix fields without definition being assigned to null, instead of just being marked as undefined

Language features

• Merging null values together gives null, and merging empty lists together gives an empty list, instead of failing with error: non mergeable terms
• Add recursive let-bindings (let rec)
• Add type wildcards. Use _ in place of a type to let the typechecker fill
  the gap. Example: let foo : _ = array.all ((==) 2) [1,2,3]
• Add builtin.to_str and string.from to convert generic values to a string
• Re-introduce an official syntax for enum types

Tooling

• Add the nickel pprint-ast command to pretty print a parsed program (mostly for debugging purpose)
• Add the nickel doc command to produce simple markdown documentation from the in-code doc metadata

Documentation

• Fix various typos and remove use of deprecated syntax in the user manual

0.1.0

Version 0.1 (2022-03-10)

First release! The main focus has been the design of the Nickel language itself.

Language features

• Gradual type system with row types, polymorphism and type inference
• Contract system for data validation
• Merge system for recursive records that supports one level of overriding
• Metadata annotations (default values, documentation, etc.)
• Unified syntax for terms, types and contracts (RFC002)
• Record destructuring

Tooling

• The main binary supports the following subcommands:

  • nickel query to show metadata and documentation of library functions,
    the field of a configuration, etc.
  • nickel export to serialize to JSON, YAML, or TOML
  • nickel repl to launch an REPL
  • nickel typecheck to do typechecking without evaluating

• An LSP-server is included

Documentation

• User manual sections on syntax, correctness (types and contracts), and
  merging
• The standard library has been documented in-code (use
  nickel query/:query to retrieve it)

Known limitations

• The roadmap for overriding and the merge system (RFC001) has not been
  implemented fully yet.

• Performance has not been prioritized.

• Due to the use of reference counting as a memory management strategy,
  mutually recursive record fields are currently leaking memory. This
  shouldn't be an issue in a standard workflow.

• Standard library APIs and language features are subject to change. There
  is no backward compatibility guarantees for this version. In general, this
  release is meant for experimenting and getting user feedback, but isn't
  intended to be used in production.