1.9.0

Nickel 1.9 includes various bug fixes and quality of life improvements.

Noteworthy additions are:

• let-blocks: declaring several variables at once instead of chaining
  let ... in ...
• explicit import: the ability to specify explicitly the format of an imported
  file (it was based on the file extension implicitly and would default
  to Nickel), e.g. as import "foo.txt" as 'Json or import "bar.ncl" as 'Text.
• the addition of a nickel test command that can extract snippets from the
  in-code documentation (the | doc metadata) together with their expected
  result and run them. The feature is detailed in a new CLI chapter of the user
  manual.

Two important future evolutions have been designed and discussed through RFCs:
package management and a performant bytecode virtual machine. Those features
aren't implemented yet, but the initial designs have been agreed upon.

Breaking changes

• Formatting: the formatting of let bindings has been fixed and improved. To
  avoid a large, irrelevant diff on your next commits, we advise formatting your
  whole codebase first after upgrading to 1.9 in a separate commit.

Core language

• Let blocks by @jneem (#2010,
  #2031,
  #2051)
• Fix unsound record contract deduplication by @yannham in #2042
• Explicit import format: import "sample.html" as 'Text by @vi
  (#2036,
  #2070)
• Thunks for resolved imports (detect import infinite loops and avoid work duplication) by @jneem in #2052
• Use a persistent vector to represent arrays instead of an Rc<[..]> by @jneem in #2057

Documentation

• Add a manual chapter for the cli. by @jneem in #2065
• [RFC006] Package management by @jneem in #1983
• [RFC007] Bytecode interpreter by @yannham in #2045

LSP

• Remove the option for an external formatter in nls by @jneem in #2064
• Fix completions in incomplete field name position. by @jneem in #2069
• Bound the length of nls completions by @jneem in #2073

Tooling

• Add --format argument to nickel query command by @suimong in #2015
• Adds a nickel test subcommand for testing examples in docs. by @jneem in #2020
• Detect infinite recursions in nickel doc by @yannham in #2055
• Strict typechecking mode by @jneem in #2077
• Switch to toml-edit for spanned deserialization fixing TOML deserialization bug by @jneem in #2074
• Make serde-wasm-bindgen optional in core by @akavel in #2089
• Move 'clap' crate dependency behind feature flag in core by @akavel in #2090

New Contributors

• @vi made their first contribution in #2036
• @epompeii made their first contribution in #2087
• @akavel made their first contribution in #2089

Full Changelog: 1.8.1...1.9.0