Changes.md

Unreleased

• Make the unprocessed alert fatal by default (#1135)
• support -H for hidden include dirs in OCaml 5.2 (#1137)
• support [@mel.*] attributes in uncurried externals (#1140)
• add Worker types to melange.dom (#1147)
• Add support for dynamic import() (#1164)
• Fix code generation of custom true / false constructors (#1175)
• Fix code generation of OCaml objects that refers to an init variable in scope (#1183)
• Support [@mel.as "string"] in variant definitions (#884)
• BREAKING: remove [@@deriving jsConverter] for variant definitions (#884). Use [@mel.as "string here"] instead.
• Support OCaml 5.3 (#1168)
• Upgrade Stdlib to the OCaml 5.3 Stdlib (#1182)
• Support [@mel.tag "the_tag"] in variant definitions (#1189)
  • combined with [@mel.as ..] in variant definitions and inline record payloads, Melange can now express types for discriminated union object shapes.

4.0.1 2024-06-07

• Support -bin-annot-occurrences on OCaml 5.2 (#1132)

4.0.0 2024-05-15

• CLI: passing --eval to melc now works as expected (#1040)
• runtime: add some bindings to Js.Bigint (#1044)
• core: emit throw new Error(..) rather than throwing a JS object with the Melange exception payload (#1036)
• stdlib: fix runtime primitive for Float.{min,max} and related functions (#1050)
• core: emit let instead of var in compiled JS (#1019)
• core: in compiled JS, stop generating closures in loops that capture mutable variables (#1020)
• runtime: add bindings to Js.Set (#1047)
• runtime: add minimal bindings for JS iterators (#1060)
• core: in compiled JS, emit const for variables that Melange knows aren't going to be reassigned (#1019, #1059).
• runtime: add minimal bindings for JS iterators (#1060)
• core: handle missing .cmj when compiling dune virtual libraries (#1067, fixes #658)
• core: print lambda IR after TRMC pass when --drawlambda is passed (#1072)
• core: remove unnecessary internal code from melange-compiler-libs, slimming down the melange executable and speeding up the build (#1075)
• core: implement warning 51 in Melange (wrong-tailcall-expectation)
  • This warning had previously been disabled entirely in the typechecker version that Melange uses. It becomes more important with TRMC support added in Melange 2.1.0.
• core: accept esm{,-global} in addition to es6{,-global} for --mel-module-type; accept --mel-module-system in addition to --mel-module-type too (#1086).
• core: upgrade the OCaml type checker version to OCaml 5.2 (#1074)
• core: upgrade the Stdlib to match OCaml 5.2's (#1078)
• runtime: add bindings for functions in WeakMap and WeakSet (#1058)
• runtime: add bindings to Js.Map (#1101)
• core: fix a recursive module code generation bug when submodule names inside recursive modules are mangled (#1111)

3.0.0 2024-01-28

• BREAKING: remove Belt as a dependency of Stdlib (#796, #797)
  • Melange no longer includes the melange.belt library by default; after this release, you need to add (libraries melange.belt) to your melange stanzas.
• Melange Runtime / Stdlib: remove deprecated modules and functions (#817):
  • Js.List: use Stdlib.List or Belt.List instead;
  • Js.Null_undefined: use Js.Nullable instead;
  • Js.Option: use Stdlib.Option or Belt.Option instead;
  • Js.Result: use Stdlib.Result or Belt.Result instead;
  • Js.Cast.
• BREAKING:
  • remove support for @bs / @bs.* attributes; Melange users should now use [@u] for uncurried application and [@mel.*] as the prefix for the FFI attributes (#818)
  • remove [@@mel.val], which was redundant in the Melange FFI (#818)
• BREAKING(runtime): rename a few keys with legacy names (#819):
  1. Exception ID RE_EXN_ID to MEL_EXN_ID
  2. BS_PRIVATE_NESTED_SOME_NONE option marker to MEL_PRIVATE_NESTED_SOME_NONE
• BREAKING(runtime): unify pipe-first / pipe-last libraries in Js modules (#731, #893, #895, #899, #963, #964, #965)
  • Modules ending with 2 (e.g. Js.String2, Js.Array2, Js.TypedArray2) are no longer available in Melange
  • The functions in their corresponding modules now take labeled arguments and one positional argument, prioritizing the usage of |> but still allowing |. (-> in Reason) when optionally labeled arguments aren't omitted.
• BREAKING(runtime): remove deprecated functions from Js.* modules (#897)
• Consistently handle empty payloads in externals: (#852)
• Fix crash when pattern matching in the presence of complex constant inlining (#871)
• Support renaming modules in the output JS with @mel.as (#879)
• Support @mel.as in @mel.obj labelled arguments (#834)
• Fix error location for empty string interpolation in {j| .. |j} (#888, #890)
• Add Js.Obj.assign to merge 2 JS objects immutably (#900, #795)
• Turn off warning 20 (ignored-extra-argument) for %mel.raw application (#915)
• Deprecate non-namespaced FFI attributes such as @string or @obj in favor of e.g. @mel.string and @mel.obj (#923)
• Improve error messages returned by melange.ppx (#924, #928, #931, #936)
• Improve error messages in the Melange compiler core (#941)
• Fix a typo in Node.node_module (pa{r,}rent) #929
• BREAKING(runtime): Remove Js.null_undefined in favor of Js.nullable (#930)
• BREAKING(ppx): disallow attribute payload in [@mel.new] in favor of the external primitive string (#938)
• FFI: support @mel.new alongisde @mel.send / @mel.send.pipe (#906)
• Don't process [@mel.config] twice (#940)
• BREAKING(ppx): remove @mel.splice in favor of @mel.variadic (#943)
• Introduce an unprocessed alert to detect unprocessed Melange code, hinting users to preprocess with melange.ppx (#911, #945, #947)
• Implement more Stdlib functions in modules String, Bytes, Buffer, BytesLabels and StringLabels (#711, #956, #958, #961)
• BREAKING(runtime): Improve Js.Int and change some of its functions to pipe-last (#966)
• BREAKING(runtime): Improve Js.Date and change some of its functions to pipe-last (#967)
• BREAKING(runtime): Improve Js.Re and change some of its functions to pipe-last (#969, #989)
• BREAKING(runtime): Improve docstrings in the Node library and change some of its functions to pipe-last (#970)
• BREAKING(runtime): Improve Js.Float and change some of its functions to pipe-last (#968)
• BREAKING(runtime): Remove unnecessary unit argument from Js.Math.atan2 (#972)
• BREAKING(runtime): Add labeled arguments to the callbacks in Js.Global (#973)
• BREAKING(runtime): Add a label to Js.Dict.map's function argument pipe-last (#974)
• runtime(Js.String): deprecate anchor, link and substr functions to match the JS standard deprecations #982
• Fix error messages related to [@mel.meth] arity mismatches (PR)
• ppx: split [@@deriving abstract] into two (#987):
  • [@@deriving jsProperties] derives a JS object creation function that can generate a JS object with optional keys (when using [@mel.optiona])
  • [@@deriving getSet] derives getter / setter functions for the JS object derived by the underlying record.
• ppx: Deprecate [@@deriving abstract] (#979)
• BREAKING(dom): remove Dom.Storage2 in favor of Dom.Storage (988)
• playground: fix reporting of PPX alerts (#991)
• Move the unicode string transformation to the compiler core so that it runs after PPX preprocessing (#995, #1037)
  • PPXes will no longer see the internal *j delimiter in unicode strings and can hook on either j or js
• Preserve unicode in format strings (#1001)
• Support @mel.as in %mel.obj (#1004)
• Upgrade the Melange JS parser to Flow v0.225.1 (#1012)
• fix: add a newline after %mel.raw expressions to avoid breaking JS output when they contain single line comments (#1017)
• BREAKING(core): only allow strings in {j| ... |j} interpolation (#1024)

2.2.0 2023-12-05

• BREAKING(core): require OCaml 5.1.1 (#926)

2.1.0 2023-10-22

• Add TRMC (Tail Recursion Modulo Cons) support (#743)
• [playground]: Add melange.dom to bundle (#779)
• Fix Sys.argv runtime to match declared type (#791)
• Make 'a Js.t abstract (again), fixing a regression when bringing back OCaml-style objects BuckleScript (#786)
• Don't issue "unused attribute" warning for well-formed @@@mel.config in interface files (#800)
• Stop showing Js__.Js_internal in types and error messages (#798)
• Fix printing of OCaml-style objects and uncurried application (#807)

2.0.0 2023-09-13

• Build executables for bytecode-only platforms too (#596)
• Move the entire builtin PPX to melange.ppx. Preprocessing with melange.ppx will needed in most cases going forward, as it's responsible for processing external declarations, @deriving attributes and more, compared to the previous release where melange.ppx just processed AST extension nodes (#583)
• Remove old BuckleScript-style conditional compilation (#605)
• Don't emit JS import / require paths with foo/./bar.js (#598, #612)
• Wrap the melange runtime (#624, #637). After this change, Melange exposes fewer toplevel modules. Melange runtime / stdlib modules are now wrapped under:
  • Caml* / Curry modules are part of the runtime and keep being exposed as before
  • Js.* contains all the modules previously accessible via Js_*, e.g. Js_int -> Js.Int
  • Belt.* wraps all the Belt modules; Belt_List etc. are not exposed anymore, but rather nested under Belt, e.g. Belt.List
  • Node.*: we now ship a melange.node library that includes the modules containing Node.js bindings. After this change, users will have to depend on melange.node explicitly in order to use the Node.* modules
  • Dom.*: we now ship a melange.dom library that includes the modules containing Node.js bindings. This library is included by default so the Dom module will always be available in Melange projects.
• Disable warning 61 (unboxable-type-in-prim-decl) for externals generated by Melange (#641, #643)
• Add --rectypes (#644) to enable recursive types
• [melange.ppx]: Deprecate bs.* attributes in favor of mel.* (#566, #662, #663)
• [melange]: Fix field access code generation when openin inline functor applications (#661, #664)
• [melange]: Upgrade the OCaml typechecker version to 5.1 (#668)
• [melange.ppx]: Deprecate [@@mel.val] and suggest its removal. This attribute is redundant and unnecessary (#675, #678)
• [melange]: remove old, unused CLI flags: -bs-ns, -bs-cmi, -bs-cmj, -bs-no-builtin-ppx, -bs-super-errors (#686).
• [melange]: generate correct code for types with the option shape (#700).
• [melange]: stop exporting $$default in the generated JavaScript when using ES6 default exports let default = .. (#708).
• [melange]: allow exporting invalid OCaml identifiers in the resulting JavaScript with @mel.as (#714, fixes #713).
• [melange]: Allow using @mel.as in external declarations without explicitly annotating @mel.{string,int} (#722, fixes #578).
• [melange]: Allow using @mel.unwrap in external declarations with @mel.obj (#724, fixes #679).
• [melange]: Support renaming fields in inline records / record extensions with @mel.as (#732, fixes #730).

1.0.0 2023-05-31

• melange: print an error message if $MELANGELIB is set to a directory that doesn't exist (#449)
• melange: fix bug where --bs-module-name didn't always affect generated JS file casing (#446)
• melange: fix bug where -o output.js didn't always write a JavaScript file (#454)
• melange: remove the -bs-read-cmi flag in favor of the builtin -intf-suffix flag, standard in OCaml (#458, #460)
• melange: return an actionable error message when no output is specified with -impl / -intf (#465, #466)
• melange: use Object.prototype.hasOwnProperty in the Caml_obj runtime (#469)
• melange: transform NonEscapeCharacter correctly in JS strings (those written using {js|string here|js}) (#469)
• melange: define MELANGE conditional compilation variable (#472)
• melange: Make Pervasives exactly match the Stdlib behavior (#476)
• melange: fix unbound error when trying to use Printexc.exn_slot_id (#482)
• melange: fix codegen issue accessing a nested module path that is also included (#487)
• melange: preserve the correct command-line order for load path directories (#492)
• melange: respect the -nostdlib option; don't add stdlib / runtime to the load path in that case (#496)
• melange: build the Melange runtime / stdlib / runtime tests with the dune integration (#493). Thus melange now requires Dune 3.8.
• melange: allow shadowing sub-modules of Stdlib in user projects (#512)
• melange, reactjs-jsx-ppx: introduce a reactjs-jsx-ppx package, remove its dependency from melange (#517)
• melange: remove the --bs-jsx <version> flag from melc now that reactjs-jsx-ppx is a separate package (#525)
• melange: add melpp executable to preprocess #if conditionals with the melange parser (#539)
• mel: delete the mel package. The dune integration is now the only officially supported workflow for orchestrating melange builds (#546)
• melange: Extract melange.ppx from the melange package. This preprocessing step interprets extensions such as %bs.obj, %bs.raw and %bs.re, [@@deriving {abstract,accessors,jsConverters}] and external declarations. (#534)
• melange: allow installing melange in more OCaml versions and compiler switches. Melange now migrates binary AST to the version it understands (#548)
• melange: don't run anonymous args function from [@@@bs.config {flags = [| ... |]}] attributes (#554)
• melange: add --preamble flag to add a preamble to emitted JS. An example is "use client"; in React Server Components, which needs to appear before imports (#545, #574)
• melange: turn off warning 20 (ignore-extra-argument) by default. This warning is rarely useful in Melange due to false positives when invoking functions defined with %bs.raw (#488, #576)

0.3.2 2022-11-19

• ppx_rescript_compat (ReScript compatibility layer): fix conversion for cases such as foo["bar"] = assignment (#441):
  • These are now correctly converted to the OCaml equivalent: foo##bar #= assignment
• mel: fix merlin generation, broken since mel was moved to its own package (#442)

0.3.1 2022-11-16

• Disable warning 69 (unused-field in record) for the private record generated by the bs.deriving attribute (#414)
• Disable warning 20 (ignored-extra-argument) when applying foo##fn arg1 arg2 (#416):
  • in cases such as external x : < .. > Js.t = "", the typechecker doesn't know the arity of the function, even though Melange will emit an uncurried function call.
• Disable warning 61 (unboxable-type-in-prim-decl) in external declarations (#415):
  • Melange externals are substantially different from OCaml externals. This warning doesn't make sense in a JS runtime.
• melc: introduce --bs-module-name flag to specify the original file name for the current compilation unit (#413)
  • Dune's namespacing implementation generates modules such as lib__Original_name. Passing --bs-module-name original_name allows melange to issue correct import / require statements to the unmangled JS file names.

0.3.0 2022-11-06

• melange Introduce 2 explicit modes of JavaScript compilation:
  • "Batch compilation": produces .cmj and .js files at the same time (this is the previous behavior -- using --bs-package-output MODULE_SYSTEM:REL_PATH:JS_EXTENSION)
  • "Separate emission": produces only .cmj files with --bs-stop-after-cmj --bs-package-output REL_PATH_ONLY, and allows emitting JavaScript files separately, with --bs-module-type MODULE_SYSTEM -o TARGET_FILE.JS_EXTENSION (#384)
• mel: Fix mel build --watch exiting after the first change (#401)
• melange: Remove dependency on reason. Reason syntax users should install reason from their preferred package manager instead, and Melange / Dune will find it in $PATH (#409)
• melange: Remove dependency on napkin (the ReScript syntax parser). Users that depend on libraries written in ReScript syntax should install the mel package and Melange / Dune will find the rescript_syntax binary in $PATH (#411)

0.2.0 2022-10-24

• Initial release supporting OCaml 4.14.

0.1.0 2022-03-08

• Initial public release

This is the only release of Melange that supports OCaml 4.12.