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Sifr does not support source compatibility with unpublished pre-v1 builds. Update old projects to the contracts on this page.

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Exact integers

Use int for arbitrary-precision integer values. Use an explicit fixed-width integer type only when a data boundary requires that representation. The former separate bigint spelling and its dedicated diagnostics are not supported.

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Standard library names

Use the names in the compiled public API. Important changes include:
  • Use math.fabs, math.pow, and the built-in min, max, and round.
  • Use random.randint, random.random, and random.uniform.
  • Use platform.system, platform.machine, platform.node, platform.release, platform.version, and platform.processor.
  • Use time.time, time.strftime, sys.argv, sys.exit, and the documented sifr.env names.
  • Use json.loads, json.dumps, tomllib.loads, fnmatch.filter, html.escape, and html.unescape.
  • Use calendar.isleap, calendar.weekday, calendar.monthrange, url.parse, and url.build.
  • Use first-class bytes methods and bytes-native hashing. Encode text before hashing it.
  • Use first-class set[T] operations. heapq and bisect now mutate their input collections.
Each operation has one public name. Private _sifr.* implementation names are not public imports.

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Method receivers

Receiver spelling is explicit: The compiler does not infer receiver mutability from the method body.

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Packages and source layout

Use one optional [source].root value. It defaults to src. The [source] table does not accept other fields. Do not use multiple source roots, manifest export lists, or Sifr manifest binary tables. Declare library exports in src/__init__.sifr. Put applications in src/main.sifr or src/bin/*.sifr. Package import resolution preserves unresolved, ambiguous, access-error, and fatal results. Tools must not collapse these results into an optional path.

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Installation layout

A managed standalone installation uses one relationship:
The preferred sysroot is $HOME/.sifr. Flat binary and receipt layouts are not managed installations.

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Diagnostics and verification

Import diagnostics use the current SIFR-IMPORT-* codes. Removed workspace codes and migration-only replacement messages are not emitted. Verification profiles use schema version 2 and structured result JSON. Passing end-to-end fixtures use Sifr assert statements for runtime expectations.

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Compiler service contracts

Compiler services receive a source provider or use a captured WorkspaceSession. Lower layers do not open disk-backed projects through paired convenience wrappers. Code generation uses structured Rust types. Unsupported source types produce a compiler diagnostic instead of a string-rendered Rust type fallback.

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Retained compatibility

External protocol and current product behavior remain supported. Examples include LSP UTF-16 defaults, Cargo metadata, DLPack capsules, supported IPC negotiation, cancellation cleanup, configuration defaults, locale fallback, supported external formats, and host portability. These retained contracts do not restore old Sifr syntax, names, schemas, or layouts.