Build Metadata (BUILD_KIND, BUILD_MODE, BUILD_VERSION)

Silk exposes a small set of compiler-provided build metadata values to both runtime code and Formal Silk (compile-time verification) so programs can adapt to build configuration and so theories can express “this code is only valid in test builds”, “this feature requires a minimum version”, and similar policies.

Notes#

• build metadata is available to runtime code via std::runtime::build (runtime).
• build metadata is available as built-in compile-time constants: BUILD_KIND, BUILD_MODE, BUILD_VERSION.

Built-In Constants#

The compiler provides the following built-in constants in every module:

• BUILD_KIND: string
• BUILD_MODE: string
• BUILD_VERSION: string
• BUILD_VERSION_MAJOR: u64
• BUILD_VERSION_MINOR: u64
• BUILD_VERSION_PATCH: u64

These behave like normal const string values:

• They do not require an import.
• They may be used anywhere a string expression is allowed.
• They are compile-time constants (their values are fixed at compile time and are embedded into the output artifact).

BUILD_KIND#

The output kind currently being built:

• "executable"
• "object"
• "static"
• "shared"

BUILD_MODE#

The build mode currently being built:

• "debug"
• "release"
• "test"

Notes:

• "test" is the mode used by silk test.
• Debug stack traces and debug assertion behavior are controlled separately by std::runtime::build::is_debug() (see runtime).

BUILD_VERSION#

The semantic version of the current package when building from a manifest.

• When building from a package manifest (silk.toml), BUILD_VERSION is the manifest version.
• When not building from a manifest, BUILD_VERSION is "0.0.0".

BUILD_VERSION_MAJOR / BUILD_VERSION_MINOR / BUILD_VERSION_PATCH#

The SemVer core triplet (major.minor.patch) of BUILD_VERSION exposed as u64 values for convenient comparisons (especially in Formal Silk).

Rules:

• These parse the major.minor.patch prefix of BUILD_VERSION.
• Any trailing -prerelease or +build suffix is ignored.
• On parse failure, all three values default to 0.

Relationship to std::runtime::build#

The standard library provides std::runtime::build functions that return the same metadata:

• std::runtime::build::kind() -> string
• std::runtime::build::mode() -> string
• std::runtime::build::version() -> string

Use std::runtime::build when you prefer explicit namespacing or when writing code intended to run under alternate stdlib roots.

The same module also owns the reusable Formal Silk vocabulary for build metadata:

• std::runtime::build::build_kind_is(...)
• std::runtime::build::build_mode_is(...)
• std::runtime::build::{requires_debug_mode,requires_release_mode,requires_executable_kind,requires_object_kind,requires_static_kind,requires_shared_kind}
• std::runtime::build::build_version_at_least(...)

Examples#

Build-mode gated behavior#

fn main () -> int {
  if BUILD_MODE == "test" {
    // Test-only behavior.
    return 0;
  }
  return 0;
}

Version-gated behavior#

For semver parsing and comparison, use std::semver at runtime. For Formal Silk version gating against build metadata, reuse std::runtime::build::build_version_at_least(...).