Lake's Environment

Definitions related to a Lake environment. A Lake environment is computed on Lake's startup from user-specified CLI options and the process environment.

structure Lake.Env : Type

A Lake environment.

• lake : Lake.LakeInstall

  The Lake installation of the environment.

• lean : Lake.LeanInstall

  The Lean installation of the environment.

• elan? : Option Lake.ElanInstall

  The Elan installation (if any) of the environment.

• reservoirApiUrl : String

  The Reservoir API endpoint URL (e.g., https://reservoir.lean-lang.org/api).

• githashOverride : String

  Overrides the detected Lean's githash as the string Lake uses for Lean traces.

• pkgUrlMap : Lean.NameMap String

  A name-to-URL mapping of URL overrides for the named packages.

• noCache : Bool

  Whether to disable downloading build caches for packages. Set via LAKE_NO_CACHE. Can be overridden on a per-command basis with--try-cache.

• initToolchain : String

  The initial Elan toolchain of the environment (i.e., ELAN_TOOLCHAIN).

• initLeanPath : System.SearchPath

  The initial Lean library search path of the environment (i.e., LEAN_PATH).

• initLeanSrcPath : System.SearchPath

  The initial Lean source search path of the environment (i.e., LEAN_SRC_PATH).

• initSharedLibPath : System.SearchPath

  The initial shared library search path of the environment.

• initPath : System.SearchPath

  The initial binary search path of the environment (i.e., PATH).

instance Lake.instInhabitedEnv : Inhabited Lake.Env

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def Lake.Env.compute (lake : Lake.LakeInstall) (lean : Lake.LeanInstall) (elan? : Option Lake.ElanInstall) (noCache : Option Bool := none) : EIO String Lake.Env

Compute a Lake.Env object from the given installs and the set environment variables.

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def Lake.Env.compute.computePkgUrlMap : EIO String (Lean.NameMap String)

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@[macro_inline]

def Lake.Env.compute.getUrlD (var default : String) : EIO String String

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def Lake.Env.leanGithash (env : Lake.Env) : String

The string Lake uses to identify Lean in traces. Either the environment-specified LEAN_GITHASH or the detected Lean's githash.

The override allows one to replace the Lean version used by a library (e.g., Mathlib) without completely rebuilding it, which is useful for testing custom builds of Lean.

Equations

• env.leanGithash = if env.githashOverride.isEmpty = true then env.lean.githash else env.githashOverride

def Lake.Env.toolchain (env : Lake.Env) : String

The preferred toolchain of the environment. May be empty. Tries env.initToolchain first and then Lake's Lean.toolchain.

Equations

• env.toolchain = if env.initToolchain.isEmpty = true then Lean.toolchain else env.initToolchain

def Lake.Env.path (env : Lake.Env) : System.SearchPath

The binary search path of the environment (i.e., PATH). Combines the initial path of the environment with that of the Lake installation.

Equations

• env.path = if env.lake.binDir = env.lean.binDir then env.lean.binDir :: env.initPath else env.lake.binDir :: env.lean.binDir :: env.initPath

def Lake.Env.leanPath (env : Lake.Env) : System.SearchPath

The Lean library search path of the environment (i.e., LEAN_PATH). Combines the initial path of the environment with that of the Lake installation.

Equations

• env.leanPath = env.lake.libDir :: env.initLeanPath

def Lake.Env.leanSrcPath (env : Lake.Env) : System.SearchPath

The Lean source search path of the environment (i.e., LEAN_SRC_PATH). Combines the initial path of the environment with that of the Lake and Lean installations.

Equations

• env.leanSrcPath = env.lake.srcDir :: env.initLeanSrcPath

def Lake.Env.sharedLibPath (env : Lake.Env) : System.SearchPath

The shared library search path of the environment. Combines the initial path of the environment with that of the Lean installation.

Equations

• env.sharedLibPath = env.lean.sharedLibPath ++ env.initSharedLibPath

def Lake.Env.noToolchainVars : Array (String × Option String)

Unset toolchain-specific environment variables.

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def Lake.Env.baseVars (env : Lake.Env) : Array (String × Option String)

Environment variable settings that are not augmented by a Lake workspace.

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def Lake.Env.vars (env : Lake.Env) : Array (String × Option String)

Environment variable settings for the Lake.Env.

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def Lake.Env.leanSearchPath (env : Lake.Env) : System.SearchPath

The default search path the Lake executable uses when interpreting package configuration files.

In order to use the Lean stdlib (e.g., Init), the executable needs the search path to include the directory with the stdlib's .olean files (e.g., from <lean-sysroot>/lib/lean). In order to use Lake's modules as well, the search path also needs to include Lake's .olean files (e.g., from build).

While this can be done by having the user augment LEAN_PATH with the necessary directories, Lake also intelligently augments the initial search path with the .olean directories of the provided Lean and Lake installations.

See findInstall? for more information on how Lake determines those directories. If everything is configured as expected, the user will not need to augment LEAN_PATH. Otherwise, they will need to provide Lake with more information (either through LEAN_PATH or through other options).

Equations

• env.leanSearchPath = env.lake.libDir :: env.lean.leanLibDir :: env.leanPath