Copyright	(C) 2026 Edward Kmett
License	UPL-1.0 AND BSD-3-Clause
Maintainer	Edward Kmett <ekmett@gmail.com>
Stability	experimental
Portability	GHC FFI; THC runtime services or native fallback implementation
Safe Haskell	Trustworthy
Language	Haskell2010

THC.Runtime

Description

Read-only runtime identity and permissions. The trusted boundary consists only of fixed, validated selectors; no raw foreign values escape this module.

Synopsis

data Available a
- = Available a
- | Unsupported
- | Disabled
- | Denied
- | Unavailable
data RuntimeKind
- = NativeGHC
- | TruffleHaskell
data Backend
- = NativeBackend
- | ASTBackend
- | BytecodeBackend
data RuntimeInfo = RuntimeInfo {
- runtimeKind :: Available RuntimeKind
- executingBackend :: Available Backend
- runtimeVersion :: Available String
- jvmVersion :: Available String
- jvmName :: Available String
}
data RuntimeCapabilities = RuntimeCapabilities {
- nativeAccessPermitted :: Available Bool
- threadCreationPermitted :: Available Bool
- cpuCapacity :: Available Int
}
runtimeInfo :: IO RuntimeInfo
runtimeCapabilities :: IO RuntimeCapabilities

Documentation

data Available a Source #

An absent metric is not zero. Queries never enable JVM-wide monitoring. fmap transforms a genuine value and preserves every non-value status:

>>> fmap (+ 1) (Available (41 :: Int))
Available 42
>>> fmap (+ 1) (Disabled :: Available Int)
Disabled
>>> map (fmap (+ 1)) [Unsupported, Disabled, Denied, Unavailable :: Available Int]
[Unsupported,Disabled,Denied,Unavailable]

Constructors

Available a	A genuine value; its scope is specified by the query.
Unsupported	The runtime or provider does not implement this service.
Disabled	Supported, but its instrumentation or sink is switched off.
Denied	The current context or host security policy forbids access.
Unavailable	Normally supported, but no value is currently available.

Instances

Instances details

Functor Available #
Instance details Defined in THC.Runtime.Types Methods fmap :: (a -> b) -> Available a -> Available b # (<$) :: a -> Available b -> Available a #
Eq a => Eq (Available a) #
Instance details Defined in THC.Runtime.Types Methods (==) :: Available a -> Available a -> Bool # (/=) :: Available a -> Available a -> Bool #
Ord a => Ord (Available a) #
Instance details Defined in THC.Runtime.Types Methods compare :: Available a -> Available a -> Ordering # (<) :: Available a -> Available a -> Bool # (<=) :: Available a -> Available a -> Bool # (>) :: Available a -> Available a -> Bool # (>=) :: Available a -> Available a -> Bool # max :: Available a -> Available a -> Available a # min :: Available a -> Available a -> Available a #
Show a => Show (Available a) #
Instance details Defined in THC.Runtime.Types Methods showsPrec :: Int -> Available a -> ShowS # show :: Available a -> String # showList :: [Available a] -> ShowS #

data RuntimeKind Source #

Runtime supplying the service ABI, independently of its selected backend.

Constructors

NativeGHC
TruffleHaskell

Instances

Instances details

Eq RuntimeKind #
Instance details Defined in THC.Runtime Methods (==) :: RuntimeKind -> RuntimeKind -> Bool # (/=) :: RuntimeKind -> RuntimeKind -> Bool #
Ord RuntimeKind #
Instance details Defined in THC.Runtime Methods compare :: RuntimeKind -> RuntimeKind -> Ordering # (<) :: RuntimeKind -> RuntimeKind -> Bool # (<=) :: RuntimeKind -> RuntimeKind -> Bool # (>) :: RuntimeKind -> RuntimeKind -> Bool # (>=) :: RuntimeKind -> RuntimeKind -> Bool # max :: RuntimeKind -> RuntimeKind -> RuntimeKind # min :: RuntimeKind -> RuntimeKind -> RuntimeKind #
Show RuntimeKind #
Instance details Defined in THC.Runtime Methods showsPrec :: Int -> RuntimeKind -> ShowS # show :: RuntimeKind -> String # showList :: [RuntimeKind] -> ShowS #

data Backend Source #

Execution backend reported by the current runtime context.

Constructors

NativeBackend
ASTBackend
BytecodeBackend

Instances

Instances details

Eq Backend #
Instance details Defined in THC.Runtime Methods (==) :: Backend -> Backend -> Bool # (/=) :: Backend -> Backend -> Bool #
Ord Backend #
Instance details Defined in THC.Runtime Methods compare :: Backend -> Backend -> Ordering # (<) :: Backend -> Backend -> Bool # (<=) :: Backend -> Backend -> Bool # (>) :: Backend -> Backend -> Bool # (>=) :: Backend -> Backend -> Bool # max :: Backend -> Backend -> Backend # min :: Backend -> Backend -> Backend #
Show Backend #
Instance details Defined in THC.Runtime Methods showsPrec :: Int -> Backend -> ShowS # show :: Backend -> String # showList :: [Backend] -> ShowS #

data RuntimeInfo Source #

Version strings are informational, not feature-detection interfaces.

Constructors

RuntimeInfo
Fields runtimeKind :: Available RuntimeKind executingBackend :: Available Backend runtimeVersion :: Available String jvmVersion :: Available String jvmName :: Available String

Instances

Instances details

Eq RuntimeInfo #
Instance details Defined in THC.Runtime Methods (==) :: RuntimeInfo -> RuntimeInfo -> Bool # (/=) :: RuntimeInfo -> RuntimeInfo -> Bool #
Show RuntimeInfo #
Instance details Defined in THC.Runtime Methods showsPrec :: Int -> RuntimeInfo -> ShowS # show :: RuntimeInfo -> String # showList :: [RuntimeInfo] -> ShowS #

data RuntimeCapabilities Source #

Permissions are for the current THC context, not the entire JVM. CPU capacity is the context's initial eligible capacity, not a thread count.

Constructors

RuntimeCapabilities
Fields nativeAccessPermitted :: Available Bool threadCreationPermitted :: Available Bool cpuCapacity :: Available Int

Instances

Instances details

Eq RuntimeCapabilities #
Instance details Defined in THC.Runtime Methods (==) :: RuntimeCapabilities -> RuntimeCapabilities -> Bool # (/=) :: RuntimeCapabilities -> RuntimeCapabilities -> Bool #
Show RuntimeCapabilities #
Instance details Defined in THC.Runtime Methods showsPrec :: Int -> RuntimeCapabilities -> ShowS # show :: RuntimeCapabilities -> String # showList :: [RuntimeCapabilities] -> ShowS #

runtimeInfo :: IO RuntimeInfo Source #

Query runtime identity and informational version strings. Each field keeps its own Available status; native GHC has no JVM identity to report.

A client can inspect one field without assuming the others are available:

info <- runtimeInfo
case runtimeKind info of
  Available kind -> print kind
  status -> print status

runtimeCapabilities :: IO RuntimeCapabilities Source #

Query context permissions and initial CPU capacity without changing them. Permission to use a service is distinct from the service being available.