Glossary

Terms specific to PWRS and the PowerShell vocabulary it relies on.

ABI. The C contract between a PWRS native library and Pwrs.Runtime: the HostVTable, the exports, the status codes and the block layouts. Version 1. See ABI Reference .

AssemblyLoadContext (ALC). The .NET mechanism Pwrs.Bootstrap uses on pwsh to load each module’s Pwrs.Runtime.dll and shell into its own context, so two modules built against different PWRS versions coexist in one session.

Binder. PowerShell’s parameter binder: the engine component that coerces command-line and pipeline values to the CLR types a cmdlet declares, applies validation attributes, and tracks which parameters were bound. PWRS declares types and attributes and lets the binder do the rest.

Block. The #[repr(C)] struct a cmdlet’s parameters, a copied class’s fields, or a proxy method’s arguments are packed into for one crossing; emitted on both sides by the generator.

Bootstrap. Pwrs.Bootstrap.dll, the small assembly with a fixed identity that the module’s .psm1 loads first, and the .psm1 itself.

cdylib. The Rust crate type a PWRS module builds as: a shared library with the PWRS exports.

Cmdlet. A PowerShell command implemented as a class deriving from PSCmdlet. In PWRS, a Rust struct with #[cmdlet] and an impl Cmdlet.

Copied class. A #[psclass] mode in which writing a value builds a generated CLR object with the field values copied out; the default.

Descriptor. The JSON a built library returns from pwrs_module_descriptor, describing every cmdlet, parameter, class, enum, completer and provider; the generator’s input.

Dirty word. The first u64 of a parameter block: a bit per parameter set when the generated setter ran since the previous phase. Non-zero means the native side binds.

Dynamic parameter. A parameter added at bind time based on the values already bound, through IDynamicParameters; in PWRS a #[dynamic_params] function.

Entry. One function pointer in the host vtable, implemented in Pwrs.Runtime, called from Rust.

Export. One extern "C" function a PWRS library provides, implemented in the pwrs runtime, called from Pwrs.Runtime.

Handle. PsHandle, the IntPtr of a GCHandle; how a managed object is referred to across the boundary. PsObject owns one.

Host. One of the two PowerShell editions a module runs in: PowerShell 7 (Core) from 7.4 on, or Windows PowerShell 5.1 on .NET Framework. The Core assembly is compiled against .NET 8’s reference pack and the System.Management.Automation 7.4 reference whichever pwsh builds it, so it references the same assemblies from every machine.

Hybrid C#. Hand-written .cs files under src/csharp/ compiled into the shell assembly beside the generated code; the cmdlets they declare are exported with the Rust ones.

Lifecycle hook. A fn() -> PsResult<()> marked #[on_import] or #[on_remove] and named in export_module!, run by the engine when the module is imported or removed through IModuleAssemblyInitializer and IModuleAssemblyCleanup on the generated shell. A removal unloads nothing, so the import hook runs on every import and the removal hook is where an import’s resources are released. See Attribute Reference .

MAML. The XML help format Get-Help reads for binary modules; PWRS generates it from doc comments.

Phase. One of begin, process, end, corresponding to BeginProcessing, ProcessRecord, EndProcessing.

Phase mask. The bits pwrs_cmdlet_create reports saying which phases a cmdlet type needs a native call for; learned once per type by observing the default begin and end bodies.

Pinned view. A managed primitive array pinned by a GCHandle and borrowed as a Rust slice; Pinned<'a, T>.

Pipeline thread. The thread running a cmdlet’s current phase, the only one on which the engine allows stream writes and session-state access. Pipeline<'ps> is the token that proves you are on it.

Provider. A PowerShell namespace provider (NavigationCmdletProvider); in PWRS a struct implementing the Provider trait with #[provider], one instance of it per drive.

Proxy class. A #[psclass] mode in which the Rust value stays in Rust and the generated CLR object reads fields, and runs #[psmethods] methods, through native calls until it is disposed.

PSObject class. A #[psclass] mode with no CLR type: a PSObject with a PSTypeName and note properties.

Runtime identifier (RID). win-x64, linux-x64, osx-arm64, freebsd-x64 and the like; the folder under runtimes/ that holds the native library for a platform.

Shell. The generated C# assembly <Module>.Shell.<stamp>.dll: the CLR types PowerShell reflects over. Logic-free. The stamp is a hash of the managed source it was compiled from, which is what lets a rebuilt surface take the cmdlets over in a live session.

Slot. A position in the vtable, or the representation of one value in a block (u8, i64, PsStr16, PsHandle, and so on).

Scale. The number of digits a System.Decimal carries after the point, 0 to 28, held in bits 16 to 23 of its flags word. Part of the value’s identity and not of its magnitude: 1.10 and 1.1 are equal and not identical, so PWRS carries the scale rather than normalizing it. A string cast does not agree across hosts; see Conversions Reference .

Terminating error. An error raised with ThrowTerminatingError, which ends the cmdlet; PsError::terminating() opts into it. The default Err is non-terminating (WriteError).

Toolchain. The fetched csc and the reference packages both compiles use, under ~/.pwrs/toolchain/, and their lock file.

Type tag. A u32 naming one of the CLR types PWRS knows, PS_TYPE_OBJECT (0) for anything else. array_element_tag answers for an array’s elements and decides whether a Vec<T> takes one pin or the element-by-element path; object_type_tag, behind PsObject::type_tag(), answers for a single object and is how a caller dispatches on a type it does not know at compile time without reading GetType().FullName.

Vtable. The HostVTable: the append-only table of entries the runtime hands a module at pwrs_module_init.