Struct VarEnv 

pub struct VarEnv { /* private fields */ }

Environment map used by expand.

Keys are stored case-sensitively in inner so iter-style consumers (and debug output) see the original casing pack authors wrote. Lookup via VarEnv::get is platform-aware:

• Unix/macOS — direct case-sensitive lookup.
• Windows — case-insensitive: a secondary lookup_index maps the ASCII-lowercased key to the original-cased key in inner. This mirrors OS behaviour where %Path% and %PATH% name the same var.

The double-map costs ~1 pointer per entry on Windows only. No new deps (UniCase et al. considered and rejected).

Implementations

impl VarEnv

pub fn new() -> Self

Construct an empty environment.

pub fn from_os() -> Self

Construct an environment snapshot from the current process.

Uses std::env::vars. On Windows, after collecting the snapshot a HOME → %USERPROFILE% fallback is materialised as a real entry when HOME is absent and USERPROFILE is present, so pack authors can write ${HOME} portably. The fallback is applied in from_os only — never in VarEnv::new or VarEnv::insert — so tests that build envs explicitly see only what they inserted.

pub fn from_map(map: HashMap<String, String>) -> Self

Build a VarEnv from an explicit map, applying the same Windows HOME→USERPROFILE fallback as VarEnv::from_os.

Exposed primarily for tests and advanced callers that construct a synthetic environment. On non-Windows targets this is a thin wrapper around the map; on Windows it populates lookup_index and the HOME fallback.

pub fn insert(&mut self, name: impl Into<String>, value: impl Into<String>)

Insert or overwrite a variable.

On Windows, also refreshes the case-insensitive lookup index so subsequent VarEnv::get calls match any casing of name.

pub fn get(&self, name: &str) -> Option<&str>

Look up a variable by name.

On Windows, an exact-case hit is tried first; on miss, the lookup falls back to an ASCII-lowercased match via the secondary index. On Unix/macOS the lookup is strictly case-sensitive.

Trait Implementations

impl Clone for VarEnv

fn clone(&self) -> VarEnv

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for VarEnv

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for VarEnv

fn default() -> VarEnv

Returns the “default value” for a type.