Struct Scope 

pub struct Scope<'a> { /* private fields */ }

An evaluation scope: a data model plus the collection context bindings resolve against.

The root scope resolves relative paths from /. Entering a template item with Scope::item pushes the item’s pointer as the new base and records the iteration index for @index.

Implementations

impl<'a> Scope<'a>

pub fn root(data: &'a Value) -> Self

The root scope of a data model.

pub fn data(&self) -> &'a Value

The data model this scope reads from.

pub fn base(&self) -> &str

The absolute pointer this scope resolves relative paths against.

pub fn index(&self) -> Option<usize>

The iteration index, when this scope is a collection item.

pub fn item(&self, collection_path: &str, index: usize) -> Scope<'a>

Descends into element index of the collection at collection_path.

collection_path is itself resolved through this scope, so nested templates compose.

pub fn resolve_pointer(&self, path: &str) -> String

Turns an A2UI path (absolute or relative) into an absolute JSON Pointer.

The empty path and / both denote the whole data model.

pub fn resolve(&self, path: &str) -> Option<&'a Value>

Resolves a path to a value in the data model, or None if absent.

pub fn resolve_string(&self, path: &str) -> String

Resolves a path and stringifies the result.

pub fn resolve_dynamic(&self, value: &Value) -> Result<Value>

Resolves a DynamicValue: a literal, a {"path": ...} binding, or a {"call": ..., "args": ...} function call.

Objects and arrays are walked recursively so nested bindings inside an action context resolve too.

Errors

Returns Error::Binding if a formatString template is malformed or names a function this crate cannot evaluate.

pub fn resolve_dynamic_with( &self, value: &Value, functions: &dyn FunctionResolver, ) -> Result<Value>

Scope::resolve_dynamic with catalog functions supplied by the caller.

Errors

See Scope::resolve_dynamic.

pub fn format_string(&self, template: &str) -> Result<String>

Interpolates a formatString template against this scope.

Expressions are written ${...} and may contain an absolute path (${/user/name}), a relative path (${name}), a literal, a nested ${...}, or a function call (${@index(offset: 1)}). A literal ${ is written \${.

Errors

Returns Error::Binding for an unterminated expression, trailing characters after an expression, or a function this crate cannot evaluate.

pub fn format_string_with( &self, template: &str, functions: &dyn FunctionResolver, ) -> Result<String>

Scope::format_string with catalog functions supplied by the caller.

Errors

See Scope::format_string.

Trait Implementations

impl<'a> Clone for Scope<'a>

fn clone(&self) -> Scope<'a>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a> Debug for Scope<'a>

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

Formats the value using the given formatter.