Struct HostContext 

pub struct HostContext { /* private fields */ }

Host state for one file, shared with the functions installed on ctx.

Debug is hand-written: requiring it on BindingResolver would burden every language implementation for the sake of one derive here.

Implementations

impl HostContext

pub fn new(tree: Tree, source: String, file_path: &str) -> Self

Build a context over a parsed file.

pub fn with_resolver_from(self, language: &dyn Language) -> Self

Attach whatever resolver a language provides, if any.

pub fn with_today(self, today: &str) -> Self

Supply the date rules see as ctx.today.

Fixed for the run by the caller, not read here: two files checked a millisecond apart must not disagree about what day it is. Without one, ctx.today is absent rather than empty — a rule comparing against undefined would silently take a branch nobody intended, where a missing property is a TypeError naming what it reached for.

pub fn date_was_read(&self) -> bool

Whether anything read ctx.today while checking this file.

The caller needs this to decide whether the result may be cached across days.

pub fn with_language(self, language: Arc<dyn Language>) -> Self

Attach the grammar querySubtree and closestAncestor compile queries against.

Without one they are absent rather than present-and-failing. A rule reaching for them then gets a TypeError naming the function, which is the truthful answer — a stub returning nothing would look like a query that matched nothing.

pub fn with_resolver(self, resolver: Arc<dyn BindingResolver>) -> Self

Attach a binding resolver, enabling the import-resolution functions.

Without one, those functions return false or undefined rather than being absent. A rule written against a language that has no resolver then behaves as though nothing resolves, which is a truthful answer — where a missing function would be a TypeError blamed on the rule.

pub fn with_file_access(self, files: Rc<FileAccess>) -> Self

Allow tracked reads of other files in the project.

Without one, readFile and fileExists are absent rather than present-and-failing. A rule reaching for them then gets a TypeError naming the function, which is the truthful answer — where a stub returning undefined would look like an empty project and produce a rule that silently checks nothing.

pub fn arena(&self) -> &Rc<RefCell<NodeArena>>

The arena, for interning query captures before invoking a handler.

pub fn take_reports(&self) -> Vec<Report>

Take everything reported so far, leaving the context empty.

pub fn take_facts(&self) -> Vec<EmittedFact>

Take everything emitted so far, in emission order, leaving the context empty.

pub fn build<'js>(&self, ctx: &Ctx<'js>) -> Result<Object<'js>>

Build the ctx object.

Errors

Returns an engine error if a property cannot be defined, which would mean a broken build rather than anything about a rule.

Trait Implementations

impl Clone for HostContext

fn clone(&self) -> HostContext

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for HostContext

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

Formats the value using the given formatter.