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Loader

blue_lang_runtime::uses

Trait Loader 

Source 
pub trait Loader {
    // Required method
    fn load(&self, name: &str) -> Result<Vec<(String, String)>, String>;

    // Provided methods
    fn entry_package(&self, _path: &Path) -> Option<String> { ... }
    fn needs(
        &self,
        _package: &str,
        _entry_dir: Option<&Path>,
    ) -> Option<BTreeSet<String>> { ... }
    fn version(
        &self,
        _package: &str,
        _entry_dir: Option<&Path>,
    ) -> Option<String> { ... }
    fn parse(&self, src: &str) -> Result<Vec<Spanned>, ParseError> { ... }
    fn available(&self) -> Vec<String> { ... }
    fn frontend(&self, _entry: &Path) -> Option<Frontend> { ... }
}
Expand description

Supplies the source of a named bidama.

One method, because resolution needs exactly one thing: given a name, the blue source that name refers to. Where it came from — a working tree, a nix store path, a git object, memory — is the implementation’s business and deliberately invisible here.

Required Methods§

Source

fn load(&self, name: &str) -> Result<Vec<(String, String)>, String>

The .b sources of name, as (label, source) pairs.

The label is for diagnostics only; nothing keys on it. A package with several files returns several pairs, and their relative order is the implementation’s to fix — FsLoader sorts by filename so a load is reproducible rather than directory-order-dependent.

Err is a human-readable reason the package could not be loaded. It must name what was looked for, because “package not found” without a name sends the reader grepping a distribution to find which one.

Provided Methods§

Source

fn entry_package(&self, _path: &Path) -> Option<String>

The bidama an ENTRY file at path belongs to, if it belongs to one: the package(name, …) of the Bluefile beside it. blue test bidamas/retsu/retsu.b checks and runs retsu’s own definitions, under retsu’s namespace, exactly as an importer sees them.

A file with no bidama around it (a script, spec/*.b) is in the root namespace, and so is every entry a loader without a filesystem is handed, which is this default.

Source

fn needs( &self, _package: &str, _entry_dir: Option<&Path>, ) -> Option<BTreeSet<String>>

The bidamas package’s Bluefile.lock records as needs (with no lock, its Bluefile’s rows), when the loader can read it. None when it cannot, and the check stage then has nothing to compare the package’s use forms against (B0019).

entry_dir is the directory of the entry file, for the entry’s own bidama, which a loader may not find under its roots.

Source

fn version(&self, _package: &str, _entry_dir: Option<&Path>) -> Option<String>

Bidama package’s Bluefile version, when the loader can read it — what a legacy_names window is measured against.

Source

fn parse(&self, src: &str) -> Result<Vec<Spanned>, ParseError>

The spanned tree of one source this loader handed out, or of the entry. Resolution parses through here, so a loader that has seen a text before (an editor’s session) can answer without parsing it again.

§Errors

The parser’s, unchanged.

Source

fn available(&self) -> Vec<String>

Every bidama this loader could load, by name, when it can enumerate them: what an editor offers behind a use the file does not have yet.

Source

fn frontend(&self, _entry: &Path) -> Option<Frontend>

Dyn Compatibility§

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors§