Rust tutorial

Configure explicitly

Parser configuration fixes the directive dialect, specification policy, host language standard, and physical source form.

use roup::api::OpenMpConfig;
use roup::version::{CStandard, HostLanguageProfile, OpenMpVersion, SourceForm};

let current = OpenMpConfig::exact(
    OpenMpVersion::V6_0,
    HostLanguageProfile::C(CStandard::C23),
    SourceForm::Pragma,
)?
.parser();

let source = "#pragma omp master";
let historical = current.parse(source)?;
assert!(historical
    .compatible_versions()
    .contains(OpenMpVersion::V6_0));
assert_eq!(historical.directive().span().slice(source), Ok("master"));
Ok::<(), Box<dyn std::error::Error>>(())

Exact mode is cumulative: it rejects syntax introduced after the selected version, but accepts older standardized syntax even if the selected specification no longer documents that spelling.

Inspect typed data

use roup::api::OpenAccConfig;
use roup::ast::{AccClausePayload, AccDirectiveKind};
use roup::version::{CStandard, HostLanguageProfile, SourceForm};

let parser = OpenAccConfig::new(
    HostLanguageProfile::C(CStandard::C23),
    SourceForm::Pragma,
)?
.parser();
let parsed = parser.parse("#pragma acc parallel async(queue)")?;
let directive = parsed.directive();

assert_eq!(directive.kind(), AccDirectiveKind::Parallel);
assert!(matches!(
    directive.clauses()[0].payload(),
    AccClausePayload::Expression(_)
));
Ok::<(), Box<dyn std::error::Error>>(())

Expressions expose a typed host-language tree through Expression::ast(). Canonical formatting walks that tree; source text is retained only as backing for checked locations. Directive and clause span() values always refer to the original physical directive, including across line continuations.

Context supplied by a compiler

Plain parse performs syntax, version, and context-independent semantic validation. When a compiler can answer declaration, association, or constant-expression questions, use parse_with_facts. Applicable facts are mandatory in that mode; an omitted fact is a hard MissingSemanticFact or MissingContext diagnostic.

use roup::validation::{AssociationKind, SemanticFacts};

let facts = SemanticFacts::new()
    .with_association(AssociationKind::SectionRegion, true);
let parsed = current.parse_with_facts("#pragma omp section", &facts)?;
assert_eq!(parsed.directive().kind().as_str(), "section");
Ok::<(), Box<dyn std::error::Error>>(())

For a sequence of paired regions, use ContextValidator with each directive’s checked source span. Mismatched or unclosed regions are errors and include the related opening location.