Line continuations and physical spans

ROUP accepts standard C/C++ line splices and Fortran directive continuations. It validates the complete logical directive before parsing and maps directive, clause, and nested-directive spans back to the original physical source.

C and C++

A C/C++ continuation is exactly a backslash immediately followed by LF or CRLF. No whitespace may occur between the backslash and the line ending. Translation removes exactly those characters and never invents a separator:

#pragma omp parallel for \
    schedule(dynamic, 4) \
    private(i, \
            j)

Source whitespace on either side of the splice remains significant. Therefore parallel\ followed immediately by for forms the single token parallelfor and is rejected; at least one actual source-space character is required to form parallel for.

A backslash followed by spaces, a bare CR, or an uncontinued physical newline with more directive text is a hard error.

Fortran free and fixed forms

Fortran continuations use a trailing &. A continuation line may repeat the sentinel for the configured dialect and may place & immediately after that sentinel. OpenMP accepts !$omp, OpenACC accepts !$acc, and both accept the standardized short !$ form, case insensitively; using one dialect’s long sentinel while parsing the other is a hard error. Only continuation syntax is removed, and any source whitespace needed to separate tokens must be present in the input.

!$omp target teams distribute &
!$omp& parallel do &
!$omp& private(i, j)

The corresponding OpenACC form uses !$acc on each line. Fixed-form input accepts the configured standard sentinel family, including !$OMP, C$OMP, and *$OMP, the matching ACC forms, and their short !$, C$, and *$ forms; leading horizontal whitespace is accepted before the sentinel. A comment may follow a valid trailing &. Missing markers, text after a purported marker, a conflicting-dialect sentinel, or another directive line reached through ordinary whitespace is an error.

Spans

Logical parsing does not discard the physical location map. For a token that crosses a C splice, its Span covers the complete physical slice, including the backslash and newline. Clause-name spans identify the exact source alias even when the semantic kind is canonicalized. Nested metadirective and construct selector directives use the same outer-source coordinate system.

See tests/openmp_line_continuations.rs, tests/openacc_line_continuations.rs, and tests/source_span_regressions.rs for executable examples.