The source positions and related helper functions
This API is completely unstable and subject to change.
Machinery for hygienic macros, inspired by the
An "interner" is a data structure that associates values with usize tags and allows bidirectional lookup; i.e. given a value, one can easily find the type, and vice versa.
A byte offset. Keep this small (currently 32-bits), as AST contains a lot of them.
A character offset. Because of multibyte utf8 characters, a byte offset is not equivalent to a character offset. The SourceMap will convert BytePos values to CharPos values as necessary.
A source code location used for error reporting
A source code location used as the result of lookup_char_pos_adj
Identifies an offset of a multi-byte character in a SourceFile
A collection of spans. Spans have two orthogonal attributes:
A single source in the SourceMap.
A compressed span.
Contains either fields of
Spans represent a region of code, used for error reporting. Positions in spans are absolute positions from the beginning of the source_map, not positions relative to SourceFiles. Methods on the SourceMap can be used to relate spans back to the original source. You must be careful if the span crosses more than one file - you will not be able to use many of the functions on spans in source_map and you cannot assume that the length of the span = hi - lo; there may be space in the BytePos range between files.
The state of the lazy external source loading mechanism of a SourceFile.
Differentiates between real files and common virtual files
Identifies an offset of a non-narrow character in a SourceFile
Dummy span, both position and length are zero, syntax context is zero as well. This span is kept inline and encoded with format 0.