The source positions and related helper functions
This API is completely unstable and subject to change.
Machinery for hygienic macros, inspired by the MTWT paper.
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 CodeMap will convert BytePos values to CharPos values as necessary.
A single source in the CodeMap.
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 FileMap
A collection of spans. Spans have two orthogonal attributes:
Spans represent a region of code, used for error reporting. Positions in spans are absolute positions from the beginning of the codemap, not positions relative to FileMaps. Methods on the CodeMap 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 codemap and you cannot assume that the length of the span = hi - lo; there may be space in the BytePos range between files.