mirror of
https://github.com/crate-ci/typos.git
synced 2024-11-22 17:11:07 -05:00
54 lines
2.3 KiB
Markdown
54 lines
2.3 KiB
Markdown
# Design
|
|
|
|
## Requirements
|
|
|
|
Spell checks source code:
|
|
- Requires special word-splitting logic to handle situations like hex (`0xDEADBEEF`), `c\nescapes`, `snake_case`, `CamelCase`, `SCREAMING_CASE`, and maybe `arrow-case`.
|
|
- Each programming language has its own quirks, like abbreviations, lack of word separator (`copysign`), etc
|
|
- Backwards compatibility might require keeping misspelled words.
|
|
- Case for proper nouns is irrelevant.
|
|
|
|
Checking for errors in a CI:
|
|
- No false-positives.
|
|
- On spelling errors, sets the exit code to fail the CI.
|
|
- Machine-independent, repo-specific configuration
|
|
- As compared to layered config with the users system or the command-line
|
|
|
|
Quick feedback and resolution for developer:
|
|
- Fix errors for the user.
|
|
- Integration into other programs, like editors:
|
|
- `fork`: easy to call into and provides a stable API, including output format
|
|
- linking: either in the language of choice or bindings can be made to language of choice.
|
|
|
|
## Trade Offs
|
|
|
|
### Corrections vs Dictionaries
|
|
|
|
Corrections: Known misspellings that map to their corresponding dictionary word
|
|
- Ignores unknown typos
|
|
- Ignores typos that follow c-escapes if they aren't handled correctly
|
|
- Good for unassisted automated correcting
|
|
- Fast, can quickly run across large code bases
|
|
|
|
Dictionary: A confidence rating is given for how close a word is to one in a dictionary
|
|
- Sensitive to false positives due to hex numbers and c-escapes
|
|
- Used in word processors and other traditional spell checking applications
|
|
- Good when there is a UI to let the user know and override any decisions
|
|
|
|
## Identifiers and Words
|
|
|
|
With a focus on spell checking source code, most text will be in the form of
|
|
identifiers that are made up of words conjoined via `snake_case`, `CamelCase`,
|
|
etc. A typo at the word level might not be a typo as part of
|
|
an identifier, so identifiers get checked and, if not in a dictionary, will
|
|
then be split into words to be checked.
|
|
|
|
Identifiers are defined using
|
|
[unicode's `XID_Continue`](https://www.unicode.org/reports/tr31/#Table_Lexical_Classes_for_Identifiers)
|
|
which includes `[a-zA-Z0-9_]`.
|
|
|
|
Words are split from identifiers on case changes as well as breaks in
|
|
`[a-zA-Z]` with a special case to handle acronyms. For example,
|
|
`First10HTMLTokens` would be split as `first`, `html`, `tokens`.
|
|
|
|
To see this in action, run `typos --identifiers` or `typos --words`.
|