typos/docs/about.md

About typos

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.

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.

Design Trade Offs

typos uses a blacklist

Blacklist: Known typos that map to their corresponding word

• Ignores unknown typos
• Ignores typos that follow c-escapes if they aren't handled correctly

Whitelist: A confidence rating is given for how close a word is to one in the whitelist

• Sensitive to false positives due to hex numbers and c-escapes
• Traditional spell checkers use a whitelist.

Related Spell Checkers

	typos	scspell3k	bloom42/misspell	client9/misspell
"Runtime"	Rust (#18)	Python	Rust	None
Dictionary	Blacklist	Whitelist	Blacklist	Blacklist
Custom Dict	No (#9)	Yes	No	?
Per-Lang Dict	No (#14)	Yes	No	?
CamelCase	Yes	Yes	No	?
snake_case	Yes	Yes	No	?
Ignore Hex	No (#19)	Yes	No	?
C-Escapes	No (#20)	Yes	No	?
Encodings	UTF-8 (#17)	Auto	UTF-8	?
API	Rust / JSON Lines	None	Rust	?
License	MIT	Apache	GPLv2	AGPL