letter

letter(m?: string): Parser

Parses an ASCII letter (a-z or A-Z).

This does not parse UTF-8 letters in general. Use uletter for that.

Example

const parser = letter()

const s = parse(parser, 'abc')
console.log(status(s))  // "ok"
console.log(success(s)) // "a"

const f = parse(parser, '123')
console.log(status(f))  // "fail"
console.log(failure(f)) // Parse error at (line 1, column 1):
                        //
                        // 123
                        // ^
                        // Expected a letter

Parameters

• m: The optional expected error message that will take the place of the default error message.

Success

• Succeeds if the next character is an ASCII letter (a-z or A-Z). Consumes and returns that character.

Failure

• Fails if the next character is any other character.

Throws

• Throws an error if m exists and is not a string.

See Also

• Parser
• alpha
• lower
• uletter
• upper