bcount

bcount(p: Parser, n: number, m?: string): Parser

Applies a parser a certain number of times, collecting the results into an array to return.

The parser p must succeed the full n times for bcount to succeed. Any fewer successes results in failure. Any input that is consumed in the process will be backtracked.

Example

const parser = bcount(letter(), 3)

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

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

const t = parse(parser, 'ab3')
console.log(status(t))  // "fail"
console.log(failure(t)) // Parse error at (line 1, column 1):
                        //
                        // ab3
                        // ^
                        // The parser backtracked after:
                        //
                        //   Parse error at (line 1, column 3):
                        //
                        //   ab3
                        //     ^
                        //   Expected a letter

Parameters

p: The parser to apply. Its results are returned in an array.
n: The number of times that p is applied.
m: The optional expected error message that will take the place of the default error message.

Success

Succeeds if p succeeds n times. The results are collected into an array and returned.

Failure

Fails if p fails before it has succeeded n times. If any input was consumed, backtracking will occur and an additional error message will be provided that details the circumstances of the backtracking.

Fatal Failure

Fails fatally if p fails fatally before it has succeeded n times.

Throws

Throws an error if p is not a parser.
Throws an error if n is not a number.
Throws an error if m exists and is not a string.