std.parser.takeWhileAsciiWhitespace

takeWhileAsciiWhitespace(text: string, start: int) -> int

모듈: std.parser →
수신자: 해당 없음
최소 인자 수: 2
최대 인자 수: 2

Declaration and parameters

사용 조건

기본 포함 · 미정

Import std.parser in language mode 5.21.

The current compiler selects std/parser.tpz for this language mode. Availability in other released editions and inclusion in each installed distribution are Pending.

수신자

해당 없음

매개변수 제약

추가 계약은 미정입니다.

Each scan uses the class named by its corresponding ASCII predicate. The starting position and result follow the zero based scalar positions.

Clamp a negative start to zero. Clamp a start greater than the scalar length to that length. The first position examined is the clamped start.

Inspect consecutive positions from left to right. Stop at the first nonmatching scalar or at the scalar length. Return that exclusive end position.

If the first scalar does not match, return the clamped start. Starting at end of input returns that end. Every scan of an empty string returns zero.

A non ASCII scalar ends the span. Scanning does not skip it, normalize it, or advance across it to find a later match.

The text expression is evaluated before the start expression, once each. Scans do not modify the text or perform I/O. An out of range start produces a bounded result without a diagnostic.

For a clamped start begin and returned end, text.slice(begin, end) is the matched text. The scan reports a position rather than a character count.

관련 규칙 · Scan a maximal ASCII span →

결과

미정

효과

미정

실패

미정

Result and effects

링크

Clamp the start to the scalar bounds and return the exclusive end of the maximal matching ASCII span.

링크

std.parser →

Scan a maximal ASCII span

링크

규칙topaz.stdlib.contract.parser-ascii-spans.rule

Scan a maximal ASCII span

Each scan uses the class named by its corresponding ASCII predicate. The starting position and result follow the zero based scalar positions.

Clamp a negative start to zero. Clamp a start greater than the scalar length to that length. The first position examined is the clamped start.

Inspect consecutive positions from left to right. Stop at the first nonmatching scalar or at the scalar length. Return that exclusive end position.

If the first scalar does not match, return the clamped start. Starting at end of input returns that end. Every scan of an empty string returns zero.

A non ASCII scalar ends the span. Scanning does not skip it, normalize it, or advance across it to find a later match.

The text expression is evaluated before the start expression, once each. Scans do not modify the text or perform I/O. An out of range start produces a bounded result without a diagnostic.

For a clamped start begin and returned end, text.slice(begin, end) is the matched text. The scan reports a position rather than a character count.

이유

Maximal spans let callers resume at the first unconsumed scalar. Clamping uses the same bounds as string slicing and gives empty input a useful result.

예제 Find the exclusive end for every ASCII class →Stop at non ASCII scalars without changing position units →Clamp starts and keep the first failing position →

Find the exclusive end for every ASCII class

링크

run · running · 검증 · 미실행

main.tpzFind the exclusive end for every ASCII class플레이그라운드 열기 →

import std.parser
import std.io
let digit = parser.takeWhileAsciiDigit("123x", 0)
let alpha = parser.takeWhileAsciiAlpha("abZ9", 0)
let alnum = parser.takeWhileAsciiAlnum("a9Z_", 0)
let space = parser.takeWhileAsciiWhitespace("\t\n\r x", 0)
io.writeLine("{digit}/{alpha}/{alnum}/{space}")

기대 출력종료 코드 0

3/3/3/4

$ topaz run main.tpz · 대상 제품 5.21.3

기대 결과

실행을 마칩니다. 종료 코드 0.

표준 오류 출력 없음.

기대 표준 출력

3/3/3/4

이 예제는 아직 실행하지 않았습니다.

Stop at non ASCII scalars without changing position units

링크

run · running · 검증 · 미실행

main.tpzStop at non ASCII scalars without changing position units플레이그라운드 열기 →

import std.parser
import std.io
let digit = parser.takeWhileAsciiDigit("é12x", 1)
let combining = parser.takeWhileAsciiAlpha("éA", 0)
let suffix = parser.takeWhileAsciiAlpha("éA", 2)
let nonbreaking = parser.takeWhileAsciiWhitespace(" ", 0)
let alnum = parser.takeWhileAsciiAlnum("Aé", 0)
io.writeLine("{digit}/{combining}/{suffix}/{nonbreaking}/{alnum}")

기대 출력종료 코드 0

3/1/3/0/1

$ topaz run main.tpz · 대상 제품 5.21.3

기대 결과

실행을 마칩니다. 종료 코드 0.

표준 오류 출력 없음.

기대 표준 출력

3/1/3/0/1

이 예제는 아직 실행하지 않았습니다.

Clamp starts and keep the first failing position

링크

run · running · 검증 · 미실행

main.tpzClamp starts and keep the first failing position플레이그라운드 열기 →

import std.parser
import std.io
let text = "12"
for start in ([-3, 0, 1, 2, 99]) {
let digit = parser.takeWhileAsciiDigit(text, start)
let alpha = parser.takeWhileAsciiAlpha(text, start)
let alnum = parser.takeWhileAsciiAlnum(text, start)
let space = parser.takeWhileAsciiWhitespace(text, start)
io.writeLine("{digit}/{alpha}/{alnum}/{space}")
}
let empty = ""
let digit = parser.takeWhileAsciiDigit(empty, 99)
let alpha = parser.takeWhileAsciiAlpha(empty, -1)
let alnum = parser.takeWhileAsciiAlnum(empty, 0)
let space = parser.takeWhileAsciiWhitespace(empty, 1)
io.writeLine("{digit}/{alpha}/{alnum}/{space}")

기대 출력종료 코드 0

2/0/2/0
2/0/2/0
2/1/2/1
2/2/2/2
2/2/2/2
0/0/0/0

$ topaz run main.tpz · 대상 제품 5.21.3

기대 결과

실행을 마칩니다. 종료 코드 0.

표준 오류 출력 없음.

기대 표준 출력

2/0/2/0
2/0/2/0
2/1/2/1
2/2/2/2
2/2/2/2
0/0/0/0

이 예제는 아직 실행하지 않았습니다.

문서 검색

std.parser.takeWhileAsciiWhitespace

Declaration and parameters

사용 조건

수신자

매개변수 제약

결과

효과

실패

Result and effects

Scan a maximal ASCII span

Scan a maximal ASCII span

이유

Find the exclusive end for every ASCII class

기대 결과

Stop at non ASCII scalars without changing position units

기대 결과

Clamp starts and keep the first failing position

기대 결과

메뉴

Declaration and parameters

사용 조건

수신자

매개변수 제약

결과

효과

실패

Result and effects

Related entries

Scan a maximal ASCII span

Scan a maximal ASCII span

이유

Find the exclusive end for every ASCII class

기대 결과

Stop at non ASCII scalars without changing position units

기대 결과

Clamp starts and keep the first failing position

기대 결과