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라이브러리 · std.decimal

Decimal.div

Divide at the requested decimal grid and return a recoverable zero divisor error.

div(other: Decimal, scale: int, mode: RoundingMode = RoundingMode.HalfEven()) -> Result<Decimal, string>

모듈: std.decimal →
수신자: Decimal
최소 인자 수: 2
최대 인자 수: 3

Declaration and parameters

사용 조건

기본 포함 · 미정

Import std.decimal in language mode 5.21.

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

수신자

Decimal

매개변수 제약

추가 계약은 미정입니다.

Decimal.div evaluates the exact quotient of its receiver and the divisor. For a nonzero divisor it rounds that quotient once to the requested decimal grid and returns Ok containing the normalized Decimal.

The requested scale and mode have the same meaning as in Decimal.round. Omitting the mode selects RoundingMode.HalfEven(). Input scales and coefficient sizes do not introduce another precision limit or an intermediate rounding step.

A nonterminating decimal quotient is rounded to the requested grid. A terminating quotient that is already on the grid remains exact. The canonical result scale can be smaller than the requested scale.

Division signs follow ordinary numeric division. All six rounding modes apply to the signed exact quotient, including negative ties and results that round to zero.

A zero divisor returns Err with the string Decimal.div: division by zero. This includes zero divided by zero and a divisor parsed from a negative zero spelling. This failure is a Result value and does not raise TPZ4002.

A zero dividend and a nonzero divisor return Ok containing zero for every valid requested scale. An internal sum of operand and requested scales must not turn a nonzero divisor into a division by zero error.

An invalid requested scale raises TPZ5001 during execution before the zero divisor is classified. The operation never replaces an invalid scale with zero or reports that scale error as a successful Result.

The receiver, divisor, scale and explicitly supplied mode expressions evaluate once in that order before their values are validated. The operation preserves both operands.

관련 규칙 · Divide with an explicit result scale →

결과

추가 계약은 미정입니다.

The declared result type is Result<Decimal, string>.

효과

미정

실패

미정

Result and effects

Round the exact quotient once with the supplied mode and normalize the result. The default mode is HalfEven. Invalid scales raise TPZ5001 during execution before zero divisor classification.

Why

An explicit result grid gives a nonterminating quotient a defined finite result while Result keeps a zero divisor recoverable.

Resolved contracts

std.decimal →

Divide with an explicit result scale

규칙topaz.stdlib.contract.decimal-division.rule

Divide with an explicit result scale

Decimal.div evaluates the exact quotient of its receiver and the divisor. For a nonzero divisor it rounds that quotient once to the requested decimal grid and returns Ok containing the normalized Decimal.

The requested scale and mode have the same meaning as in Decimal.round. Omitting the mode selects RoundingMode.HalfEven(). Input scales and coefficient sizes do not introduce another precision limit or an intermediate rounding step.

A nonterminating decimal quotient is rounded to the requested grid. A terminating quotient that is already on the grid remains exact. The canonical result scale can be smaller than the requested scale.

Division signs follow ordinary numeric division. All six rounding modes apply to the signed exact quotient, including negative ties and results that round to zero.

A zero divisor returns Err with the string Decimal.div: division by zero. This includes zero divided by zero and a divisor parsed from a negative zero spelling. This failure is a Result value and does not raise TPZ4002.

A zero dividend and a nonzero divisor return Ok containing zero for every valid requested scale. An internal sum of operand and requested scales must not turn a nonzero divisor into a division by zero error.

An invalid requested scale raises TPZ5001 during execution before the zero divisor is classified. The operation never replaces an invalid scale with zero or reports that scale error as a successful Result.

The receiver, divisor, scale and explicitly supplied mode expressions evaluate once in that order before their values are validated. The operation preserves both operands.

이유

A division result needs an explicit decimal grid because a finite pair of decimals can have a nonterminating quotient. Rounding the exact quotient once avoids hidden precision loss. A recoverable zero divisor stays distinct from invalid configuration and from internal scale arithmetic.

예제 Distinguish exact and repeating quotients at the requested grid →Apply every rounding mode to signed quotient ties →Return a recoverable error for every zero divisor →Keep a zero quotient at the largest valid scale →Evaluate the receiver and division arguments once in order →Reject an invalid scale before classifying a zero divisor →Reject an invalid scale before classifying a zero divisor →

진단 TPZ5001 →

Distinguish exact and repeating quotients at the requested grid

run · running · 검증 · 미실행

main.tpzDistinguish exact and repeating quotients at the requested grid플레이그라운드 열기 →

import std.decimal { Decimal }
import std.test
import std.io
function show(result: Result<Decimal, string>) -> () {
let value: Decimal = test.assertOk(result)
io.writeLine("{value.toString()} {value.scale()}")
}
let one: Decimal = (1).toDecimal()
let third: Result<Decimal, string> = one.div((3).toDecimal(), 6)
let eighth: Result<Decimal, string> = one.div((8).toDecimal(), 2)
let negativeTie: Result<Decimal, string> = (-1).toDecimal().div((8).toDecimal(), 2)
let exact: Result<Decimal, string> = (100).toDecimal().div((4).toDecimal(), 4)
let integerGrid: Result<Decimal, string> = (2).toDecimal().div((3).toDecimal(), 0)
show(third)
show(eighth)
show(negativeTie)
show(exact)
show(integerGrid)

기대 출력종료 코드 0

$ topaz run main.tpz · 대상 제품 5.21.3

기대 결과

기대 결과

실행을 마칩니다. 종료 코드 0.

표준 오류 출력 없음.

기대 표준 출력

0.333333 6
0.12 2
-0.12 2
25 0
1 0

이 예제는 아직 실행하지 않았습니다.

Apply every rounding mode to signed quotient ties

run · running · 검증 · 미실행

main.tpzApply every rounding mode to signed quotient ties플레이그라운드 열기 →

import std.decimal { Decimal, RoundingMode }
import std.test
import std.io
function read(text: string) -> Decimal {
let parsed: Option<Decimal> = Decimal.parse(text)
let value: Decimal = test.assertSome(parsed)
return value
}
function quotient(text: string, mode: RoundingMode) -> string {
let value: Decimal = read(text)
let result: Result<Decimal, string> = value.div((2).toDecimal(), 0, mode)
let rounded: Decimal = test.assertOk(result)
return rounded.toString()
}
let modes: Array<RoundingMode> = [RoundingMode.Down(), RoundingMode.Up(), RoundingMode.TowardZero(), RoundingMode.AwayFromZero(), RoundingMode.HalfUp(), RoundingMode.HalfEven()]
for mode in (modes) {
let a = quotient("5", mode)
let b = quotient("7", mode)
let c = quotient("-5", mode)
let d = quotient("-7", mode)
io.writeLine("{a} {b} {c} {d}")
}

기대 출력종료 코드 0

2 3 -3 -4
3 4 -2 -3
2 3 -2 -3
3 4 -3 -4
3 4 -3 -4
2 4 -2 -4

$ topaz run main.tpz · 대상 제품 5.21.3

기대 결과

기대 결과

실행을 마칩니다. 종료 코드 0.

표준 오류 출력 없음.

기대 표준 출력

2 3 -3 -4
3 4 -2 -3
2 3 -2 -3
3 4 -3 -4
3 4 -3 -4
2 4 -2 -4

이 예제는 아직 실행하지 않았습니다.

Return a recoverable error for every zero divisor

run · running · 검증 · 미실행

main.tpzReturn a recoverable error for every zero divisor플레이그라운드 열기 →

import std.decimal { Decimal }
import std.test
import std.io
function read(text: string) -> Decimal {
let parsed: Option<Decimal> = Decimal.parse(text)
let value: Decimal = test.assertSome(parsed)
return value
}
let divisor: Decimal = read("-0.000")
let numerators: Array<Decimal> = [(0).toDecimal(), (1).toDecimal()]
for numerator in (numerators) {
let result: Result<Decimal, string> = numerator.div(divisor, 2)
match (result) {
case Err(message) => io.writeLine(message)
case Ok(_) => io.writeLine("accepted")
}
}
io.writeLine(divisor.toString())

기대 출력종료 코드 0

Decimal.div: division by zero
Decimal.div: division by zero
0

$ topaz run main.tpz · 대상 제품 5.21.3

기대 결과

기대 결과

실행을 마칩니다. 종료 코드 0.

표준 오류 출력 없음.

기대 표준 출력

Decimal.div: division by zero
Decimal.div: division by zero
0

이 예제는 아직 실행하지 않았습니다.

Keep a zero quotient at the largest valid scale

run · running · 검증 · 미실행

main.tpzKeep a zero quotient at the largest valid scale플레이그라운드 열기 →

import std.decimal { Decimal }
import std.test
import std.io
function read(text: string) -> Decimal {
let parsed: Option<Decimal> = Decimal.parse(text)
let value: Decimal = test.assertSome(parsed)
return value
}
let divisor: Decimal = read("0.1")
let result: Result<Decimal, string> = (0).toDecimal().div(divisor, 4294967295)
match (result) {
case Ok(value) => io.writeLine(value.toString())
case Err(_) => io.writeLine("unexpected error")
}

기대 출력종료 코드 0

$ topaz run main.tpz · 대상 제품 5.21.3

기대 결과

기대 결과

실행을 마칩니다. 종료 코드 0.

표준 오류 출력 없음.

기대 표준 출력

0

이 예제는 아직 실행하지 않았습니다.

Evaluate the receiver and division arguments once in order

run · running · 검증 · 미실행

main.tpzEvaluate the receiver and division arguments once in order플레이그라운드 열기 →

import std.decimal { Decimal, RoundingMode }
import std.test
import std.io
function receiver() -> Decimal {
io.writeLine("receiver")
return (6).toDecimal()
}
function divisor() -> Decimal {
io.writeLine("divisor")
return (4).toDecimal()
}
function scale() -> int {
io.writeLine("scale")
return 1
}
function mode() -> RoundingMode {
io.writeLine("mode")
return RoundingMode.HalfEven()
}
let result: Result<Decimal, string> = receiver().div(divisor(), scale(), mode())
let value: Decimal = test.assertOk(result)
io.writeLine(value.toString())

기대 출력종료 코드 0

receiver
divisor
scale
mode
1.5

$ topaz run main.tpz · 대상 제품 5.21.3

기대 결과

기대 결과

실행을 마칩니다. 종료 코드 0.

표준 오류 출력 없음.

기대 표준 출력

receiver
divisor
scale
mode
1.5

이 예제는 아직 실행하지 않았습니다.

Reject an invalid scale before classifying a zero divisor

run · running · 검증 · 미실행

main.tpzReject an invalid scale before classifying a zero divisor플레이그라운드 열기 →

import std.decimal { Decimal }
import std.io
let value: Decimal = (1).toDecimal()
value.div((0).toDecimal(), -1)
io.writeLine("after")

기대 출력0이 아닌 종료 코드

표준 출력 없음.

$ topaz run main.tpz · 대상 제품 5.21.3

기대 결과

기대 결과

거절 단계 run. 종료 코드가 0이 아닙니다.

TPZ5001 →
stdlib-decimal-scale at main.tpz:4:1

표준 출력 없음.

이 예제는 아직 실행하지 않았습니다.

Reject an invalid scale before classifying a zero divisor

run · running · 검증 · 미실행

main.tpzReject an invalid scale before classifying a zero divisor플레이그라운드 열기 →

import std.decimal { Decimal }
import std.io
let value: Decimal = (1).toDecimal()
value.div((0).toDecimal(), 4294967296)
io.writeLine("after")

기대 출력0이 아닌 종료 코드

표준 출력 없음.

$ topaz run main.tpz · 대상 제품 5.21.3

기대 결과

기대 결과

거절 단계 run. 종료 코드가 0이 아닙니다.

TPZ5001 →
stdlib-decimal-scale at main.tpz:4:1

표준 출력 없음.

이 예제는 아직 실행하지 않았습니다.

Diagnostics

Runtime value guard →