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80 lines
1.8 KiB
Go
80 lines
1.8 KiB
Go
// Copyright (c) 2023 IBM Corp.
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// All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package readerioeither
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import (
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"context"
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"io"
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"os"
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B "github.com/IBM/fp-go/bytes"
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F "github.com/IBM/fp-go/function"
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IO "github.com/IBM/fp-go/io"
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IOE "github.com/IBM/fp-go/ioeither"
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)
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var (
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openFile = F.Flow3(
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IOE.Eitherize1(os.Open),
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FromIOEither[*os.File],
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ChainFirstIOK(F.Flow2(
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(*os.File).Name,
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IO.Logf[string]("Opened file [%s]"),
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)),
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)
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)
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func closeFile(f *os.File) ReaderIOEither[string] {
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return F.Pipe1(
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TryCatch(func(_ context.Context) func() (string, error) {
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return func() (string, error) {
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return f.Name(), f.Close()
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}
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}),
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ChainFirstIOK(IO.Logf[string]("Closed file [%s]")),
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)
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}
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func ExampleWithResource() {
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stringReader := WithResource[string](openFile("data/file.txt"), closeFile)
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rdr := stringReader(func(f *os.File) ReaderIOEither[string] {
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return F.Pipe2(
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TryCatch(func(_ context.Context) func() ([]byte, error) {
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return func() ([]byte, error) {
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return io.ReadAll(f)
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}
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}),
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ChainFirstIOK(F.Flow2(
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B.Size,
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IO.Logf[int]("Read content of length [%d]"),
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)),
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Map(B.ToString),
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)
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})
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contentIOE := F.Pipe2(
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context.Background(),
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rdr,
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IOE.ChainFirstIOK[error](IO.Printf[string]("Content: %s")),
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)
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contentIOE()
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// Output: Content: Carsten
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}
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