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116 lines
4.2 KiB
Text
116 lines
4.2 KiB
Text
interface File
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exposes [ReadErr, WriteErr, writeUtf8, writeBytes, readUtf8, readBytes]
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imports [Effect, Task.{ Task }, InternalTask, InternalFile, Path.{ Path }, InternalPath]
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ReadErr a : [
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FileReadErr InternalFile.ReadErr
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]a
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WriteErr a : [
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FileWriteErr InternalFile.WriteErr
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]a
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## For example, suppose you have a [JSON](https://en.wikipedia.org/wiki/JSON)
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## [EncodingFormat] named `Json.toCompactUtf8`. Then you can use that format
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## to write some encodable data to a file as JSON, like so:
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##
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## File.write
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## (Path.fromStr "output.json")
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## { some: "json stuff" }
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## Json.toCompactUtf8
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## # Writes the following to the file `output.json`:
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## #
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## # {"some":"json stuff"}
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##
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## If writing to the file fails, for example because of a file permissions issue,
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## the task fails with [WriteErr].
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##
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## This opens the file first and closes it after writing to it.
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##
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## To write unformatted bytes to a file, you can use [File.writeBytes] instead.
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# write : Path, val, fmt -> Task {} (WriteErr *) [Write [File]*]*
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# | val has Encode.Encoding, fmt has Encode.EncoderFormatting
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# write = \path, val, fmt ->
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# Encode.toBytes val fmt
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# # TODO handle encoding errors here, once they exist
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# |> writeBytes
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## Write bytes to a file.
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##
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## # Writes the bytes 1, 2, 3 to the file `myfile.dat`.
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## File.writeBytes (Path.fromStr "myfile.dat") [1, 2, 3]
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##
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## This opens the file first and closes it after writing to it.
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##
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## To format data before writing it to a file, you can use [File.write] instead.
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writeBytes : Path, List U8 -> Task {} (WriteErr *) [Write [File]*]*
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writeBytes = \path, bytes ->
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InternalPath.toBytes path
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|> Effect.fileWriteBytes bytes
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|> InternalTask.fromEffect
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|> Task.mapFail FileWriteErr
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## Write a [Str] to a file, encoded as [UTF-8](https://en.wikipedia.org/wiki/UTF-8).
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##
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## # Writes "Hello!" encoded as UTF-8 to the file `myfile.txt`.
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## File.writeUtf8 (Path.fromStr "myfile.txt") "Hello!"
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##
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## This opens the file first and closes it after writing to it.
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##
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## To write unformatted bytes to a file, you can use [File.writeBytes] instead.
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writeUtf8 : Path, Str -> Task {} (WriteErr *) [Write [File]*]*
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writeUtf8 = \path, str ->
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InternalPath.toBytes path
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|> Effect.fileWriteUtf8 str
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|> InternalTask.fromEffect
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|> Task.mapFail FileWriteErr
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## Read all the bytes in a file.
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##
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## # Read all the bytes in `myfile.txt`.
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## File.readBytes (Path.fromStr "myfile.txt")
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##
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## This opens the file first and closes it after reading its contents.
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##
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## To read and decode data from a file, you can use [File.read] instead.
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readBytes : Path -> Task (List U8) (ReadErr *) [Read [File]*]*
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readBytes = \path ->
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InternalPath.toBytes path
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|> Effect.fileReadBytes
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|> InternalTask.fromEffect
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|> Task.mapFail FileReadErr
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## Read a [Str] from a file containing [UTF-8](https://en.wikipedia.org/wiki/UTF-8)-encoded text.
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##
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## # Reads UTF-8 encoded text into a `Str` from the file `myfile.txt`.
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## File.readUtf8 (Path.fromStr "myfile.txt")
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##
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## This opens the file first and closes it after writing to it.
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## The task will fail with `FileReadUtf8Err` if the given file contains invalid UTF-8.
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##
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## To read unformatted bytes from a file, you can use [File.readBytes] instead.
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readUtf8 : Path -> Task Str (ReadErr [FileReadUtf8Err _]*) [Read [File]*]*
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readUtf8 = \path ->
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effect = Effect.map (Effect.fileReadBytes (InternalPath.toBytes path)) \result ->
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when result is
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Ok bytes ->
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Str.fromUtf8 bytes
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|> Result.mapErr FileReadUtf8Err
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Err readErr -> Err (FileReadErr readErr)
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InternalTask.fromEffect effect
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# read : Path, fmt -> Task val (ReadErr [FileReadDecodeErr DecodeError]*) [Read [File]*]*
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# | val has Decode.Decoding, fmt has Decode.DecoderFormatting
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# read = \path ->
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# effect = Effect.after (Effect.fileReadBytes path) \result ->
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# when result is
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# Ok bytes ->
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# when Decode.fromBytes bytes fmt is
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# Ok val -> InternalTask.succeed val
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# Err decodingErr -> Err (FileReadDecodeErr decodingErr)
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# Err readErr -> Err (FileReadErr readErr)
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# InternalTask.fromEffect effect
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