Text.Writer

Writing text to a byte writer through an encoding.

A text writer encodes each string it is given, as a whole, before emitting any of it, so a string with an unrepresentable character emits nothing; earlier writes stay written. The scopes flush when their callback returns, including when it returns an Err value, but not when it aborts. The byte writer’s own buffering still decides when bytes reach its sink.

Writer

type Writer eSource

A text writer whose operations perform e.

borrow

borrow : Writer e -> (Writer {#s} ->{#s} a) ->{e} aSource

over for a nested encoder that leaves the flush boundary to its caller: it performs no final flush, though flush still reaches the parent.

collecting

collecting : (Writer {#s} ->{#s} a) ->{e} (a, String)Source

Runs action with a text writer that keeps everything written in memory, and answers the result with that text. Its flush does nothing. With no other effects in the callback, the call is pure.

import Text.Writer

written =
    Text.Writer.collecting { writer ->
        Text.Writer.write writer "ab"
        Text.Writer.writeChar writer 'c'
    }

written == ((), "abc")

flush

flush : Writer e ->{e} ()Source

Flushes the underlying byte writer.

over

over : Writer e -> (Writer {#s} ->{#s} a) ->{e} aSource

Runs action with a UTF-8 text writer over parent, which cannot fail to encode, and flushes when action returns.

overWith

overWith : Encoding -> Writer e -> (Writer {#s} ->{#s} a) ->{Fail Error, e} aSource

Runs action with a text writer over parent in encoding. An unrepresentable character fails with Fail Encoding.Error; handle it around the scope, or use tryWrite.

tryWrite

tryWrite : Writer e -> String ->{e} Result Error ()Source

Writes the text, answering an encoding error as a value instead of failing, so a consumer can recover from one failed write.

write

write : Writer e -> String ->{e} ()Source

Writes the text.

writeChar

writeChar : Writer e -> Char ->{e} ()Source

Writes one character.