haskell/aeson

JSON parsing with accumulative errors

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#578 建立於 2017年8月24日

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 (8 留言) (1 反應) (0 負責人)Haskell (1,298 star) (334 fork)batch import
help wanted

描述

When parsing an incorrect JSON with Aeson, you only get the first error instead of all the errors like so:

Data.Aeson> eitherDecode "[1,19,\"a\", 20]" :: Either String [Text]
Left "Error in $[0]: expected Text, encountered Number"

It would be better to have another function to return all the errors instead of just the first one, for example:

Data.Aeson> eitherDecode "[1,19,\"a\", 20]" :: Either [(String, String)] [Text]
Left [("$[0]", "Expected Text, encountered Number"), ("$[1]", "Expected Text, encountered Number"), ("$[3]", "Expected Text, encountered Number")]

This kind of feature would be very useful in web development where errors in request payload are all checked at once to save network round trip.

I'm thinking maybe this library can be used instead of Either https://hackage.haskell.org/package/Validation-0.2.0/docs/Data-Validation.html

貢獻者指南

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backenddeveloper experience
議題類型
feature
難度面向新貢獻者的預計實作難度，1 表示很小改動，5 表示專家級工作。
3
預計時間有經驗貢獻者完成調查、實作、測試並準備 pull request 的粗略時間範圍。
half day
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stale
清晰度議題是否清楚說明預期改動、驗收標準和下一步。
clear
前置要求
Haskell programmingAeson libraryJSON parsing
新手友善度1-100 的估計分數，表示該議題對首次貢獻者的友善程度。
50
研究方向
Investigate the current error handling in Aeson's parser, likely in Data/Aeson/Types.hs or Data/Aeson/Parser.hs. Review the issue comments for additional discussion on implementation approach. Consider using a Validation type to accumulate errors as suggested in the issue. Look at existing functions like 'eitherDecode' and 'eitherDecodeWith' to understand the current error reporting mechanism.