How to escape double quotes in a string?

Help
#1

I’m trying to build an <a> tag element by concatenating strings like so

module Main
  ( formatLinks
  )
  where

import Prelude

import Effect (Effect)
import Effect.Console (logShow)

formatLinks :: Array String -> Array String
formatLinks ss =
  map (\s -> "<a"
  <> " src=\"" <> s <> "\""
  <> "</a>") ss

main :: Effect Unit
main = do
  logShow $ formatLinks ["link1", "link2"]

which produce the following result

["<a src=\"link1\"</a>","<a src=\"link2\"</a>"]

How do I escape double quotes properly or log it without backslash character?

#2

Hi and welcome,

how do you test/run your code? Literally putting this into a fresh spago init project and doing spago run does produce the desired output for me.

#3

Sorry, I corrected the original post to make it runable. I looked at compiled JS code and I think it is a problem with logShow. It has it’s own custom formatting for arrays.

#4

ah ok - yes logShow uses show behind the scene and show for String will escape everything as if you would input it

1 Like
#5

Thank you for the prompt reply. I was able to get desired output with log as you suggested. Here is the solution using joinWith helper function to convert Array String -> String

module Main
  ( formatLinks
  , main
  )
  where

import Prelude

import Data.String (joinWith)
import Effect (Effect)
import Effect.Console (log)

formatLinks :: Array String -> Array String
formatLinks ss =
  map (\s -> "<a"
  <> " src=\"" <> s <> "\""
  <> "</a>") ss

main :: Effect Unit
main = do
  formatLinks ["link1", "link2"] 
    # joinWith "\n"
    # log

Will produce

<a src="link1"</a>
<a src="link2"</a>
1 Like
#6

yes that is a nice solution - I’d personally do formatLink instead and use map with it - and I would throw in fold (here from the 'purescript-arrays` package) to make the concat a bit nicer:

import Data.Array (fold)
import Data.String.Common (joinWith)
import Effect (Effect)
import Effect.Console (log)

formatLink :: String → String
formatLink s =
  fold [ "<a src=\"", s, "\">" ]

main :: Effect Unit
main = do
  log $ joinWith ", " $ map formatLink $ [ "link1", "link2" ]

but that’s probably just personal style

1 Like
#7

Wow that fold is pretty cool! I was looking for a cleaner way to do string concatenation but could not find one.

#8

You can also use triple quotes to avoid having the escape, though it’s not all that useful in this case:

#9

Yeah, I saw that option. Mb that would be useful in conjunction with replace :thinking: