shakespeare-js fails to compile on Heroku

haskell deployment heroku web-deployment yesod

The problem is that the type PreConvert changed between shakespeare-1.0.2 and shakespeare-1.0.3.

In the older version, preEscapeBegin and preEscapeEnd were fields of the constructor PreConvert, but they have been removed in version 1.0.3.

So the solution is to

use the older version of shakespeare, specify shakespeare < 1.0.3 or
use a new enough version of shakespeare-js, specify shakespeare-js >= 1.1.2.

(There may be further adjustments necessary if you use the newer shakespeare version, I haven't tried.)

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