Wednesday, October 21, 2020

October 2020 Haskell 1-Liners

  • 2020-10-21: Curry `key` from
    secondPassFilter :: Ord a => a -> Set a -> Maybe b
    secondPassFilter key = spf key . Set.lookupGE key

    Given spf :: a -> Maybe a -> Maybe b
  • 2020-10-21: given: updater :: b -> Maybe b
    and firstPass :: Ord a => Map a b -> Map a b
    firstPass m = foldr (Map.update updater) m (Map.keys m)
    #Curry away `m` from the firstPass-function
    • Social Justice Cleric @noaheasterly
      firstPass = foldr (Map.update updater) <*> Map.keys
  • 2020-10-20: all (\c -> any (`isPrefixOf` c) setb) notinb
    #Curry away the `c` lambda argument.

Friday, October 9, 2020

October 2020 1HaskellADay Problems and Solutions

  • 2020-10-27: Military alliances from a @wikidata query.
  • 2020-10-26: Today's #haskell problem captures the Cypher of countries, continents, and airbases.
  • 2020-10-23: Today's #haskell problem: "Unicode? What, even, is that?" ... sez Haskell, smh.  Also, if you know how to get Text not to escape unicode points on output (to, say, a REST endpoint), much obliged if you told me this dark magic. Today's #haskell solution shows airbases (with their associated countries) added to the graph database

  • 2020-10-20: Next evolutionary step. We have Continents and countries as data structures. For today's #haskell problem let's find out how we can (can't?) merge in airbases with countriesHoo, doggies! "Upload airbases to the graph database!" he said. "It'll be easy!" he said. Today's #haskell solution, if not in book-form, then in book-length! 
  • 2020-10-16: Map of a -> b or b -> a? ... If you're asking that question, why not Graph? Today's #haskell exercise. A mapping of continents to countries. Surprisingly, does not have this as data amenable to extraction. 

  • 2020-10-15: From continent->country mapping to country->continent mapping for today's #haskell problem. `sequence` is the secret-sauce for today's #haskell solution. 
  • 2020-10-14: Today's #haskell problem is to get countries by continent from a ... 'markdown' file? That is not markdown. Deal with it. Countries: meet your Continents. 
  • 2020-10-13: Okay. #StringsAreWrong. Everybody knows this. Wikidata: "Let's encode LongLats as strings ... IN JSON!" Please let's not. Today's #haskell exercise. The solution that produces airbases with lat/longs. REAL lat/longs, smh. 
  • 2020-10-12: Today's #haskell problem is airbases of the world from ... with some duplicates. Today's #haskell solution reads in JSON, even ... 'JSON' that encodes 'LongLat's (not lat/longs) as ... strings? Really? Yes, even points-as-strings. Remember: #StringsAreWrong ~ Richard A. O'Keefe, 26 April 1994 
  • 2020-10-09: Today's #haskell problem is this: Production data: "Let's see if we can make the simple act of parsing a 'JSON file' [that isn't a JSON file] impossible for the ol' el geophf!" Nice try, production data. Nice try.