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Common

export OPT=/opt
export BUILDS=/some/where/mini_linux
mkdir -p $BUILDS

Linux kernel

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Typing Haskell in Haskell

MARK P. JONES

Pacific Software Research Center

Department of Computer Science and Engineering

Oregon Graduate Institute of Science and Technology

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Sample types:

isDigit :: Monad f => Char -> f Bool
any :: Monad f => (a -> f Bool) -> [a] -> f Bool
reverse :: Monad f => [a] -> f [a]
map :: Monad f => (a -> f b) -> [a] -> f [b]
"hello" :: Monad f => f String
putStrLn :: (MonadIO f) => String -> f ()
show :: (Show a,Monad f) => a -> f String

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*** Exception: Couldn't resolve constraint

  <record getter>

due to problem

  missing field for field access

arising from record-error.hell:2:24

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// Define the custom HTMX extension
htmx.defineExtension('trigger-href', {
  onEvent: function(name, evt) {
    // <https://htmx.org/events/#htmx:afterProcessNode>
    if (name == 'htmx:afterProcessNode') {
      const es = evt.detail.elt.querySelectorAll('a[hx-trigger-href]');
      for (const e of es) {
        if (typeof e.href == 'string') {
          e.addEventListener('click',(e) => {
            e.stopPropagation();

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--------------------------------------------------------------------------------
-- Variants

-- NB: By the types here, you can't construct a @Variant NilL@.
data Variant xs where
  LeftV :: forall k a xs. a -> Variant (ConsL k a xs)
  RightV :: Variant xs -> Variant (ConsL k a xs)

-- Construction:
bar :: Variant (ConsL "String" Text (ConsL "Number" Double NilL))

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-- RHS size: {terms: 254, types: 135, coercions: 0}
Xeno.$wparse [InlPrag=[0]]
  :: GHC.Prim.Addr#
     -> GHC.ForeignPtr.ForeignPtrContents
     -> GHC.Prim.Int#
     -> GHC.Prim.Int#
     -> ()
[GblId,
 Arity=4,
 Str=DmdType <L,U><L,U><L,U><S,U>,

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Basic unit type:

λ> replTy "()"
() :: ()

Basic functions:

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BUILDKIT_PROGRESS=plain docker image build . -t ghc-javascript:2024-10-10

$ docker run -v`pwd`:`pwd` -w`pwd` --rm ghc-javascript:2024-10-10 ghcjs HelloJS.hs
[1 of 2] Compiling Main             ( HelloJS.hs, HelloJS.o )
[2 of 2] Linking HelloJS.jsexe

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#!/usr/bin/env hell

-- How to run this:
--
-- socat TCP-LISTEN:8081,fork,reuseaddr,max-children=20 EXEC:"./handler.hell"

main = do
 line <- Text.getLine
 let content =
      Text.concat ["<h1>Hello, World!</h1><p>This is generated by Hell.</p><pre>", line, "</pre>"]