85 lines
2.9 KiB
Text
85 lines
2.9 KiB
Text
def String.words (s : String) :=
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s.split Char.isWhitespace |>.filter (¬·.isEmpty)
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def String.lines (s : String) :=
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s.splitOn "\n" |>.filter (¬·.isEmpty)
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def List.unlines (xs : List String) : String
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:= xs.intersperse "\n" |> String.join
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def ex := "The heat bloomed\tin December\nas the carnival season\n kicked into gear.\nNearly helpless with sun and glare, I avoided Rio's brilliant\nsidewalks\n and glittering beaches,\npanting in dark corners\nand waiting out the inverted southern summer."
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#eval ex.words
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#eval ex.lines
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#eval IO.println ex.lines.unlines
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def sep : List a → List a → List a
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| a1::a1s, a2::a2s => a1::a2::sep a1s a2s
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| a1, _ => a1
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def justify : Nat → List String → String
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| _, [word] => word
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| width, words =>
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let wordsLength := List.sum (String.length <$> words)
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let spacesNeeded := width - wordsLength
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let numSpaces := words.length - 1
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let smallSpaceLen := spacesNeeded / numSpaces
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let smallSpace := List.replicate smallSpaceLen ' '
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let largeSpaces := spacesNeeded % numSpaces
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let smallSpaces := numSpaces - largeSpaces
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let largeSpace := ' '::smallSpace
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let spaces := List.replicate largeSpaces largeSpace
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++ List.replicate smallSpaces smallSpace
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|>.map List.asString
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String.join $ sep words spaces
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#eval justify 1 "Hello, world, how is it going?".words
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#eval justify 1 "Hello, world, how is it going?".words |>.length
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def breakUp (width : Nat) (words : List String) : List (List String) :=
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let (_, line, lines) := words.foldl
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(λ(left, line, lines) word ↦
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if word.length < left
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then (left - (word.length + 1), line++[word], lines)
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else (width - word.length, [word], lines++[line]))
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(width, [], [])
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lines++[line]
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-- def breakUp (width : Nat) (words : List String)
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-- : List (List String) :=
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-- if width = 0 then [] else go width words [] []
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-- where
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-- go (left : Nat) (words line : List String) (lines : List $ List String) :=
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-- match left, words, line, lines with
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-- | _, [], l, ls => ls++[l]
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-- | left, (w::ws), l, ls =>
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-- if width < w.length
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-- then go width ws [w] ls
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-- else if left < w.length + 1
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-- then go width (w::ws) [] (ls++[l])
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-- else go (left - (w.length + 1)) ws (l++[w]) ls
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-- termination_by (left, words)
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def solve (width : Nat) :=
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List.unlines ∘ List.map (justify width) ∘ breakUp width ∘ String.words
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#eval IO.println $ solve 40 ex
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def usage := "Usage: justify WIDTH"
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def fail : IO UInt32 := do IO.println usage; return 1
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def main : List String → IO UInt32
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| [width] =>
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if let some width := width.toNat?
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then do
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let mut text := ""
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let stdin ← IO.getStdin
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while true do
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let line ← stdin.getLine
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if line.isEmpty then break
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text := text ++ line
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IO.println $ solve width text
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return 0
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else fail
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| _ => fail
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