X-Git-Url: https://mattmccutchen.net/match/match.git/blobdiff_plain/bbabbd0161ab6e633f7d7027e0167892633519f7..a70586aac4e53552ace2fe83655af176e6ec9e1a:/program/TSV.hs

diff --git a/program/TSV.hs b/program/TSV.hs
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+++ b/program/TSV.hs
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+module TSV (
+	parseTSV, formatTSV
+) where
+import Data.List
+
+-- Simple implementation of tab-separated values with a trailing newline and no
+-- quoting support.
+
+splitList :: Eq a => a -> Bool -> [a] -> [[a]]
+splitList delim terminated =
+	let sl [] | terminated = []
+	    sl l = case break (== delim) l of
+	           (hh, []) -> [hh]
+	           (hh, {-delim-} _ : t) -> hh : sl t
+	in sl
+
+-- We use the Eq only to check the validity...
+joinList :: Eq a => a -> Bool -> [[a]] -> [a]
+joinList delim terminated l =
+	if any (any (== delim)) l then error "joinList: item contains delimiter"
+	else if terminated
+	then concatMap (++ [delim]) l
+	else intercalate [delim] l
+
+type TSV = [[String]]
+
+formatTSV :: TSV -> String
+formatTSV = joinList '\n' True . map (joinList '\t' False)
+
+parseTSV :: String -> TSV
+parseTSV = map (splitList '\t' False) . splitList '\n' True