X-Git-Url: https://mattmccutchen.net/match/match.git/blobdiff_plain/df3d7779b79713973898f91d7bd9d418bf41eebe..86e209954803086a9a880fe3cd538d2c866cb8d6:/program/Main.hs

diff --git a/program/Main.hs b/program/Main.hs
index 0bbfdda..d45755e 100644
--- a/program/Main.hs
+++ b/program/Main.hs
@@ -7,13 +7,21 @@ import Data.Array.Unboxed
 import ArrayStuff
 import Text.CSV
 
+-- Command-line interface with simple tab-separated input/output formats.
+-- ./match <example.in
+
 -- pretty silly but it does the job
 swapTabCommaIn s = map (\c -> if c == '\t' then ',' else if c == ',' then '\t' else c) s
 removeQuotes s = filter (\c -> not (c == '"')) s
-parseTSV fname str = case parseCSV fname (swapTabCommaIn str) of
+
+-- Some versions of Text.CSV do not use or accept a trailing newline; compensate for that.
+removeTrailingNewline s = if not (null s) && last s == '\n' then init s else s
+addTrailingNewline s = if not (null s) && last s /= '\n' then s ++ ['\n'] else s
+
+parseTSV fname str = case parseCSV fname (swapTabCommaIn $ removeTrailingNewline str) of
 	Left pe -> Left pe
 	Right ll -> Right $ map (map swapTabCommaIn) ll
-printTSV ll = removeQuotes $ swapTabCommaIn $ printCSV $ map (map swapTabCommaIn) ll
+printTSV ll = addTrailingNewline $ removeQuotes $ swapTabCommaIn $ printCSV $ map (map swapTabCommaIn) ll
 
 main = do
 	incsv <- hGetContents stdin