HXT/Practical/Simple2
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{-# LANGUAGE Arrows, NoMonomorphismRestriction #-}
import Text.XML.HXT.Core
-- This example demonstrates a more complex XML parse,
-- involving multiple levels, attributes, inner lists,
-- and dealing with optional data.
-- Example data drawn from:
-- http://www.ibiblio.org/xml/books/bible/examples/05/5-1.xml
-- save as: simple2.xml
data Team = Team
{ teamName, division, league, city :: String,
players :: [Player] }
deriving (Show, Eq)
data Player = Player
{ firstName, lastName, position :: String,
atBats, hits :: Maybe Int,
era :: Maybe Float }
deriving (Show, Eq)
parseXML file = readDocument [ withValidate no
, withRemoveWS yes -- throw away formating WS
] file
atTag tag = deep (isElem >>> hasName tag)
-- Incremental development of the getTeams function:
-- First, list the teams.
-- Try it out in GHCi:
-- Main> runX (parseXML "simple2.xml" >>> getTeams1)
getTeams1 = atTag "LEAGUE" >>>
proc l -> do
leagName <- getAttrValue "NAME" -< l
divi <- atTag "DIVISION" -< l
diviName <- getAttrValue "NAME" -< divi
team <- atTag "TEAM" -< divi
teamName <- getAttrValue "NAME" -< team
returnA -< (leagName, diviName, teamName)
-- getTeams2 also lists the players.
-- But there is a catch; now teams without players
-- are being left out. (This behavior is familiar to
-- users of the List monad)
getTeams2 = atTag "LEAGUE" >>>
proc l -> do
leagName <- getAttrValue "NAME" -< l
divi <- atTag "DIVISION" -< l
diviName <- getAttrValue "NAME" -< divi
team <- atTag "TEAM" -< divi
teamName <- getAttrValue "NAME" -< team
player <- atTag "PLAYER" -< team
fName <- getAttrValue "GIVEN_NAME" -< player
lName <- getAttrValue "SURNAME" -< player
returnA -< (leagName, diviName, teamName, fName, lName)
-- What we really want is to capture the players in a list
-- at this level; and if there are no players then the
-- empty list will suffice. listA is used for this purpose.
getPlayer1 = atTag "PLAYER" >>>
proc p -> do
fName <- getAttrValue "GIVEN_NAME" -< p
lName <- getAttrValue "SURNAME" -< p
returnA -< (fName, lName)
getTeams3 = atTag "LEAGUE" >>>
proc l -> do
leagName <- getAttrValue "NAME" -< l
divi <- atTag "DIVISION" -< l
diviName <- getAttrValue "NAME" -< divi
team <- atTag "TEAM" -< divi
teamName <- getAttrValue "NAME" -< team
players <- listA getPlayer1 -< team
returnA -< (leagName, diviName, teamName, players)
-- Try capturing some statistics about the players
significant = not . all (`elem` " \n\r\t")
-- Use our definition of "significant" strings to
-- capture the value; or else nothing.
getStat attr =
(getAttrValue attr >>> isA significant >>> arr Just)
`orElse` (constA Nothing)
getPlayer2 = atTag "PLAYER" >>>
proc p -> do
fName <- getAttrValue "GIVEN_NAME" -< p
lName <- getAttrValue "SURNAME" -< p
position <- getAttrValue "POSITION" -< p
hits <- getStat "HITS" -< p
atBats <- getStat "AT_BATS" -< p
era <- getStat "ERA" -< p
returnA -< Player
{ firstName = fName,
lastName = lName,
position = position,
hits = read `fmap` hits,
atBats = read `fmap` atBats,
era = read `fmap` era }
getTeams4 = atTag "LEAGUE" >>>
proc l -> do
leagName <- getAttrValue "NAME" -< l
divi <- atTag "DIVISION" -< l
diviName <- getAttrValue "NAME" -< divi
team <- atTag "TEAM" -< divi
teamName <- getAttrValue "NAME" -< team
city <- getAttrValue "CITY" -< team
players <- listA getPlayer2 -< team
returnA -< Team
{ league = leagName,
division = diviName,
teamName = teamName,
city = city,
players = players }
-- Our final choices
getPlayer = getPlayer2
getTeams = getTeams4
main = do
teams <- runX (parseXML "simple2.xml" >>> getTeams)
print teams
The Data
Included here for convenience.
<SEASON YEAR="1998">
<LEAGUE NAME="National League">
<DIVISION NAME="East">
<TEAM CITY="Atlanta" NAME="Braves">
<PLAYER GIVEN_NAME="Marty" SURNAME="Malloy" POSITION="Second Base" GAMES="11" GAMES_STARTED="8" AT_BATS="28" RUNS="3" HITS="5" DOUBLES="1" TRIPLES="0" HOME_RUNS="1" RBI="1" STEALS="0" CAUGHT_STEALING="0" SACRIFICE_HITS="0" SACRIFICE_FLIES="0" ERRORS="0" WALKS="2" STRUCK_OUT="2" HIT_BY_PITCH="0">
</PLAYER>
<PLAYER GIVEN_NAME="Ozzie" SURNAME="Guillen" POSITION="Shortstop" GAMES="83" GAMES_STARTED="59" AT_BATS="264" RUNS="35" HITS="73" DOUBLES="15" TRIPLES="1" HOME_RUNS="1" RBI="22" STEALS="1" CAUGHT_STEALING="4" SACRIFICE_HITS="4" SACRIFICE_FLIES="2" ERRORS="6" WALKS="24" STRUCK_OUT="25" HIT_BY_PITCH="1">
</PLAYER>
<PLAYER GIVEN_NAME="Danny" SURNAME="Bautista" POSITION="Outfield" GAMES="82" GAMES_STARTED="27" AT_BATS="144" RUNS="17" HITS="36" DOUBLES="11" TRIPLES="0" HOME_RUNS="3" RBI="17" STEALS="1" CAUGHT_STEALING="0" SACRIFICE_HITS="3" SACRIFICE_FLIES="2" ERRORS="2" WALKS="7" STRUCK_OUT="21" HIT_BY_PITCH="0">
</PLAYER>
<PLAYER GIVEN_NAME="Gerald" SURNAME="Williams" POSITION="Outfield" GAMES="129" GAMES_STARTED="51" AT_BATS="266" RUNS="46" HITS="81" DOUBLES="18" TRIPLES="3" HOME_RUNS="10" RBI="44" STEALS="11" CAUGHT_STEALING="5" SACRIFICE_HITS="2" SACRIFICE_FLIES="1" ERRORS="5" WALKS="17" STRUCK_OUT="48" HIT_BY_PITCH="3">
</PLAYER>
<PLAYER GIVEN_NAME="Tom" SURNAME="Glavine" POSITION="Starting Pitcher" GAMES="33" GAMES_STARTED="33" WINS="20" LOSSES="6" SAVES="0" COMPLETE_GAMES="4" SHUT_OUTS="3" ERA="2.47" INNINGS="229.1" HOME_RUNS_AGAINST="13" RUNS_AGAINST="67" EARNED_RUNS="63" HIT_BATTER="2" WILD_PITCHES="3" BALK="0" WALKED_BATTER="74" STRUCK_OUT_BATTER="157">
</PLAYER>
<PLAYER GIVEN_NAME="Javier" SURNAME="Lopez" POSITION="Catcher" GAMES="133" GAMES_STARTED="124" AT_BATS="489" RUNS="73" HITS="139" DOUBLES="21" TRIPLES="1" HOME_RUNS="34" RBI="106" STEALS="5" CAUGHT_STEALING="3" SACRIFICE_HITS="1" SACRIFICE_FLIES="8" ERRORS="5" WALKS="30" STRUCK_OUT="85" HIT_BY_PITCH="6">
</PLAYER>
<PLAYER GIVEN_NAME="Ryan" SURNAME="Klesko" POSITION="Outfield" GAMES="129" GAMES_STARTED="124" AT_BATS="427" RUNS="69" HITS="117" DOUBLES="29" TRIPLES="1" HOME_RUNS="18" RBI="70" STEALS="5" CAUGHT_STEALING="3" SACRIFICE_HITS="0" SACRIFICE_FLIES="4" ERRORS="2" WALKS="56" STRUCK_OUT="66" HIT_BY_PITCH="3">
</PLAYER>
<PLAYER GIVEN_NAME="Andres" SURNAME="Galarraga" POSITION="First Base" GAMES="153" GAMES_STARTED="151" AT_BATS="555" RUNS="103" HITS="169" DOUBLES="27" TRIPLES="1" HOME_RUNS="44" RBI="121" STEALS="7" CAUGHT_STEALING="6" SACRIFICE_HITS="0" SACRIFICE_FLIES="5" ERRORS="11" WALKS="63" STRUCK_OUT="146" HIT_BY_PITCH="25">
</PLAYER>
<PLAYER GIVEN_NAME="Wes" SURNAME="Helms" POSITION="Third Base" GAMES="7" GAMES_STARTED="2" AT_BATS="13" RUNS="2" HITS="4" DOUBLES="1" TRIPLES="0" HOME_RUNS="1" RBI="2" STEALS="0" CAUGHT_STEALING="0" SACRIFICE_HITS="0" SACRIFICE_FLIES="0" ERRORS="1" WALKS="0" STRUCK_OUT="4" HIT_BY_PITCH="0">
</PLAYER>
</TEAM>
<TEAM CITY="Florida" NAME="Marlins">
</TEAM>
<TEAM CITY="Montreal" NAME="Expos">
</TEAM>
<TEAM CITY="New York" NAME="Mets">
</TEAM>
<TEAM CITY="Philadelphia" NAME="Phillies">
</TEAM>
</DIVISION>
<DIVISION NAME="Central">
<TEAM CITY="Chicago" NAME="Cubs">
</TEAM>
<TEAM CITY="Cincinnati" NAME="Reds">
</TEAM>
<TEAM CITY="Houston" NAME="Astros">
</TEAM>
<TEAM CITY="Milwaukee" NAME="Brewers">
</TEAM>
<TEAM CITY="Pittsburgh" NAME="Pirates">
</TEAM>
<TEAM CITY="St. Louis" NAME="Cardinals">
</TEAM>
</DIVISION>
<DIVISION NAME="West">
<TEAM CITY="Arizona" NAME="Diamondbacks">
</TEAM>
<TEAM CITY="Colorado" NAME="Rockies">
</TEAM>
<TEAM CITY="Los Angeles" NAME="Dodgers">
</TEAM>
<TEAM CITY="San Diego" NAME="Padres">
</TEAM>
<TEAM CITY="San Francisco" NAME="Giants">
</TEAM>
</DIVISION>
</LEAGUE>
<LEAGUE NAME="American League">
<DIVISION NAME="East">
<TEAM CITY="Baltimore" NAME="Orioles">
</TEAM>
<TEAM CITY="Boston" NAME="Red Sox">
</TEAM>
<TEAM CITY="New York" NAME="Yankees">
</TEAM>
<TEAM CITY="Tampa Bay" NAME="Devil Rays">
</TEAM>
<TEAM CITY="Toronto" NAME="Blue Jays">
</TEAM>
</DIVISION>
<DIVISION NAME="Central">
<TEAM CITY="Chicago" NAME="White Sox">
</TEAM>
<TEAM CITY="Kansas City" NAME="Royals">
</TEAM>
<TEAM CITY="Detroit" NAME="Tigers">
</TEAM>
<TEAM CITY="Cleveland" NAME="Indians">
</TEAM>
<TEAM CITY="Minnesota" NAME="Twins">
</TEAM>
</DIVISION>
<DIVISION NAME="West">
<TEAM CITY="Anaheim" NAME="Angels">
</TEAM>
<TEAM CITY="Oakland" NAME="Athletics">
</TEAM>
<TEAM CITY="Seattle" NAME="Mariners">
</TEAM>
<TEAM CITY="Texas" NAME="Rangers">
</TEAM>
</DIVISION>
</LEAGUE>
</SEASON>