在haskell中生成给定月份和年份的日历

我从一周开始学习haskell，现在面临着不同的问题。这一次，我必须根据给定的月份和年份创建日历。我几乎完成了，但问题是我不能从开始的那一天开始填满时间

我的解决办法是

getDaysInMonth year month=(nDays,sDay) 
                          where nDays = gregorianMonthLength year month
                                sDay= digitToInt(last(showWeekDate (fromGregorian year month 01)))
year=2013
month=10
months=["JANUARY","FEBRUARY","MARCH","APRIL","MAY","JUNE","JULY","AUGUST","SEPTEMBER","OCTOBER","NOVEMBER","DECEMBER"]
mnth=months!!(month-1)
monthDate = getDaysInMonth year month
startAt=snd(monthDate)
totalDays = fst(monthDate)
printLine = "\n"++concat ["+---\t" | r <- [1..7]]
check x | x>totalDays=""
        | x<=totalDays=show x
genDays n m="\n "++concat[check(x)++"\t|"|x<-[n..m]]
genD 6=""
genD sP=genDays ((sP-1)*7+1) (sP*7) ++genD (sP+1)
generateCalendar=printLine++"\n "++
                        concat [[r]++"\t|" | r <- mnth]++printLine++
                        "\n Sun\t|Mon\t|Tue\t|Wed\t|Thu\t|Fri\t|Sat"++printLine++
                        genD 1
main=do
     putStrLn generateCalendar

---

所以问题是十月应该从周一开始。我认为解决方案的实施有点混乱，但我如何解决这个问题

提前感谢

解决此问题的更“实用”的方法是：

cells = [ "", "", "", "1", "2", "3", ..., "31", "", "" ]

创建一个包含35个字符串的列表，每个字符串要么是空字符串，要么是一个（字符串化的）数字

将列表分成7个元素的块（这样你就得到5个块）

对于每个区块，将元素渲染为日历中的一行

例如，2013年10月，35个字符串的列表为：

cells = [ "", "", "", "1", "2", "3", ..., "31", "", "" ]

可以使用以下帮助函数创建块：

chunksOf7 (a:b:c:d:e:f:g:rest) = [ [a,b,c,d,e,f,g] ] ++ chunksOf7 rest
chunksOf7 xs = xs

（有更好的方法来定义

块7

，但这就足够了。）

要渲染块，请执行以下操作：

renderChunk cells =  (concat $ map renderCell cells) ++ "\n"
renderCell c = pad 3 c ++ "|"
pad n str = str ++ (replicate (n-(length str)) ' ')

pad n str

在字符串

str

的右侧填充空格，直到总长度为

n

。

replicate n a

创建一个值为

a

重复

n

次的列表

并将其放在一起（一旦有了

单元格

列表）：

现在，给定一年零一个月，您只需编写一个函数来定义什么是

单元格。
单元格列表将包括：


一些前导空字符串
然后是1到30（或31或该月的最后一天）
后跟一些尾随的空字符串

i、 e:

cellsForYearAndMonth y y m=（复制n1“”）
++[show d | d谢谢@user5402。我终于得到了工作版本

import Data.Time.Calendar
import Data.Time.Calendar.WeekDate
import Data.Char
year=2014
month=2
months=["JANUARY","FEBRUARY","MARCH","APRIL","MAY","JUNE","JULY","AUGUST","SEPTEMBER","OCTOBER","NOVEMBER","DECEMBER"]
mnth=months!!(month-1)
monthDate = getDaysInMonth year month
startAt=snd(monthDate)
totalDays = fst(monthDate)

getDaysInMonth year month=(nDays,sDay) 
                      where nDays = gregorianMonthLength year month
                            sDay= digitToInt(last(showWeekDate (fromGregorian year month 01)))
cells = (replicate n1 "")
                          ++ [ show d | d <- [1..lastday] ]
                          ++ (replicate n2 "")
          where lastday = totalDays
                n1=(startAt-1)
                n2=(7-(totalDays-(29-startAt)))
chunksOf7 []=[]
chunksOf7 (a:b:c:d:e:f:g:rest) = [ [a,b,c,d,e,f,g] ] ++ chunksOf7 rest

pad n str = str ++ (replicate (n-(length str)) ' ')
renderCell c = pad 3 c ++ "|"
renderChunk cells =  (concat $ map renderCell cells) ++ "\n"

printLine = "\n"++concat ["+---" | r <- [1..7]]++"\n"
monthLine=concat [[r]++" |" | r <- mnth]
dayLine="Sun|Mon|Tue|Wed|Thu|Fri|Sat"
heading=concat[printLine,"Year: ",show year,printLine,monthLine,printLine,dayLine,printLine]

renderCalendarBody cells =  heading++concat (map renderChunk chunks)
  where chunks = chunksOf7 cells

main= do putStrLn $ renderCalendarBody cells

导入Data.Time.Calendar
导入Data.Time.Calendar.WeekDate
导入数据.Char
年份=2014年
月份=2
月份=[“一月”、“二月”、“三月”、“四月”、“五月”、“六月”、“七月”、“八月”、“九月”、“十月”、“十一月”、“十二月”]
mnth=月份！！（第1个月）
monthDate=getDaysInMonth年月份
startAt=snd（月日）
totalDays=fst（月日）
getDaysInMonth年月=（星期日，星期四）
式中，nDays=gregorianMonthLength年-月
sDay=数字点（最后一个（显示工作日（从公历年第01个月开始）））
细胞=（复制n1“”）
++[show d | d“我认为解决方案的实现有点[混乱]”-然后清理它！有什么理由不能在几个月和几天内使用自定义
数据类型吗？不使用字符串会更干净、更安全。2013年10月从周二开始。
cellsForYearAndMonth y m = (replicate n1 "")
                              ++ [ show d | d <- [1..lastday] ]
                              ++ (replicate n2 "")
  where lastday = ...
        n1 = ... number of leading empty strings ...
        n2 = ... number of trailing empty strings ...

import Data.Time.Calendar
import Data.Time.Calendar.WeekDate
import Data.Char
year=2014
month=2
months=["JANUARY","FEBRUARY","MARCH","APRIL","MAY","JUNE","JULY","AUGUST","SEPTEMBER","OCTOBER","NOVEMBER","DECEMBER"]
mnth=months!!(month-1)
monthDate = getDaysInMonth year month
startAt=snd(monthDate)
totalDays = fst(monthDate)

getDaysInMonth year month=(nDays,sDay) 
                      where nDays = gregorianMonthLength year month
                            sDay= digitToInt(last(showWeekDate (fromGregorian year month 01)))
cells = (replicate n1 "")
                          ++ [ show d | d <- [1..lastday] ]
                          ++ (replicate n2 "")
          where lastday = totalDays
                n1=(startAt-1)
                n2=(7-(totalDays-(29-startAt)))
chunksOf7 []=[]
chunksOf7 (a:b:c:d:e:f:g:rest) = [ [a,b,c,d,e,f,g] ] ++ chunksOf7 rest

pad n str = str ++ (replicate (n-(length str)) ' ')
renderCell c = pad 3 c ++ "|"
renderChunk cells =  (concat $ map renderCell cells) ++ "\n"

printLine = "\n"++concat ["+---" | r <- [1..7]]++"\n"
monthLine=concat [[r]++" |" | r <- mnth]
dayLine="Sun|Mon|Tue|Wed|Thu|Fri|Sat"
heading=concat[printLine,"Year: ",show year,printLine,monthLine,printLine,dayLine,printLine]

renderCalendarBody cells =  heading++concat (map renderChunk chunks)
  where chunks = chunksOf7 cells

main= do putStrLn $ renderCalendarBody cells