lib/csv.nit

   1 # This file is part of NIT ( http://www.nitlanguage.org ).
   2 #
   3 # Licensed under the Apache License, Version 2.0 (the "License");
   4 # you may not use this file except in compliance with the License.
   5 # You may obtain a copy of the License at
   6 #
   7 #     http://www.apache.org/licenses/LICENSE-2.0
   8 #
   9 # Unless required by applicable law or agreed to in writing, software
  10 # distributed under the License is distributed on an "AS IS" BASIS,
  11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 # See the License for the specific language governing permissions and
  13 # limitations under the License.
  14
  15 # CSV output facilities
  16 module csv
  17
  18 # A CSV document representation
  19 class CSVDocument
  20         super Streamable
  21
  22         var header: Array[String] = new Array[String] is writable
  23         var lines: Array[Array[String]] = new Array[Array[String]]
  24
  25         fun set_header(values: Object...) do
  26                 header.clear
  27                 for value in values do
  28                         header.add(value.to_s)
  29                 end
  30         end
  31
  32         fun add_line(values: Object...) do
  33                 if values.length != header.length then
  34                         print "CSV error: header declares {header.length} columns, line contains {values.length} values"
  35                         abort
  36                 end
  37                 var line = new Array[String]
  38                 for value in values do
  39                         line.add(value.to_s)
  40                 end
  41                 lines.add(line)
  42         end
  43
  44         private fun write_line_to(line: Collection[String], stream: OStream)
  45         do
  46                 var i = line.iterator
  47                 if i.is_ok then
  48                         stream.write(i.item)
  49                         i.next
  50                         while i.is_ok do
  51                                 stream.write(";")
  52                                 stream.write(i.item)
  53                                 i.next
  54                         end
  55                 end
  56                 stream.write("\n")
  57         end
  58
  59         redef fun write_to(stream)
  60         do
  61                 write_line_to(header, stream)
  62                 for line in lines do write_line_to(line, stream)
  63         end
  64
  65         # deprecated alias for `write_to_file`
  66         fun save(file: String) do write_to_file(file)
  67 end