lib/csv/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         # The header.
  23         #
  24         # Contains the name of all fields in this table.
  25         var header: Array[String] = new Array[String] is writable
  26
  27         # The list of the records.
  28         #
  29         # All records must have the same length than `header`.
  30         var records: Array[Array[String]] = new Array[Array[String]]
  31
  32         # Replace the header by the specified row.
  33         fun set_header(values: Object...) do
  34                 header.clear
  35                 for value in values do header.add(value.to_s)
  36         end
  37
  38         # Append the specfied record.
  39         fun add_record(values: Object...) do
  40                 assert values.length == header.length else
  41                         sys.stderr.write "CSV error: Header declares {header.length} columns, record contains {values.length} values.\n"
  42                 end
  43                 var record = new Array[String]
  44                 for value in values do record.add(value.to_s)
  45                 records.add(record)
  46         end
  47
  48         private fun write_line_to(line: Collection[String], stream: OStream)
  49         do
  50                 var i = line.iterator
  51                 if i.is_ok then
  52                         stream.write(i.item)
  53                         i.next
  54                         while i.is_ok do
  55                                 stream.write(";")
  56                                 stream.write(i.item)
  57                                 i.next
  58                         end
  59                 end
  60                 stream.write("\n")
  61         end
  62
  63         redef fun write_to(stream) do
  64                 write_line_to(header, stream)
  65                 for record in records do write_line_to(record, stream)
  66         end
  67
  68         # Deprecated alias for `write_to_file`.
  69         fun save(file: String) do write_to_file(file)
  70 end