Read a configuration file

Read a configuration file is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

The task is to read a configuration file in standard configuration file, and set variables accordingly. For this task, we have a configuration file as follows:

# This is a configuration file in standard configuration file format
#
# Lines that begin with a hash symbol or semicolon are treated as
# comments and will be ignored

# This is the fullname parameter
FULLNAME Foo Barber

# This is a favourite fruit
FAVOURITEFRUIT banana

# This is a boolean that should be set
NEEDSPEELING

# This boolean is commented out
; SEEDSREMOVED

For the task we need to set four variables according to the configuration entries as follows:

• fullname = Foo Barber
• favouritefruit = banana
• needspeeling = true
• seedsremoved = false

D

A version to abusing module std.getopt. <lang d>import std.stdio, std.getopt, std.string, std.conv ;

template VarName(alias Var) { enum VarName = Var.stringof.toupper ; }

void main(string[] args) {

   string fullname, favouritefruit ;
   bool needspeeling, seedsremoved ; // default false ;
   int count ; // a line of "COUNT 5" added at end of config file
   foreach(line ; File("readcfg.txt").byLine) {
       auto opt = ("--" ~ text(chomp(line))).split(" ") ;
       opt = (["program name dummy"] ~ opt[0]) ~ opt[1..$].join(" ") ;
       getopt( opt ,
           std.getopt.config.passThrough,      // ignore unknown option
           std.getopt.config.caseSensitive,
           "FULLNAME", &fullname,
           "FAVOURITEFRUIT", &favouritefruit,
           "NEEDSPEELING", &needspeeling ,
           "SEEDSREMOVED", &seedsremoved,
           "COUNT", &count) ;
   }
   writefln("%14s = %s", VarName!fullname, fullname) ;
   writefln("%14s = %s", VarName!favouritefruit, favouritefruit) ;
   writefln("%14s = %s", VarName!needspeeling, needspeeling) ;
   writefln("%14s = %s", VarName!seedsremoved, seedsremoved) ;
   writefln("%14s = %s", VarName!count, count) ;

}</lang>

J

<lang j>require'regex' set=:4 :'(x)=:y'

cfgString=:4 :0

 y set 
 (1;&,~'(?i:',y,')\s*(.*)') y&set rxapply x

)

cfgBoolean=:4 :0

 y set 0
 (1;&,~'(?i:',y,')\s*(.*)') y&set rxapply x
 if.-.0-:y do.y set 1 end.

)

taskCfg=:3 :0

 cfg=: ('[#;].*';) rxrplc 1!:1<y
 cfg cfgString 'fullname'
 cfg cfgString 'favouritefruit'
 cfg cfgBoolean 'needspeeling'
 cfg cfgBoolean 'seedsremoved'
 i.0 0

)</lang>

Example use:

<lang j> taskCfg 'fruit.conf'

  (,' = ',]&.do)&>;: 'fullname favouritefruit needspeeling seedsremoved'

fullname = Foo Barber favouritefruit = banana needspeeling = 1 seedsremoved = 0 </lang>

Ruby

<lang ruby>fullname = favouritefruit = needspeeling = seedsremoved = false

open("fruit.conf", "r") do |file|

 file.each_line do |line|
   line.chomp!
   key, value = line.split(nil, 2)
   case key
   when /^([#;]|$)/; # ignore line
   when "FULLNAME"; fullname = value
   when "FAVOURITEFRUIT"; favouritefruit = value
   when "NEEDSPEELING"; needspeeling = true
   when "SEEDSREMOVED"; seedsremoved = true
   when /^./; puts "#{key}: unknown key"
   end
 end

end

puts "fullname = #{fullname}" puts "favouritefruit = #{favouritefruit}" puts "needspeeling = #{needspeeling}" puts "seedsremoved = #{seedsremoved}"</lang>