load data from txt file

[Tony]

On Thursday, 4 January 2018 at 05:52:35 UTC, codephantom wrote:
> On Wednesday, 3 January 2018 at 05:45:32 UTC, Tony wrote:
>>
>> Someone else should know what the correct replacement
>> is for removechars().
>>
>
> the replacement is known as 'programming' ;-)
>
> //string trimmed = removechars!string(line,"[\\[\\]\"\n\r]");
> string trimmed;
> foreach(c; line)
> {
>     if(c != '[' && c != ']' && c != '\"' && c != '\r' && c != 
> '\n' )
>       trimmed ~= c;
> }

OK, thanks. The removechars() note about deprecation said to use 
std.regex instead so I have been looking at that and after a 
struggle did make some use of std.regex.replaceAll. Reminded me 
of the famous Jamie Zawinski quote: "Some people, when confronted 
with a problem, think "I know, I'll use regular expressions." Now 
they have two problems.

import std.stdio;
import std.string;
import std.algorithm;
import std.regex;
import std.file;
import std.format : format;

void checkLine(string line,long line_number)
{
    // not expecting any whitespace or extra colons. Each line:
    // ["key":"value"]

    long colon_pos = std.string.indexOf(line,':');
    assert(colon_pos != -1,format("ERROR: no colon on line 
%s",line_number));
    long splitter_string_pos = std.string.indexOf(line,"\":\"");
    assert(splitter_string_pos != -1,
	  format("ERROR: line %s missing quote(s) adjacent to 
:",line_number));
    assert(line[0..2] == "[\"",format("ERROR: no [\" at line %s 
start",line_number));
    assert(line[line.length - 2 .. line.length] == "\"]",
	  format("ERROR: no \"] at end of line %s",line_number));
}

void main()
{
    string[string] data;
    string filename = "users.txt";
    assert( std.file.exists(filename), format("ERROR: file %s not 
found",filename));
    auto f = std.stdio.File("users.txt","r");
    scope(exit) { f.close(); }
    string line = f.readln!();
    long line_number = 0;
    while ( line !is null)
    {
       import std.uni : lineSep;
       line_number++;
       checkLine(std.string.chomp!(string)(line),line_number);
       auto fields  = std.algorithm.findSplit(line,"\":\"");
       string key   = 
std.regex.replaceAll(fields[0],regex(`^\["(.*)$`),"$1");
       string value = 
std.regex.replaceAll(fields[2],regex(`^(.*)"\]\r?\n$`),"$1");
       data[key] = value;
       line = f.readln!();   				
    }
    writeln(data);
    writeln("value for key admin:",data["admin"]);
    writeln("value for key test:",data["test"]);
}