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digitalmars.D.learn - chaining splitters

reply "dnoob" <Flamencofantasy gmail.com> writes:
Hello,

I am parsing some text and I have the following;

string text = "some very long text";

foreach(line; splitter(text, [13, 10]))
{
	foreach(record; splitter(line, '*'))
	{
		foreach(field; splitter(record, '='))
		{
			foreach(value; splitter(field, ','))
			{
				// do something...
			}
		}
	}
}

I know there is a better way to do that but I'm a total D noob.

Thanks!
Mar 10 2015
next sibling parent "Dennis Ritchie" <dennis.ritchie mail.ru> writes:
On Wednesday, 11 March 2015 at 00:00:39 UTC, dnoob wrote:

 Hello,

 I am parsing some text and I have the following;

 string text = "some very long text";

 foreach(line; splitter(text, [13, 10]))
 {
 	foreach(record; splitter(line, '*'))
 	{
 		foreach(field; splitter(record, '='))
 		{
 			foreach(value; splitter(field, ','))
 			{
 				// do something...
 			}
 		}
 	}
 }

 I know there is a better way to do that but I'm a total D noob.

 Thanks!


I don't understand what you want to do. Maybe you want to do this:

import std.stdio;
import std.string;

void main() {

	string text = "some very long text";
	
	foreach(line; text.split) {
		writeln(line);
	}
}
Mar 10 2015
prev sibling next sibling parent ketmar <ketmar ketmar.no-ip.org> writes:
On Wed, 11 Mar 2015 00:00:38 +0000, dnoob wrote:


 Hello,
=20
 I am parsing some text and I have the following;
=20
 string text =3D "some very long text";
=20
 foreach(line; splitter(text, [13, 10]))
 {
 	foreach(record; splitter(line, '*'))
 	{
 		foreach(field; splitter(record, '=3D'))
 		{
 			foreach(value; splitter(field, ','))
 			{
 				// do something...
 			}
 		}
 	}
 }
=20
 I know there is a better way to do that but I'm a total D noob.
=20
 Thanks!


it depends of the thing you want to do. please, describe your task, as=20
the solutions can differ depending of your needs. if you needs only=20
values and don't care about everything other, this can help:

  import std.regex;
  import std.stdio;

  void main () {
    string text =3D "some,very=3Dlong,text*another=3Dshit";
    foreach (immutable v; text.splitter(regex("[,=3D*\n\r]"))) {
      writeln(v);
    }
  }
=
Mar 11 2015
prev sibling next sibling parent reply "Dave S" <wrrx11 gmail.com> writes:
On Wednesday, 11 March 2015 at 00:00:39 UTC, dnoob wrote:

 Hello,

 I am parsing some text and I have the following;

 string text = "some very long text";

 foreach(line; splitter(text, [13, 10]))
 {
 	foreach(record; splitter(line, '*'))
 	{
 		foreach(field; splitter(record, '='))
 		{
 			foreach(value; splitter(field, ','))
 			{
 				// do something...
 			}
 		}
 	}
 }

 I know there is a better way to do that but I'm a total D noob.

 Thanks!


You can use std.algorithm's map to apply some function to all the
items in a range:
---

import std.stdio, std.algorithm;

void main()
{
	string text = "foo*bar=qux\r\nHello*world!\r\nApril,May,June";

	auto lines = splitter(text, "\r\n");
	auto records = map!(a => splitter(a, '*'))(lines).joiner();
	auto fields = map!(a => splitter(a, '='))(records).joiner();
	auto values = map!(a => splitter(a, ','))(fields).joiner();

	foreach (value; values)
	{
		writeln(value);
	}
}

---
This produces the output:

foo
bar
qux
Hello
world!
April
May
June

The joiner() is necessary because when you pass a range of
strings to splitter using map the result is a range of ranges of
strings. joiner() joins these together into one range of strings.
Consider this code, for example:
---

string str = "foo*bar=qux\r\nHello*world!\r\nApril,May,June";

auto lines = splitter(str, [13, 10]);
auto result = map!(a => splitter(a, '*'))(lines);
auto tokens = result.joiner();

---
The contents of result are:

["foo", "bar=qux"]
["Hello", "world!"]
["April,May,June"]

The contents of tokens are:

["foo", "bar=qux", "Hello", "world!", "April,May,June"]

I am not a D expert by any means so there it's possible there is
another way that I am not aware of.
Mar 11 2015
parent "dnoob" <crayolist gmail.com> writes:
Yes. That's it! Thanks a lot.


On Wednesday, 11 March 2015 at 09:29:12 UTC, Dave S wrote:

 On Wednesday, 11 March 2015 at 00:00:39 UTC, dnoob wrote:

 Hello,

 I am parsing some text and I have the following;

 string text = "some very long text";

 foreach(line; splitter(text, [13, 10]))
 {
 	foreach(record; splitter(line, '*'))
 	{
 		foreach(field; splitter(record, '='))
 		{
 			foreach(value; splitter(field, ','))
 			{
 				// do something...
 			}
 		}
 	}
 }

 I know there is a better way to do that but I'm a total D noob.

 Thanks!


 You can use std.algorithm's map to apply some function to all 
 the
 items in a range:
 ---

 import std.stdio, std.algorithm;

 void main()
 {
 	string text = "foo*bar=qux\r\nHello*world!\r\nApril,May,June";

 	auto lines = splitter(text, "\r\n");
 	auto records = map!(a => splitter(a, '*'))(lines).joiner();
 	auto fields = map!(a => splitter(a, '='))(records).joiner();
 	auto values = map!(a => splitter(a, ','))(fields).joiner();

 	foreach (value; values)
 	{
 		writeln(value);
 	}
 }

 ---
 This produces the output:

 foo
 bar
 qux
 Hello
 world!
 April
 May
 June

 The joiner() is necessary because when you pass a range of
 strings to splitter using map the result is a range of ranges of
 strings. joiner() joins these together into one range of 
 strings.
 Consider this code, for example:
 ---

 string str = "foo*bar=qux\r\nHello*world!\r\nApril,May,June";

 auto lines = splitter(str, [13, 10]);
 auto result = map!(a => splitter(a, '*'))(lines);
 auto tokens = result.joiner();

 ---
 The contents of result are:

 ["foo", "bar=qux"]
 ["Hello", "world!"]
 ["April,May,June"]

 The contents of tokens are:

 ["foo", "bar=qux", "Hello", "world!", "April,May,June"]

 I am not a D expert by any means so there it's possible there is
 another way that I am not aware of.
Mar 12 2015
prev sibling parent "Baz" <bb.temp gmx.com> writes:
On Wednesday, 11 March 2015 at 00:00:39 UTC, dnoob wrote:

 Hello,

 I am parsing some text and I have the following;

 string text = "some very long text";

 foreach(line; splitter(text, [13, 10]))
 {
 	foreach(record; splitter(line, '*'))
 	{
 		foreach(field; splitter(record, '='))
 		{
 			foreach(value; splitter(field, ','))
 			{
 				// do something...
 			}
 		}
 	}
 }

 I know there is a better way to do that but I'm a total D noob.

 Thanks!


For this kind of things i tend to write a small lexer because you 
have a good control on what to do where to do it and the finally 
the pattern is quite simple:
---
// empty/front/popFront for build-in arrays
import std.array;

string identifier;
while (!text.empty)
{
   auto current = text.front;
   //
   // test whites/memorize identifier/resetidentifier
   // test punctuation/reset identifier...
   // test keywords/reset identifier...
   identifier ~= current;
   text.popFront;
}
---
Mar 11 2015