Storing string templates

Question

Template Strings.

This link might help a little bit: Does PHP have a feature like Python's template strings?

What my main issue is, is to know if there's a better way to store Text Strings.

Now, is this normally done with one folder (DIR), and plenty of single standalone files with different strings, and depending on what one might need, grab the contents of one file, process and replace the {tags} with values.

Or, is it better to define all of them inside one single file array[]?

greetings.tpl.txt

['welcome'] = 'Welcome {firstname} {lastname}'.
['good_morning'] = 'Good morning {firstname}'.
['good_afternoon'] = 'Good afternoon {firstname}'.

Here's another example, https://github.com/oren/string-template-example/blob/master/template.txt

Thx in advance!

Answers that include solutions, that state that one should use include("../file.php"); are NEVER ACCEPTED HERE. A solution that shows how to read a LIST of defined strings into an array. The definition is already array based.

Answer 1

To add values to templates, you can use strtr. Example below:

$msg = strtr('Welcome {firstname} {lastname}', array(
    '{firstname}' => $user->getFistName(),
    '{lastname}' => $user->getLastName()
));

Regarding storing strings, you can save one array per language and then load only relevent one. E.g. you'll have a directory with 2 files:

• language
  • en.php
  • de.php

Each file should contain the following:

<?php

return (object) array(
    'WELCOME' => 'Welcome {firstname} {lastname}'
);

When you need translations, you can just do the following:

$dictionary = include('language/en.php');

And the dictionary will then have an object that you can address. Changing the example above, it will be something like this:

$dic = include('language/en.php');
$msg = strtr($dic->WELCOME, array(
    '{firstname}' => $user->getFistName(),
    '{lastname}' => $user->getLastName()
));

To avoid the situation when you don't have the template in dictionary, you can use a ternary operator with the default text:

$dic = include('language/en.php');
$tpl = $dic->WELCOME ?: 'Welcome {firstname} {lastname}';
$msg = strtr($tpl, array(
    '{firstname}' => $user->getFistName(),
    '{lastname}' => $user->getLastName()
));

What people usually do to be able to edit the texts in db, you can have a simple export (e.g. var_export) script to sync from db to files.

Hope this helps.

Answer 2

First, take a look at gettext. It is widely used and there is plenty of tools to handle translation process, like xgettext and POEdit. It is more comfortable to use real english strings in source code and then extract them using xgettext tool. Gettext can handle plural forms of practically all languages, which is not possible when using simple arrays of strings.

Very useful function to combine with gettext is sprintf() (or printf(), if you want to output text directly).

Example:

printf(gettext('Welcome %s %s.'), $firstname, $lastname);
printf(ngettext('You have %d new message.', 'You have %d new messages.',
    $number_of_new_messages), $number_of_new_messages);

Then, when you want to translate this into language where last name usually precedes first name, you can use this: 'Welcome %2$s, %1$s.'

The second example, the plural form, can be translated using more than two strings, because part of localization file is how plural forms are arranges. While for english it is nplurals=2; plural=(n != 1);, for example in czech it is nplurals=3; plural=(n==1) ? 0 : (n>=2 && n<=4) ? 1 : 2; (three forms, first is for one item, second for 2 to 4 items and third for the rest). For example Irish language has five plural forms.

To extract strings from source code use xgettext -L php .... I recommend writing short script with the exact command fitting your project, something like:

# assuming this file is in locales directory
# and source code in src directory
find ../src -type f -iname '*.php' > "files.list"
xgettext -L php --from-code 'UTF-8' -f "files.list" -o messages.pot

You may want to add custom function names using -k argument.

Answer 3

OK John I will elaborate.

The best way is to create a php file, for each language, containing the definition of an array of texts, using printf format for string substitution. If the amount of text is very large, you might consider partitioning it further. (a few MB is usually fine)

This is efficient in production, assuming the OS has a well tuned file cash. Slightly more so, it you use numerical indexes to the array.

It is much more efficient to let php populate the array, then to do it your self, reading a text file. this is after all, I assume, static text? If production performance is not an issue, please disregard this post.

greetings_tpl_en.php

$text_tpl={
   'welcome' => 'Welcome %s %s'
  ,'good_morning' => 'Good morning %s'
  ,'good_afternoon' => 'Good afternoon %s'
};

your.php

$language="en";
require('greetings_tpl_'. $language .'php');
....
printf($text_tpl['welcome'],$first_name,$last_name);

printf i a nice legacy from the C language. sprintf returns a string instead of outputting it.

You can find the full description of the php printf format here: http://php.net/manual/en/function.sprintf.php

(Do read Josef Kufner post again, when this is solved. +1 :c)

Hope this helps?

Answer 4

You could store all the templates in one associative array and also the variables that are to replace the placeholders, like

$capt=array('welcome' => 'Welcome {firstname} {lastname}',
            'good_morning' => 'Good morning {firstname}',
            'good_afternoon' => 'Good afternoon {firstname}');

$vars=array('firstname'=>'Harry','lastname'=>'Potter', 'profession'=>'wizzard');

Then, you could transform the sentences through a simple preg_replace_callback call like

function repl($a){ global $vars;  
  return $vars[$a[1]];
}
function getcapt($type){ global $capt; 
  $str=$capt[$type];
  $str=preg_replace_callback('/\{([^}]+)\}/','repl' ,$str);
  echo "$str<br>";                      
}
getcapt('welcome');
getcapt('good_afternoon');

This example would produce

Welcome Harry Potter
Good afternoon Harry