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dev:technologies [2011/04/21 13:51] – improve, I hope ajlyondev:technologies [2017/12/07 13:42] – bwiernik
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-A very brief introduction to some commonly used technologies used in translator development.+Three commonly-used technologies in [[dev:translators|translator development]] are CSS Selectors, XPath, and Regex. Resources for learning these technologies are linked to below:
  
-====== XPath ====== +==== CSS Selectors ==== 
-XPath provides a way to refer to specific parts of HTML or XML documents. It's usually the best way to extract data from webpages when writing a translator.+A comprehensive and accessible resource is available from W3Schools:\\ 
 +https://www.w3schools.com/cssref/css_selectors.asp
  
-An XPath expression is a chain of pieces that specify the path to a node of the document. The main pieces of expressions are:+The Mozilla Development Network (MDN) also provides a CSS Selector resource:\\ 
 +https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Selectors
  
-  * ''/'' Separator between parts of the path +==== XPath ====
-  * ''*'' match any tag +
-  * ''/ /'' one or more levels deeper (no space) +
-  * ''..'' go up one level +
-  * ''[]'' match a tag that has this (the contents of the brackets) +
-  * ''@key'' an attribute named ''key'' +
-  * ''text()'' match a text node +
-  * ''[2]'' match the second matching node  +
-  * ''[last()]'' match the last matching node +
-  * ''div[@class="important"]'' match a ''<div>'' with the attribute ''class'', with the value ''important''. +
-  * ''td[contains(text(),"Expect")]'' match a ''<td>'' which contains text that contains "Expect" +
-  * Plus much more. See the [[http://www.w3.org/TR/xpath/|XPath specification]] and the [[https://developer.mozilla.org/en/xpath|XPath documentation]] of the Mozilla Developer Network.+
  
-The best introduction to XPath for use in translators is Mozilla's [[https://developer.mozilla.org/en/Introduction_to_using_XPath_in_JavaScript|Introduction to using XPath in JavaScript]], but it may be even easier to model your code off of the logic in existing translators, which provide a wide array of XPath techniques to pick apart fussy sites.+A tutorial is available from Liquid Technologies:\\ 
 +https://www.liquid-technologies.com/xpath-tutorial
  
-=== Examples === +==== Regex ====
-<code html> +
-<div id="names"> +
-  <span class="editor">George Spelvin</span>, +
-  <span class="translator">Andrea Johnson</span> +
- </div> +
- <table> +
-  <tr class="odd"> +
-   <td>Great Expectations</td> +
-   <td>Mediocre Plans</td> +
-  </tr> +
- </table> +
-</code> +
-For the sample document above, these expressions would refer to... +
-  * ''/ /tr[@class="odd"]/td'': a result set with the nodes ''<td>Great Expectations</td>'' and ''<td>Great Expectations</td>'' +
-  * ''/ /table/ /td'': Same as previous +
-  * ''/ /span[@class="editor"]'': a result set with the single node ''<span class="editor">George Spelvin</span>''+
  
-====== Regular Expressions ====== +There are many high-quality regex tutorials available online. A comprehensive guide is provided all in one page at:\\ 
-  * ''.'' matches any character +https://github.com/zeeshanu/learn-regex/blob/master/README.md
-  * ''[a-z01]'' matches any of the lowercase English letters and the numbers 0 and 1 ( +
-  * ''()'' surround a match expression +
-  * ''+'' Match one or more of the preceding expression +
-  * ''*'' Match 0 or more of the preceding expression +
-  * ''?'' Match 0 or 1 of the preceding expression+
  
 +Regex 101 also provides a useful platform for testing regex structures:\\
 +http://regex101.com/