A concrete syntax tree represents the source text exactly in parsed form. In general, it conforms to the context-free grammar defining the source language. However, the concrete grammar and tree have a lot of things that are necessary to make source text unambiguously parseable, but do not contribute to actual meaning. For example, to implement … Read more
I saw this question a lot when I worked for an address verification company. I’m posting the answer here to make it more accessible to programmers searching around with the same question. The company I was at processed billions of addresses, and we learned a lot in the process. First, we need to understand a … Read more
If you want an easy way to code parsers, or you are tight on space, you should hand-code a recursive descent parser; these are essentially LL(1) parsers. This is especially effective for languages which are as “simple” as Basic. (I did several of these back in the 70s!). The good news is these don’t contain … Read more
This is caused by the third param of your Mage::helper(‘core/string’)->truncate() call, where the ending string delimiter seems to be missing. You get the unexpected T_STRING error, because the interpreter reaches the next string (‘short’), while knowing that the previous string end wasn’t found yet. Replace this line <h3 class=”product-name”><a href=”https://stackoverflow.com/questions/10328245/<?php echo $_product->getProductUrl() ?>” title=”<?php echo … Read more
Is an automatic quiz generator possible? It depends on what you call automatic, and what you consider a successful level of functionality. Something is definitely possible. Is it that automatic, or do you have to enter your own questions and correct answers? Can it observe text syntax so that it can create questions based on … Read more