I think that most of us learn by relating new things we hear or read or see to things we already know. For example, most of us were taught how to multiply integers in elementary school by showing us how multiplication was really like adding (which we already knew), but that we were now adding same-sized groups of things instead of adding individual things. We were taught multiplication based on our already assumed knowledge of how to perform addition. Likening multiplication to addition not only helped us to learn multiplication quicker, but also served as a memory device. If we ever forgot the mechanics of multiplication (forgot the multiplication tables we memorized), we could return to our understanding of multiplication related to addition to remember what the product of two numbers is.
Most of us learn about software the same way. I started learning and working with Ruby before transitioning from Java 1.4.2 to Java 5 and the experience helped me to be more comfortable with the Java 5 enhanced for-each loop because I had seen a similar looping syntax in Ruby. Likewise, Ruby on Rails helped to introduce the concept of convention over configuration to me, which made it trivial to understand the Java Persistence API's (JPA's) configuration by exception concept. When I first experimented with Java, my C++ experience was significantly helpful in understanding Java syntax and in learning Java more quickly than I would have without C++ experience. Similarly, my first experiments with C# went much quicker thanks to my Java and C++ experience.
The final example I wanted to cover of this concept has to do with the quantifier symbol notation that is common to XML DTDs, regular expressions, and XQuery.
In regular expressions, the symbols
*have special meanings as metacharacters. It turns out that the DTD creators and XQuery creators took advantage of this and gave these same symbols similar meanings in their respective specifications. The table below lists what these three symbols mean in each of these categories.
|High-level Technology||Specifically Affected||?||+||*|
|Regular Expressions||Number of Characters or Groups||Optional||One or more||Any number|
|XML DTD||Occurrence Indicators (XML Elements)||Optional||One or more||Any number|
|XQuery||Occurrence Indicators (Type Expressions)||Optional||One of more||Any number|
As the table above indicates, the symbol
?means optional (one or zero occurrence) for any character or group it follows in a regular expression and means that same thing for any defined element it follows in a DTD and for any XQuery type expression it follows. Similarly,
+means one or more (one to many) for all three (regular expressions, DTD, and XQuery) and
*means zero or more (zero to many) for all three areas.
The purpose of this blog has been to both illustrate how software development experience can make a software developer more productive and more adaptable to new technologies and to explicitly demonstrate the the common symbolic notation used for regular expressions, DTDs, and XQuery for specifying quantities of "things" in each area.
There is one downside to all of this, however. While an experienced developer can apply previously learned knowledge and skills to learning a new knowledge or skill, he or she must be cautious about allowing current knowledge to block the ability to think creatively and in new ways. The tendency to always do things the way we've done them before has its downsides and has led to the business lingo favorite: "Think outside of the box."