http://lifesend.com/ Worship en-us <!-- Found 0 labeled equations eq ids: --> <!-- Found 1 figures fig ids: scala_logo --> <style type="text/css">pre.code { background-color: #DDD; color: #112; padding: 10px; font-size: 90%; overflow: auto; margin: 4px 0px; width: 95%;}pre .normal {}pre .comment { color: #005; font-style: italic; }pre .keyword { color: #A00; font-weight: bold; }pre .method { color: #077; }pre .class { color: #074; }pre .module { color: #050; }pre .punct { color: #447; font-weight: bold; }pre .symbol { color: #099; }pre .string { color: #944; }pre .char { color: #F07; }pre .ident { color: #004; }pre .constant { color: #07F; }pre .regex { color: #B66; }pre .number { color: #F99; }pre .attribute { color: #5bb; }pre .global { color: #7FB; }pre .expr { color: #227; }pre .escape { color: #277; }div .aao_footer{ font-size: 80%; }</style> <div id=header> <h2>Thoughts on Scala</h2> Aaron Radke <br> 2009-07-20 <br> <em>A few thoughts and notes on Scala</em><p> </div> <div style="text-align:center"><a name="fig_scala_logo"></a><a href='/static/fig/scala_logo.png'><img src="/static/fig/scala_logo_500x500_sh.png" border="none" alt="scala_logo_500x500_sh.png" align="center" width="500" ></a><!-- <div class="caption"> Figure 1: none </div> --></div><p> <h2><a id="paradigmsyntax_general_principles"></a> paradigm/syntax general principles </h2> <h3><a id="from_ruby"></a> from ruby</h3> <ul> <li>mixins over inheritance</li> <li>the last statement of a function is the return value (encourages small modular code)</li> <li>no semicolon</li> <li>symbols with a prime before them like 'this</li> <li>everything is an object even primitives</li> <li>higher order functions for loop constructs</li> </ul> <h3><a id="from_mathematica"></a> from Mathematica</h3> <ul> <li>List based hierarchy and functional operations</li> <li>Powerful pattern matching for code branch decisions</li> </ul> <h3><a id="new"></a> new</h3> <ul> <li>syntax</li> <ul> <li>methods, classes, operators can all look the same to make a scalable language</li> <li>simple but expansive predifened associativity :, precedence provide scalability</li> <li>{}, () replacable</li> <li>_ for multiple fill on based on contexts</li> <li>pattern imports</li> </ul> <li>types</li> <ul> <li>imultibility (val, List)</li> <li>multibility (var, Array)</li> </ul> <li>operators</li> <ul> <li>Parenthesis on an object calls the apply method</li> <li>Parenthesis on an object with an equals assignment calls the update method</li> <li>Single argument methods do not require a dot</li> <li>Any method can be used in operator notation</li> <li>predefined prefix unary operators +,-,!,~</li> <li>postfix operators are methods that take no arguments</li> <li>methods ending in : are for right called objects in operator notation</li> <li>equals == test uniformly verifies value with a pre null check</li> <li>methods are operators, precedence is sorted by beginning characters and associativity is sorted by ending character(:)</li> </ul> <li>classes</li> <ul> <li>Factory methods make use of apply</li> <li>Companion objects for cleaner instantiation of a companion class</li> <li>base code is the build in constructor</li> <li>parameters are fields</li> <li>parameters can have preconditions with require</li> <li>separate companion objects for static like pieces</li> <li>case classes for field pattern matching and companion object construction</li> </ul> <li>traits</li> <ul> <li>linearization</li> </ul> <li>pattern matching</li> <ul> <li>case classes for field pattern matching and companion object construction</li> </ul> <li>control structures</li> <ul> <li>everything returns values</li> <li>nested loops by additional generators</li> <li>currying to make language like control structures</li> </ul> <li>functions</li> <ul> <li>first class functions</li> <li>function literals</li> blank _ assumed input parameter patterns partially applied functions with an automatic apply wrapping with _ matching </ul> <li>typing inference</li> <ul> <li>target typing</li> <li>simple flow typing versus complex Haskel typing for better OO interoperation</li> </ul> <li>built in tools</li> <ul> <li>xml</li> <li>combinator parsers: these are really powerful and really useful. These provide whole new levels of abstraction</li> </ul> </ul> <div class=aao_footer> <hr> </div> Aaron Radke Mon, 20 Jul 2009 16:57:57 +0000 <a href="/feed/scala">/scala</a> <a href="/feed/scala">/scala</a>