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copied!<p>1) Apparently, there are others: <a href="http://en.wikipedia.org/wiki/Type_system" rel="nofollow">http://en.wikipedia.org/wiki/Type_system</a></p> <p>2)</p> <p><code>Dynamic</code> => Type checking is done during runtime (program execution) e.g. Python.</p> <p><code>Static</code> (as opposed to Dynamic) => Type checking is done during compile time e.g. C++</p> <p><code>Strong</code> => Once the type system decides that a particular object is of a type, it doesn't allow it to be used as another type. e.g. Python</p> <p><code>Weak</code> (as opposed to Strong) => The type system allows objects types to change. e.g. perl lets you read a number as a string, then use it again as a number</p> <p><code>Type safety</code> => I can only best describe with a 'C' statement like:</p> <pre><code>x = (int *) malloc (...); </code></pre> <p><code>malloc</code> returns a (void *) and we simply type-cast it to (int *). At compile time there is no check that the pointer returned by the function malloc will actually be the size of an integer => Some C operations aren't type safe.</p> <p>I am told that some 'purely functional' languages are inherently type safe, but I do not know any of these languages. I think Standard ML or Haskell would be type safe.</p> <p>3) "If a language allows you to change the type of a variable in runtime (e.g. a variable that used to store an int is later used to store a string), what category does that fall in?":</p> <p>This may be dynamic - variables are untyped, values may carry implicit or explicit type information; alternatively, the type system may be able to cope with variables that change type, and be a static type system. </p> <p>4) Python: It's dynamically and strongly typed. Type safety is something <em>I</em> don't know python (and type safety itself) enough to say anything about.</p> <p>5) "Is there anything else I should know about type systems?": Maybe read the book @BasileStarynkevitch suggests?</p>

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