Tutorial by Examples: d

Guard patterns can be used to check that a value satisfies an arbitrary test-form. (dotimes (i 5) (format t "~d: ~a~%" i (match i ((guard x (oddp x)) "Odd!") (_ "Even!")))) ; 0: Even! ; 1: Odd! ; 2: Even! ; 3: Odd! ; 4: ...

CL-PPCRE:REGISTER-GROUPS-BIND will match a string against a regular expression, and if it matches, bind register groups in the regex to variables. If the string does not match, NIL is returned. (defun parse-date-string (date-string) (cl-ppcre:register-groups-bind (year month day) (...

A pointer to base class can be converted to a pointer to derived class using static_cast. static_cast does not do any run-time checking and can lead to undefined behaviour when the pointer does not actually point to the desired type. struct Base {}; struct Derived : Base {}; Derived d; Base* p1 ...

Say you want to print variables in a 3 character column. Note: doubling { and } escapes them. s = """ pad {{:3}} :{a:3}: truncate {{:.3}} :{e:.3}: combined {{:>3.3}} :{a:>3.3}: {{:3.3}} :{a:3.3}: {{:3.3}} :{c:3...

A class, functions as a template that defines the basic characteristics of a particular object. Here's an example: class Person(object): """A simple class.""" # docstring species = "Homo Sapiens" ...

We can omit the argument in the call if that argument is an Optional Argument Every Optional Argument has its own default value It will take default value if we do not supply the value A default value of a Optional Argument must be a Constant expression. Must be a value type such as enum or s...

The ref keyword for callers of methods is now optional when calling into methods supplied by COM interfaces. Given a COM method with the signature void Increment(ref int x); the invocation can now be written as either Increment(0); // no need for "ref" or a place holder variable any m...

A new pseudo-type dynamic is introduced into the C# type system. It is treated as System.Object, but in addition, any member access (method call, field, property, or indexer access, or a delegate invocation) or application of an operator on a value of such type is permitted without any type checking...

XML <Galaxy> <Light>sun</Light> <Device>satellite</Device> <Sensor>human</Sensor> <Name>Milky Way</Name> </Galaxy> XPATH /Galaxy/*[local-name()='Light' or local-name()='Device' or local-name()='Sensor'] or //*[...

XML <Data> <BioLight> <name>Firefly</name> <model>Insect</model> </BioLight> <ArtificialLight> <name>Fire</name> <model>Natural element</model> <source>flint<...

XML <College> <FootBall> <Members>20</Members> <Coach>Archie Theron</Coach> <Name>Wild cats</Name> <StarFootballer>David Perry</StarFootballer> </FootBall> <Academics> ...

XML <College> <FootBall> <Members>20</Members> <Coach>Archie Theron</Coach> <Name>Wild cats</Name> <StarPlayer>David Perry</StarPlayer> </FootBall> <VolleyBall> <Me...

XML <Galaxy> <Light>sun</Light> <Device>satellite</Device> <Sensor>human</Sensor> <Name>Milky Way</Name> </Galaxy> XPATH /Galaxy/*[lower-case(local-name())="light"] or //*[lower-case(local-name())=&qu...

To create a function which accepts an undetermined number of arguments, there are two methods depending on your environment. 5 Whenever a function is called, it has an Array-like arguments object in its scope, containing all the arguments passed to the function. Indexing into or iterating over th...

XML <Galaxy> <name>Milky Way</name> <CelestialObject name="Earth" type="planet"/> <CelestialObject name="Sun" type="star"/> </Galaxy> XPATH /Galaxy/*[@name] or //*[@name] OUTPUT <CelestialObje...

XML <Galaxy> <name>Milky Way</name> <CelestialObject name="Earth" type="planet"/> <CelestialObject name="Sun" type="star"/> </Galaxy> XPATH /Galaxy/*[@name='Sun'] or //*[@name='Sun'] OUTPUT <C...

XML <Galaxy> <name>Milky Way</name> <CelestialObject name="Earth" type="planet"/> <CelestialObject name="Sun" type="star"/> </Galaxy> XPATH /Galaxy/*[contains(@name,'Ear')] or //*[contains(@name,'Ear...

XML <Galaxy> <name>Milky Way</name> <CelestialObject name="Earth" type="planet"/> <CelestialObject name="Sun" type="star"/> </Galaxy> XPATH /Galaxy/*[contains(lower-case(@name),'ear')] or //*[contain...

XML <Galaxy> <name>Milky Way</name> <CelestialObject name="Earth" type="planet"/> <CelestialObject name="Sun" type="star"/> </Galaxy> XPATH /Galaxy/*[starts-with(lower-case(@name),'ear')] or //*[star...

XML <Galaxy> <name>Milky Way</name> <CelestialObject name="Earth" type="planet"/> <CelestialObject name="Sun" type="star"/> </Galaxy> XPATH /Galaxy/*[ends-with(lower-case(@type),'tar')] or //*[ends-w...