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diff --git a/doc/codewalk/functions.xml b/doc/codewalk/functions.xml deleted file mode 100644 index db518dcc06..0000000000 --- a/doc/codewalk/functions.xml +++ /dev/null @@ -1,105 +0,0 @@ -<codewalk title="First-Class Functions in Go"> - -<step title="Introduction" src="doc/codewalk/pig.go"> - Go supports first class functions, higher-order functions, user-defined - function types, function literals, closures, and multiple return values. - <br/><br/> - - This rich feature set supports a functional programming style in a strongly - typed language. - <br/><br/> - - In this codewalk we will look at a simple program that simulates a dice game - called <a href="http://en.wikipedia.org/wiki/Pig_(dice)">Pig</a> and evaluates - basic strategies. -</step> - -<step title="Game overview" src="doc/codewalk/pig.go:/\/\/ A score/,/thisTurn int\n}/"> - Pig is a two-player game played with a 6-sided die. Each turn, you may roll or stay. - <ul> - <li> If you roll a 1, you lose all points for your turn and play passes to - your opponent. Any other roll adds its value to your turn score. </li> - <li> If you stay, your turn score is added to your total score, and play passes - to your opponent. </li> - </ul> - - The first person to reach 100 total points wins. - <br/><br/> - - The <code>score</code> type stores the scores of the current and opposing - players, in addition to the points accumulated during the current turn. -</step> - -<step title="User-defined function types" src="doc/codewalk/pig.go:/\/\/ An action/,/bool\)/"> - In Go, functions can be passed around just like any other value. A function's - type signature describes the types of its arguments and return values. - <br/><br/> - - The <code>action</code> type is a function that takes a <code>score</code> - and returns the resulting <code>score</code> and whether the current turn is - over. - <br/><br/> - - If the turn is over, the <code>player</code> and <code>opponent</code> fields - in the resulting <code>score</code> should be swapped, as it is now the other player's - turn. -</step> - -<step title="Multiple return values" src="doc/codewalk/pig.go:/\/\/ roll returns/,/true\n}/"> - Go functions can return multiple values. - <br/><br/> - - The functions <code>roll</code> and <code>stay</code> each return a pair of - values. They also match the <code>action</code> type signature. These - <code>action</code> functions define the rules of Pig. -</step> - -<step title="Higher-order functions" src="doc/codewalk/pig.go:/\/\/ A strategy/,/action\n/"> - A function can use other functions as arguments and return values. - <br/><br/> - - A <code>strategy</code> is a function that takes a <code>score</code> as input - and returns an <code>action</code> to perform. <br/> - (Remember, an <code>action</code> is itself a function.) -</step> - -<step title="Function literals and closures" src="doc/codewalk/pig.go:/return func/,/return roll\n\t}/"> - Anonymous functions can be declared in Go, as in this example. Function - literals are closures: they inherit the scope of the function in which they - are declared. - <br/><br/> - - One basic strategy in Pig is to continue rolling until you have accumulated at - least k points in a turn, and then stay. The argument <code>k</code> is - enclosed by this function literal, which matches the <code>strategy</code> type - signature. -</step> - -<step title="Simulating games" src="doc/codewalk/pig.go:/\/\/ play/,/currentPlayer\n}/"> - We simulate a game of Pig by calling an <code>action</code> to update the - <code>score</code> until one player reaches 100 points. Each - <code>action</code> is selected by calling the <code>strategy</code> function - associated with the current player. -</step> - -<step title="Simulating a tournament" src="doc/codewalk/pig.go:/\/\/ roundRobin/,/gamesPerStrategy\n}/"> - The <code>roundRobin</code> function simulates a tournament and tallies wins. - Each strategy plays each other strategy <code>gamesPerSeries</code> times. -</step> - -<step title="Variadic function declarations" src="doc/codewalk/pig.go:/\/\/ ratioS/,/string {/"> - Variadic functions like <code>ratioString</code> take a variable number of - arguments. These arguments are available as a slice inside the function. -</step> - -<step title="Simulation results" src="doc/codewalk/pig.go:/func main/,/\n}/"> - The <code>main</code> function defines 100 basic strategies, simulates a round - robin tournament, and then prints the win/loss record of each strategy. - <br/><br/> - - Among these strategies, staying at 25 is best, but the <a - href="http://www.google.com/search?q=optimal+play+pig">optimal strategy for - Pig</a> is much more complex. -</step> - -</codewalk> |