Difference between revisions of "Control Structures"

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imported>StDoodle
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imported>StDoodle
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{{TOCright}}
 
{{TOCright}}
=Conditional=
+
==Conditional==
==if==
+
===if===
 
{{
 
{{
 
CodeSample|
 
CodeSample|
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   // curly braces aren't required if only one statement follows the conditional
 
   // curly braces aren't required if only one statement follows the conditional
 
</syntaxhighlight>}}
 
</syntaxhighlight>}}
==else==
+
===else===
 
{{
 
{{
 
CodeSample|
 
CodeSample|
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</syntaxhighlight>}}
 
</syntaxhighlight>}}
  
==else if==
+
===else if===
 
{{
 
{{
 
CodeSample|
 
CodeSample|
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</syntaxhighlight>}}
 
</syntaxhighlight>}}
  
==switch==
+
===switch===
  
  
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       break;  
 
       break;  
 
   }
 
   }
=Looping=
+
==Looping==
== while ==
+
===while===
 
   while (boolean)
 
   while (boolean)
 
    
 
    
 
   {}
 
   {}
== repeat until ==
+
===repeat until===
 
   repeat
 
   repeat
 
   {}
 
   {}
 
   until (boolean);
 
   until (boolean);
== for ==
+
===for===
 
   for x from a to b by c
 
   for x from a to b by c
  
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If you don't specify "c", it defaults to incrementing/decrementing by 1.  The first iteration is at a and the last is at b (that is to say, it goes from a to b, inclusive).
 
If you don't specify "c", it defaults to incrementing/decrementing by 1.  The first iteration is at a and the last is at b (that is to say, it goes from a to b, inclusive).
  
== foreach ==
+
===foreach===
 
   foreach x in map
 
   foreach x in map
 
    
 
    
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   }
 
   }
 
See http://kolmafia.sourceforge.net/advanced.html#maps for more details on maps.
 
See http://kolmafia.sourceforge.net/advanced.html#maps for more details on maps.
== continue/break ==
+
===continue/break===
 
Like many languages with looping structures, ASH supports the break and continue statements.  All looping structures (for, while, repeat until, and foreach) support these statements.
 
Like many languages with looping structures, ASH supports the break and continue statements.  All looping structures (for, while, repeat until, and foreach) support these statements.
  

Revision as of 06:56, 14 March 2010

Conditional

if

if ( boolean )
{
   // any statements here
   // are only going to be executed
   // if the boolean returns true
}

Single-statement conditionals may omit the curly braces.

if ( boolean )
   // curly braces aren't required if only one statement follows the conditional

else

if ( boolean )
{
   // statements if true
}
else
{
   // the statements here
   // are only going to be executed
   // if the boolean returns false
}


else if

if ( boolean1 )
{
   // statements if true
}
else if ( boolean2 )
{
   // the statements here
   // are only going to be executed
   // if boolean1 returns false
   // & boolean2 returns true
}


switch

 switch (value) 
 {
   case expression:
     statement
     statement
     ...
     break;
   default:
     statement
     statement
     ...
     break; 
 }

Looping

while

 while (boolean)
 
 {}

repeat until

 repeat
 {}
 until (boolean);

for

 for x from a to b by c

is the general case. You don't need to specify whether it's going up or down - although doing so by using upto or downto does allow a runtime check to make sure you didn't screw up.

If you don't specify "c", it defaults to incrementing/decrementing by 1. The first iteration is at a and the last is at b (that is to say, it goes from a to b, inclusive).

foreach

 foreach x in map
 
 {}

"map" must be an aggregate - a map or a slice. x takes on each value of the map index in turn. If there is more than one index, x iterates over the first index.

For example:

 boolean [int][string] map;
 map[15]["test"] = true;
 foreach int_index in map
 {
   print(int_index); //this will print '15' once, since there is only one valid value for this index
   foreach string_index in map[int_index] //this iterates over the "slice" of the map where 1 is fixed as the index
   { 
     print(string_index); //This will print "test" once, since there is only one valid value for this index
     print(map[int_index][string_index]); //this will print "true"
   }
 }

So the output is

 15
 test
 true

Note that instead of nesting foreach statements, for a multidimensional map, two iterators can be used inline.

 foreach x,y in map

is identical to

 foreach x in map
 {
   foreach y in map[x]
 }

See http://kolmafia.sourceforge.net/advanced.html#maps for more details on maps.

continue/break

Like many languages with looping structures, ASH supports the break and continue statements. All looping structures (for, while, repeat until, and foreach) support these statements.

 break;

Breaks out of the smallest enclosing loop. In a switch statement, breaks out of the switch statement. Execution resumes at the first statement after the end of the loop/switch statement.

 continue;

Continues on to the next iteration of the loop (skipping any statments in this iteration that occur after the continue statement). In a switch statement, continue is allowed iff the switch is inside a loop, and acts as any other continue.