Differences

This shows you the differences between two versions of the page.

--- lara:docs:sheet [2018/10/23 12:48]
tdrc [Regular Expressions]
+++ lara:docs:sheet [2019/09/22 15:47]
@@ Line 1: / Line 1: @@
-====== LARA Fundamentals ======
-==== Aspects ====
-Aspectdef definition
-<code lara>
-aspectdef MyFirstAspect // The main aspect is the first declared in the file
-   // aspect code
-end
-aspectdef ASecondAspect // An aspect that can be called in the main aspect
-   // aspect code
-end
-</code>
-==== Select ====
-Select with full join point chain:
-<code lara>
-select program.file.function.body.loop end
-</code>
-Select with only last join point. The chain is induced, produces the same result as above:
-<code lara>
-select loop end
-</code>
-Assign the selected join points to a variable for later use:
-<code lara>
-LOOPS: select loop end
-</code>
-Assign an alias for specific join points:
-<code lara>
-select ($p=loop).($c=loop) end
-</code>
-==== Apply ====
-Apply after a select:
-<code lara>
-select loop end
-apply
-    println($loop.rank);
-end
-</code>
-Apply on a previously selected set of join points:
-<code lara>
-apply to LOOPS
-    println($loop.rank);
-end
-</code>
-It is possible to perform a natural join on two sets of join points:
-<code lara>
-LOOP_START: select function.body.loop.($loop_start = first) end
-FUNCTION_FIRST: select function.body.first end
-apply to LOOP_START::FUNCTION_FIRST
-    // Init counters at the beginning of the function
-    $first.insert before%{counter_[[$loop.uid]] = 0;}%;
-    // Increment counters when entering the loop
-    $loop_start.insert before%{counter_[[$loop.uid]] = counter_[[$loop.uid]] +1;}%;
-    // ...
-end
-</code>
-Use of join points with aliases inside the apply statement:
-<code lara>
-select ($p=loop).($c=loop) end
-apply
-   $p.exec Interchange($c);
-end
-</code>
-==== Conditions ====
-Using a condition block:
-<code lara>
-select function end
-apply
-    // ...
-end
-condition
-    $function.name == 'kernel'
-end
-</code>
-Combining conditions using && (and) and || (or) operators:
-<code lara>
-select loop end
-apply
-    $loop.exec Unroll(2);
-end
-condition
-    $loop.is_innermost &&
-    $loop.type=="for"
-end
-</code>
-Using "filter" conditions on the join point chain:
-<code lara>
-select function{name=='kernel'} end
-apply
-    // ...
-end
-// OR
-select function{'kernel'} end // uses the default attribute of the join point
-apply
-    // ...
-end
-</code>
-==== Aspect Inputs and Outputs ====
-Input parameter definition:
-<code lara>
-input
-    funcs,
-    opt
-end
-</code>
-Input parameter definition with default values:
-<code lara>
-input
-    funcs = ['kernel'],
-    opt = ['unroll', 'interchange', 'tile']
-end
-</code>
-Output definition. Output cannot be initialized inside the **output** block:
-<code lara>
-output
-    optFuncs,
-    code
-end
-optFuncs = [];
-code = '';
-</code>
-==== Calling Aspects ====
-Simple aspect call:
-<code lara>
-call OptimizeProgram();
-</code>
-Calling an aspect with arguments:
-<code lara>
-call OptimizeFunctions(functions, optimizations);
-</code>
-Calling an aspect with named arguments:
-<code lara>
-call OptimizeFunctions(opt: optimizations, funcs: ['gridIterate']);
-</code>
-Calling an aspect and retrieving the outputs:
-<code lara>
-// Current syntax
-var optimizer = call OptimizeFunctions(functions, optimizations);
-// Previous syntax
-call optimizer : OptimizeFunctions(functions, optimizations);
-var changedFuncs = optimizer.optFuncs;
-var finalCode = optimizer.code;
-</code>
-Assigning an aspect call to a variable for later use. Can still use input arguments and outputs as shown before:
-<code lara>
-var optimizer = new OptimizeFunctions(functions, optimizations);
-call optimizer(); // or optimizer.call()
-var changedFuncs = optimizer.optFuncs;
-var finalCode = optimizer.code;
-</code>
-Aspects can also be called inside Javascript files (.js). You need to build the aspect object and reference the complete path, separated by dollar signs ($):
-<code lara>
-// Calling aspect MeasureEnergy from inside a .js file
-(new lara$profiling$Energy$EnergyTest()).call();
-</code>
-==== Using LARA Actions ====
-Actions are used inside apply statements. There are two default actions, **insert** and **def**. Then, it is possible to use weaver-specific actions, which are called with the **exec** keyword:
-<code lara>
-select function{'kernel'} end
-apply
-    insert before '/* Creating a clone. */';  // add a comment before the function
-    def name = 'original_kernel';  // redefine the name of the kernel function
-    exec clone('cloned_kernel');  // use a MANET-specific action to create a 'kernel' clone named 'cloned_kernel'
-end
-</code>
-When calling an action we can specify any join point in the chain to be the action target:
-<code lara>
-select function.loop end
-apply
-    $loop.exec tile(8);
-    $function.insert before '/* This function was transformed. */';
-end
-</code>
-It is possible to omit the target, the last join point in the chain is used:
-<code lara>
-select function.loop end
-apply
-    exec unroll(2);  // performed on the same loop as below
-    $loop.exec tile(8);  // performed on the same loop as above
-end
-</code>
-If the action returns a result, we can use the following syntax:
-<code lara>
-   var result = $jp.exec <action_name>;
-</code>
-If 'result' is a variable that already exists, 'var' can be omitted:
-<code lara>
-   result = $jp.exec <action_name>;
-</code>
-The keyword '.exec' can be omitted if you prefix the name of the action with the target join point, and add parenthesis:
-<code lara>
-  result = $jp.<action_name>();
-</code>
-==== Calling shell commands ====
-You can invoke shell commands from LARA using the function cmd. The first argument is the command, and the second an array with the arguments for the command:
-<code lara>
-cmd("ls", ["-l", "-v"]);
-</code>
-==== Using LARA from the Command Line ====
-=== Include Folder ===
-To add include folders, use the flag -i. To add more than one folder, use double quotes and separate the folders with the file separator character of your current system
-<code>
-larai -i "libs1;libs2"
-</code>
-=== Passing Arguments to the Aspect ===
-To pass arguments to the top-level aspect use the flag -av. The input is a JSON representation of the input:
-<code>
-larai -av "{inputFile:'data.json',execute:true,iterations:10}"
-</code>
-==== Codedef Sections ====
-To insert sections of code that span several lines, you can define codedef sections, which act as templates. Example:
-<code lara>
-codedef CodeTemplate(param1, param2) %{
-// This code is inserted as-is, without escaping
-// To apply the values of parameters, use [[]]
-var [[param1]] = [[param2]];
-}% end
-</code>
-Declared codedefs can then be used in the code as functions:
-<code lara>
-code = CodeTemplate("varName", 2);
-</code>
-====== Miscellaneous ======
-==== Regular Expressions ====
-Lara supports JavaScript regular expressions, for instance:
-<code lara>
-var regex = /(return\s+)(10)(\s*;)/;
-regex.test("return 10;"); // Returns 'true'
-</code>
-Since **exec** is a LARA keyword, calling **regex.exec** is not permitted. However, you can access object properties using strings to circumvent this limitation:
-<code lara>
-(regex['exec']("return 10;"))[2]; // Returns '10'
-</code>
-Alternatively, you can also use the **match** function in strings:
-<code lara>
-String('aaaa').match(new RegExp('a*')) // Returns 'aaaa'
-</code>
-Or you can also use the **match** boolean operator ( **~=** ):
-<code lara>
-'aaaa' ~= 'a*' // Returns true
-</code>
-==== Importing LARA Files ====
-LARA supports importing LARA files that are present in the include path using the keyword **import**. To import a file, you have to use the path to the file from the include folder, using *.* as separator and omitting the extension of the file. For instance, if you add as include the folder *~/foo* and you want to import the file *~/foo/bar/Aspect.lara*, you can write the following code:
-<code lara>
-import bar.Aspect;
-</code>
-Import statements must be the first statements in a LARA file. LARA weavers come bundled with support for a set of imports, which are part of their API (e.g., [[http://specs.fe.up.pt/tools/clava/doc/|Clava API]]).
-==== Reading/Writing JSON Files ====
-LARA supports reading from and writing to JSON objects with the object **Io**:
-<code lara>
-import lara.Io;
-...
-Io.writeJson("file.json", anObject);
-var loadedObject = Io.readJson("file.json");
-</code>

LARA Wiki

User Tools

Site Tools

Differences

Page Tools