Macro Examples

The following examples show the structure and syntax of macros in rules.

Here’s an example macro showing the use of attributes, parameters, and “path” statements.

1"macros":
2 [ 
3        { 
4            "namespace": "myMacroNamespace",
5             "definitions": [ 
6                { 
7                    "name": "multiplyTwoNumbers",
8                     "parameters": [ 
9                        "firstNumber",
10                         "secondNumber" 
11                    ],
12                     "returns": "${p.firstNumber * p.secondNumber}" 
13                },
14                  { 
15                    "name": "deleteWidget",
16                     "description": "Deletes a widget and any references to the widget.",
17                     "parameters": [ 
18                        "widgetName" 
19                    ],
20                     "actions": [ 
21                        { 
22                            "action": "eval",
23                             "key": "results",
24                             "path": "${json:searchPaths(\”$.state.widget['p.widgetName']\”)}” 
25                       },
26                          { 
27                            "condition": "${!empty results}",
28                             "action": "delete",
29                             "path": "$.state.widgets['${p.widgetName}']" 
30                        },
31                          { 
32                            "condition": "${!empty results}",
33                             "action": "delete",
34                             "path": "$.state.gridLayouts..pages..widgets[?(@.name=='${p.widgetName}')]" 
35                        } 
36                    ] 
37                } 
38            ] 
39        } 
40    ],
41      "constants": [...],
42      "rules": [...] }

The following example calls a macro with namespace 'myNS' and macro name 'getSomething' defined with no parameters. Results of the macro are stored in the template context, and can be referenced using this expression: ${Rules.Eval.macroResults}.

1{
2  "action": "eval",
3  "key": "macroResults",
4  "value": "${myNS:getSomething()}"
5}

This example sets the JSON node at path $.path.to.json.node with the result of macro myNS:getJsonValue defined with no parameters. This action will only be called if the macro myNS:shouldExecute (defined with one parameter) returns true.

1{
2  "action": "set",
3  "condition": "${myNS:shouldExecute(true)}",
4  "path": "$.path.to.json.node",
5  "value": "${myNS:getJsonValue()}"
6}