Extend operators and functions in expressionParser.js

[fgalan]

Expression plugin includes a basic set of operators and functions in expressionParser.js. However, it could be extended with the following ones:

• if(cond,then,else) function
• Comparison operators: <, <=, >, <=
• Logical operators: and, or, not
• Bitwise operations: <<, >>, and, or, not
• Math functions: sin, cos, abs, min, man, random, mod, floor, ceiling, round
• String functions: uppercase, lowercase, replace, slice

[fgalan]

Implemented by PR #688

[fgalan]

Sometimes we need to use expressions to build JSON attribute values like this one:

{
   "devices":[
      {
         "device_id":"manu49",
         "protocol":"IoTA-UL",
         "entity_name":"manu49",
         "entity_type":"WasteContainer",
         "attributes":[
            {
               "name":"location",
               "type":"string",
               "expression": "{"type":"Point","coordinates": ["${@latitude}","${@longitude}"]}"
            },
            {
               "name":"fillingLevel",
               "type":"Number",
               "expression": "${@level / 100}"
            },
            {
               "object_id":"tt",
               "name":"temperature",
               "type":"Number"
            }
         ]
      }
   ]
}

Detail:

"expression": "{"type":"Point","coordinates": ["${@latitude}","${@longitude}"]}"

We should take this into account.

Not fully sure if this part of this issue or is somehow related with this more general one about JSON value attributes at CB: #549

CC: @manucarrace

[fgalan]

Duplicated (somehow) of #1052. Closing.