Helper Functions

These functions are helpful in mFQL query compositions.

GetByAddress

The getByAddress function is used in applying the results of one query to another. For example, we might have a node of particular interest, and we want our query to return only nodes that join (in some way) to the specified node.

     getByAddress(node: number)

This sample builds a set containing the single node related to the address specified:

     getByAddress(11256)

To create a set of more than one node, use several calls to the node function from within a union join.  This sample creates a set of three specific nodes:

     union(

     getByAddress(11256),

     getByAddress(55388),

     getByAddress(117740)

     )

GetByPosition

getByPosition(File: String, Offset: Number)

The getByPosition function is used to return the inner most node that covers a certain position in a file.  This function is useful for locating a position in the AST based upon a file position.

Distinct

distinct(source: set)

The distinct function ensures that a set has no duplicate values.  All duplicate values are excluded from the result set.

This function is required to handle a side effect of the move function; it can create a set that includes duplicate nodes.  The move function operates in this manner by design – it should only remove nodes that fail the specified traversal, ensuring the resulting set is discrete is beyond its scope and (in some cases) undesirable behavior.