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Finding ZefOps

Getting Details on a specific ZefOp​

yo(trim_left)

yo can be used across the board on various data structure, ZefOps, ValueTypes, graphs, etc. It prints a short summary.

Searching for Specific ZefOps​

Zef allows you to treat your codebase like a database. You can write queries in a declarative style when you're looking for things.

Let's look at an example. Suppose we're looking for all operators that are part of the core Zef library that operate on Strings. 

ops | all[OperatesOn(List)] | collect  
  
# also works when there is no type for this  
ops | all[UsedFor['control flow']] | collect

ops is a namespace that comes with Zef and contains all commonly used operators. In these queries we always start with a general set on the left (ops here) and now we can search for ones that fulfill some specified attributes.

The all Query Operator​

all is an operator itself that acts similar to filter. It differs from filter in that it interprets the dataflow argument to the left liberally as some kind of implicit set. For instance, a namespace, a FlatGraph, a ZefDB Graph may all be interpreted as a starting set in the context of a query.

Queries using LogicTypes / Sets​

In queries we want to specify what we want in a declarative and composable way. In Zef Logic Types (which are ValueTypes) are used for this. They denote sets of things. We can specify each constraint on what we want using a ValueType.

Defining Custom LogicTypes​

OperatesOn is a function that returns a value of type ValueType.
The details of which set of things it defines for some given input arguments are encapsulated inside the function body. Anything you can express via a predicate function my_predicate, you can directly wrap as a Logic Type using Is[my_predicate].

OperatesOn is a predefined function that is aware of the structure used in ZefOp's docstrings. OperatesOn(List) denotes the set of all ZefOps which are tagged to act on the type List.

Further examples of queries: 

ops | all[OperatesOn(List) & UsedFor("control flow")] | collect  
ops | all[OperatesOn(Stream) & UsedFor("string manipulation")] | collect  
ops | all[UsedFor("string manipulation") & ~OperatesOn(String)] | collect  
ops | all[RelatedOps(filter)] | collect