class_schema_setops: Schema: set operations for schemas
In jeanmathieupotvin/cargo: Data containers, schemas and prototypes

Description Usage Arguments Details Value See Also

Similar to base R set functions, but for objects of class Schema. Functions sintersect(), sdiff() and sequal() compare any R object that has a defined as_schema() method to an object of class Schema.

sintersect(x, y, what = c("inputs", "types"))

sdiff(x, y, what = c("inputs", "types"))

sequal(x, y, what = c("inputs", "types", "strict"))

x

an object of class Schema or any other R object that has a defined as_schema() method.

y

an object of class Schema.

what

a character equal to:

"inputs" (match inputs only),
"types" (match prototypes' classes of common inputs) or
"strict" (for sequal() only, match everything).

Argument what is matched partially and can be abbreviated

These functions compare the structure of x to what y dictates. Comparisons are always done with respect to y:

sintersect() returns the common inputs or prototypes between y and x.
sdiff() returns the differences between inputs or prototypes of y and x. If the underlying schema of x is a superset of y, then only the intersection of y and x is looked at. The rest is ignored.

Function sequal() is a wrapper to sdiff(). A "strict" comparison checks both inputs and prototypes. If the intersection of y and x is y, then x and y are considered to be equal schemas.

Method dispatch

If x is not an object of class Schema, it it coerced to such an object by using the appropriate as_schema() method. This is why set functions are not generic functions, method dispath is implicitely done by as_schema().

Comparing prototypes

Comparing prototypes makes sense only for common inputs to y and x. Consequently, comparing prototypes triggers a comparison between inputs first.

Functions sintersect() and sdiff() return a named character, possibly empty. The output of sintersect() is the set of common inputs (in the sense given by what) to y and x, while the output of sdiff() is the set of inputs that are in y but not in x.

Function sequal() returns a logical. A TRUE implies equality in the sense given by what.

Other Schema: Schema-accessors, Schema-class, Schema-coercions, Schema-extractors, Schema-methods, Schema-validators, is_schema()