Torin Sandall 3672a3f892 Improve call result handling ...

Previously, if callers omitted output terms from call expressions, the
result would be ignored. This was fine for most calls which would only
return true if they were defined, however, for functions could return
false this became confusing because an expression like "f(1)" where f(1)
= false would be succeed and yield a result.

With these changes, built-in functions that used to only return true
always return true or false and the eval engine takes care to check if
the result is false when the the caller omits the output term.

This provides consistent behaviour across cases like...

f(1)            => undefined (previously {})
f(1,x)          => {x:false} (previously {x:false})
neq(1,1,x)      => {x:false} (previously undefined)
neq(1,1,false)  => {}        (previously undefined)
neq(1,1,true)   => undefined (previously undefined)

In the next set of changes, the Rego package will be updated to capture
values for expressions like the first one above so that function calls
behave like refs (i.e., their values are returned).

2018-02-17 08:21:04 -08:00

..

types_test.go

Improve call result handling

2018-02-17 08:21:04 -08:00

types.go

Improve call result handling

2018-02-17 08:21:04 -08:00