idris - Data Type Encompassing Two Sum Types? -

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given these 2 sum types:

data foo = int | b string data bar = c int | d string

i'd define function returns either (foo or bar) string.

so, attempted make:

data higher = foo | bar

but failed compile:

*adt> :r type checking ./adt.idr adt.idr:3:6:main.foo defined adt.idr:4:6:main.bar defined

how can create higher data type, consists of foo or bar?

yes can indeed!

data foo = int | b string data bar = c int | d string  data higher : type     injfoo : foo -> higher     injbar : bar -> higher

now can injfoo (b "hello") or injbar (c 5).


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