Output changed to a bit stranger ! a = 3\na from just 3

[adamritter]

Hi guys,

I just updated HVM3 after a month (I was a bit afraid of backwards compatibility problems, but it's awesome).

It's really not important, just an observation:

the output for a program

@main = 3

changed to

! a = 3
a

from just 3

It's strange because I haven't created any variable, but as I said it's very minor issue

[nicolas-abril]

I got reminded of your issue while reading the HVM code. The reason we changed to adding a Let is so that the Dups can be lifted to the outer scope and be printed after the root term. So for example:

λx. !0{a b} = x; λp. (p a b)

becomes

!a = λx. λp. (p a b);
!0{a b} = x;
a

For small outputs this might seems annoying, but the duplications really get in the way of reading long complicated terms.