Personnel

• Owner: @vgurevich
• Supporters: @mbudiu-vmw

Design

• Document: See below

Implementation

• p4-spec:
• p4c:

Process

• LDWG discussed:
• LDWG approved:
• Merged into p4-spec:
• Merged into p4c:

Hello,

I was wondering if it is possible to initialize header stacks, and if yes, how.

Obviously, we can initialize headers using tuples:

vlan_tag_t vtag = { 3w5, 1w0, 12w100, 16w0x0800 };

However, it is not clear what to do with a stack. I tried a tuple of tuples, which didn't go well:

vlan_tag_t[2] vtag = {
    { 3w5, 1w0, 12w100, 16w0x0800 },
    { 3w5, 1w0, 12w100, 16w0x0800 }
};

The compiler said: "Cannot unify Tuple(2) to header vlan_tag_t[]"

I tried to flatten the initializer, by removing the internal braces. In that case the compiler could not unify Tuple(8) to vlan_tag_t[].

Casting didn't work either.

Is there any kind of tuple that can be unified with a header stack?

Thanks,
Vladimir