@include std.builtins
@include std.mem

smo Segment(nominal, str value)
    -> @args // return all inputs

smo Segment(String _value)
    value = _value:str 
    -> nominal:Segment(value)

smo combine(Segment[] segments)
    &s = "":str  // mutable
    on Stack:arena(1024)
        range(segments:len)
        :while next(u64 &i)
            // from null-termiated nstr result to str
            s = str(s+segments[i].value+" ")
    -- -- -> combined // end block x2, return

service main()
    segments = Segment[] 
    :push("I think.":Segment)
    :push("Therefore I am.":Segment)
    print(segments:combine)
    --

Details

In the example, freeing the arena is safely delayed until printing. All operations are also zero-cost abstractions over performant implementations at the core of the standard library. Furthermore:

• smo definitions can fail and produce nominal values.
• nominal declares a nominal type variation.
• service runs safely; if a smo fails, memory is cleaned up.
• & denotes mutable variables.
• on is automatically added as first argument (here to store string addition on a fast arena allocator).
• : curries arguments.
• [] declares buffers.
• --, -> mark block ends and returns.