try { expression } catch err { handler }
set result (try { expr } catch e { fallback })

set result (try { 42 } catch e { 0 })
# result is 42

set result (try { [throw "boom"] } catch e { "caught: $e" })
# result is "caught: boom"

try {
    set data [unwrap [fs/read "missing.txt"]]
    [process $data]
} catch err {
    echo "Error: $err"
}