001 match basic

// Regex match as control flow — first e2e. `std/regex:match(input)`
// dispatches to the first `…`-pattern branch that fully matches, else
// `no-match`. Patterns are compiled to specialized DFA matchers at compile
// time. `match` is an ordinary module event (NOT a keyword): the invocation
// must be qualified, pattern branches bind or discard the payload (`_`),
// and `no-match` is void — bindingless by the linear rule (KORU101).
import std/regex
import std/io

std/regex:match("foo@bar")
| `[a-z]+@[a-z]+` _ |> std/io:print.ln("matched-email")
| `[0-9]+` _ |> std/io:print.ln("matched-number")
| no-match |> std/io:print.ln("no-match")