no precompilation; unit module Grammar::ToAST; our proto cst2ast (|) is export { say 'cst2ast proto'; {*} } multi cst2ast (Match $_ where *.ast) { say '.ast'; .ast } # if arg is capture, with `.ast`, then return it multi cst2ast (Match $_ where *.list) { say '.list'; .&hashcheck: 0; .&cst2ast for .list } # else `cst2ast` of numbered captures if any multi cst2ast (Match $_ where *.hash) { say '.hash'; .&hashcheck: 1; cst2ast .hash.pairs[0].value } # else `cst2ast` of first named capture value multi cst2ast (Match $_) { say 'Match'; $_ } # else return capture as is multi cst2ast (@_) { say '@_'; .&cst2ast for @_ } # if NOT a single capture, then `cst2ast` args sub hashcheck ($_, $element-count) { # expecting either 0 or 1 hash elements return if .hash == $element-count; note "cst2ast ignoring hash pairs(s):\n", .hash.pairs[$element-count..*].join: "\n" } our proto hung (|) is export { say 'hung proto'; {*} } # Multi that will match for a *quantified* sub-capture `$` (eg sub-rule was `*` or `+`, NOT `` or `?`). multi hung (List $captures where *.all ~~ Match) { say '.all'; .&hung for $captures } # Multis that will match for a *non* quantified sub-capture `$` (i.e. sub-rule was eg ``, NOT eg `*`). multi hung (Match $_ where .ast) { say '.ast'; .ast } # if .ast already generated then use that multi hung (Match $_ where .list) { say '.list'; .&hung for .list } # elsif positional captures then use them multi hung (Match $_ where .hash) { say '.hash'; .hash.pairs[0].value } # elsif named captures then use the first value multi hung (Match $_) { say '$_'; $_ } # else use cst (concrete syntax tree capture) sub msg ($msg) { warn "hung $msg" } our proto hang (|) is export { say 'hang proto'; {*} } multi hang () { CALLERS::<$/> .make: hung CALLERS::<$/> } # if nullary `hang` then write caller's `hung` to its `.ast` multi hang ($ast) { CALLERS::<$/> .make: $ast } # elsif unary `hang` then write passed arg to caller's `.ast` multi hang (*@hung) { CALLERS::<$/> .make: do .&hung for @hung } # otherwise write list of `hung` of each passed arg to caller's `.ast` proto wrap { * } multi wrap () { :wrap }

Shane's Turing complete language; P6 grammar, parser