yet another approach

more.rx

9 variable: prefix:CHAR

create prefix:TABLE
  256 allot

: getc:internal  ( -c )  &getc 2 + @ do ;

[ dup @prefix:CHAR ==
  [ drop getc:internal
    "prefix:TABLE" find drop @d->xt + @ dup 0 <>
    [ dip cr ] [ drop ] if 0
  ] ifTrue
  dup '| ==
  [ drop getc:internal dup putc space prefix:TABLE + &' do swap ! cr 0 ] ifTrue
] is remapKeys

: prefix:tab 09 !prefix:CHAR ;
: prefix:space 32 !prefix:CHAR ;

: (matching) ;
: bindTo: ( quote "character" - )
  getc "prefix:TABLE" find drop @d->xt + ! ;

[ cr
  "?        help text\n" puts
  "d<word>  documentation for word\n" puts
  "s        show stack contents\n" puts
  "p<char>  change trigger character to <char>\n" puts ] bindTo: ?

[ "display docs for: " puts
  getToken find [ cr @d->doc 0; puts ] [ drop cr "no docs found!" puts ] if ] bindTo:
 d

[ "display functions matching: " puts
  getToken cr (matching) ] bindTo: m

[ getc:internal dup putc !prefix:CHAR ] bindTo: p

|wwords
|s.s