match.tes

! match - jump to (or return the position of) the matching bracket ! 

! -usage-                                                !
! 0 prefix (default) : jump to the matching bracket      !
! 1 prefix : return the position of the matching bracket !
! -1 prefix : force reverse direction                    !

! -registers used- !
! o : options      !
! c : count        !
! r : return       !
! p : position     !
! s : start symbol !
! e : end symbol   !
! d : direction    !  

[o[c[r[f[s[e[d  ! save resisters !

+0Uo  ! load prefix into options !

1Uc   ! set count to 1 by default   !
.Up   ! store the starting position !
.Ur   ! store the return position   !
0aUs  ! store the current char      !

1<
 Qs-^^("= ^^)Ue 1Ud  1;'  ! ( -> )             !
 Qs-^^)"= ^^(Ue -1Ud 1;'  ! ( <- )             !
 Qs-^^["= ^^]Ue 1Ud  1;'  ! [ -> ]             !
 Qs-^^]"= ^^[Ue -1Ud 1;'  ! [ <- ]             !
 Qs-^^{"= ^^}Ue 1Ud  1;'  ! { -> }             !
 Qs-^^}"= ^^{Ue -1Ud 1;'  ! { <- }             !
 Qs-^^<"= ^^>Ue 1Ud  1;'  ! < -> >             !
 Qs-^^>"= ^^<Ue -1Ud 1;'  ! < <- >             !
 Qs-^^""= ^^"Ue 1Ud  1;'  ! " -> "             !
 Qs-^^""= ^^"Ue -1Ud 1;'  ! " <- "             !
 Qs-^^'"= ^^'Ue 1Ud  1;'  ! ' -> '             !
 Qs-^^'"= ^^'Ue -1Ud 1;'  ! ' <- '             !
 0Ud                      ! set direction to 0 !
>

Qo+1"=  ! if option is -1     !
 -1Ud'  ! set direction to -1 !

Qd"N         ! if direction is not 0 (therefore valid)       !
<            ! main loop                                     !
 Qd:c"N      ! if we can move in the right direction         !
  0a-Qe"=    ! if the current char matches the ending symbol !
   Qc-1Uc    ! decrement count                               !
   Qc"=      ! if count is zero                              !
    .Ur      ! store current location in r                   !
    Qo-1"=   ! if option is 1                                !
     Qpj'    ! jump back to very start                       !
    1;       ! quit loop                                     !
   '
  |          ! if current char is not the ending symbol        !
   0a-Qs"=   ! if the current char matches the starting symbol !
    Qc+1Uc'  ! increment counter                               !
  '
 |     ! if we can't move       !
  Qpj  ! jump back to the start !
  1;'  ! exit from main loop    !
>      ! end of main loop       !
'

Qr  ! return matching bracket position !

]d]e]s]f]r]c]o  ! re-load saved registers !