1. Strings

! -----------------------------
: string ( -- str ) "\\n" ;                 ! two characters, \ and an n
: string ( -- str ) "Jon 'Maddog' Orwant" ; ! literal single quotes
! -----------------------------
: string ( -- str ) "\n" ;                      ! a "newline" character
: string ( -- str ) "Jon \"Maddog\" Orwant" ;   ! literal double quotes
! -----------------------------
! Multiline strings need the multiline vocabulary

USE: multiline

STRING: a
This is a multiline document
terminated by ; on a line by itself
;

: a ( -- str )
    <" This is a multiline document
terminated by double quotes plus greater sign"> ;
! -----------------------------

! -----------------------------
! use subseq from the sequences vocabulary, since strings are just sequences
from to str subseq

1 3 "abcdefg" subseq .
! "bc"

! The rest from a given position is handled by tail
str n tail

1 "abcdefg" tail .
! "bcdefg"

! Replacing a substring with replace-slice
newstr from to str replace-slice

"1234" 3 7 "abcdefg" [ replace-slice ] keep .
!"abc1234"

: replace-tail ( new from seq -- )
    dup length swap [ replace-slice ] keep ;

"1234" 3 "abcdefg" replace-tail .
! "abc1234"

! -----------------------------

! split at five character boundaries
USE: splitting
5 group     ! Splits sequence/string on top of stack into an array

"abcdefghijklmnopqrstuvwxyz" 5 group .
! { "abcde" "fghij" "klmno" "pqrst" "uvwxy" "z" }

! chop string into individual characters
1 group

"abcd" 1 group .
! { "a" "b" "c" "d" }

! -----------------------------
: str ( -- str ) "This is what you have" ;
!                +012345678901234567890  Indexing forwards  (left to right)
!                 109876543210987654321- Indexing backwards (right to left)
!                  note that 0 means 10 or 20, etc. above

0 1 str subseq  ! "T" (on top of stack)
str 1 head      ! "T"
5 7 str subseq  ! "is"
str 13 tail     ! "you have"
str 1 tail*     ! "e"
str 4 tail*     ! "have"
! 8 indexed from backward, 3 characters
str length 8 - dup 3 + str subseq   ! "you"
! Or with a new word, using the locals vocabulary
USE: locals
:: chars-from-rindex ( from count str -- newstr )
    str length from - dup count + str subseq ;

8 3 str chars-from-rindex   ! "you"

! -----------------------------
SYMBOL: str
"This is what you have" str set

str get print
! This is what you have

str get
! Top of stack: "This is what you have"

[ 5 head ] [ 7 tail ] bi "wasn't" swap 3append   ! change "is" to "wasn't"
! Top of stack: "This wasn't what you have"

13 head "ondrous" append    ! replace last 12 characters
! Top of stack: "This wasn't wondrous"

1 tail      ! delete first character
! Top of stack: "his wasn't wondrous"

10 head*    ! delete last 10 characters
! Top of stack: "his wasn'"

str set
! str = "his wasn'"

str get print
! his wasn'
! -----------------------------
! you can test substrings with "subseq?"

10 tail* "substring" swap subseq?
    [ "\"substring\" within the last 10 characters" print ]
    when

! substitute "at" for "is", restricted to first five characters
USING: peg peg.search ;

5 cut >r "is" token [ drop "at" ] action replace r> append

! -----------------------------
! exchange the first and last letters in a string
"make a hat"
1 cut 1 cut* spin 3append
print
! take a ham

! -----------------------------

! -----------------------------
swap
! -----------------------------

! -----------------------------
! The "csv" vocabulary allows to parse real CSV

! reading the file "testdata.csv", UTF-8 encoded, CSV format
USE: csv

"testdata.csv" utf8 <file-reader> csv
! An array of row arrays is on the top of the stack now.

! -----------------------------
! You could use the word "<string-reader>" to turn a string into a stream.

USING: csv io.streams.string ;

"XYZZY,\"\",\"O'Reilly, Inc\",\"Wall, Larry\",\"a \"\"glug\"\" bit,\",5,\"Error, Core Dumped\""
    <string-reader> csv .
!    {
!        {
!            "XYZZY"
!            ""
!            "O'Reilly, Inc"
!            "Wall, Larry"
!            "a \"glug\" bit,"
!            "5"
!            "Error, Core Dumped"
!        }
!    }
! -----------------------------