REBOL 3 CSV-DECODE

; Copyright (c) 2012 Gregory Higley

; Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation
; files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy,
; modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software
; is furnished to do so, subject to the following conditions:

; The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
; OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
; LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
; CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.


rebol [
    Author: "Gregory Higley"
    Title: "Revolucent CSV Library"
;   Type: module
;   Needs: [2.101.0]
]

whitespace: charset " ^-"

csv-decode: funct [
    "Parses a single line of CSV and returns a block of quoted values."
    line [string!]
    /separated-by
        sep-char [char!] "Defaults to comma"
    /quoted-by
        quote-char [char!] "Defaults to double quote"
    /escaped-by
        escape-char [char! none!] "Defaults to none"
    /local
        chunk [string!]
        item [string!]
        items [block!]
] [
    default quote-char first {"}
    default sep-char #","
    items: copy []
    characters: complement charset rejoin [" ^-" sep-char]
    either escape-char [
        ; If we have an escape char our quoted-item becomes much more complex
        escaped-quote: rejoin [escape-char quote-char]
        quoted-item: [
            (item: copy "")
            quote-char
            any [ copy chunk to escaped-quote escaped-quote (repend item [chunk quote-char]) ]
            copy chunk to quote-char (append item chunk)
            quote-char
        ]
    ] [
        quoted-item: [quote-char copy item to quote-char quote-char]
    ]
    rules: [
        any [
            any whitespace sep-char (append items "")
        |   quoted-item any whitespace sep-char (append items item)
        |   copy item some characters any whitespace sep-char (append items item)
        |   any whitespace
        ]
        opt [
            any whitespace end (append items "")
        |   quoted-item any whitespace end (append items item)
        |   copy item some characters any whitespace end (append items item)
        ]
    ]
    either parse line rules [items] [none]
    items
]