# CSV

CSV parser and unparser.

(import :std/text/csv)

# Overview

It is configurable through parameters to fit whichever CSV options your files use, defaulting to the "standard" from the creativyst specification. Parameters for RFC4180 are just a call-with- function call around.

The parameters are: csv-separator, csv-quote, csv-unquoted-quotequote?, csv-loose-quote?, csv-eol, csv-line-endings, csv-skip-whitespace?, csv-allow-binary?

Functions to locally set the parameters to known values are call-with-creativyst-csv-syntax, call-with-rfc4180-csv-syntax, call-with-strict-rfc4180-csv-syntax

The parsing and unparsing functions are read-csv-line, read-csv-lines, read-csv-file, write-csv-line, write-csv-lines.

# read-csv-line

(read-csv-line port) -> list | error

  port := input port

Read one line from port in CSV format, using the current syntax parameters. Return a list of strings, one for each field in the line. Entries are read as strings; it is up to you to interpret the strings as whatever you want. Signals an error on malformed CSV entries.

# read-csv-lines

(read-csv-lines port) -> list | error

  port := input port

> (let ((csv-data "id;city;population\n01;Foobar;1200000\n02;Barville;250001\n03;Baz;21\n"))
    (read-csv-lines (open-input-string csv-data)))
(("id;city;population") ("01;Foobar;1200000") ("02;Barville;250001")("03;Baz;21"))

Read lines from port in CSV format, using the current syntax parameters. Return a list of list of strings, one entry for each line, that contains one entry for each field. Entries are read as strings; it is up to you to interpret the strings as whatever you want. Signals an error malformed CSV entries.

# read-csv-file

(read-csv-file path [settings]) -> list | error

  path := file path to csv file as string
  settings := optional settings configuring csv parsing

Open the file designated by the path, using the provided settings if any, and call read-csv-lines on it.

# write-csv-line

(write-csv-line fields port) -> void

  fields := list of strings
  port   := output port

Format one line of fields to port in CSV format, using the current syntax parameters.

# write-csv-lines

(write-csv-lines lines port) -> void

  lines := list of strings
  port  := output port

Given a list of lines, each of them a list of fields, and a PORT, format those lines as CSV according to the current syntax parameters.

# write-csv-file

(write-csv-file path lines . settings) -> void

  lines    := list of strings
  path     := output path
  settings := optional path settings

Writes lines to the designated path using write-csv-lines and the provided settings. Check section 17.7.1 Filesystem devices of the Gambit Manual if you want to know more about the settings parameter.

> (write-csv-file "/tmp/foo.csv" [["hello" "world"] ["a" "b"]])
;; hello,world\na,b

> (write-csv-file "/tmp/foo.csv" [["and" "more"]] append: #t)
;; hello,world\na,b\nand,more

# call-with-creativyst-csv-syntax

(call-with-creativyst-csv-syntax thunk) -> any

  thunk := procedure without parameters

Sets CSV parsing to match rules by creativyst and calls procedure thunk returning its value.

# call-with-rfc4180-csv-syntax

(call-with-rfc4180-csv-syntax thunk) -> any

  thunk := procedure without parameters

Sets CSV parsing to match rules by RFC4180 and calls procedure thunk returning its value.

# call-with-strict-rfc4180-csv-syntax

(call-with-strict-rfc4180-csv-syntax thunk) -> any

  thunk := procedure without parameters

Sets CSV parsing to match rules by strict RFC4180 and calls procedure thunk returning its value.

# csv-separator

csv-separator

Separator used between CSV fields, defaults to ,.

# csv-quote

csv-quote

Delimiter of string data; pascal-like quoted as double itself in a string. Defaults to ".

# csv-unquoted-quotequote?

csv-unquoted-quotequote?

Boolean to control does a pair of quotes represent a quote outside of quotes? M$, RFC says #f, csv.3tcl says #t. Defaults to #f.

# csv-loose-quote?

csv-loose-quote?

Boolean to control can quotes appear anywhere in a field? Defaults to #f.

# csv-eol

csv-eol

Line ending when exporting CSV. Defaults to [+crlf+ +lf+].

# csv-line-endings

csv-line-endings

Acceptable line endings when importing CSV. Defaults to [+cr+ +lf+ +crlf+].

# csv-skip-whitespace?

csv-skip-whitespace?

Boolean controls shall we skip unquoted whitespace around separators? Defaults to #t.

# csv-allow-binary?

csv-allow-binary?

Boolean to control do we accept non-ascii data? Defaults to #t.