gsv - v3.0.1

gsv

Types

LineEnding

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Possible line endings used when turning a parsed csv back into a string with the from_lists and from_dicts functions.

pub type LineEnding {
  Windows
  Unix
}

Constructors 

  • Windows

    The CRLF line ending: \r\n.

  • Unix

    The LF line ending: \n.

ParseError

</> 
pub type ParseError {
  UnescapedQuote(position: Int)
  UnclosedEscapedField(start: Int)
}

Constructors 

  • UnescapedQuote(position: Int)

    This error can occur if there is a csv field contains an unescaped double quote ".

    A field can contain a double quote only if it is escaped (that is, surrounded by double quotes). For example wibb"le would be an invalid field, the correct way to write such a field would be like this: "wibb""le".

    Arguments

    • position

      The byte index of the unescaped double.

  • UnclosedEscapedField(start: Int)

    This error can occur when the file ends without the closing " of an escaped field. For example: "hello.

    Arguments

    • start

      The byte index of the start of the unclosed escaped field.

Functions

from_dicts

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pub fn from_dicts(
  rows: List(Dict(String, String)),
  separator separator: String,
  line_ending line_ending: LineEnding,
) -> String

Takes a list of dicts and writes it to a csv string. Will automatically escape strings that contain double quotes or line endings with double quotes (in csv, double quotes get escaped by doing a double doublequote) The string he"llo\n becomes "he""llo\n"

from_lists

</> 
pub fn from_lists(
  rows: List(List(String)),
  separator separator: String,
  line_ending line_ending: LineEnding,
) -> String

Takes a list of lists of strings and turns it to a csv string, automatically escaping all fields that contain double quotes or line endings.

Examples

let rows = [["hello", "world"], ["goodbye", "mars"]]
from_lists(rows, separator: ",", line_ending: Unix)
// "hello,world
// goodbye,mars"

let rows = [[]]

to_dicts

</> 
pub fn to_dicts(
  input: String,
) -> Result(List(Dict(String, String)), ParseError)

Parses a csv string into a list of dicts: the first line of the csv is interpreted as the headers’ row and each of the following lines is turned into a dict with a value for each of the headers.

If a field is empty then it won’t be added to the dict.

Examples

"pet,name,cuteness
dog,Fido,100
cat,,1000
"
|> gsv.to_dicts
// Ok([
//    dict.from_list([
//      #("pet", "dog"), #("name", "Fido"), #("cuteness", "100")
//    ]),
//    dict.from_list([
//      #("pet", "cat"), #("cuteness", "1000")
//    ]),
// ])

Just list to_lists this implementation tries to stick as closely as possible to RFC4180. You can look at to_lists’ documentation to see how it differs from the RFC.

to_lists

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pub fn to_lists(
  input: String,
) -> Result(List(List(String)), ParseError)

Parses a csv string into a list of lists of strings: each line of the csv will be turned into a list with an item for each field.

Examples

"hello, world
goodbye, mars"
|> gsv.to_lists
// Ok([
//    ["hello", " world"],
//    ["goodbye", " mars"],
// ])

This implementation tries to stick as closely as possible to RFC4180, with a couple notable convenience differences:

  • both \n and \r\n line endings are accepted.
  • a line can start with an empty field ,two,three.
  • empty lines are allowed and just ignored.
  • lines are not forced to all have the same number of fields.
  • a line can end with a comma (meaning its last field is empty).
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