shahryarjb

shahryarjb

What is the best way for Parsing a string and convert to map

Hello, I wanted to use the NimbleParsec library to convert a string into the map I need. But I think I got it wrong and this is more for me to equle with something and not to make the output I need like regex. it’s true?

For example I have this string

"sanitize(trim, lowercase) validate(not_empty, max_len = 20)"
# And I need something like this:
# Output: %{sanitize: ['trim', 'lowercase'], validate: ['not_empty', {'max_len', '20'}]}

It should be a bit dynamic for example:

"sanitize(trim, lowercase, downcase, replace= T) validate(not_empty, max_len = 20, not_integer)"
# Output: %{sanitize: ['trim', 'lowercase', 'downcase', {'replace', 'T'}], validate: ['not_empty', {'max_len', '20'}, 'not_integer']}

Now, without regex is there a good way? or NimbleParsec can create something like this?

It should be noted I have many items for each part like `trim, lowercase, downcase and etc..

Thank you in advance

Most Liked

hst337

hst337

The shortest solution is

for line in String.split(input, ")"), do: Code.string_to_quoted!(line <> ")")
LostKobrakai

LostKobrakai

NimbleParsec is not regex. It’s not “searching” through your input.

A parser works by going though the input string front → end and at each step you need to define what can be matched next. In your example you tell it to match either "validate" or "sanitize". It starts from the front, finds "sanitize" and then the next char is (, which matches neither of your expected values, so parsing halts.

NimbleParsec — NimbleParsec v1.3.1 has an example of something similar, parsing things wrapped in " instead of parenthesis.

cmo

cmo

With NimbleParsec, you create rules for the things you want to parse and then define a parser, e.g parsing a gmail-like search string. Should be pretty straight forward to parse your text format.

  ...

  field =
    choice([
      string("message:") |> replace(:message),
      string("user:") |> replace(:user),
      string("ip:") |> replace(:ip)
    ])
    |> ignore(optional(whitespace))

  param =
    repeat(
      lookahead_not(concat(optional(whitespace), choice([field, value_field, time_field])))
      |> optional(whitespace)
      |> utf8_string([not: ?\s], min: 1)
    )
    |> ignore(choice([whitespace, eos()]))
    |> post_traverse(:join)

  ...

  defparsec :parse_search_string,
            ignore(optional(whitespace))
            |> times(
              choice([
                concat(field, param),
                value_field_param,
                time_field
              ])
              |> post_traverse(:group)
              |> ignore(optional(whitespace)),
              

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