75 lines
2.0 KiB
Elixir
75 lines
2.0 KiB
Elixir
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defmodule Form do
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@moduledoc """
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A collection of loosely related functions helpful for filling out various forms at the city office.
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"""
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@type address_map :: %{
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street: String.t(),
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postal_code: String.t(),
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city: String.t()
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}
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@type address_tuple :: {
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street :: String.t(),
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postal_code :: String.t(),
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city :: String.t()
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}
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@type address :: address_map | address_tuple
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@doc """
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Generates a string of a given length.
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This string can be used to fill out a form field that is supposed to have no value.
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Such fields cannot be left empty because a malicious third party could fill them out with false data.
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"""
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@spec blanks(non_neg_integer()) :: String.t()
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def blanks(n) do
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String.duplicate("X", n)
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end
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@doc """
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Splits the string into a list of uppercase letters.
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This is needed for form fields that don't offer a single input for the whole string,
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but instead require splitting the string into a predefined number of single-letter inputs.
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"""
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@spec letters(String.t()) :: [String.t()]
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def letters(word) do
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word
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|> String.upcase()
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|> String.split("", trim: true)
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end
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@doc """
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Checks if the value has no more than the maximum allowed number of letters.
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This is needed to check that the values of fields do not exceed the maximum allowed length.
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It also tells you by how much the value exceeds the maximum.
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"""
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@spec check_length(String.t(), non_neg_integer()) :: :ok | {:error, pos_integer()}
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def check_length(word, length) do
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diff = String.length(word) - length
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if diff <= 0 do
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:ok
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else
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{:error, diff}
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end
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end
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@doc """
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Formats the address as an uppercase multiline string.
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"""
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@spec format_address(address) :: String.t()
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def format_address(%{street: street, postal_code: postal_code, city: city}) do
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format_address({street, postal_code, city})
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end
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def format_address({street, postal_code, city}) do
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"""
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#{String.upcase(street)}
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#{String.upcase(postal_code)} #{String.upcase(city)}
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"""
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end
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end
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