Ensure a value matches a regular expression.

Options

• :with: The regular expression.
• :message: Optional. A custom error message. May be in EEx format and use the fields described in "Custom Error Messages," below.

The regular expression can be provided in place of the keyword list if no other options are needed.

Examples

iex> Vex.Validators.Format.validate("foo", ~r/^f/)
:ok
iex> Vex.Validators.Format.validate("foo", ~r/o{3,}/)
{:error, "must have the correct format"}
iex> Vex.Validators.Format.validate("foo", [with: ~r/^f/])
:ok
iex> Vex.Validators.Format.validate("bar", [with: ~r/^f/, message: "must start with an f"])
{:error, "must start with an f"}
iex> Vex.Validators.Format.validate("", [with: ~r/^f/, allow_blank: true])
:ok
iex> Vex.Validators.Format.validate(nil, [with: ~r/^f/, allow_nil: true])
:ok

Custom Error Messages

Custom error messages (in EEx format), provided as :message, can use the following values:

iex> Vex.Validators.Format.__validator__(:message_fields)
[value: "The bad value", pattern: "The regex that didn't match"]

An example:

iex> Vex.Validators.Format.validate("bar", [with: ~r/"^f"/, message: "<%= value %> doesn't start with an f"])
{:error, "bar doesn't start with an f"}