HL7v2.Separator (HL7v2 v3.10.1)

Detects and manages HL7v2 message delimiters from MSH-1/MSH-2.

Every HL7v2 message declares its delimiter set in the first 9 characters of the MSH segment: MSH (3 chars) + field separator (MSH-1, 1 char) + encoding characters (MSH-2, 4 or 5 chars). The defaults are |^~\& but the standard allows any single-byte characters.

HL7 v2.7+ allows an optional 5th encoding character: the truncation character. When present (e.g., ^~\&#), it indicates that field values ending with this character were truncated. It is a display hint, not a delimiter.

Examples

iex> HL7v2.Separator.default()
%HL7v2.Separator{field: ?|, component: ?^, repetition: ?~, escape: ?\\, sub_component: ?&, truncation: nil, segment: ?\r}

iex> {:ok, sep} = HL7v2.Separator.from_msh("MSH|^~\\&|SENDING_APP|")
iex> sep.field
?|

iex> {:ok, sep} = HL7v2.Separator.from_msh("MSH|^~\\&#|SENDING_APP|")
iex> sep.truncation
?#

Summary

Types

t()

Functions

default()

Returns the default HL7v2 delimiter set (|^~\& with CR segment terminator, no truncation character).

encoding_characters(sep)

Returns the encoding characters string (MSH-2 value) for this separator set.

from_msh(arg1)

Extracts delimiters from an MSH header binary.

Types

t()

@type t() :: %HL7v2.Separator{
  component: non_neg_integer(),
  escape: non_neg_integer(),
  field: non_neg_integer(),
  repetition: non_neg_integer(),
  segment: non_neg_integer(),
  sub_component: non_neg_integer(),
  truncation: non_neg_integer() | nil
}

Functions

default()

@spec default() :: t()

Returns the default HL7v2 delimiter set (|^~\& with CR segment terminator, no truncation character).

encoding_characters(sep)

@spec encoding_characters(t()) :: binary()

Returns the encoding characters string (MSH-2 value) for this separator set.

When a truncation character is present (v2.7+), the returned string is 5 characters.

Examples

iex> HL7v2.Separator.encoding_characters(HL7v2.Separator.default())
"^~\\&"

from_msh(arg1)

@spec from_msh(binary()) :: {:ok, t()} | {:error, term()}

Extracts delimiters from an MSH header binary.

MSH-1 is the single character immediately after "MSH" (the field separator). MSH-2 is the next 4 characters (component, repetition, escape, sub-component), written as a literal string and NOT delimited. In HL7 v2.7+, a 5th character (truncation) may follow. The truncation character is distinguished from the start of the next field by checking whether the 5th byte equals the field separator: if it does not, it is the truncation character.

Returns {:ok, separator} or {:error, reason}.

Examples

iex> {:ok, sep} = HL7v2.Separator.from_msh("MSH|^~\\&|SendApp|")
iex> sep.field
?|
iex> sep.component
?^

iex> {:ok, sep} = HL7v2.Separator.from_msh("MSH|^~\\&#|SendApp|")
iex> sep.truncation
?#