PhoenixKit.Templates.Substitution (phoenix_kit_templates v0.1.0)

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{{variable}} substitution.

The syntax matches what the database-backed email templates used, so content exported from those rows carries over unchanged. Surrounding whitespace is allowed: {{user_email}} and {{ user_email }} are the same placeholder.

Unbound placeholders are left alone

A placeholder with no matching variable is emitted verbatim, not blanked. Both are wrong, but a visible {{user_emial}} announces the typo in a preview or a test, while a silent empty string reads as finished copy and ships. The renderer never raises over one — a message with a flawed placeholder must still send — so callers that want it to be an error ask missing/2 up front.

Summary

Types

variables()

Variables to interpolate. Keys may be atoms or strings.

Functions

missing(content, variables)

Placeholder names in content that variables does not bind.

substitute(content, variables)

Replaces every bound placeholder in content.

variables(content)

The placeholder names appearing in content, in order, without duplicates.

Types

variables()

@type variables() :: %{optional(atom() | String.t()) => term()}

Variables to interpolate. Keys may be atoms or strings.

Functions

missing(content, variables)

@spec missing(String.t() | nil, variables()) :: [String.t()]

Placeholder names in content that variables does not bind.

Empty means every placeholder will be filled.

iex> PhoenixKit.Templates.Substitution.missing("{{a}} {{b}}", %{a: 1})
["b"]

substitute(content, variables)

@spec substitute(String.t() | nil, variables()) :: String.t() | nil

Replaces every bound placeholder in content.

iex> PhoenixKit.Templates.Substitution.substitute("Hi {{name}}", %{name: "Ada"})
"Hi Ada"

iex> PhoenixKit.Templates.Substitution.substitute("Hi {{name}}", %{})
"Hi {{name}}"

variables(content)

@spec variables(String.t() | nil) :: [String.t()]

The placeholder names appearing in content, in order, without duplicates.

iex> PhoenixKit.Templates.Substitution.variables("Hi {{name}}, {{ name }} again")
["name"]