ED-E is a templating language written in Haskell with a specific set of features:
Logicless within reason. A small set of consistent predicates
and expressions for formatting and presentational logic are provided.
Secure. No arbitrary code evaluation, with input data required to be fully specified
at render time.
Stateless. Parsing and rendering are separate steps so that loading, parsing,
include resolution, and embedding of the compiled template can optionally be
done ahead of time, amortising cost.
Markup agnostic. ED-E is used to write out everything from configuration files for
system services, to HTML and formatted emails.
Control over purity. Users can choose pure or IO-based resolution of
include expressions.
No surprises. All parsing, type assurances, and rendering steps report helpful
error messages with line/column metadata. Variable shadowing, unprintable expressions,
implicit type coercion, and unbound variable access are all treated as errors.