From eacb54ae44f655c010fdfc2b7292d24f06ffc445 Mon Sep 17 00:00:00 2001 From: Lukasz Kasprzak Date: Wed, 19 Aug 2026 08:01:11 +0200 Subject: feat(render): logic-less template parser Placeholders, sections, inverted sections, comments. Nothing else: no partials, no lambdas, no expression evaluation, no raw form. A template is data, never a program, which is what keeps an untrusted template safe. Errors rather than silence on a malformed template: an unterminated tag, an unclosed section, a mismatched close and a partial all return Error. Swallowing '{{name' as text is how a typo becomes invisible missing output in a printed booklet. --- lib/render/template.mli | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 lib/render/template.mli (limited to 'lib/render/template.mli') diff --git a/lib/render/template.mli b/lib/render/template.mli new file mode 100644 index 0000000..3f9ef97 --- /dev/null +++ b/lib/render/template.mli @@ -0,0 +1,28 @@ +(** A deliberately logic-less template engine (spec section 5). + + A template is DATA, never a program: placeholders, sections, inverted + sections and comments, and nothing else. There are no partials, no lambdas, + no expression evaluation, no arithmetic, and no filesystem or process + access. There is deliberately no "raw" or triple-brace form -- a template + cannot opt out of its flavour's escaping. + + Anything a calendar needs that this cannot express (a month grid's leading + blanks, week bucketing) is computed in {!View} and handed in as data. That + division is the design, not a workaround. *) + +(** What a template can be rendered against. *) +type value = + | Str of string + | Bool of bool + | List of value list + | Obj of (string * value) list + +type node = + | Text of string + | Var of string list (** dotted path, e.g. ["name"; "la"] *) + | Section of string list * node list + | Inverted of string list * node list + +(** Never raises; a malformed template is an [Error] with a human-readable + reason, because the template is user input. *) +val parse : string -> (node list, string) result -- cgit v1.3