Html

Html — HTML safety primitives for Bastion templates.

Provides auto-escaping for template interpolation and the Safe type for marking pre-rendered HTML as trusted. Used by the ~H sigil desugarer and the .march.html lowering pass.

Auto-escaping rules: String → HTML-escaped (& < > " ') Int, Float, Bool → converted to string, then escaped Html.Safe → inserted verbatim IOList → flattened verbatim

The {=expr} raw interpolation syntax in .march.html templates requires the expression to have type IOList or Html.Safe — the compiler rejects plain String to make unsafety visible at the call site.

Functions

fnescapeescape(s : String) : String#

HTML-escape a string by replacing the five dangerous characters.

Escapes &, <, >, ", and ' so the string is safe to embed in HTML
element content or attribute values.

    Html.escape("<script>alert('xss')</script>")
    -- "&lt;script&gt;alert(&#39;xss&#39;)&lt;/script&gt;"

fnhtml_auto_escape_boolhtml_auto_escape_bool(val : Bool) : String#

Auto-escape a Bool value for template interpolation.

    html_auto_escape_bool(true)  -- "true"

fnhtml_auto_escape_inthtml_auto_escape_int(val : Int) : String#

Auto-escape an Int value for template interpolation.

Converts to string first, then escapes (integers are always safe,
but going through escape is consistent and costs nothing).

    html_auto_escape_int(42)  -- "42"

fnhtml_auto_escape_safehtml_auto_escape_safe(val : Safe) : String#

Return the raw string from a Safe value for template interpolation.

Safe values bypass escaping — the caller asserted the content is trusted.

fnhtml_auto_escape_stringhtml_auto_escape_string(val : String) : String#

Auto-escape a String value for template interpolation.

This is the workhorse called by the ~H sigil desugarer for every
{expr} interpolation site.  It HTML-escapes the string.

    html_auto_escape_string("A & B")  -- "A &amp; B"

fnis_emptyis_empty(s : Safe) : Bool#

Check whether a Safe value is empty.

fnsafesafe(s : String) : Safe#

Mark a string as safe (trusted) HTML.

The resulting Safe value will not be escaped when interpolated in a
template.  Use only for content you trust — e.g., output from a
Markdown renderer you control.

    Html.safe("<em>already escaped</em>")

fnto_stringto_string(s : Safe) : String#

Extract the inner string from a Safe value.

    Html.to_string(Html.safe("<b>hi</b>"))  -- "<b>hi</b>"