Function parse_query_template 

pub fn parse_query_template(
    template: &str,
    placeholder: char,
) -> Result<QueryTemplate, CamelError>

Parses a Camel-style SQL template into fragments and parameter slots.

Token types (using # as default placeholder):

• :#in:name → InClause(“name”) — IN clause expansion
• :#${expr} → Expression(“expr”) — dynamic expression (body.field, header.name, property.key)
• :#name → Named(“name”) — named parameter (name is alphanumeric + underscore)
• # (standalone) → Positional(N) — positional parameter (N increments per positional)

Arguments

• template - The SQL template string to parse
• placeholder - The character used as placeholder (typically ‘#’)

Returns

A QueryTemplate with fragments and parameter slots.