Crate mst_parser 

mst-parser

A zero-dependency, mustache-style template parser supporting nested variables.

This crate provides a recursive descent parser for {{variable}} style syntax. It produces an Abstract Syntax Tree (AST) but does not perform any rendering or substitution.

Features

• Nested Variables: Supports {{ key.{{subsection}} }} syntax.
• Safety: Configurable limits on recursion depth and node count to prevent malicious inputs.
• no_std: Compatible with #![no_std] environments (requires alloc).
• Diagnostics: Optional tracing integration for parser debugging.

Example

use mst_parser::{parse, Limits, Node, Parser};

let input = "Hello {{user.{{attr}}}}!";
// Use default limits
let nodes = parse(input).unwrap();

assert_eq!(nodes.len(), 3);
match &nodes[1] {
    Node::Variable { parts } => {
        // parts represents: "user.", {{attr}}
        assert_eq!(parts.len(), 2);
    }
    _ => panic!("Expected variable"),
}

// Or with custom limits
let limits = Limits { max_depth: 2, ..Limits::default() };
let parser = Parser::new(limits);
let nodes = parser.parse(input).unwrap();

Structs

Limits

Configuration limits to prevent resource exhaustion attacks.

Parser

A configured template parser.

Enums

Error

Errors that can occur during template parsing.

Node

Represents a node in the parsed template AST.

Functions

parse

Convenience function that parses with default limits.