Function parse_input 

pub fn parse_input(path: &Path) -> Result<InputData, ParseError>

Parse an OpenMECP input file.

This function reads and parses a complete OpenMECP input file, extracting all configuration parameters, geometries, constraints, and additional keywords. It supports the custom section-based input format with support for external geometry files.

Arguments

• path - Path to the input file (e.g., “input.inp”)

Returns

Returns Ok(InputData) on successful parsing, or Err(ParseError) if:

• The file cannot be read (I/O error)
• The file format is invalid
• Required sections are missing
• External geometry files cannot be read

Examples

Basic usage:

use omecp::parser::parse_input;
use std::path::Path;

let input_path = Path::new("input.inp");
match parse_input(input_path) {
    Ok(input_data) => {
        println!("Parsed {} atoms", input_data.geometry.num_atoms);
        println!("QM program: {:?}", input_data.config.program);
    }
    Err(e) => eprintln!("Parse error: {}", e),
}

Parsing with external geometry file:

// input.inp
*GEOM
@molecule.xyz
*

program = gaussian
method = B3LYP/6-31G*
// ... other parameters ...

use omecp::parser::parse_input;
use std::path::Path;

let input_data = parse_input(Path::new("input.inp"))?;
// Geometry will be read from molecule.xyz