Function parse_constraint 

fn parse_constraint(
    line: &str,
    constraints: &mut Vec<Constraint>,
) -> Result<(), ParseError>

Parses a single constraint line from the *CONSTR section.

Supports the following constraint types:

• r atom1 atom2 target_distance - Bond length constraint
• a atom1 atom2 atom3 target_angle - Bond angle constraint (degrees)
• d atom1 atom2 atom3 atom4 target_dihedral - Dihedral angle constraint (degrees)

Arguments

• line - The constraint line to parse
• constraints - Mutable vector to add parsed constraints to

Returns

Ok(()) if parsing succeeds, Err(ParseError) with detailed error information if parsing fails.

Examples

// Bond constraint: keep atoms 1-2 at 1.5 Angstrom
r 1 2 1.5

// Angle constraint: keep angle 1-2-3 at 120 degrees
a 1 2 3 120.0

// Dihedral constraint: keep dihedral 1-2-3-4 at 180 degrees
d 1 2 3 4 180.0