rhaj/rhai_engine/rhaibook/engine/debugging/break-points.md

Break-Points

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A break-point always stops the current evaluation and calls the [debugging][debugger] callback.

A break-point is represented by the debugger::BreakPoint type, which is an enum with the following variants.

BreakPoint variant	Not available under	Description
AtPosition { source, pos, enabled }	[no_position]	breaks at the specified position in the specified source (empty if none); if pos is at beginning of line, breaks anywhere on the line
AtFunctionName { name, enabled }		breaks when a function matching the specified name is called (can be [operator])
AtFunctionCall { name, args, enabled }		breaks when a function matching the specified name (can be [operator]) and the specified number of arguments is called
AtProperty { name, enabled }	[no_object]	breaks at the specified property access

Access Break-Points

The following [debugger::Debugger] methods allow access to break-points for manipulation.

Method	Return type	Description
break_points	&[BreakPoint]	returns a slice of all BreakPoint's
break_points_mut	&mut Vec<BreakPoint>	returns a mutable reference to all BreakPoint's

Example

use rhai::debugger::*;

let debugger = &mut context.global_runtime_state_mut().debugger_mut();

// Get number of break-points.
let num_break_points = debugger.break_points().len();

// Add a new break-point on calls to 'foo(_, _, _)'
debugger.break_points_mut().push(
    BreakPoint::AtFunctionCall { name: "foo".into(), args: 3 }
);

// Display all break-points
for bp in debugger.break_points().iter() {
    println!("{bp}");
}

// Clear all break-points
debugger.break_points_mut().clear();