This module provides an interface for development tools to set and
delete break-points, giving a location in the source. Development tools
that want to track changes to breakpoints must use user:message_hook/3
to intercept these message terms:
Note that the hook must fail after creating its side-effects to give
other hooks the opportunity to react.
- set_breakpoint(+File, +Line, +Char, -Id) is det
- set_breakpoint(+Owner, +File, +Line, +Char, -Id) is det
- Put a breakpoint at the indicated source-location. File is a current
sourcefile (as reported by source_file/1). Line is the 1-based line
in which Char is. Char is the position of the break.
First, '$clause_from_source'/4 uses the SWI-Prolog clause-source
information to find the last clause starting before Line.
'$break_pc' generated (on backtracking), a list of possible
Note that in addition to setting the break-point, the system must be
in debug mode for the breakpoint to take effect. With threading
enabled, there are various different ways this may be done. See
debug/0, tdebug/0 and tdebug/1. Therefore, this predicate does not
enable debug mode.
- delete_breakpoint(+Id) is det
- Delete breakpoint with given Id. If successful,
print_message(breakpoint(delete, Id)) is called. Message hooks
working on this message may still call breakpoint_property/2.
- breakpoint_property(?Id, ?Property) is nondet
- True when Property is a property of the breakpoint Id. Defined
- Provided if the breakpoint is in a clause associated to a
file. May not be known.
- Line of the breakpoint. May not be known.
- character_range(Start, Len)
- One-based character offset of the break-point. May not be
- Reference of the clause in which the breakpoint resides.
- file_line(+File, +StartIndex, -Line) is det[private]
- True when Line is the 1-based line offset in which we find
- break_location(+ClauseRef, +PC, -File, -AZ) is det[private]
- True when File and AZ represent the location of the goal called
at PC in ClauseRef.
|AZ||- is a term A-Z, where A and Z are character positions
The following predicates are exported, but not or incorrectly documented.
- set_breakpoint(Arg1, Arg2, Arg3, Arg4, Arg5)