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Debugging & diagnostics

Source mapping

BPP+ maintains bidirectional mapping between source and output line numbers:

source_map = {
    basic_line → (source_file, source_line)
}

Line number lookup

Query source location for compiled line:

bpp -l <line_number> <source_file>

Example workflow

rem C64 runtime error
?SYNTAX ERROR IN 47
READY.

; Source lookup
$ bpp -l 47 game.bpp

BASIC line 47 corresponds to:
  Source file: game.bpp
  Source line: 23

Line not found

If the requested line number doesn't exist in the compiled output:

$ bpp -l 999 game.bpp

BASIC line 999 not found in compiled output

This typically means the line number is outside the range of your program, or the program didn't compile successfully.

Cross-file debugging

Works across include boundaries:

$ bpp -l 89 main.bpp

BASIC line 89 corresponds to:
  Source file: lib/collision.bpp
  Source line: 15

Error reporting

BPP+ provides detailed error messages with context:

error: line 23: could not resolve label 'player.shoot'
  in file: game.bpp
  context: gosub player.shoot

Diagnostic verbosity

Standard error stream used for all diagnostics:

bpp source.bpp > output.bas 2> errors.log

For exit codes and compilation status, see Error handling.

See also