Debugging

textX supports debugging on the meta-model (grammar) and model levels. If debugging is enabled, textX will print various debugging messages.

If the debug parameter of the meta-model construction is set to True, debug messages during grammar parsing and meta-model construction will be printed. Additionally, a parse tree created during the grammar parsing as well as meta-model (if constructed successfully) dot files will be generated:

form textx.metamodel import metamodel_from_file

robot_metamodel = metamodel_from_file('robot.tx', debug=True)

If debug is set in the model_from_file/str calls, various messages during the model parsing and construction will be printed. Additionally, parse tree created from the input as well as the model will be exported to dot files.

  robot_program = robot_metamodel.model_from_file('program.rbt', debug=True)

Alternatively, you can use textx check or generate command in debug mode.

$ textx --debug generate --grammar robot.tx program.rbt --target dot

*** PARSING LANGUAGE DEFINITION ***
New rule: grammar_to_import -> RegExMatch
New rule: import_stm -> Sequence
New rule: rule_name -> RegExMatch
New rule: param_name -> RegExMatch
New rule: string_value -> OrderedChoice
New rule: rule_param -> Sequence
Rule rule_param founded in cache.
New rule: rule_params -> Sequence
...

>> Matching rule textx_model=Sequence at position 0 => */* This ex
  >> Matching rule ZeroOrMore in textx_model at position 0 => */* This ex
      >> Matching rule import_stm=Sequence in textx_model at position 0 => */* This ex
        ?? Try match rule StrMatch(import) in import_stm at position 0 => */* This ex
        >> Matching rule comment=OrderedChoice in import_stm at position 0 => */* This ex
            ?? Try match rule comment_line=RegExMatch(//.*?$) in comment at position 0 => */* This ex
            -- NoMatch at 0
            ?? Try match rule comment_block=RegExMatch(/\*(.|\n)*?\*/) in comment at position 0 => */* This ex

...


Generating 'robot.tx.dot' file for meta-model.
To convert to png run 'dot -Tpng -O robot.tx.dot'
Generating 'program.rbt.dot' file for model.
To convert to png run 'dot -Tpng -O program.rbt.dot'

This command renders parse trees and parser models of both textX and your language to dot files. Also, a meta-model and model of the language will be rendered if parsed correctly.