launch.frontend.parser module

Module for Parser class and parsing methods.

exception launch.frontend.parser.InvalidFrontendLaunchFileError

Bases: InvalidLaunchFileError

Exception raised when the given frontend launch file is not valid.

class launch.frontend.parser.Parser

Bases: object

Abstract class for parsing launch actions, substitutions and descriptions.

Implementations of the parser class, should override the load method. They could also override the parse_substitution and/or get_file_extensions methods, or not. load_launch_extensions, parse_action, parse_description, get_available_extensions, may_parse, is_filename_valid, get_parsers_from_filename and get_file_extensions_from_parsers are not supposed to be overridden.

escape_characters(value: str) → str

Escape characters in strings.

extensions_loaded = False

frontend_parsers = None

classmethod get_available_extensions() → List[str]

Return the registered extensions.

classmethod get_file_extensions() → Set[str]

Return the set of file extensions known to this parser.

classmethod get_file_extensions_from_parsers() → Set[Type[Parser]]

Return a set of file extensions known to the parser implementations.

classmethod get_parser_from_extension(extension: str) → Type[Parser] | None

Return an entity loaded with a markup file.

classmethod get_parsers_from_filename(filename: str) → List[Type[Parser]]

Return a list of parsers which entity loaded with a markup file.

classmethod is_extension_valid(extension: str) → bool

Return an entity loaded with a markup file.

classmethod is_filename_valid(filename: str) → bool

Return True if the filename is valid for any parser.

classmethod load(file: FilePath | TextIO) → Tuple[Entity, Parser]

Parse an Entity from a markup language-based launch file.

Parsers are exposed and provided by available frontend implementations. To choose the right parser, it’ll first attempt to infer the launch description format based on the filename extension, if any. If format inference fails, it’ll try all available parsers one after the other.

classmethod load_launch_extensions()

Load launch extensions, in order to get all the exposed substitutions and actions.

classmethod load_parser_implementations()

Load all the available frontend entities.

classmethod may_parse(filename: str) → bool

Return True if the filename is valid for this parser.

parse_action(entity: Entity) → Action

Parse an action, using its registered parsing method.

parse_description(entity: Entity) → LaunchDescription

Parse a launch description.

parse_if_substitutions(value: str | Path | Substitution | Iterable[str | Path | Substitution] | int | float | bool | Sequence[int | str] | Sequence[float | str] | Sequence[bool | str] | Sequence[str]) → List[Substitution] | int | float | bool | str | List[int | List[Substitution]] | List[float | List[Substitution]] | List[bool | List[Substitution]] | List[str | List[Substitution]]

See launch.frontend.parser.parse_if_substitutions().

parse_substitution(value: str) → List[Substitution]

Parse a substitution.