bidsbuilder.schema.interpreter.selectors

class SelectorParser

Bases: object

Selector Parser is a recursive descent parser to interpret BIDS schema logic into executable python functions

It includes a from_raw() method enabling tokenisation and parsing from the raw string expression

ADD_OPS = {'+': <built-in function add>, '-': <built-in function sub>}
EQ_OPS = {'!=': <built-in function ne>, '<': <built-in function lt>, '<=': <built-in function le>, '==': <built-in function eq>, '>': <built-in function gt>, '>=': <built-in function ge>, 'in': <function contains>}
EVAL_FUNCS = {'allequal': <function allequal>, 'count': <function count>, 'exists': <function exists>, 'index': <function index>, 'intersects': <function intersects>, 'length': <function length>, 'match': <function nMatch>, 'max': <function max>, 'min': <function min>, 'sorted': <function nSorted>, 'substr': <function substr>, 'type': <function nType>}
FIELDS_MAP = {'associations': <function associations>, 'columns': <function columns>, 'dataset': <function dataset>, 'datatype': <function datatype>, 'entities': <function entities>, 'extension': <function extension>, 'gzip': <function gzip>, 'json': <function json>, 'modality': <function modality>, 'nifti_header': <function nifti_header>, 'ome': <function ome>, 'path': <function path>, 'schema': <function schema>, 'sidecar': <function sidecar>, 'subject': <function subject>, 'suffix': <function suffix>, 'tiff': <function tiff>}
LOGIC_OPS = {'&&': <function op_and>, '||': <function op_or>}
MULT_OPS = {'*': <built-in function mul>, '/': <built-in function truediv>}
POSTFIX_OPS = {'.': <function get_property>, '[': <function get_list_index>}
UNARY_OPS = {'!': <built-in function not_>, '+': <built-in function pos>, '-': <built-in function neg>}
__init__(tokens)
Parameters:

tokens (list)

additive_term()
advance()
boolean()
brackets()
property cur_token: token
equality_term()
classmethod from_raw(selector)

used to instantiate a selectorParser from a raw string, so tokenises the input before returning an instance with the correct tokens

Return type:

selectorFunc

Parameters:

selector (str | None)

identifier()

identifier is a bit special as it adds “tags”

identifier holds the predefined bids vocabulary of interpreted functions and fields

Each field and the function “exists()” is considered a tag (these are attributes belonging to a file which can be hooked and allow to re-check the schema if these attributes change)

logic_term()
match(*types)
Return type:

Any

mult_term()
nanToken = token(val=None, kind='NONE')
property next_token: token
number()
p_float()
parentheses()
parse()
Return type:

selectorFunc

postfix_term()
property prev_token: token
primary()

lowest level priority. These are all considered terminal and just return the interpreted value

string()
tok_regex = '(?P<FLOAT>\\d+\\.\\d+|\\.\\d+)|(?P<NUMBER>\\d+)|(?P<STRING>"[^"]*"|\\\'[^\\\']*\\\')|(?P<EQ_OP>==|!=|<=|>=|\\bin\\b|[<>])|(?P<ADD_OP>[+\\-])|(?P<MULT_OP>[*/])|(?P<LOGIC_OP>&&|\\|\\|)|(?P<BOOL>false|true)|(?P<ID>[A-Za-z_]\\w*)|(?P<LPAREN>\\()|(?P<RPAREN>\\))|(?P<LBRACK>\\[)|(?P<RBRACK>\\])|(?P<SEP>[, \\t]+)|(?P<UNARY>!)|(?P<DOT>\\.)|(?P<MISMATCH>.)'
token_specification = [('FLOAT', '\\d+\\.\\d+|\\.\\d+'), ('NUMBER', '\\d+'), ('STRING', '"[^"]*"|\\\'[^\\\']*\\\''), ('EQ_OP', '==|!=|<=|>=|\\bin\\b|[<>]'), ('ADD_OP', '[+\\-]'), ('MULT_OP', '[*/]'), ('LOGIC_OP', '&&|\\|\\|'), ('BOOL', 'false|true'), ('ID', '[A-Za-z_]\\w*'), ('LPAREN', '\\('), ('RPAREN', '\\)'), ('LBRACK', '\\['), ('RBRACK', '\\]'), ('SEP', '[, \\t]+'), ('UNARY', '!'), ('DOT', '\\.'), ('MISMATCH', '.')]
tokenizer(string, pos=0, endpos=9223372036854775807)

Matches zero or more characters at the beginning of the string.

unary_term()
class selectorFunc

Bases: object

__init__(val, args=NOTHING, requires_input=False, is_callable=False)

Method generated by attrs for class selectorFunc.

Parameters:

  • val (Any)

  • args (list[Any])

  • requires_input (bool)

  • is_callable (bool)

Return type:

None

args: list[Any]
evaluate_static_nodes()
Return type:

bool

is_callable: bool
requires_input: bool
tags: Optional[set]
val: Any
class selectorHook

Bases: object

__init__(funcs, original, tags=NOTHING)

Method generated by attrs for class selectorHook.

Parameters:

  • funcs (list[Callable])

  • original (list[str])

  • tags (set[str])

Return type:

None

classmethod from_raw(r_selector)
Return type:

selectorHook

Parameters:

r_selector (list[str])

funcs: list[Callable]
original: list[str]
tags: set[str]
class token

Bases: object

token(val: ‘str’, kind: ‘str’)

__init__(val, kind)
Parameters:

  • val (str)

  • kind (str)

Return type:

None

kind: str
val: str