delphin.vpm

Variable property mapping (VPM).

Variable property mappings (VPMs) convert grammar-internal variables (e.g. event5) to the grammar-external form (e.g. e5), and also map variable properties (e.g. PNG: 1pl might map to PERS: 1 and NUM: pl).

See also

• Wiki about VPM: https://github.com/delph-in/docs/wiki/RmrsVpm

Module functions

delphin.vpm.load(source, semi=None)

Read a variable-property mapping from source and return the VPM.

Parameters:

• source – a filename or file-like object containing the VPM definitions

• semi (SemI, optional) – if provided, it is passed to the VPM constructor

Returns:

a VPM instance

Classes

class delphin.vpm.VPM(typemap, propmap, semi=None)

A variable-property mapping.

This class contains the rules for mapping variable properties from the grammar-internal definitions to grammar-external ones, and back again.

Parameters:

• typemap – an iterable of (src, OP, tgt) iterables

• propmap – an iterable of (featset, valmap) tuples, where featmap is a tuple of two lists: (source_features, target_features); and valmap is a list of value tuples: (source_values, OP, target_values)

• semi (SemI, optional) – if provided, this is used for more sophisticated value comparisons

apply(var, props, reverse=False)

Apply the VPM to variable var and properties props.

Parameters:

• var – a variable

• props – a dictionary mapping properties to values

• reverse – if True, apply the rules in reverse (e.g. from grammar-external to grammar-internal forms)

Returns:

a tuple (v, p) of the mapped variable and properties

Exceptions

exception delphin.vpm.VPMSyntaxError(message=None, filename=None, lineno=None, offset=None, text=None)

Bases: PyDelphinSyntaxError

Raised when loading an invalid VPM.