58 lines
2.0 KiB
Python
58 lines
2.0 KiB
Python
"""
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Validator for a regular langage.
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"""
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from __future__ import unicode_literals
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from prompt_toolkit.validation import Validator, ValidationError
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from prompt_toolkit.document import Document
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from .compiler import _CompiledGrammar
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__all__ = (
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'GrammarValidator',
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)
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class GrammarValidator(Validator):
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"""
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Validator which can be used for validation according to variables in
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the grammar. Each variable can have its own validator.
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:param compiled_grammar: `GrammarCompleter` instance.
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:param validators: `dict` mapping variable names of the grammar to the
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`Validator` instances to be used for each variable.
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"""
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def __init__(self, compiled_grammar, validators):
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assert isinstance(compiled_grammar, _CompiledGrammar)
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assert isinstance(validators, dict)
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self.compiled_grammar = compiled_grammar
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self.validators = validators
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def validate(self, document):
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# Parse input document.
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# We use `match`, not `match_prefix`, because for validation, we want
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# the actual, unambiguous interpretation of the input.
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m = self.compiled_grammar.match(document.text)
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if m:
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for v in m.variables():
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validator = self.validators.get(v.varname)
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if validator:
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# Unescape text.
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unwrapped_text = self.compiled_grammar.unescape(v.varname, v.value)
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# Create a document, for the completions API (text/cursor_position)
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inner_document = Document(unwrapped_text, len(unwrapped_text))
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try:
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validator.validate(inner_document)
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except ValidationError as e:
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raise ValidationError(
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cursor_position=v.start + e.cursor_position,
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message=e.message)
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else:
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raise ValidationError(cursor_position=len(document.text),
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message='Invalid command')
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