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68 lines
2.1 KiB
68 lines
2.1 KiB
from __future__ import unicode_literals
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from . import LogicAdapter
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from ..conversation import Statement
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class MathematicalEvaluation(LogicAdapter):
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"""
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The MathematicalEvaluation logic adapter parses input to determine
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whether the user is asking a question that requires math to be done.
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If so, the equation is extracted from the input and returned with
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the evaluated result.
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For example:
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User: 'What is three plus five?'
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Bot: 'Three plus five equals eight'
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:kwargs:
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* *language* (``str``) --
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The language is set to 'ENG' for English by default.
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"""
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def __init__(self, **kwargs):
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super(MathematicalEvaluation, self).__init__(**kwargs)
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self.language = kwargs.get('language', 'ENG')
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self.cache = {}
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def can_process(self, statement):
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"""
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Determines whether it is appropriate for this
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adapter to respond to the user input.
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"""
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response = self.process(statement)
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self.cache[statement.text] = response
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return response.confidence == 1
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def process(self, statement):
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"""
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Takes a statement string.
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Returns the equation from the statement with the mathematical terms solved.
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"""
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from mathparse import mathparse
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input_text = statement.text
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# Use the result cached by the process method if it exists
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if input_text in self.cache:
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cached_result = self.cache[input_text]
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self.cache = {}
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return cached_result
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# Getting the mathematical terms within the input statement
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expression = mathparse.extract_expression(input_text, language=self.language)
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response = Statement(text=expression)
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try:
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response.text += ' = ' + str(
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mathparse.parse(expression, language=self.language)
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)
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# The confidence is 1 if the expression could be evaluated
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response.confidence = 1
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except mathparse.PostfixTokenEvaluationException:
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response.confidence = 0
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return response
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