# Copyright 2019-2020 The Lux Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from lux.vis.Clause import Clause
from lux.core.frame import LuxDataFrame
from typing import List, Union
[docs]class Parser:
"""
The parser takes in the user's input specifications (with string `description` fields),
then generates the Lux internal specification through lux.Clause.
"""
[docs] @staticmethod
def parse(intent: List[Union[Clause,str]]) -> List[Clause]:
"""
Given the string description from a list of input Clauses (intent),
assign the appropriate clause.attribute, clause.filter_op, and clause.value.
Parameters
----------
intent : List[Clause]
Underspecified list of lux.Clause objects.
Returns
-------
List[Clause]
Parsed list of lux.Clause objects.
"""
if type(intent)!=list:
raise TypeError("Input intent must be a list consisting of string descriptions or lux.Clause objects."
"\nSee more at: https://lux-api.readthedocs.io/en/latest/source/guide/intent.html"
)
import re
# intent = ldf.get_context()
new_context = []
#checks for and converts users' string inputs into lux specifications
for clause in intent:
valid_values = []
if isinstance(clause,list):
valid_values = []
for v in clause:
if type(v) is str: # and v in list(ldf.columns): #TODO: Move validation check to Validator
valid_values.append(v)
temp_spec = Clause(attribute = valid_values)
new_context.append(temp_spec)
elif isinstance(clause,str):
#case where user specifies a filter
if "=" in clause:
eqInd = clause.index("=")
var = clause[0:eqInd]
if "|" in clause:
values = clause[eqInd+1:].split("|")
for v in values:
# if v in ldf.unique_values[var]: #TODO: Move validation check to Validator
valid_values.append(v)
else:
valid_values = clause[eqInd+1:]
# if var in list(ldf.columns): #TODO: Move validation check to Validator
temp_spec = Clause(attribute = var, filter_op = "=", value = valid_values)
new_context.append(temp_spec)
#case where user specifies a variable
else:
if "|" in clause:
values = clause.split("|")
for v in values:
# if v in list(ldf.columns): #TODO: Move validation check to Validator
valid_values.append(v)
else:
valid_values = clause
temp_spec = Clause(attribute = valid_values)
new_context.append(temp_spec)
elif type(clause) is Clause:
new_context.append(clause)
intent = new_context
# ldf._intent = new_context
for clause in intent:
if (clause.description):
#TODO: Move validation check to Validator
#if ((clause.description in list(ldf.columns)) or clause.description == "?"):# if clause.description in the list of attributes
if any(ext in [">","<","=","!="] for ext in clause.description): # clause.description contain ">","<". or "="
# then parse it and assign to clause.attribute, clause.filter_op, clause.values
clause.filter_op = re.findall(r'/.*/|>|=|<|>=|<=|!=', clause.description)[0]
split_description = clause.description.split(clause.filter_op)
clause.attribute = split_description[0]
clause.value = split_description[1]
if re.match(r'^-?\d+(?:\.\d+)?$', clause.value):
clause.value = float(clause.value)
elif (type(clause.description) == str):
clause.attribute = clause.description
elif (type(clause.description)==list):
clause.attribute = clause.description
# else: # then it is probably a value
# clause.values = clause.description
return intent
# ldf._intent = intent