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# mypy: allow-untyped-defs
import operator
from . import base
from ..parser import parse
class Compiler(base.Compiler):
"""Compiler backend that evaluates conditional expressions
to give static output"""
def compile(self, tree, expr_data, data_cls_getter=None, **kwargs):
"""Compile a raw AST into a form with conditional expressions
evaluated.
tree - The root node of the wptmanifest AST to compile
expr_data - A dictionary of key / value pairs to use when
evaluating conditional expressions
data_cls_getter - A function taking two parameters; the previous
output node and the current ast node and returning
the class of the output node to use for the current
ast node
"""
self._kwargs = kwargs
self.expr_data = expr_data
return self._compile(tree, data_cls_getter, **kwargs)
def visit_KeyValueNode(self, node):
key_name = node.data
key_value = None
for child in node.children:
value = self.visit(child)
if value is not None:
key_value = value
break
if key_value is not None:
self.output_node.set(key_name, key_value)
def visit_ConditionalNode(self, node):
assert len(node.children) == 2
if self.visit(node.children[0]):
return self.visit(node.children[1])
def visit_StringNode(self, node):
value = node.data
for child in node.children:
value = self.visit(child)(value)
return value
def visit_VariableNode(self, node):
value = self.expr_data[node.data]
for child in node.children:
value = self.visit(child)(value)
return value
def visit_IndexNode(self, node):
assert len(node.children) == 1
index = self.visit(node.children[0])
return lambda x: x[index]
def visit_UnaryExpressionNode(self, node):
assert len(node.children) == 2
operator = self.visit(node.children[0])
operand = self.visit(node.children[1])
return operator(operand)
def visit_BinaryExpressionNode(self, node):
assert len(node.children) == 3
operator = self.visit(node.children[0])
operand_0 = self.visit(node.children[1])
operand_1 = self.visit(node.children[2])
return operator(operand_0, operand_1)
def visit_UnaryOperatorNode(self, node):
return {"not": operator.not_}[node.data]
def visit_BinaryOperatorNode(self, node):
return {"and": operator.and_,
"or": operator.or_,
"==": operator.eq,
"!=": operator.ne}[node.data]
def compile_ast(ast, expr_data, data_cls_getter=None, **kwargs):
return Compiler().compile(ast,
expr_data,
data_cls_getter=data_cls_getter,
**kwargs)
def compile(stream, expr_data, data_cls_getter=None, **kwargs):
return compile_ast(parse(stream),
expr_data,
data_cls_getter=data_cls_getter,
**kwargs)