Replace tokens into YAML during load

yaml_apply_context.py

import string
import yaml
 
def load_yaml(f, context=None):
 
    if context is None:
        context = {}
 
    def string_constructor(loader, node):
 
        t = string.Template(node.value)
        value = t.substitute(context)
 
        return value
 
 
    l = yaml.SafeLoader
    l.add_constructor('tag:yaml.org,2002:str', string_constructor)
 
    token_re = string.Template.pattern
    l.add_implicit_resolver('tag:yaml.org,2002:str', token_re, None)
 
    x = yaml.load(f, Loader=l)
    return x
 
y = """\
aa: bb
cc: dd $EE ff
"""
 
context = {
    'EE': '123',
}
 
d = waw.utility.load_yaml(y, context)
print(d)