Is there a way to get a list of all placeholders in a cheetah template

Question

For example, if I have a template such as

"SELECT * FROM myOrders WHERE order_id = ${orderId} and order_date = ${orderDate}"

I would like to get a list of all placeholders in that template, i.e. ['orderId', 'orderDate']

Answer 1

I can use a regex to pull those placeholders out.

p.s. Still, it would be nice to have that feature in the Cheetah API, perhaps in the Template class.

example:

import re
templateDef = """
SELECT * FROM myOrders WHERE order_id = ${orderId} and order_date = ${orderDate}
"""
placeholders = re.findall(r"\${(\w+)}", templateDef)
print placeholders

Answer 2

Formatter.parse should work:

s = "SELECT * FROM myOrders WHERE order_id = ${orderId} and order_date = ${orderDate}"

from string import Formatter
#literal_text, field_name, format_spec, conversion
print([plh for _, plh, _,_  in Formatter().parse(s) if plh])
['orderId', 'orderDate']

Answer 3

This code:

vars = set()

class DummyDict:
    def __getitem__(self, key):
        vars.add(key)
        return 'X'

str(Template('Hello $A $B $C', searchList=[DummyDict()]))

print(vars)

Prints:

{'B', 'A', 'C'}