Pyparsing - name not starting with a character

Question

I am trying to use Pyparsing to identify a keyword which is not beginning with $ So for the following input:

$abc = 5 # is not a valid one
abc123 = 10 # is valid one
abc$ = 23 # is a valid one

I tried the following

var = Word(printables, excludeChars='$')
var.parseString('$abc') 

But this doesn't allow any $ in var. How can I specify all printable characters other than $ in the first character position? Any help will be appreciated.

Thanks Abhijit

Answer 1

You can use the method I used to define "all characters except X" before I added the excludeChars parameter to the Word class:

NOT_DOLLAR_SIGN = ''.join(c for c in printables if c != '$')
keyword_not_starting_with_dollar = Word(NOT_DOLLAR_SIGN, printables)

This should be a bit more efficient than building up with a Combine and a NotAny. But this will match almost anything, integers, words, valid identifiers, invalid identifiers, so I'm skeptical of the value of this kind of expression in your parser.