r - Unexpected Symbol in As Formula, Can't Find -

i've been using as.formula setting glm, , can't figure out unexpected symbol is. part of problem character vector i'm converting long. it's 700 words + inserted in between in order turn formula. error presents follows:

error in parse(text = x, keep.source = false) :     <text>:2:10080: unexpected symbol 

with following snippet of text:

2: c_1_e + campaign_search_payroll_generic_1_p + campaign_search_performing_core_keywords + campaign_self_employment_e + campaign_self_employment_p + campaign_withholding + campaign_youtube + sou 

things know sure:

1. no item repeated.
2. no symbols other alphanumerics , underscore (_).
3. no item starts number.

i'm not versed enough in r understand reading documentation as.formula or function call itself.

any ideas?

the <text>:2:10080 giving location of error. 2nd line, 10080th character. consider:

parse(text="1 + 1 + 2\n - 3 b") # error in parse(text = "1 + 1 + 2\n - 3 b") :  #   <text>:2:8: unexpected symbol 

here, error b, illegal use of symbol, , you'll note 8th character of second line.

most you're missing +, though no way of knowing without data behind error. also, not judge or anything, that's helluva lot variables sticking model. hope have lots of data points.