The haproxy configuration manual contains a matrix listing configuration keywords and their applicability by haproxy section (defaults, listen, backend, frontend). This code parses the manual and produces a json hash of sections and the keywords that apply in those sections.

parse_haproxy_matrix.py

#!/usr/bin/env python

from collections import defaultdict
import json
import requests

config_url = "http://haproxy.1wt.eu/download/1.5/doc/configuration.txt"
longest_keyword = 42  #works for haproxy 1.5 docs, but might need to be adjusted

# first, get the lines that pertain to the matrix
matrix_lines = []
in_matrix = False
configuration = requests.get(config_url)
for line in configuration.text.split('\n'):
   if line.split() == ['keyword', 'defaults', 'frontend', 'listen', 'backend']:
      in_matrix = False if in_matrix else True

   if in_matrix:
      matrix_lines.append(line)

# now parse the lines to figure out keyword/section applicability
fields = defaultdict(lambda: [])
allowed = {}

for l in matrix_lines:
   if l.startswith('-') or l.startswith(' '):
      continue

   names, boxes = l[0:longest_keyword], l[longest_keyword:]
   name = names.split('(')[0].strip()
   allowed['defaults'], allowed['frontend'], allowed['listen'], allowed['backend'] = [
         p == 'X' for p in boxes.split()]

   for section in allowed:
      if allowed[section]:
         fields[section].append(name)

print json.dumps(fields)