gistfile1.lua

[[
01234567890123456789012345678901234567890123456789012345678901234567890123456789
]]

-- NOTE: requires 'LPEG' module
local re = require're'
local assert = assert
local min, max = math.min, math.max

-- PEG Grammar 1:
local GG1 = [[
  osm    <- '<?xml' (!'?' .)+ '?>' <xml> <ws>
  xml    <- <node>* -> {}
  node   <- <ws> '<' {:tag: <name> :} <param>*
            <ws> ('/>' / '>' <xml> <ws> '</' <ws> =tag <ws> '>')
  param  <- (<ws> <name> '=' <string> <ws>) -> processData
  string <- '"' { (!'"' .)* } '"'
  name   <- { %w+ }
  ws     <- %s*
]]

-- PEG Grammar 2:
local GG2 = [[
  osm     <- ((<ws> '<' (<node> / <tag>))*)  <ws>
  node    <- 'node' <param>* <ws> <endnode>
  endnode <- '/>'
           / (!'</node>' .)* '</node>'
  param   <- (<ws> <name> '=' <string> <ws>) -> processData
  tag     <- (!'>' .)* '>'
  string  <- '"' { (!'"' .)* } '"'
  name    <- { %w+ }
  ws      <- %s*

]]


-- TEST:

local Bounds = {
  reset = function(self)
            assert(self)
            self.minlat = 1E9
            self.maxlat = -1E9
            self.minlon = 1E9
            self.maxlon = -1E9
            return self
          end
}

local function processData(key,val)
  if     key == 'lat' then
    local lat = assert(tonumber(val))
    Bounds.minlat = min(lat,Bounds.minlat)
    Bounds.maxlat = max(lat,Bounds.maxlat)
  elseif key == 'lon' then
    local lon = assert(tonumber(val))
    Bounds.minlon = min(lon,Bounds.minlon)
    Bounds.maxlon = max(lon,Bounds.maxlon)
  end
end

local Parser1 = re.compile(GG1,{processData = processData})
local Parser2 = re.compile(GG2,{processData = processData})

-- http://downloads.cloudmade.com/asia/singapore/singapore.osm.bz2
local singapore = assert(io.open("singapore.osm"):read('*a'))


-- ------------
Bounds:reset()
local t1 = os.clock()
local result = re.match(singapore,Parser1)
print('Parser1',os.clock()-t1,'sec')

print("Bounds.minlat",  Bounds.minlat)
print("Bounds.maxlat",  Bounds.maxlat)
print("Bounds.minlon",  Bounds.minlon)
print("Bounds.maxlon",  Bounds.maxlon)
-- ------------


-- ------------
Bounds:reset()
local t1 = os.clock()
local result = re.match(singapore,Parser2)
print('Parser2',os.clock()-t1,'sec')

print("Bounds.minlat",  Bounds.minlat)
print("Bounds.maxlat",  Bounds.maxlat)
print("Bounds.minlon",  Bounds.minlon)
print("Bounds.maxlon",  Bounds.maxlon)
-- ------------