require 'posix'
List = require 'pl.List'
stringx = require 'pl.stringx'
file = require 'pl.file'
-- seed random number generator
seed = posix.unistd.getpid() * os.time()
seed = seed % (2^31)
math.randomseed(seed)
-- return a random integer in the range 1..value
function randomval (value)
return (math.ceil(math.random() * value))
end
-- split a string on a delimiter (stripping whitespice around delimiters)
function split(str, delim)
delim = delim and ('%s*'..delim..'%s*') or '%s+'
local t = List.new()
local fpat = '(.-)'..delim
local last_end = 1
local s, e, cap = str:find(fpat, 1)
while s do
if s ~= 1 or cap ~= "" then
t:append(cap)
end
last_end = e + 1
s, e, cap = str:find(fpat, last_end)
end
if last_end <= #str then
cap = str:sub(last_end)
t:append(cap)
end
return t
end
-- select a random member of a List
function pickone (choices)
return (split(choices[randomval(#choices)]))
end
-- return the index of the first word in wordlist that is a key in dict
function find_key (dict, wordlist)
for i = 1, #wordlist do
if (dict[wordlist[i]]) then
return i
end
end
return nil
end
-- Recursively process a list of words, expanding the dictionary keys into
-- randomly-selected replacement phrases"
function generate_phrase (words)
if #words == 0 then
return List.new()
end
local left, choices, right
local divvy = function(i)
left = words:slice(1, i-1)
choices = repl[words[i]]
right = words:slice(i+1, -1)
end
local i = find_key(repl, words)
if i and pcall(divvy, i) then
return (left .. generate_phrase(pickone(choices)..right))
else
return (words)
end
end
-- load the data file
function load_data (filename)
filename = filename or "/ext/www/foods.txt"
local content = file.read(filename)
local data = stringx.splitlines(content)
sentence = data:pop(1)
repl = List.new()
for i,line in pairs(data) do
line = split(line, ':')
repl[line:pop(1)] = line -- store replacement phrases in dictionary
end
end
-- capitalize the first letter of a string
function capitalize (str)
return (str:sub(1,1):upper()..str:sub(2))
end
-- CGI/HTML helper functions
function content_type (typ, fp)
typ = typ or 'text/html'
fp = fp or io.stdout
fp:write("Content-type: "..typ.."\n\n")
end
function doc_type(fp)
fp = fp or io.stdout
fp:write('\n')
end
function headers(title, fp)
title = title or "unknown"
fp = fp or io.stdout
fp:write("\n")
fp:write(""..title.."\n")
fp:write("\n")
fp:write('\n')
end
function startlist(header, fp)
fp = fp or io.stdout
if header then
fp:write("" .. header .. ":
\n")
end
fp:write("\n")
end
function bullet(item, fp)
fp = fp or io.stdout
fp:write("- "..item.."\n")
end
function endlist(fp)
fp = fp or io.stdout
fp:write("
")
end
function footer(fp)
fp = fp or io.stdout
fp:write("\n")
end
function howmany()
local url = os.getenv("REQUEST_URI")
local n
if not url then
return (5)
end
_, _, n = url:find('?n=(%d+)')
if n then n = tonumber(n) end
if not n then
n = 5
elseif n > 100 then
n = 100
end
return (n)
end
--
-- main
--
load_data()
-- generate HTML
content_type()
headers("Potluck menu")
startlist("This week's potluck will feature")
for i = 1, howmany() do
food = generate_phrase(split(sentence)):join(' ')
bullet (capitalize(food))
end
endlist()
footer()