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-- random code from http://lua-users.org/wiki/TextJustification
-- easy queue implementation ------------------------------------------
function q_create()
local q = {}
q.first = 0
q.last = 0
return q
end
function q_insert(q, s)
q[q.last] = s
q.last = q.last + 1
end
function q_empty(q)
return q.first >= q.last
end
function q_remove(q)
if q_empty(q) then
return nil
end
local s = q[q.first]
q[q.first] = nil
q.first = q.first+1
return s
end
function q_card(q)
return q.last - q.first
end
function q_length(q, f)
local l, i = 0, q.first
while i < q.last do
l = l + strlen(q[i])
i = i + 1
end
return l
end
-- line creation routines ------------------------------------------
-- justifies one line to fit into MAX columns
function justify(q)
local blanks = MAX - q_length(q)
local skips = q_card(q) - 1
local line = q_remove(q)
local quotient = floor(blanks/skips)
local reminder = blanks/skips - quotient
local error = 0
while skips > 0 do
error = error + reminder
if error >= 0.5 then
error = error - 1
line = line .. strrep(" ", quotient+1)
else
line = line .. strrep(" ", quotient)
end
line = line .. q_remove(q)
skips = skips - 1
end
return line or ""
end
-- join all words with one space between them
function catenate(q)
local line = q_remove(q)
while not q_empty(q) do
line = line .. " " .. q_remove(q)
end
return line or ""
end
-- main program -----------------------------------------------------
DEFMAX = 72
-- tries to get MAX from command-line
if not arg or getn(arg) < 1 then
MAX = DEFMAX
else
MAX = tonumber(arg[1])
if not MAX or MAX < 0 then
MAX = DEFMAX
end
end
-- collects all text from stdin
text = q_create()
line = read()
while line do
_, n = gsub(line, "(%S+)", function (s) q_insert(%text, s) end)
if n == 0 then
q_insert(text, "\n")
end
line = read()
end
-- justify paragraphs
line = q_create()
word = q_remove(text)
size = 0
while word do
if word == "\n" then
if not q_empty(line) then
write(catenate(line), "\n\n")
else
write("\n")
end
size = 0
elseif size + strlen(word) > MAX then
write(justify(line), "\n")
size = 0
end
if word ~= "\n" then
q_insert(line, word)
size = size + strlen(word) + 1
end
word = q_remove(text)
end
write(catenate(line), "\n")
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