Re: lpeg to compile lua server page.

[zhiguo zhao <zhaozg@...>]

<% a=1 b=1 %>B"B"B<%= abc %><h1>h1</h1><%! a.html %>cc

has been translate to:

a=1 b=1 print("B\"B\"B")printf( abc )print("<h1>h1</h1>")include( a.html )print("cc")print("cc")

2010/12/18 zhiguo zhao <zhaozg@gmail.com>

Hi, all.

 I study lp compile in cgilua, then I want to rewrite it with lpeg. But I think I not have enough knowledge of lpeg, so I think I used more lpeg.Cg and lpeg.Cb.

Welcome any solution to make it clear and faster,

local lpeg = require"lpeg" 

local B = lpeg.P("<%")      --begin

local E = lpeg.P("%>")      --end

local I = lpeg.S("=!@ ")    --instruction

local NB = (1 - B)^0

local NE = (1 - E)^0

function parse(s,text,script)

    local IN    = lpeg.Cg(I,'INS')      --instruction named

    local TN    = lpeg.Cg(NB,'TEXT')

    local SN    = lpeg.Cg(NE,'SCRIPT')  --script named

    local TP = lpeg.Cmt(TN*lpeg.Cb('TEXT'),text)                                   --text process

    local SP = lpeg.Cmt(IN^-1 * SN * lpeg.Cb('INS') * lpeg.Cb('SCRIPT'),script)   --script process

    local LS = B * SP * E               --script block

    local handle = (TP * LS)^0 * TP     --all context

    return lpeg.match(handle,s)

end

function translate(s)

    local res = {}

    ptext = function(_,_,s)

        if(s~='') then

            table.insert(res,string.format('print(%q)',s))

        end

        return true

    end

    pscript = function(all, _, i, s)

        if( i=='=') then

            table.insert(res,string.format('printf(%s)',s))

        elseif(i=='!') then

            table.insert(res,string.format('include(%s)',s))

        elseif(s=='@') then

            table.insert(res,string.format('@@@@(%s)',s))

        else

            table.insert(res,s)

        end

        return true

    end

    if(parse(s,ptext,pscript)) then

        print(#res)

        return table.concat(res)

    end

    return nil

end

local content = '<% a=1 b=1 %>B"B"B<%= abc %><h1>h1</h1><%! a.html %>cc'

--local content = 'cc'

print(content)

print('after translate')

print(translate(content))