474 lines
14 KiB
Lua
474 lines
14 KiB
Lua
--- Lexical scanner for creating a sequence of tokens from text. <br>
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-- <p><code>lexer.scan(s)</code> returns an iterator over all tokens found in the
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-- string <code>s</code>. This iterator returns two values, a token type string
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-- (such as 'string' for quoted string, 'iden' for identifier) and the value of the
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-- token.
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-- <p>
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-- Versions specialized for Lua and C are available; these also handle block comments
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-- and classify keywords as 'keyword' tokens. For example:
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-- <pre class=example>
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-- > s = 'for i=1,n do'
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-- > for t,v in lexer.lua(s) do print(t,v) end
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-- keyword for
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-- iden i
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-- = =
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-- number 1
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-- , ,
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-- iden n
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-- keyword do
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-- </pre>
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-- See the Guide for further <a href="../../index.html#lexer">discussion</a> <br>
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-- @class module
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-- @name pl.lexer
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local yield,wrap = coroutine.yield,coroutine.wrap
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local strfind = string.find
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local strsub = string.sub
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local append = table.insert
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--[[
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module ('pl.lexer',utils._module)
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]]
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local function assert_arg(idx,val,tp)
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if type(val) ~= tp then
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error("argument "..idx.." must be "..tp, 2)
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end
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end
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local lexer = {}
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local NUMBER1 = '^[%+%-]?%d+%.?%d*[eE][%+%-]?%d+'
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local NUMBER2 = '^[%+%-]?%d+%.?%d*'
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local NUMBER3 = '^0x[%da-fA-F]+'
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local NUMBER4 = '^%d+%.?%d*[eE][%+%-]?%d+'
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local NUMBER5 = '^%d+%.?%d*'
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local IDEN = '^[%a_][%w_]*'
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local WSPACE = '^%s+'
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local STRING1 = "^'.-[^\\]'"
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local STRING2 = '^".-[^\\]"'
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local STRING3 = '^[\'"][\'"]'
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local PREPRO = '^#.-[^\\]\n'
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local plain_matches,lua_matches,cpp_matches,lua_keyword,cpp_keyword
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local function tdump(tok)
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return yield(tok,tok)
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end
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local function ndump(tok,options)
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if options and options.number then
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tok = tonumber(tok)
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end
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return yield("number",tok)
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end
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-- regular strings, single or double quotes; usually we want them
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-- without the quotes
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local function sdump(tok,options)
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if options and options.string then
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tok = tok:sub(2,-2)
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end
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return yield("string",tok)
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end
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-- long Lua strings need extra work to get rid of the quotes
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local function sdump_l(tok,options)
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if options and options.string then
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tok = tok:sub(3,-3)
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end
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return yield("string",tok)
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end
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local function chdump(tok,options)
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if options and options.string then
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tok = tok:sub(2,-2)
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end
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return yield("char",tok)
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end
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local function cdump(tok)
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return yield('comment',tok)
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end
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local function wsdump (tok)
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return yield("space",tok)
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end
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local function pdump (tok)
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return yield('prepro',tok)
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end
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local function plain_vdump(tok)
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return yield("iden",tok)
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end
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local function lua_vdump(tok)
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if lua_keyword[tok] then
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return yield("keyword",tok)
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else
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return yield("iden",tok)
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end
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end
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local function cpp_vdump(tok)
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if cpp_keyword[tok] then
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return yield("keyword",tok)
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else
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return yield("iden",tok)
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end
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end
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--- create a plain token iterator from a string or file-like object.
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-- @param s the string
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-- @param matches an optional match table (set of pattern-action pairs)
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-- @param filter a table of token types to exclude, by default {space=true}
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-- @param options a table of options; by default, {number=true,string=true},
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-- which means convert numbers and strip string quotes.
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function lexer.scan (s,matches,filter,options)
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--assert_arg(1,s,'string')
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local file = type(s) ~= 'string' and s
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filter = filter or {space=true}
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options = options or {number=true,string=true}
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if filter then
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if filter.space then filter[wsdump] = true end
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if filter.comments then
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filter[cdump] = true
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end
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end
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if not matches then
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if not plain_matches then
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plain_matches = {
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{WSPACE,wsdump},
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{NUMBER3,ndump},
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{IDEN,plain_vdump},
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{NUMBER1,ndump},
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{NUMBER2,ndump},
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{STRING3,sdump},
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{STRING1,sdump},
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{STRING2,sdump},
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{'^.',tdump}
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}
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end
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matches = plain_matches
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end
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function lex ()
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local i1,i2,idx,res1,res2,tok,pat,fun,capt
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local line = 1
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if file then
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s = file:read()
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if not s then return nil end -- empty file
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s = s ..'\n'
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end
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local sz = #s
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local idx = 1
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--print('sz',sz)
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while true do
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for _,m in ipairs(matches) do
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pat = m[1]
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fun = m[2]
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if fun == nil then print(pat); os.exit() end
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i1,i2 = strfind(s,pat,idx)
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if i1 then
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tok = strsub(s,i1,i2)
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idx = i2 + 1
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if not (filter and filter[fun]) then
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lexer.finished = idx > sz
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res1,res2 = fun(tok,options)
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end
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if res1 then
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local tp = type(res1)
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-- insert a token list
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if tp=='table' then
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yield('','')
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for _,t in ipairs(res1) do
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yield(t[1],t[2])
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end
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elseif tp == 'string' then -- or search up to some special pattern
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i1,i2 = strfind(s,res1,idx)
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if i1 then
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tok = strsub(s,i1,i2)
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idx = i2 + 1
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yield('',tok)
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else
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yield('','')
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idx = sz + 1
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end
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--if idx > sz then return end
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else
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yield(line,idx)
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end
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end
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if idx > sz then
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if file then
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--repeat -- next non-empty line
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line = line + 1
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s = file:read()
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if not s then return end
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--until not s:match '^%s*$'
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s = s .. '\n'
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idx ,sz = 1,#s
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break
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else
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return
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end
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else break end
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end
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end
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end
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end
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return wrap(lex)
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end
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local function isstring (s)
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return type(s) == 'string'
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end
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--- insert tokens into a stream.
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-- @param tok a token stream
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-- @param a1 a string is the type, a table is a token list and
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-- a function is assumed to be a token-like iterator (returns type & value)
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-- @param a2 a string is the value
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function lexer.insert (tok,a1,a2)
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if not a1 then return end
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local ts
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if isstring(a1) and isstring(a2) then
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ts = {{a1,a2}}
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elseif type(a1) == 'function' then
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ts = {}
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for t,v in a1() do
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append(ts,{t,v})
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end
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else
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ts = a1
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end
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tok(ts)
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end
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--- get everything in a stream upto a newline.
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-- @param tok a token stream
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-- @return a string
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function lexer.getline (tok)
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local t,v = tok('.-\n')
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return v
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end
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--- get current line number. <br>
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-- Only available if the input source is a file-like object.
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-- @param tok a token stream
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-- @return the line number and current column
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function lexer.lineno (tok)
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return tok(0)
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end
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--- get the rest of the stream.
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-- @param tok a token stream
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-- @return a string
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function lexer.getrest (tok)
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local t,v = tok('.+')
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return v
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end
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--- get the Lua keywords as a set-like table.
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-- So <code>res["and"]</code> etc would be <code>true</code>.
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-- @return a table
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function lexer.get_keywords ()
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if not lua_keyword then
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lua_keyword = {
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["and"] = true, ["break"] = true, ["do"] = true,
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["else"] = true, ["elseif"] = true, ["end"] = true,
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["false"] = true, ["for"] = true, ["function"] = true,
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["if"] = true, ["in"] = true, ["local"] = true, ["nil"] = true,
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["not"] = true, ["or"] = true, ["repeat"] = true,
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["return"] = true, ["then"] = true, ["true"] = true,
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["until"] = true, ["while"] = true
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}
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end
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return lua_keyword
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end
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--- create a Lua token iterator from a string or file-like object.
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-- Will return the token type and value.
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-- @param s the string
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-- @param filter a table of token types to exclude, by default {space=true,comments=true}
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-- @param options a table of options; by default, {number=true,string=true},
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-- which means convert numbers and strip string quotes.
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function lexer.lua(s,filter,options)
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filter = filter or {space=true,comments=true}
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lexer.get_keywords()
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if not lua_matches then
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lua_matches = {
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{WSPACE,wsdump},
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{NUMBER3,ndump},
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{IDEN,lua_vdump},
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{NUMBER4,ndump},
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{NUMBER5,ndump},
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{STRING3,sdump},
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{STRING1,sdump},
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{STRING2,sdump},
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{'^%-%-.-\n',cdump},
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{'^%[%[.+%]%]',sdump_l},
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{'^%-%-%[%[.+%]%]',cdump},
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{'^==',tdump},
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{'^~=',tdump},
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{'^<=',tdump},
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{'^>=',tdump},
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{'^%.%.%.',tdump},
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{'^.',tdump}
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}
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end
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return lexer.scan(s,lua_matches,filter,options)
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end
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--- create a C/C++ token iterator from a string or file-like object.
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-- Will return the token type type and value.
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-- @param s the string
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-- @param filter a table of token types to exclude, by default {space=true,comments=true}
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-- @param options a table of options; by default, {number=true,string=true},
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-- which means convert numbers and strip string quotes.
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function lexer.cpp(s,filter,options)
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filter = filter or {comments=true}
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if not cpp_keyword then
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cpp_keyword = {
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["class"] = true, ["break"] = true, ["do"] = true, ["sizeof"] = true,
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["else"] = true, ["continue"] = true, ["struct"] = true,
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["false"] = true, ["for"] = true, ["public"] = true, ["void"] = true,
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["private"] = true, ["protected"] = true, ["goto"] = true,
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["if"] = true, ["static"] = true, ["const"] = true, ["typedef"] = true,
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["enum"] = true, ["char"] = true, ["int"] = true, ["bool"] = true,
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["long"] = true, ["float"] = true, ["true"] = true, ["delete"] = true,
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["double"] = true, ["while"] = true, ["new"] = true,
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["namespace"] = true, ["try"] = true, ["catch"] = true,
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["switch"] = true, ["case"] = true, ["extern"] = true,
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["return"] = true,["default"] = true,['unsigned'] = true,['signed'] = true,
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["union"] = true, ["volatile"] = true, ["register"] = true,["short"] = true,
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}
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end
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if not cpp_matches then
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cpp_matches = {
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{WSPACE,wsdump},
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{PREPRO,pdump},
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{NUMBER3,ndump},
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{IDEN,cpp_vdump},
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{NUMBER4,ndump},
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{NUMBER5,ndump},
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{STRING3,sdump},
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{STRING1,chdump},
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{STRING2,sdump},
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{'^//.-\n',cdump},
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{'^/%*.-%*/',cdump},
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{'^==',tdump},
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{'^!=',tdump},
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{'^<=',tdump},
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{'^>=',tdump},
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{'^->',tdump},
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{'^&&',tdump},
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{'^||',tdump},
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{'^%+%+',tdump},
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{'^%-%-',tdump},
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{'^%+=',tdump},
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{'^%-=',tdump},
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{'^%*=',tdump},
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{'^/=',tdump},
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{'^|=',tdump},
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{'^%^=',tdump},
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{'^::',tdump},
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{'^.',tdump}
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}
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end
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return lexer.scan(s,cpp_matches,filter,options)
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end
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--- get a list of parameters separated by a delimiter from a stream.
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-- @param tok the token stream
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-- @param endtoken end of list (default ')'). Can be '\n'
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-- @param delim separator (default ',')
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-- @return a list of token lists.
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function lexer.get_separated_list(tok,endtoken,delim)
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endtoken = endtoken or ')'
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delim = delim or ','
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local parm_values = {}
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local level = 1 -- used to count ( and )
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local tl = {}
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local function tappend (tl,t,val)
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val = val or t
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append(tl,{t,val})
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end
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local is_end
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if endtoken == '\n' then
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is_end = function(t,val)
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return t == 'space' and val:find '\n'
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end
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else
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is_end = function (t)
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return t == endtoken
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end
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end
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local is_delim
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if type(delim) == 'function' then
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is_delim = delim
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else
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is_delim = function(t)
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return t == delim
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end
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end
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local token,value
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while true do
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token,value=tok()
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if not token then return nil,'EOS' end -- end of stream is an error!
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if is_end(token,value) and level == 1 then
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append(parm_values,tl)
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break
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elseif token == '(' then
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level = level + 1
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tappend(tl,'(')
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elseif token == ')' then
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level = level - 1
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if level == 0 then -- finished with parm list
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append(parm_values,tl)
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break
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else
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tappend(tl,')')
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end
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elseif level == 1 and is_delim(token) then
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append(parm_values,tl) -- a new parm
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tl = {}
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else
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tappend(tl,token,value)
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end
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end
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return parm_values,{token,value}
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end
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--- get the next non-space token from the stream.
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-- @param tok the token stream.
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function lexer.skipws (tok)
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local t,v = tok()
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while t == 'space' do
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t,v = tok()
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end
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return t,v
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end
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local skipws = lexer.skipws
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--- get the next token, which must be of the expected type.
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-- Throws an error if this type does not match!
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-- @param tok the token stream
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-- @param expected_type the token type
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-- @param no_skip_ws whether we should skip whitespace
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function lexer.expecting (tok,expected_type,no_skip_ws)
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assert_arg(1,tok,'function')
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assert_arg(2,expected_type,'string')
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local t,v
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if no_skip_ws then
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t,v = tok()
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else
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t,v = skipws(tok)
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end
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if t ~= expected_type then error ("expecting "..expected_type,2) end
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return v
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end
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return lexer
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