342 lines
9.9 KiB
Lua
342 lines
9.9 KiB
Lua
--- Simple Input Patterns (SIP).
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-- SIP patterns start with '$', then a
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-- one-letter type, and then an optional variable in curly braces.
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--
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-- sip.match('$v=$q','name="dolly"',res)
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-- ==> res=={'name','dolly'}
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-- sip.match('($q{first},$q{second})','("john","smith")',res)
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-- ==> res=={second='smith',first='john'}
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--
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-- ''Type names''
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--
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-- v identifier
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-- i integer
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-- f floating-point
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-- q quoted string
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-- ([{< match up to closing bracket
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--
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-- See @{08-additional.md.Simple_Input_Patterns|the Guide}
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--
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-- @module pl.sip
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local loadstring = rawget(_G,'loadstring') or load
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local unpack = rawget(_G,'unpack') or rawget(table,'unpack')
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local append,concat = table.insert,table.concat
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local ipairs,loadstring,type,unpack = ipairs,loadstring,type,unpack
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local io,_G = io,_G
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local print,rawget = print,rawget
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local patterns = {
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FLOAT = '[%+%-%d]%d*%.?%d*[eE]?[%+%-]?%d*',
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INTEGER = '[+%-%d]%d*',
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IDEN = '[%a_][%w_]*',
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FILE = '[%a%.\\][:%][%w%._%-\\]*',
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OPTION = '[%a_][%w_%-]*',
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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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--[[
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module ('pl.sip',utils._module)
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]]
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local sip = {}
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local brackets = {['<'] = '>', ['('] = ')', ['{'] = '}', ['['] = ']' }
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local stdclasses = {a=1,c=0,d=1,l=1,p=0,u=1,w=1,x=1,s=0}
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local _patterns = {}
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local function group(s)
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return '('..s..')'
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end
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-- escape all magic characters except $, which has special meaning
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-- Also, un-escape any characters after $, so $( passes through as is.
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local function escape (spec)
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--_G.print('spec',spec)
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local res = spec:gsub('[%-%.%+%[%]%(%)%^%%%?%*]','%%%1'):gsub('%$%%(%S)','$%1')
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--_G.print('res',res)
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return res
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end
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local function imcompressible (s)
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return s:gsub('%s+','\001')
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end
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-- [handling of spaces in patterns]
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-- spaces may be 'compressed' (i.e will match zero or more spaces)
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-- unless this occurs within a number or an identifier. So we mark
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-- the four possible imcompressible patterns first and then replace.
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-- The possible alnum patterns are v,f,a,d,x,l and u.
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local function compress_spaces (s)
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s = s:gsub('%$[vifadxlu]%s+%$[vfadxlu]',imcompressible)
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s = s:gsub('[%w_]%s+[%w_]',imcompressible)
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s = s:gsub('[%w_]%s+%$[vfadxlu]',imcompressible)
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s = s:gsub('%$[vfadxlu]%s+[%w_]',imcompressible)
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s = s:gsub('%s+','%%s*')
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s = s:gsub('\001',' ')
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return s
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end
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local pattern_map = {
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v = group(patterns.IDEN),
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i = group(patterns.INTEGER),
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f = group(patterns.FLOAT),
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o = group(patterns.OPTION),
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r = '(%S.*)',
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p = '([%a]?[:]?[\\/%.%w_]+)'
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}
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function sip.custom_pattern(flag,patt)
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pattern_map[flag] = patt
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end
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--- convert a SIP pattern into the equivalent Lua string pattern.
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-- @param spec a SIP pattern
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-- @param options a table; only the <code>at_start</code> field is
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-- currently meaningful and esures that the pattern is anchored
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-- at the start of the string.
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-- @return a Lua string pattern.
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function sip.create_pattern (spec,options)
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assert_arg(1,spec,'string')
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local fieldnames,fieldtypes = {},{}
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if type(spec) == 'string' then
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spec = escape(spec)
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else
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local res = {}
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for i,s in ipairs(spec) do
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res[i] = escape(s)
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end
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spec = concat(res,'.-')
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end
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local kount = 1
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local function addfield (name,type)
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if not name then name = kount end
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if fieldnames then append(fieldnames,name) end
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if fieldtypes then fieldtypes[name] = type end
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kount = kount + 1
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end
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local named_vars, pattern
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named_vars = spec:find('{%a+}')
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pattern = '%$%S'
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if options and options.at_start then
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spec = '^'..spec
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end
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if spec:sub(-1,-1) == '$' then
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spec = spec:sub(1,-2)..'$r'
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if named_vars then spec = spec..'{rest}' end
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end
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local names
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if named_vars then
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names = {}
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spec = spec:gsub('{(%a+)}',function(name)
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append(names,name)
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return ''
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end)
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end
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spec = compress_spaces(spec)
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local k = 1
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local err
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local r = (spec:gsub(pattern,function(s)
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local type,name
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type = s:sub(2,2)
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if names then name = names[k]; k=k+1 end
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-- this kludge is necessary because %q generates two matches, and
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-- we want to ignore the first. Not a problem for named captures.
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if not names and type == 'q' then
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addfield(nil,'Q')
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else
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addfield(name,type)
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end
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local res
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if pattern_map[type] then
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res = pattern_map[type]
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elseif type == 'q' then
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-- some Lua pattern matching voodoo; we want to match '...' as
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-- well as "...", and can use the fact that %n will match a
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-- previous capture. Adding the extra field above comes from needing
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-- to accomodate the extra spurious match (which is either ' or ")
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addfield(name,type)
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res = '(["\'])(.-)%'..(kount-2)
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else
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local endbracket = brackets[type]
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if endbracket then
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res = '(%b'..type..endbracket..')'
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elseif stdclasses[type] or stdclasses[type:lower()] then
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res = '(%'..type..'+)'
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else
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err = "unknown format type or character class"
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end
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end
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return res
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end))
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--print(r,err)
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if err then
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return nil,err
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else
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return r,fieldnames,fieldtypes
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end
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end
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local function tnumber (s)
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return s == 'd' or s == 'i' or s == 'f'
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end
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function sip.create_spec_fun(spec,options)
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local fieldtypes,fieldnames
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local ls = {}
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spec,fieldnames,fieldtypes = sip.create_pattern(spec,options)
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if not spec then return spec,fieldnames end
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local named_vars = type(fieldnames[1]) == 'string'
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for i = 1,#fieldnames do
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append(ls,'mm'..i)
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end
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local fun = ('return (function(s,res)\n\tlocal %s = s:match(%q)\n'):format(concat(ls,','),spec)
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fun = fun..'\tif not mm1 then return false end\n'
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local k=1
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for i,f in ipairs(fieldnames) do
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if f ~= '_' then
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local var = 'mm'..i
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if tnumber(fieldtypes[f]) then
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var = 'tonumber('..var..')'
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elseif brackets[fieldtypes[f]] then
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var = var..':sub(2,-2)'
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end
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if named_vars then
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fun = ('%s\tres.%s = %s\n'):format(fun,f,var)
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else
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if fieldtypes[f] ~= 'Q' then -- we skip the string-delim capture
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fun = ('%s\tres[%d] = %s\n'):format(fun,k,var)
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k = k + 1
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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 fun..'\treturn true\nend)\n', named_vars
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end
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--- convert a SIP pattern into a matching function.
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-- The returned function takes two arguments, the line and an empty table.
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-- If the line matched the pattern, then this function return true
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-- and the table is filled with field-value pairs.
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-- @param spec a SIP pattern
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-- @param options optional table; {anywhere=true} will stop pattern anchoring at start
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-- @return a function if successful, or nil,<error>
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function sip.compile(spec,options)
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assert_arg(1,spec,'string')
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local fun,names = sip.create_spec_fun(spec,options)
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if not fun then return nil,names end
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if rawget(_G,'_DEBUG') then print(fun) end
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local chunk,err = loadstring(fun,'tmp')
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if err then return nil,err end
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return chunk(),names
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end
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local cache = {}
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--- match a SIP pattern against a string.
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-- @param spec a SIP pattern
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-- @param line a string
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-- @param res a table to receive values
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-- @param options (optional) option table
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-- @return true or false
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function sip.match (spec,line,res,options)
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assert_arg(1,spec,'string')
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assert_arg(2,line,'string')
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assert_arg(3,res,'table')
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if not cache[spec] then
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cache[spec] = sip.compile(spec,options)
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end
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return cache[spec](line,res)
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end
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--- match a SIP pattern against the start of a string.
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-- @param spec a SIP pattern
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-- @param line a string
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-- @param res a table to receive values
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-- @return true or false
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function sip.match_at_start (spec,line,res)
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return sip.match(spec,line,res,{at_start=true})
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end
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--- given a pattern and a file object, return an iterator over the results
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-- @param spec a SIP pattern
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-- @param f a file - use standard input if not specified.
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function sip.fields (spec,f)
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assert_arg(1,spec,'string')
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f = f or io.stdin
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local fun,err = sip.compile(spec)
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if not fun then return nil,err end
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local res = {}
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return function()
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while true do
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local line = f:read()
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if not line then return end
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if fun(line,res) then
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local values = res
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res = {}
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return unpack(values)
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end
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end
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end
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end
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--- register a match which will be used in the read function.
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-- @string spec a SIP pattern
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-- @func fun a function to be called with the results of the match
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-- @see read
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function sip.pattern (spec,fun)
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assert_arg(1,spec,'string')
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local pat,named = sip.compile(spec)
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append(_patterns,{pat=pat,named=named,callback=fun or false})
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end
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--- enter a loop which applies all registered matches to the input file.
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-- @param f a file object; if nil, then io.stdin is assumed.
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function sip.read (f)
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local owned,err
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f = f or io.stdin
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if type(f) == 'string' then
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f,err = io.open(f)
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if not f then return nil,err end
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owned = true
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end
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local res = {}
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for line in f:lines() do
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for _,item in ipairs(_patterns) do
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if item.pat(line,res) then
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if item.callback then
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if item.named then
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item.callback(res)
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else
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item.callback(unpack(res))
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end
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end
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res = {}
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break
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end
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end
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end
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if owned then f:close() end
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end
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return sip
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