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-rw-r--r--macros/luatex/generic/penlight/pl/stringio.lua158
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diff --git a/macros/luatex/generic/penlight/pl/stringio.lua b/macros/luatex/generic/penlight/pl/stringio.lua
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+--- Reading and writing strings using file-like objects. <br>
+--
+-- f = stringio.open(text)
+-- l1 = f:read() -- read first line
+-- n,m = f:read ('*n','*n') -- read two numbers
+-- for line in f:lines() do print(line) end -- iterate over all lines
+-- f = stringio.create()
+-- f:write('hello')
+-- f:write('dolly')
+-- assert(f:value(),'hellodolly')
+--
+-- See @{03-strings.md.File_style_I_O_on_Strings|the Guide}.
+-- @module pl.stringio
+
+local unpack = rawget(_G,'unpack') or rawget(table,'unpack')
+local tonumber = tonumber
+local concat,append = table.concat,table.insert
+
+local stringio = {}
+
+-- Writer class
+local SW = {}
+SW.__index = SW
+
+local function xwrite(self,...)
+ local args = {...} --arguments may not be nil!
+ for i = 1, #args do
+ append(self.tbl,args[i])
+ end
+end
+
+function SW:write(arg1,arg2,...)
+ if arg2 then
+ xwrite(self,arg1,arg2,...)
+ else
+ append(self.tbl,arg1)
+ end
+end
+
+function SW:writef(fmt,...)
+ self:write(fmt:format(...))
+end
+
+function SW:value()
+ return concat(self.tbl)
+end
+
+function SW:__tostring()
+ return self:value()
+end
+
+function SW:close() -- for compatibility only
+end
+
+function SW:seek()
+end
+
+-- Reader class
+local SR = {}
+SR.__index = SR
+
+function SR:_read(fmt)
+ local i,str = self.i,self.str
+ local sz = #str
+ if i > sz then return nil end
+ local res
+ if fmt == '*l' or fmt == '*L' then
+ local idx = str:find('\n',i) or (sz+1)
+ res = str:sub(i,fmt == '*l' and idx-1 or idx)
+ self.i = idx+1
+ elseif fmt == '*a' then
+ res = str:sub(i)
+ self.i = sz
+ elseif fmt == '*n' then
+ local _,i2,idx
+ _,idx = str:find ('%s*%d+',i)
+ _,i2 = str:find ('^%.%d+',idx+1)
+ if i2 then idx = i2 end
+ _,i2 = str:find ('^[eE][%+%-]*%d+',idx+1)
+ if i2 then idx = i2 end
+ local val = str:sub(i,idx)
+ res = tonumber(val)
+ self.i = idx+1
+ elseif type(fmt) == 'number' then
+ res = str:sub(i,i+fmt-1)
+ self.i = i + fmt
+ else
+ error("bad read format",2)
+ end
+ return res
+end
+
+function SR:read(...)
+ if select('#',...) == 0 then
+ return self:_read('*l')
+ else
+ local res, fmts = {},{...}
+ for i = 1, #fmts do
+ res[i] = self:_read(fmts[i])
+ end
+ return unpack(res)
+ end
+end
+
+function SR:seek(whence,offset)
+ local base
+ whence = whence or 'cur'
+ offset = offset or 0
+ if whence == 'set' then
+ base = 1
+ elseif whence == 'cur' then
+ base = self.i
+ elseif whence == 'end' then
+ base = #self.str
+ end
+ self.i = base + offset
+ return self.i
+end
+
+function SR:lines(...)
+ local n, args = select('#',...)
+ if n > 0 then
+ args = {...}
+ end
+ return function()
+ if n == 0 then
+ return self:_read '*l'
+ else
+ return self:read(unpack(args))
+ end
+ end
+end
+
+function SR:close() -- for compatibility only
+end
+
+--- create a file-like object which can be used to construct a string.
+-- The resulting object has an extra `value()` method for
+-- retrieving the string value. Implements `file:write`, `file:seek`, `file:lines`,
+-- plus an extra `writef` method which works like `utils.printf`.
+-- @usage f = create(); f:write('hello, dolly\n'); print(f:value())
+function stringio.create()
+ return setmetatable({tbl={}},SW)
+end
+
+--- create a file-like object for reading from a given string.
+-- Implements `file:read`.
+-- @string s The input string.
+-- @usage fs = open '20 10'; x,y = f:read ('*n','*n'); assert(x == 20 and y == 10)
+function stringio.open(s)
+ return setmetatable({str=s,i=1},SR)
+end
+
+function stringio.lines(s,...)
+ return stringio.open(s):lines(...)
+end
+
+return stringio