+ Penlight

1 files changed, 158 insertions, 0 deletions

diff --git a/Data/Libraries/Penlight/lua/pl/stringio.lua b/Data/Libraries/Penlight/lua/pl/stringio.lua
new file mode 100644
index 0000000..666f415
--- /dev/null
+++ b/Data/Libraries/Penlight/lua/pl/stringio.lua
@@ -0,0 +1,158 @@
+--- 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