From 5d1cb5619ea720968e01ec9a63422b2cc30295ef Mon Sep 17 00:00:00 2001
From: Determinant <ted.sybil@gmail.com>
Date: Sun, 24 May 2015 19:11:59 +0800
Subject: add utils.lua from Penlight

---
 pl/utils.lua | 476 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 476 insertions(+)
 create mode 100644 pl/utils.lua

(limited to 'pl/utils.lua')

diff --git a/pl/utils.lua b/pl/utils.lua
new file mode 100644
index 0000000..f933afb
--- /dev/null
+++ b/pl/utils.lua
@@ -0,0 +1,476 @@
+--- Generally useful routines.
+-- See  @{01-introduction.md.Generally_useful_functions|the Guide}.
+-- @module pl.utils
+local format,gsub,byte = string.format,string.gsub,string.byte
+local compat = require 'pl.compat'
+local clock = os.clock
+local stdout = io.stdout
+local append = table.insert
+local unpack = rawget(_G,'unpack') or rawget(table,'unpack')
+
+local collisions = {}
+
+local utils = {
+    _VERSION = "1.3.2",
+    lua51 = compat.lua51,
+    setfenv = compat.setfenv,
+    getfenv = compat.getfenv,
+    load = compat.load,
+    execute = compat.execute,
+    dir_separator = _G.package.config:sub(1,1),
+    unpack = unpack
+}
+
+--- end this program gracefully.
+-- @param code The exit code or a message to be printed
+-- @param ... extra arguments for message's format'
+-- @see utils.fprintf
+function utils.quit(code,...)
+    if type(code) == 'string' then
+        utils.fprintf(io.stderr,code,...)
+        code = -1
+    else
+        utils.fprintf(io.stderr,...)
+    end
+    io.stderr:write('\n')
+    os.exit(code)
+end
+
+--- print an arbitrary number of arguments using a format.
+-- @param fmt The format (see string.format)
+-- @param ... Extra arguments for format
+function utils.printf(fmt,...)
+    utils.assert_string(1,fmt)
+    utils.fprintf(stdout,fmt,...)
+end
+
+--- write an arbitrary number of arguments to a file using a format.
+-- @param f File handle to write to.
+-- @param fmt The format (see string.format).
+-- @param ... Extra arguments for format
+function utils.fprintf(f,fmt,...)
+    utils.assert_string(2,fmt)
+    f:write(format(fmt,...))
+end
+
+local function import_symbol(T,k,v,libname)
+    local key = rawget(T,k)
+    -- warn about collisions!
+    if key and k ~= '_M' and k ~= '_NAME' and k ~= '_PACKAGE' and k ~= '_VERSION' then
+        utils.printf("warning: '%s.%s' will not override existing symbol\n",libname,k)
+        return
+    end
+    rawset(T,k,v)
+end
+
+local function lookup_lib(T,t)
+    for k,v in pairs(T) do
+        if v == t then return k end
+    end
+    return '?'
+end
+
+local already_imported = {}
+
+--- take a table and 'inject' it into the local namespace.
+-- @param t The Table
+-- @param T An optional destination table (defaults to callers environment)
+function utils.import(t,T)
+    T = T or _G
+    t = t or utils
+    if type(t) == 'string' then
+        t = require (t)
+    end
+    local libname = lookup_lib(T,t)
+    if already_imported[t] then return end
+    already_imported[t] = libname
+    for k,v in pairs(t) do
+        import_symbol(T,k,v,libname)
+    end
+end
+
+utils.patterns = {
+    FLOAT = '[%+%-%d]%d*%.?%d*[eE]?[%+%-]?%d*',
+    INTEGER = '[+%-%d]%d*',
+    IDEN = '[%a_][%w_]*',
+    FILE = '[%a%.\\][:%][%w%._%-\\]*'
+}
+
+--- escape any 'magic' characters in a string
+-- @param s The input string
+function utils.escape(s)
+    utils.assert_string(1,s)
+    return (s:gsub('[%-%.%+%[%]%(%)%$%^%%%?%*]','%%%1'))
+end
+
+--- return either of two values, depending on a condition.
+-- @param cond A condition
+-- @param value1 Value returned if cond is true
+-- @param value2 Value returned if cond is false (can be optional)
+function utils.choose(cond,value1,value2)
+    if cond then return value1
+    else return value2
+    end
+end
+
+local raise
+
+--- return the contents of a file as a string
+-- @param filename The file path
+-- @param is_bin open in binary mode
+-- @return file contents
+function utils.readfile(filename,is_bin)
+    local mode = is_bin and 'b' or ''
+    utils.assert_string(1,filename)
+    local f,err = io.open(filename,'r'..mode)
+    if not f then return utils.raise (err) end
+    local res,err = f:read('*a')
+    f:close()
+    if not res then return raise (err) end
+    return res
+end
+
+--- write a string to a file
+-- @param filename The file path
+-- @param str The string
+-- @return true or nil
+-- @return error message
+-- @raise error if filename or str aren't strings
+function utils.writefile(filename,str)
+    utils.assert_string(1,filename)
+    utils.assert_string(2,str)
+    local f,err = io.open(filename,'w')
+    if not f then return raise(err) end
+    f:write(str)
+    f:close()
+    return true
+end
+
+--- return the contents of a file as a list of lines
+-- @param filename The file path
+-- @return file contents as a table
+-- @raise errror if filename is not a string
+function utils.readlines(filename)
+    utils.assert_string(1,filename)
+    local f,err = io.open(filename,'r')
+    if not f then return raise(err) end
+    local res = {}
+    for line in f:lines() do
+        append(res,line)
+    end
+    f:close()
+    return res
+end
+
+--- split a string into a list of strings separated by a delimiter.
+-- @param s The input string
+-- @param re A Lua string pattern; defaults to '%s+'
+-- @param plain don't use Lua patterns
+-- @param n optional maximum number of splits
+-- @return a list-like table
+-- @raise error if s is not a string
+function utils.split(s,re,plain,n)
+    utils.assert_string(1,s)
+    local find,sub,append = string.find, string.sub, table.insert
+    local i1,ls = 1,{}
+    if not re then re = '%s+' end
+    if re == '' then return {s} end
+    while true do
+        local i2,i3 = find(s,re,i1,plain)
+        if not i2 then
+            local last = sub(s,i1)
+            if last ~= '' then append(ls,last) end
+            if #ls == 1 and ls[1] == '' then
+                return {}
+            else
+                return ls
+            end
+        end
+        append(ls,sub(s,i1,i2-1))
+        if n and #ls == n then
+            ls[#ls] = sub(s,i1)
+            return ls
+        end
+        i1 = i3+1
+    end
+end
+
+--- split a string into a number of values.
+-- @param s the string
+-- @param re the delimiter, default space
+-- @return n values
+-- @usage first,next = splitv('jane:doe',':')
+-- @see split
+function utils.splitv (s,re)
+    return unpack(utils.split(s,re))
+end
+
+--- convert an array of values to strings.
+-- @param t a list-like table
+-- @param temp buffer to use, otherwise allocate
+-- @param tostr custom tostring function, called with (value,index).
+-- Otherwise use `tostring`
+-- @return the converted buffer
+function utils.array_tostring (t,temp,tostr)
+    temp, tostr = temp or {}, tostr or tostring
+    for i = 1,#t do
+        temp[i] = tostr(t[i],i)
+    end
+    return temp
+end
+
+--- execute a shell command and return the output.
+-- This function redirects the output to tempfiles and returns the content of those files.
+-- @param cmd a shell command
+-- @param bin boolean, if true, read output as binary file
+-- @return true if successful
+-- @return actual return code
+-- @return stdout output (string)
+-- @return errout output (string)
+function utils.executeex(cmd, bin)
+    local mode
+    local outfile = os.tmpname()
+    local errfile = os.tmpname()
+
+    if utils.dir_separator == '\\' then
+        outfile = os.getenv('TEMP')..outfile
+        errfile = os.getenv('TEMP')..errfile
+    end
+    cmd = cmd .. [[ >"]]..outfile..[[" 2>"]]..errfile..[["]]
+
+    local success, retcode = utils.execute(cmd)
+    local outcontent = utils.readfile(outfile, bin)
+    local errcontent = utils.readfile(errfile, bin)
+    os.remove(outfile)
+    os.remove(errfile)
+    return success, retcode, (outcontent or ""), (errcontent or "")
+end
+
+--- 'memoize' a function (cache returned value for next call).
+-- This is useful if you have a function which is relatively expensive,
+-- but you don't know in advance what values will be required, so
+-- building a table upfront is wasteful/impossible.
+-- @param func a function of at least one argument
+-- @return a function with at least one argument, which is used as the key.
+function utils.memoize(func)
+    return setmetatable({}, {
+        __index = function(self, k, ...)
+            local v = func(k,...)
+            self[k] = v
+            return v
+        end,
+        __call = function(self, k) return self[k] end
+    })
+end
+
+
+utils.stdmt = {
+    List = {_name='List'}, Map = {_name='Map'},
+    Set = {_name='Set'}, MultiMap = {_name='MultiMap'}
+}
+
+local _function_factories = {}
+
+--- associate a function factory with a type.
+-- A function factory takes an object of the given type and
+-- returns a function for evaluating it
+-- @tab mt metatable
+-- @func fun a callable that returns a function
+function utils.add_function_factory (mt,fun)
+    _function_factories[mt] = fun
+end
+
+local function _string_lambda(f)
+    local raise = utils.raise
+    if f:find '^|' or f:find '_' then
+        local args,body = f:match '|([^|]*)|(.+)'
+        if f:find '_' then
+            args = '_'
+            body = f
+        else
+            if not args then return raise 'bad string lambda' end
+        end
+        local fstr = 'return function('..args..') return '..body..' end'
+        local fn,err = utils.load(fstr)
+        if not fn then return raise(err) end
+        fn = fn()
+        return fn
+    else return raise 'not a string lambda'
+    end
+end
+
+--- an anonymous function as a string. This string is either of the form
+-- '|args| expression' or is a function of one argument, '_'
+-- @param lf function as a string
+-- @return a function
+-- @usage string_lambda '|x|x+1' (2) == 3
+-- @usage string_lambda '_+1 (2) == 3
+-- @function utils.string_lambda
+utils.string_lambda = utils.memoize(_string_lambda)
+
+local ops
+
+--- process a function argument.
+-- This is used throughout Penlight and defines what is meant by a function:
+-- Something that is callable, or an operator string as defined by <code>pl.operator</code>,
+-- such as '>' or '#'. If a function factory has been registered for the type, it will
+-- be called to get the function.
+-- @param idx argument index
+-- @param f a function, operator string, or callable object
+-- @param msg optional error message
+-- @return a callable
+-- @raise if idx is not a number or if f is not callable
+function utils.function_arg (idx,f,msg)
+    utils.assert_arg(1,idx,'number')
+    local tp = type(f)
+    if tp == 'function' then return f end  -- no worries!
+    -- ok, a string can correspond to an operator (like '==')
+    if tp == 'string' then
+        if not ops then ops = require 'pl.operator'.optable end
+        local fn = ops[f]
+        if fn then return fn end
+        local fn, err = utils.string_lambda(f)
+        if not fn then error(err..': '..f) end
+        return fn
+    elseif tp == 'table' or tp == 'userdata' then
+        local mt = getmetatable(f)
+        if not mt then error('not a callable object',2) end
+        local ff = _function_factories[mt]
+        if not ff then
+            if not mt.__call then error('not a callable object',2) end
+            return f
+        else
+            return ff(f) -- we have a function factory for this type!
+        end
+    end
+    if not msg then msg = " must be callable" end
+    if idx > 0 then
+        error("argument "..idx..": "..msg,2)
+    else
+        error(msg,2)
+    end
+end
+
+--- bind the first argument of the function to a value.
+-- @param fn a function of at least two values (may be an operator string)
+-- @param p a value
+-- @return a function such that f(x) is fn(p,x)
+-- @raise same as @{function_arg}
+-- @see func.bind1
+function utils.bind1 (fn,p)
+    fn = utils.function_arg(1,fn)
+    return function(...) return fn(p,...) end
+end
+
+--- bind the second argument of the function to a value.
+-- @param fn a function of at least two values (may be an operator string)
+-- @param p a value
+-- @return a function such that f(x) is fn(x,p)
+-- @raise same as @{function_arg}
+function utils.bind2 (fn,p)
+    fn = utils.function_arg(1,fn)
+    return function(x,...) return fn(x,p,...) end
+end
+
+
+--- assert that the given argument is in fact of the correct type.
+-- @param n argument index
+-- @param val the value
+-- @param tp the type
+-- @param verify an optional verfication function
+-- @param msg an optional custom message
+-- @param lev optional stack position for trace, default 2
+-- @raise if the argument n is not the correct type
+-- @usage assert_arg(1,t,'table')
+-- @usage assert_arg(n,val,'string',path.isdir,'not a directory')
+function utils.assert_arg (n,val,tp,verify,msg,lev)
+    if type(val) ~= tp then
+        error(("argument %d expected a '%s', got a '%s'"):format(n,tp,type(val)),lev or 2)
+    end
+    if verify and not verify(val) then
+        error(("argument %d: '%s' %s"):format(n,val,msg),lev or 2)
+    end
+end
+
+--- assert the common case that the argument is a string.
+-- @param n argument index
+-- @param val a value that must be a string
+-- @raise val must be a string
+function utils.assert_string (n,val)
+    utils.assert_arg(n,val,'string',nil,nil,3)
+end
+
+local err_mode = 'default'
+
+--- control the error strategy used by Penlight.
+-- Controls how <code>utils.raise</code> works; the default is for it
+-- to return nil and the error string, but if the mode is 'error' then
+-- it will throw an error. If mode is 'quit' it will immediately terminate
+-- the program.
+-- @param mode - either 'default', 'quit'  or 'error'
+-- @see utils.raise
+function utils.on_error (mode)
+    if ({['default'] = 1, ['quit'] = 2, ['error'] = 3})[mode] then
+      err_mode = mode
+    else
+      -- fail loudly
+      if err_mode == 'default' then err_mode = 'error' end
+      utils.raise("Bad argument expected string; 'default', 'quit', or 'error'. Got '"..tostring(mode).."'")
+    end
+end
+
+--- used by Penlight functions to return errors.  Its global behaviour is controlled
+-- by <code>utils.on_error</code>
+-- @param err the error string.
+-- @see utils.on_error
+function utils.raise (err)
+    if err_mode == 'default' then return nil,err
+    elseif err_mode == 'quit' then utils.quit(err)
+    else error(err,2)
+    end
+end
+
+--- is the object of the specified type?.
+-- If the type is a string, then use type, otherwise compare with metatable
+-- @param obj An object to check
+-- @param tp String of what type it should be
+function utils.is_type (obj,tp)
+    if type(tp) == 'string' then return type(obj) == tp end
+    local mt = getmetatable(obj)
+    return tp == mt
+end
+
+raise = utils.raise
+
+--- load a code string or bytecode chunk.
+-- @param code Lua code as a string or bytecode
+-- @param name for source errors
+-- @param mode kind of chunk, 't' for text, 'b' for bytecode, 'bt' for all (default)
+-- @param env  the environment for the new chunk (default nil)
+-- @return compiled chunk
+-- @return error message (chunk is nil)
+-- @function utils.load
+
+---------------
+-- Get environment of a function.
+-- With Lua 5.2, may return nil for a function with no global references!
+-- Based on code by [Sergey Rozhenko](http://lua-users.org/lists/lua-l/2010-06/msg00313.html)
+-- @param f a function or a call stack reference
+-- @function utils.getfenv
+
+---------------
+-- Set environment of a function
+-- @param f a function or a call stack reference
+-- @param env a table that becomes the new environment of `f`
+-- @function utils.setfenv
+
+--- execute a shell command.
+-- This is a compatibility function that returns the same for Lua 5.1 and Lua 5.2
+-- @param cmd a shell command
+-- @return true if successful
+-- @return actual return code
+-- @function utils.execute
+
+return utils
+
+
-- 
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