eval

Is it possible to achieve dynamic scoping in JavaScript without resorting to eval?

由 蹲街弑〆低调 提交于 2019-12-27 10:55:01
问题 JavaScript has lexical scoping which means that non-local variables accessed from within a function are resolved to variables present in the parents' scope of that function when it was defined. This is in contrast to dynamic scoping in which non-local variables accessed from within a function are resolved to variables present in the calling scope of that function when it is called. x=1 function g () { echo $x ; x=2 ; } function f () { local x=3 ; g ; } f # does this print 1, or 3? echo $x #

Error when making functions in my Python in python

由 时光怂恿深爱的人放手 提交于 2019-12-26 16:03:09
问题 I have made a code. It works like we are running the original python. It uses eval and exec . When I try to make a function or any if statement in it ,it don't works. Here is the code: print("Python\n") while True: command =input(">>> ") if command == "quit()":break try: try: eval(command) except: exec(command) except Exception as err: print("Exception: "+str(err)) Running: Python >>> a = input("Enter your name: ") Enter your name: abc >>> print(a) abc >>> if True: Exception: unexpected EOF

Error when making functions in my Python in python

由 谁都会走 提交于 2019-12-26 16:02:36
问题 I have made a code. It works like we are running the original python. It uses eval and exec . When I try to make a function or any if statement in it ,it don't works. Here is the code: print("Python\n") while True: command =input(">>> ") if command == "quit()":break try: try: eval(command) except: exec(command) except Exception as err: print("Exception: "+str(err)) Running: Python >>> a = input("Enter your name: ") Enter your name: abc >>> print(a) abc >>> if True: Exception: unexpected EOF

学习笔记，大神勿喷

由 回眸只為那壹抹淺笑 提交于 2019-12-26 11:42:24
if在对字符串进行判断时，首先对字符串的位进行逐一比较： 例如：字符串下的 "123" < "18",比较时，首位“1”先 进行比较，然后对第二位“2”和“8”进行比较。 相关参照ASCII表，数字<大写字母<小写字母 【逻辑语句 or and not 进行if判断时拓展】 a = (（变量1）or （变量2） or （变量3）or ...) print(a) 当“变量1”为“True”时，a的值取“变量1”，当“变量1”为“False” 而“变量2”为“True”时，a取值于 “变量2”, 既，a 取值于第一个为“True”的变量，如果都为“False”，a的值为 0; b = （（变量1） and （变量2） and （变量3）...（变量n）) print（b） 此种情况，当“变量1”为“False”时，b取值 0; 如果“变量1”为“True”而“变量2”为“Fasle”，则b取值为 0; 如果“变量1”和“变量2”均为“True”而“变量3”为“False”时，同样b依然取值 0;即，当变量中有“False”时，b取值为 0 ，当所有变量均为“True”时，b取最末尾的“变量n”的值！ if 进行比较“==”判断时，“==”左侧和右侧的变量要属于同一数据类型，str == str; int == int; float == float;bool == bool

Eval vs IF statements (many IF statements)

由 穿精又带淫゛_ 提交于 2019-12-25 21:05:50
问题 This fiddle pretty much explains what I'm looking for. I'm trying to find the simplest way to go about coding something WITHOUT using eval . I can do it without eval but I think I will have to write 1000s of IF statements. Or is there another way? http://jsfiddle.net/243rz8eq/9/ HTML Eval way...<br> <a href="javascript:core.launch('wins.a({x:1})');">Window-A</a><br> <a href="javascript:core.launch('wins.b({x:1})');">Window-B</a><br> <a href="javascript:core.launch('wins.c({x:1})');">Window-C<

设定ls 显示的颜色

由 邮差的信 提交于 2019-12-25 19:53:59
LS 显示颜色的设定 Enable 打开bashrc 文件 vim ~/.bashrc 插入如下的一条命令 eval “ dircolors -b ~/.dir_colors ” 修改颜色 打开dir_colors 文件，如果没有可以使用 dircolors -p > ~/.dir_colors 修改文件 vim ~/.dir_colors 找到"DIR 01;34", 修改依据下面的颜色配置 找到STICKY_OTHER_WRITABLE 和 OTHER_WRITABLE 效果 来源： CSDN 作者： small_a_black 链接： https://blog.csdn.net/small_a_black/article/details/103703174

Racket: argument is non-null error

由 会有一股神秘感。 提交于 2019-12-25 14:32:33
问题 At first I defined HALF , QUARTER and EIGHT to their values with define and with it the quoted symbols would get introduced as arguments in the note function thus making an error. Then I used let and now I get the error stream-rec->C: argument is not non-null `stream-rec' pointer argument: #f My theory is that stream still processes HALF as 'HALF instead of 30000 . I tried putting it into an eval list in note , in random-length in let bindings and in random-note and neither worked. What can I

Racket: argument is non-null error

由 匆匆过客 提交于 2019-12-25 14:32:07
问题 At first I defined HALF , QUARTER and EIGHT to their values with define and with it the quoted symbols would get introduced as arguments in the note function thus making an error. Then I used let and now I get the error stream-rec->C: argument is not non-null `stream-rec' pointer argument: #f My theory is that stream still processes HALF as 'HALF instead of 30000 . I tried putting it into an eval list in note , in random-length in let bindings and in random-note and neither worked. What can I

Convert string into operator in Scala

由 我们两清 提交于 2019-12-25 14:29:41
问题 How can I convert a string in Scala into a corresponding operator? Given two integers and the string "+" I want the result of adding these two integers. 回答1: The last question is very simple: def applyOperator(x: Int, y: Int, operator: String) = operator match { case "+" => x + y case "-" => x - y ... } You could try using Twitter's Eval library or reflection, but I wouldn't recommend it given the simpler solution. For the first question: operators themselves aren't values, so you can't

python SyntaxError: unexpected EOF while parsing

由 痞子三分冷 提交于 2019-12-25 07:48:35
问题 So I have this code m, b = eval(input()) the aim is to have a whole bunch of comma separated values inputted and then have python unpack the tuple into the variables but when i run i get this error x, y = eval(input()) File "<string>", line 1 1,2 ^ SyntaxError: unexpected EOF while parsing what did i do wrong? im using python 3 回答1: You should not use eval for things like this. It will be impossible to write it in a way such that the user can't break it (by mistake or on purpose). Do
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