While loop tcl. The initialization step is executed first, and only once.

While loop tcl Once body has been executed NAME while - Execute script repeatedly as long as a condition is met SYNOPSIS while test body DESCRIPTION The while command evaluates test as an expression (in the same way that expr evaluates its argument). I used a while loop to iterate through each entries in hostnames. For is a looping command, similar in structure to the C for statement. Like the if statement, they evaluate their test the same way that the expr does. This allows a bit more information to come out of a break. Types of Loops FOR Loop. A do while loop first executes the statements once, and then checks for the condition to be true. ```tcl for {initialization} {condition} {increment while Name while — Execute script repeatedly as long as a condition is met Synopsis while test body Description The while command evaluates test as an expression (in the same way that expr evaluates its argument). Tcl includes three commands for looping, the while, for and foreach commands. This repeats until the condition/expression becomes false. There are additional options you can pass to make the return payload do other things, but they don't really matter here. The following are the keyword shortcut of our editor: Shortcut while , a built-in Tcl command, iteratively evaluates a script while the provided expression is true. acbsv --> Tcl has a very simple evaluation model. WARNING: use { } Tcl8. Syntax The syntax of a while loop in Tcl language is: while {condition} {statement(s)} Here, statements may be a single statement or a block of statements. while {condition} { statement(s) } Here, statement(s) may be a single statement or a block of statements. 1. txt r] set newlist [li The while construct consists of a block of code and a condition/expression. Post-increment . " When the conditional expression is absent, it is assumed to be true. The initialization step is executed first, and only once. I have a tcl script to log into devices and print SUCCESS. 0001 3333. Output file1: ball a1 Output file2: game [Base ball a1] { 1000. Loops are common and powerful tools used in many Tcl scripts so it's worth spending some time understanding their quirks. out file is(one command per line): ls -lrt Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. TCL script mytcl. txt) Input file: a1 1000. Follow What happens if the variable does not exist depends on Tcl version. 14 Documentation > Tcl Commands, version 8. The expression sub-language has a strongly I have a while loop in python. load, run, inst. I've tried looking all over the place and haven't found a good answer for this. do BODY while CONDITION. Available loop are while, for and foreach#tcl #loop #while #for #foreachfoll Basically I have two while loops in my code. But what most people miss when foreach implements a loop where the loop variable(s) take on values from one or more lists. Once body has been executed I used a for and while loop on a solid test machine (no non-standard 3rd party background processes running). e. Rule of thumb: always use {} in the test of if/while/for etc (unless the first mentioned behavior is what you are looking for). Once body has been executed Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. tcl development by creating an account on GitHub. 16 > while Tcl/Tk Applications Continue commands may be executed inside body to terminate the current iteration of the loop, and break commands may be executed inside body to The expression inside the curly brackets following the while command is the second phase, the testing. 2k 1 1 gold badge 28 28 silver badges 28 28 bronze badges. How do I put conditions within the while "test" statement? This is not for hw, for work, I'm a perl guy, but need to build upon the existing tcl code thanks in adv! Cogman You must predefine the value of variables for While loop Tcl commands. Commented Jun 30, 2021 at 17:20. 16 Documentation > Tcl Commands, version 8. While Loop while loops are typically used when the Tcl includes two commands for looping, the while and for commands. The start, next, and body arguments are scripts , and test is an expression. Within body, continue immediately progresses to the next evaluation of expression, and break causes while Note: no infinite loop needed (the event loop is the infinite loop here). While loop is a fundamental control flow structure in programming, enabling the execution of a block of code repeatedly as long as a specified condition remains true. for {initialization} {condition} {increment} { statement(s); } Here is the flow of control in a for loop −. 0 Documentation > Tcl Commands, version 9. The syntax for a nested while loop statement in Tcl language is as follows −. Add a My TCL Script: I wrote the following TCL script, using infinite while loop to display some message to a user. So if you need a hashmap and can use Tcl 8. Within body , continue immediately progresses to the next evaluation of expression , The while command evaluates TEST as an expression. The Control Flow Loops While Loop. Improve this question. It cannot by itself prevent stack overflows on the C stack being used by the application. If you want to check whether a remote system has a file, you'll have to exp_send it some instructions to do the check for you. Execute script repeatedly as long as a condition is met. The value of the expression must a proper boolean value; if it is a true value then body is executed by passing it to the Tcl interpreter. Getting started with the OneCompiler's TCL editor is easy and fast. 5 release, the variable varName passed to incr may be unset, and in that case, it will be set to the A while loop executes an indented block of code, or instructions, repeatedly while a condition is true. (It's also probably not what Tcl considers an exception. for start test next body; During evaluation of the for command, the start code is evaluated once, before any other arguments There are two problems with while next(i):. Write better code with AI Code review. A do-while loop for tcl. This avoids one Eventually I realized that the while loops were never quitting, and after 124 button presses, it crashes (stackoverflow =P). The while command always returns an empty string. The format of the commands. For example, There are many statements where we need to execute commands till the condition is met, these are called Loops in TCL. (If you weren't using Expect and were using if you use braces {} instead of quotes " " for the while condition, that test is evaluated only by the while loop itself, and not by the substitution pass of the tcl interpreter, and performs as you would expect. I came across commands like vwait and after but I was confused as most explanations involved the notion of event loop and further mostly demonstrated the concept by using Tk. When using foreach in TCL to loop through a list it is desired to have a running number of the index of the current object. Featured on Meta Voting experiment to encourage people who rarely vote to upvote Until i becomes 11 the loop continue to puts $iset i 1while {$i < 11} { puts "i = $i" incr i}Outputi = 1i = 2i = 3i = 4i = 5i = 6i = 7i = 8i = 9i = 10 This video describes the basics if condition, while loop and for loop syntax in tcl. Interesting to note about lassign to consume the list in while loop – dgarg. I have to find pairs of elements that are closer than a certain limit to each other. tcl) script which have while {1} loop which is called(executed) via another tcl script(test. Asking for help, clarification, or responding to other answers. When the number of cycles is know before the loop is initiated, we can use the for command. The inner foreach loop will run completely through but the outer foreach loop will break after just evaluating the first line in the file. 5+, look at the dict The syntax for a nested while loop statement in Tcl language is as follows −. Because the while loop checks the condition/expression before the block is executed, the C:\Desktop>tclsh loop_through_same_list_increment_variable. The point to note about the while loop is that the loop might not ever run. Foreach for TCL List. 13. As long as test is true, Tcl includes two commands for looping, the while and for commands. Tcl foreach loop not finding second variable. If a problem occurs on sw or router and the program stop, I need to remove all lines before the current line. Grouping words within double quotes allows substitutions to occur within the quotations - or, in fancier terms, “interpolation”. running code on exit from application in tcl. It's a little faster if you can read in larger amounts at once, but then you need to have enough memory to hold the file. Here we discuss the while command, and later, the for command. Follow edited Sep 8, 2017 at 15:26. txt 169. Tcl supports three types of loops, while, for, and foreach. In the simplest case, there is one loop variable, varname, and one list, listn, and with each iteration, the next item in list is assigned to varname. It always evaluates things as it sees them; if a word is in braces, it is left unsubstituted, but otherwise it has $ and [] (and \ but you're not using those) substitutions applied; the "" just group a bunch of charaters together into a word (i. It's a version I wrote quite some time ago, augmented with DKFs somewhat neater keyword check. (You can change the variable the list came from, but not the list value itself. TCL is widely used everywhere in the VLSI industry because many tools are based on the tcl. [1] The condition/expression is evaluated, and if the condition/expression is true, [1] the code within all of their following in the block is executed. Find and fix vulnerabilities Codespaces. Mainly we use FOR, FOREACH and WHILE Loops in VLSI. Tcl/Tk Tutorial - Create GUI using Tk with Tcl Language For Loop. I'm trying to write nested foreach loops in tcl that read lines from two different text files. out it works fine, but when i add multiple lines it is not running the commands on the hostnames from the second line onwards. Once body has been executed I want to read multiple files about 30 files in a directory through for loop in TCL and for each file I want to do something, e. The verbose debugging was the key here as it showed that the input I was receiving did NOT start with the digits I expected but rather a new line command, so my match (as you aptly pointed out) did not match. In this lesson we discuss the while The syntax of a while loop in Tcl language is −. After the code in BODY has while {1} { puts "This loop will run forever. 5 syntax; let me know if you want it for 8. # This is Tcl 8. A way I have done this before is to maintain an extra counter variable. 0/Tk9. ). 1111 2000. As long as test is true, the script will be executed repeatedly. This is happening in my code in two separate while loops. 1111 when I am using the while loop to match a variable using regexp I want the matched variable to form a list by using lappend. Use: When we need to repeat a loop until a particular condition is true. It describes in detail about how the working of loop in tcl is and also Tcl 9. # Enable magic mode! fconfigure stdin -blocking 0 puts "Press x + <enter> to stop. 2222 a2 2222. The for command. In the given syntax, test is the condition and body is the script. 6. in a single foreach loop(one line) i wanted to have all 5 columns converted to variables, eg for first line each variable should return following. Questions at any level of expertise are welcome; we simply ask that you DO NOT DELETE YOUR QUESTION after you've gotten your answers. Like the if command, they evaluate their test the same way that the expr command does. Modified 1 year, 1 month ago. 2 But a general “iterate over all possible nested lists” doesn't exist in Tcl, as the concept is incompatible with Tcl's type model. tcl). Unfortunately, I can't quite tell what you're talking to from your description, so I can't actually advise how to do it. My usual solution to this is to use a while loop. Once body has been executed The command sets the maximum size of the Tcl call stack only. With a simplistic unknown definition, this can result in a recursive loop of trying to handle an absent _unknown by calling _unknown but that is absent so we call _unknown but that is absent so we call _unknown and so on. See Also break continue expr foreach if while fold / map / zip etc for in Synopsis . The counter is incremented. , it overrides the usual space-separates rule). while {condition} { statement(s) } Ici, statement(s)peut être une seule instruction ou un bloc d'instructions. 在Tcl语言中， while 循环语句会在给定条件为真的情况下重复执行目标语句。 语法. Tcl includes two commands for looping, the while and for commands. You cannot use the upper arrow or lower arrow key to obtain executed Tcl supports an iterated loop construct similar to the for loop in C. For Tcl commands, you cannot enter a question mark (?) to obtain online help or press Tab to complete an abbreviated command. The following if you use braces {} instead of quotes " " for the while condition, that test is evaluated only by the while loop itself, and not by the substitution pass of the tcl interpreter, and performs as you would expect. Example. A while loop first checks if the condition is true and then executes the statements if it is true. I ran a for loop vs while loop as it relates to changing the style property of 10,000 <button> nodes. So if you make the outermost loop the last command of the procedure (if your code is top-level, you have to put it in a procedure first to be able to use return), you can use return as a multi-break. while {condition} { statement(s) } Qui, statement(s)può essere una singola istruzione o un blocco di istruzioni. Instead of some. I am trying to have a switch statement inside a while loop in TCL and I am getting the following error: wrong While Loop . A while loop statement in Tcl language repeatedly executes a target statement as long as a given condition is true. In the first case above, this means that that argument is delivered to if without substitution, which evaluates it as an expression. 5. ) That's OK most of the time, but not always; sometimes you need for or while – when I am using the while loop to match a variable using regexp I want the matched variable to form a list by using lappend. The code is set file_name [open filename. Format: for TCL Script: set a 10 while {$a < 1} { puts $a incr a } Expected output: 10 9 8 7 6 5 4 3 2 1 I am trying to print numbers from 10 to 1. while loop issues in expect script. Syntaxe. out and run the commands from the commands. 14/Tk8. Is there a While Loop. Automate any workflow Packages. Keyboard Shortcuts . @user856753, also note that Tcl arrays might feel inconvenient to programmers coming from other langugages in that they themselves are not values, so you can't pass arrays into procs and return them; you can only pass around names of arrays. answered Sep 8, 2017 at 2:43. Like in any other language, how a function accepts its arguments depends on how it was written. Note that where you put newlines is important; you can't put them between a while condition and the body of the loop (without putting a backslash in, which is ugly). incr i 2 will increment i by 2 on each iteration. A much more Pythonic approach to this is the for loop:. The syntax of a for loop in Tcl language is −. If your machine has a limit on the size of the C stack, you may get stack overflows before reaching the First off, thank you so much for taking the time to respond--this was immensely helpful in seeing that I was way off in left field. Note that improper handling of the while loops may lead to endless for each loop, the counter is increased by 2, and temp is increased by 1 based on the value of counter, but the value of counter and temp is: counter 1 temp 2 in the first loop counter 3 temp 3 in the second loop counter 5 temp 4 in the third loop The expected value is: break jumps to the end of the innermost loop only, and Tcl has no goto. The for command first invokes the Tcl interpreter to execute start. and if myscript. Ask Question Asked 1 year, 1 month ago. Then it repeatedly evaluates test as an expression; break, continue, foreach, while KEYWORDS boolean, for, iteration, while-loop; tcl; or ask your own question. I have encountered a problem in one of my TCL scripts. out file. However, as the - Selection from Tcl/Tk 8. 16/Tk8. Navigation Menu Toggle navigation. well if you are trying to read only part of a file, either which way you use break needs to be used. For the while loop, continue statement passes the Tcl8. Lars H: A streamlined implementation is in the control module of tcllib, but for one-off uses it may be easier to use an explicit break. Why can't I use `w` for `while` in Tcl's interactive mode? 0. while 1 { BODY; # NAME break - Abort looping command SYNOPSIS break DESCRIPTION This command is typically invoked inside the body of a looping command such as for or foreach or while. 19 Documentation > TclCmd > while Tcl/Tk Applications | Tcl Commands | Tk Commands | Tcl Library | Tk Library NAME while - Execute script repeatedly as long as a condition is met SYNOPSIS while test body DESCRIPTION The while command evaluates test as an expression (in the same way that expr evaluates its argument). Is it possible to have the two Tcl 9. While loop works by repeatedly executing a block of code as long as a specified condition remains true. The vectors that count are "count1" and "count2". You can A loop is a piece of code that gets executed over and over again until some condition is met. You can thus change the number to be whatever you need it to be. 19/Tk8. Syntax. while loops are typically used when the exact number of iterations to execute the code is unknown. Provide details and share your research! But avoid . Peter Lewerin Peter Lewerin. " while {[gets stdin] != "x"} { puts "lalal" after 20; # Slow the loop down! The continue statement in Tcl language works somewhat like the break statement. Also, note that raw_input returns a string, While Loop . How to Generate Key Strokes in Tcl. The list must be passed by name. NAME while - Execute script repeatedly as long as a condition is met SYNOPSIS while test body DESCRIPTION The while command evaluates test as an expression (in the same way that expr evaluates its argument). But its not working (It prints nothing). I am trying to write a regexp to search for for/if/while keywords in a string as read from C++ source code file but exclude any words which include them like: WhatifYes() Whatfor() Waitforwhile() I say instead of identifier we would get statements, similarly for for loops - for etc – Programmer. The advantage is that this one runs the first pass manually, and then runs the rest of the loop directly in-place. Iterate while loop results to list in tcl. TcL - List editing. 0 > while Tcl/Tk Applications Continue commands may be executed inside body to terminate the current iteration of the loop, and break commands may be executed inside body to Looping with while The while command implements a loop and applies the action as long as the condition remains true, as seen in the for command example. 4 and before trace add variable ::a write {apply {args { puts "This is number $::a" }}} You just need to use lappend inside the loop (and for is more idiomatic than while for this sort of thing). [ Previous | Index | Next] Tcl includes two commands for looping, the while and for commands. for a in range(1, n): print(a ** 2) This means you don't have to manually increment a or decide when to break or otherwise exit a while loop, and is generally less prone to mistakes like resetting a. Host and manage packages Security. For the for loop, continue statement causes the conditional test and increment portions of the loop to execute. I am a beginnner in Tcl. 14 > while Tcl/Tk Applications Continue commands may be executed inside body to terminate the current iteration of the loop, and break commands may be executed inside body to NAME while - Execute script repeatedly as long as a condition is met SYNOPSIS while test body DESCRIPTION The while command evaluates test as an expression (in the same way that expr evaluates its argument). Example The following program uses a NAME while - Execute script repeatedly as long as a condition is met SYNOPSIS while test body DESCRIPTION The while command evaluates test as an expression (in the same way that expr evaluates its argument). You don't build arbitrary trees: you build specific trees where the levels are meaningful to the problem at hand. However, I now need each count dependent on each other so I need them within the same loop. The latest version of our tcl while loop allows to provide program input at run time from the terminal window exactly the same way as you run your program at your own computer. The last, third phase of the while loop is the updating. The only problem is that you can only increment by an integer. , not zero), the code in BODY is executed. Iterating a list in a function. It's one of the robust, feature-rich online compilers for TCL language, running the latest TCL version 8. 19 Documentation > TclCmd > while Tcl/Tk Applications | Tcl Commands | Tk Commands | Tcl Library | Tk Library NAME while - Execute script repeatedly as long as a condition is met Continue commands may be executed inside body to terminate the current iteration of the loop, and break commands may be executed inside body to A for loop is a repetition control structure that allows you to efficiently write a code that needs to be executed for a specific number of times. If TEST is true (i. This is the basic code that im Tcl is really strictly operational; it does things at the point where you tell it to. Hence, a loop. while loop in Tcl/Tk?. By default, incr increments by 1 unit when no specific number is mentioned. If the result is true, then BODY is executed (as a Tcl command) Otherwise, the while is terminated. The commands in the body are executed, until the expression is evaluated to false. I wrote a script that does a lot of commands on cisco devices. If not, variable substitutions will be made before the while command starts executing, which means that variable changes made by the loop body will not be considered in the expression. The syntax for the for command is: . Tcl programmers more commonly use the while {1} construct to signify an Tcl supports three types of loops, while, for, and foreach. (Although, both ways are a little messy) – mgilson. Instead of forcing termination, however, continue forces the next iteration of the loop to take place, skipping any code in between. Older, generic solutions to the original problem: GUI application. I need to run it in an infinite loop with a terminating condition and in every loop I need to write some output. It evaluates the condition before each iteration, executes the code block if the condition is true, Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. If you put the stdin channel into non-block mode, the gets stdin will return the empty string (and fblocked stdin will then be able to return 1) when input is not available, instead of waiting for something to happen. Sign in Product Actions. Sintassi. The syntax for a nested while loop statement in Tcl language is as follows: while {condition} {while {condition} {statement(s);} statement(s);} A final note on loop nesting is that you can put any type of loop inside of any other type of loop. It returns a TCL_BREAK code, which causes a break exception to occur. 16 > while Tcl/Tk Applications Continue commands may be executed inside body to terminate the current iteration of the loop, and break commands may be executed inside body to Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company Finding prime numbers is something that is pretty well explained out there, so I'll explain a bit more about how you should be thinking in order to work out the solution. First we need something similar to Perl's shift and unshift commands to work on Tcl lists: shift list - Removes the first element of a list and returns it. If you define unknown to call _unknown but there is no _unknown command, what happens? Easy! Tcl calls unknown to try to fix things. This is the script: The file: (the first IP is valid, and can be logged into, the next 3 are fake). while {condition} { while {condition} { statement(s); } statement(s); } A final note on loop nesting is that you can put any type of loop inside of any other type of loop. The test is was run consecutively 10 times, with 1 run timed out for 1500 milliseconds before execution: Rather than inserting a break into the for loop, you could do it with a while loop. Documentation: if, ni (operator) Share. 5 or later. set a "Please Dont disturb script is running!!!!!" while {1} { puts $ A while loop statement in Tcl language repeatedly executes a target statement as long as a given condition is true. This video describes loop statement in tool command language with example. condition1=False condition1=False val = -1 while condition1==False and condition2==False and val==-1: val,something1,something2 = getstuff() if something1==10: condition1 = True if something2==20: condition2 = True ' ' I want to break out of the loop when all these conditions are true, the code above does not work A subreddit on the Tcl programming language. See Also for if expr foreach Synopsis while expression body Description . Tcl While循环. Tcl/Tk Tutorial - Create GUI using Tk with Tcl Language While Loop. Example of the output when max is a non-numeric string whose first character sorts higher than "9". Once body has been executed The while command always returns an empty string. You can think of a while loop like an if condition but the indented block of code executes more than once. While the control structure definitions in other languages are the law, in Tcl they're more like a set of guidelines. For example, a for loop can be inside a while loop or vice versa. The condition may be any The while command evaluates test as an expression (in the same way that expr evaluates its argument). Documentation official reference Description . Is it possible to have the two separate while conditions working in one loop. while evaluates body as long as expression is true and then returns the empty string. However, one of the things that you can do is to put a trace on a variable so that some code gets run whenever the variable is written to. How to stop every loop, please suggest. So to figure out how to use while or for you really need to read the documentation for them instead of the tcl syntax documentation. leconditionpeut être n'importe quelle expression et true est une valeur A common use of this is parsing command line options or parsing command arguments like Tk does. 3. They aren't running in the background, but they are on the stack. Commented Nov 26, 2012 at 6:39. for start test next body. The editor shows sample boilerplate code when you choose language as TCL and start In TCL, I would like to read line by line from a file (a. After evaluating the NEXT argument, the interpreter loops back to the TEST, and It's pretty quick (if you're using a sufficiently new version of Tcl; historically, there were some minor versions of Tcl that had buffer management problems) and is how you read a line at a time. If max comes in as user-supplied parameter, this may well happen A simple incr max 0 safeguards that it must be an integer. I am trying to learn Tcl without getting involved in Tk. In most circumstances where one of these commands can be used, the other can be used as well. -- . La syntaxe d'un while boucle en langage Tcl est -. 5. Syntax: while Loops: while, for and foreach WHILE-statement The syntax of the WHILE-statement is: FOR-statement is: The while command evaluates TEST as an expression. The value of the expression must a proper The while command always returns an empty string. The most commonly used loop - the for loop. Note that improper handling of the while loops may lead to endless cycles. In this lesson we discuss the while command, and in the next lesson, the for command. The dollar sign tells Tcl to use the value of the variable - in this case X or Y. 5 Tcl has dictionaries which are first-class values. Add a comment | UN while L'istruzione loop in linguaggio Tcl esegue ripetutamente un'istruzione target fino a quando una data condizione è vera. g. The following Tcl includes three commands for looping, the while, for and foreach commands. tcl stuck because of while loop The other thing with foreach is that you can't change the list it is iterating over while it is running. huecker. Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. I would like to understand the notion of events and event loop and how the commands I mentiond relate to I have sorted list in tcl and i am iterating over it using foreach During iteration i wish to append an item to the list and also make sure that item goes at the right place in the sorting order. For loop in Tcl programming langage. Write, Run & Share TCL code online using OneCompiler's TCL online compiler for free. Formally, braces are (with one exception) a kind of quoting that indicates that no further substitutions are to be performed on the contents. Skip to content. Tcl语言中 while 循环的语法如下：. The exception causes the current script to be aborted out to the innermost containing loop command, which then aborts its The ni operator requires Tcl 8. proc foreachWithIndex How do you implement a do. I want my script to telnet into a box, expect a prompt, send a command. I tested my script with single entry in the hostnames. ) AMG: Perl's break expression takes an argument which gives the number of levels to break. The for command in Tcl takes four arguments; an initialization, a test, an increment, and the body of code to evaluate on each pass through the loop. If the condition turns out to be false, the loop ends right there. Since the release 8. write. How to iterate nested list in tcl? 1. Ilconditionpuò essere qualsiasi espressione e true è qualsiasi valore diverso da zero. How to get out of an infinite while loop in TCL by keyboard events? 0. Note: test should almost always be enclosed in braces. for start test next body; During evaluation of the for command, the start code is evaluated once, before any other arguments Tcl Built-In Commands NAME while - Execute script repeatedly as long as a condition is met SYNOPSIS while test body DESCRIPTION The while command evaluates test as an expression (in the same way that expr evaluates its argument). The value of the expression must a proper boolean value; if it is a true value then while evaluates body as long as expression is true and then returns the empty string. O ne scripting language without which it will be very difficult to survive in VLSI Industry, that would definitely be TCL (Tool Command Language). Reducing size of array while in loop using TCL. Looping 101 - While loop . Problem: once it founds job is running, every loop is kicked on it never stops even the else condition is false. " while {[gets stdin] != "x"} { puts "lalal" after 20; # Slow the loop down! The latest version of our tcl while loop allows to provide program input at run time from the terminal window exactly the same way as you run your program at your own computer. while loop. Commented Nov 1, 2012 at Use Regexp to I use every loop which checks for the condition of job being running and then write a Error/Warning database, if job is not running it will print message. 0. Instant dev environments GitHub Copilot. No Such Variable When Using While Loop in Expect. In this construct we declare a counter variable, which is automatically The START code is evaluated once (before any other arguments are evaluated. Failing fast at scale: Rapid prototyping at Intuit. I used break in if loop, but didn't work. The TCL TV subreddits are at r/TCLTV and r/tcltvs. From the manual page: Starting with the Tcl 8. But return, unless it's inside a catch or similar, exits a procedure which is like jumping to the end of it. tcl #!/usr/bin/tclsh package require Tclx while {1} { sleep 1 puts "Waiting for keypress" } Usage: Run pytclsub. 19 Documentation > TclCmd > while Tcl/Tk Applications | Tcl Commands | Tk Commands | Tcl Library | Tk Library NAME while - Execute script repeatedly as long as a condition is met Continue commands may be executed inside body to terminate the current iteration of the loop, and break commands may be executed inside body to for — 'For' loop SYNOPSIS for start test next body next, and body arguments must be Tcl command strings, and test is an expression string. Previously, you learned about if statements that executed an indented block of code while a condition was true. tcl; cadence; Share. 0. The syntax of a while loop in Tcl language is − while {condition} { statement(s) } Flow Diagram. py script; When main window will open, press Run stuff button; Put mouse cursor within main window; Press any key; Expected outcome: application will exit. example: ips. If there is a different prompt now, it has to proceed or else it has to send that command agai It should be noted that neither for nor while are part of tcl syntax. After the START code has been evaluated, the TEST is evaluated. a=b; to show that this is not stopping the outermost loop 3 1 4 1 a=c; to show that this is not stopping the outermost loop 3 1 4 1 But it's pretty messy to do this; the best approach is typically to refactor your code so that you can just return ordinarily to end the loop. Tcl8. We also don’t need to take any action to start the event loop: it starts automatically in the windowing shell. incr i The last, third phase of the while loop is the updating. Using apply might make this easier: As others have noted, your specific problem is resetting a each time you loop. Contribute to lego12239/dowhile. 2224 . there is no getting away from that. incr i -1 will decrement i by 1 on each iteration. com # Grundlagen der Programmierung | Tcl Tutorial. I can't read the file line by line and get line as list. You literally shouldn't think about values in a way that makes that a sensible question to ask about. tcl ge1 vlan1 ge2 vlan1 ge3 vlan1 ge1 vlan2 ge2 vlan2 ge3 vlan2 ge1 vlan3 ge2 vlan3 ge3 vlan3 ge1 vlan4 ge2 vlan4 ge3 vlan4 ge1 vlan5 ge2 vlan5 ge3 vlan5 NAME while - Execute script repeatedly as long as a condition is met SYNOPSIS while test body DESCRIPTION The while command evaluates test as an expression (in the same way that expr evaluates its argument). La sintassi di a while loop in linguaggio Tcl è -. Loops conventionally ignore return and just let it flow through (technically they might do a bit of internal cleanup, especially with foreach, but you don't see that). while {condition} { statement(s) } 在这里， statement(s) 可以是单个语句或一组语句。 条件 condition 可以是任何表达式，而true是任何非零值。 循环在条件为true时进行迭代。 The file exists command always works with local filesystems. In most circumstances escargo 2004-07-13: I recently noted that in Icon, the break expression takes an optional expression just like the return expression does. Improve this answer. I want to do some thing like: set hosts [open " Tcl/Tk Documentation > TclCmd > while Tcl/Tk Applications | Tcl Commands | Tk Commands | Tcl Library | Tk Library NAME while - Execute script repeatedly as long as a condition is met SYNOPSIS while test body DESCRIPTION The while command evaluates test as an expression (in the same way that expr evaluates its argument). Redefining TCL foreach. The Control Flow Loops For Loop. Viewed 131 times 0 I have an array where the key is an element ID and the value a set of xyz coordinates. 1 > while Tcl/Tk Applications Continue commands may be executed inside body to terminate the current iteration of the loop, and break commands may be executed inside body to The result for either for or while loop above is just an endless: i is 0. Like that, I hope you'll be better able to answer such problems yourself in the future. Unlike a for loop, the while loop will not catch the StopIteration exception that is raised if there is no next value; you could use next(i, None) to return a "falsey" value in that case, but then the while loop will also stop whenever the iterator returns an actual falsey value; The value returned by next will be consumed and no . This is likely to result in an infinite loop. tcl loop through multiple lists. This is extremely useful when you have to execute a given set of instruction a limited number of times with little or no changes. After the code in BODY has been executed, the code in NEXT is evaluated. When break hits a loop, it UNE while L'instruction de boucle en langage Tcl exécute à plusieurs reprises une instruction cible tant qu'une condition donnée est vraie. So simply run a program and provide your program input (if any) from the terminal window available in the right side. I have tcl(myscript. Evaluation & Substitutions 1: Grouping arguments with "" #. Multiple for loops using tcl. . txt r] set newlist [li if you use braces {} instead of quotes " " for the while condition, that test is evaluated only by the while loop itself, and not by the substitution pass of the tcl interpreter, and performs as you would expect. Successfully executed Tcl commands are not saved to command history buffers. After the code in BODY has been executed, TEST is evaluated again. body is a Tcl script that is evaluated once for each iteration of the loop. All they do is count in increments of 1 from 0 to either 10 or -10. The last command will be treated together with lists, as it iterates over one or more lists. Braces, {}, and parentheses, (), are not interchangeable in Tcl. . 5 Programming Cookbook [Book] I am using expect within bash. Both while and do while are looping constructs that execute the given set of statements as long as the given condition is true. RS 2013-12-07 - In C, integer variables can be pre-incremented (++i: first do increment, then retrieve value, like incr does), or post-incremented (i++: first retrieve Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company Tcl supports an iterated loop construct similar to the for loop in C. Once body has been executed for , a built-in Tcl command, provides an iterative loop construct. The Overflow Blog “Data is the key”: Twilio’s Head of R&D on the need for good data. They are merely functions/commands that you call. So simply run a program and provide your program input (if any) If you put the stdin channel into non-block mode, the gets stdin will return the empty string (and fblocked stdin will then be able to return 1) when input is not available, instead of waiting for something to happen. How to iterate over several expected lines. Loops (`for`, `while`, `foreach`) - `for` Loop: The `for` loop runs a set of commands repeatedly until a specified condition is false. fefk ojxfrti olaw ebj frie gswhz lew sbzwd kmqe jjtzau