This page is not available in other languages. Here's my little take on toot in a nutshell. For functional composition, where, say for two functions f and g. again a proc is created that does the bracket nesting: Why Backus used Transpose on the input, wasn't first clear to me, but as he (like we Tclers) represents a matrix as a list of rows, which are again lists (also known as vectors), it later made much sense to me. TCL scripting is much sought after skill set for every VLSI engineer. Another example, cooked up by myself this time, computes the average of a list. Other streams may provide a finite but very large number of elements, which would be impractical to process in one go. Tcl/Tk 8.5 Programming Cookbook (2011) , by Bert Wheeler, provides over 100 recipes to effectively use Tcl/Tk 8.5. Ramanujan numbers: The pairs generator can be used to find Ramanujan numbers, which can be represented as the sum of two integer cubes in more than one way. This can be plugged into a filter chain to see what's going on: # or, to get a stream of even numbers, starting from 0: "to recall is to call -- (1 || 1) == 1", "PONG [info hostname] [lindex [split $line] 1]", "Try http://wiki.tcl.tk/[lindex $args end]", "Why do [string map {I you my your your my you me} $args]? Task 1:- Input Output File Handling & Rearranging Data Step 1: Create a file and named it "file_input1.txt" (Content of "file_input1.txt" is given below - Remember, you have create file exactly same as given. $ wish ex1proc.tcl. On the other hand, Tk is a cross platform widget toolkit used for building GUI in many languages. They can be more precise than any "float" or "double" numbers on computers, as those can't exactly represent any fractions whose denominator isn't a power of 2 consider 13 which can not at any precision be exactly represented as floating-point number to base 2, nor as decimal fraction (base 10), even if bignum. Clif is the author of the TclTutor package2 and the books Tcl/Tk for Real Programmers and Tcl/Tk: A Developer's Guide3. Accessing fields in a table is more fun with the field names than the numeric indexes, which is made easy by the fact that the field names are in the first row: Here is how to filter a table by giving pairs of field name and glob-style expression in addition to the header line, all rows that satisfy at least one of those come through (you can force AND behavior by just nesting such calls): This filters (and, if wanted, rearranges) columns, sort of what is called a "view": In the following few chapters you'll see how easy it is to emulate or explore other programming languages with Tcl. We still have the canonical truth values 0 and 1 as returned from expr with a comparison operator. Retrieving fields that may not physically exist needs a tolerant access function: In a classical database we have to define tables: which fields of what type and of which width. In Spencer-Brown's terms, [] (which is "", the empty string with no arguments) is false ("nil" in LISP), and [<>] is the negation of "", i.e. So 8 is the associated integer of a&&b, but not only of this we get the same integer for ! Tcl is a high-level language well suited for rapid development and prototyping. In J, it looks like this: which may better explain why I wouldn't want to code in J:^) J has ASCIIfied the zoo of APL strange character operators, at the cost of using braces and brackets as operators too, without regard for balancing, and extending them with dots and colons, so e.g. This way, a stream can promise to be a potentially endless source of data, while taking only finite time to process and deliver what's really wanted. Now we can write n(f), which, given a Boolean function of one or more arguments, returns its characteristic number, by iterating over all cases in the truth table, and setting a bit where appropriate: So the characteristic integer is not the same as the Goedel number of a function, which would encode the structure of operators used there. execution of the script "++" should sum its three arguments (1+(2+3)), and return 6. The following example code opens a file, configures it to binary translation (i.e. The "machine" itself takes a list of alternating labels and state code; if a state code does not end in a goto or break, the same state will be repeated as long as not left, with goto or break (implicit endless loop). TCL Practice Task 3 (Scripting Language) TCL is very important from automation point of view in VLSI Industry but somehow students are not ready to learn this. The Tcl Programming Language is a comprehensive guide to Tcl, covering Tcl 8.6.. See the official book page for more information and a detailed Table of Contents.. Tcl/Tk 8.2.3 and Tcl/Tk 8.3.0 under windows. One could edit that file (not recommended), or rename unknown to something else and provide one's own unknown handler, that falls through to the original proc if unsuccessful, as shown in Radical language modification. A simpler example is pipes in Unix/DOS (use TYPE for cat there): where the "cat" delivers lines of the file as long as "more" will take them, and waits otherwise (after all, stdin and stdout are just streams). But if the database grows in size, it's a good idea to create indexes which cross-reference tags and values to IDs. The book includes a short introduction to TCP/IP, as well as longer introductions to writing client . Called Logical OR Operator. Here, pushing has to be done by dedicated code because a previous instance would have to be removed: The first element is the least recently, the last the most recently used. For this, we reformat the expression to a list of values of type x or !x, that is in turn dumped into a local array for existence checking. This video covers the basics that you need to start writing scripts with Tool Command Language (TCL or Tickle).Following topics are explained with simple exa. All Tcl files will have an extension, i.e., .tcl. Formally, what happened to the bracketed call is that it went through "applicative order" evaluation (i.e., do it now), while the braced commands wait for "normal order" evaluation (i.e., do when needed, maybe never the need is expressed through eval/upvar or similar commands). Tcl is a powerful scripting language that runs under Unix, Linux, VMS, DOS/Windows, OS/2, and MacOS (at least). (I might have called it fun as well it sure is.) The special item "" (the empty string) indicates that the stream is exhausted. The authors provide sample chapters available to download for free. to make it understand and do things that before raised an error, the easiest way is to write a proc. "Tacit programming" (tacit: implied; indicated by necessary connotation though not expressed directly) is one of the styles possible in J, and means coding by combining functions, without reference to argument names. and let's discuss it. They always return a result (even if it is the empty string ""), so to call them functions might be most appropriate. #-- We can compute the modulo of a number by its index vector: #-- and turn all elements where the remainder is 0 to 1, else 0: #-- Hence, 7 is only divisible by 1 and itself, hence it is a prime. The print version is available from Amazon in USA/Canada and their European sites including UK , Germany , France , Spain and Italy . It is a scripting language that aims at providing the ability for applications to communicate with each other. Book . Tcl casts everything into the mold of a command, even programming constructs like variable assignment and procedure definition. Doing more steps towards functional programming, I came upon this interesting problem, and will shortly demonstrate that it can easily be solved in pure-Tcl. The "runtime engine" is just called "r" (not to be confused with the R language), and it boils down to a three-way switch done for each word, in eleven lines of code: Joy's rich quoting for types ([list], {set}, "string", 'char) conflict with the Tcl parser, so lists in "r" are {braced} if their length isn't 1, and (parenthesized) if it is but the word shall not be evaluated now. So I tried with another a^2+b^2=c^2 set, and HEUREKA! The numbers of the bits finally still set are supposed to be primes, and returned: Here's code to count the number of 1-bits in a bit vector, represented as an integer list. Getting more daring, let's try a distributive law: Daring more: what if we postulate the equivalence? I only had to take care that when moving beyond its ends, I had to attach a space (written as _) on that end, and adjust the position pointer when at the beginning. The coin values should be passed to change as a variable number of arguments which are the coin values in units (e.g., a quarter would be represented as 25) in any order. Here is a simpler way that allows to extend unknown "in place" and incrementally: We let unknown "know" what action it shall take under what conditions. Sorting roman numerals: I,V,X already come in the right order; for the others we have to introduce temporary collation transformations, which we'll undo right after sorting: As "control structures" are really nothing special in Tcl, just a set of commands, it is easier than in most other languages to create one's own. In an RPN language, the example might look like this: which has the advantage that execution goes from left to right, but requires some stack awareness (and some swaps to set the stack right;^), Implementing Def, I took an easy route by just creating a proc that adds an argument and leaves it to the "functional" to do the right thing (with some quoting heaven:-) }. Adding "records" to the table is as easy as. ;-): And beyond industry-standard SQL, we can search multiple indices in one query: gives you all (case-independent) occurrences of MARK, be it in patron's names, book's authors or titles. If bitval is given, sets the bit at numeric position position to 1 if bitval != 0, else to 0; in any case returns the bit value at specified position. if someone mentions its name (minibot), tries to parse the message and answer. Implement an evaluator for a very simple subset of Forth. Called Logical AND operator. The GOTO "jumping" instruction is considered harmful in programming for many years now, but still it might be interesting to experiment with. Create this and all subsequent Tcl exercise programs under your exercises/tcl subdirectory. ", as it might also stand for factorial and see the shortest function body I ever wrote:^): Without big mention, functions implemented by recursion have a pattern for which func is well suited (see fac and gcd above). Tcl is a string based scripting language. J's "from" operator { takes zero or more elements from a list, possibly repeatedly. Training will provide the detailed practical exposure on each aspect of project flow setup mostly focused on Physical Design, STA, and functional verification with multiple hands on examples. following Backus' FP language with the "Def" command. Tcl is a scripting language somewhat like Perl but extensible and clearer. Here I use a global array for recording results: delivers in hardly noticeable time the R. numbers 1729, 4104, 13832 Or, how's this infinite Fibonacchi number generator, which on more fibo produces all the F.numbers (0,1,1,2,3,5,8,13,21) you might want? After version 8.0/8.0, the unusually fast development of Tcl/Tk has slowed to a more normal pace. Here I want to explore how a database can be implemented in the Tcl spirit of simplicity, and how far that approach takes us. Tcl/Tk for Programmers is an introduction to the high-level Tcl/Tk scripting language for experienced programmers with either Unix or Windows background. Threads are for people who can't program state machines.". But the admittedly still very trivial challenge was met in truly function-level style, concerning the definitions of median, center and mean no variable left behind. The following scripts are plain Tcl, they don't use the Tk GUI toolkit (there's a separate chapter for those). An alternative solution could involve recursion (if you can follow this, youre advanced! Tcl Scripting Basic Examples Introducing 4th Gen Intel Xeon Scalable Processors Introducing 4th Gen Intel Xeon Scalable Processors Introducing 4th Gen Intel Xeon Scalable Processors The browser version you are using is not recommended for this site. The first formats a matrix (a list of lists to Tcl) with newlines and aligned columns for better display: Short again, and slightly cryptic, as is the "outer product" routine, which takes a function f and two vectors, and produces a matrix where f was applied to every pair of a x b in APL they had special compound operators for this job, in this case ".x": Again, lmap (the collecting foreach) figures prominently, so here it is in all its simplicity: With these parts in place, we can see that multable2 works as we want: So why write six procedures, where one did the job already? Tcl (Tool Command Language) is a very powerful but easy to learn dynamic programming language, suitable for a very wide range of uses, including web and desktop applications, networking, administration, testing and many more. #-- Two abbreviations for frequently used list operations: #-- So let's try to implement "mean" in tacit Tcl! In this article, we will know how to use procedures in TCL. Assume John Smith borrows "The Tempest". Grade School Given students' names along with the grade that they are in, create a roster for the school. Practical Programming in Tcl and Tk by Brent Welch, Ken Jones. They are for instance the building blocks of relational databases and spreadsheets. Write a function to determine if a list is a sublist of another list. It just remains to check whether it does what we want. Tcl is much similar to other unix shell languages like Bourne Shell (Sh), the C Shell (csh), the Korn Shell (sh), and Perl. returns the first solution found, or else an empty string: A record is a nonempty set of fields with a unique ID, A field is a pair of tag and nonempty value, both being strings, a set F of functions that map objects into objects (, an operation, application (very roughly, eval), a set FF of functional forms, used to combine functions or objects to form new functions in F, a set D of definitions that map names to functions in F, "tcl" evaluates the top of stack as a Tcl script, scalar @ scalar scalar (like expr does), vector @ vector vector (all of same dimensions, element-wise), measure the stack balance for each bytecode, iterate once over very many possible programs, computing their stack balance, partition them (put into distinct subsets) by stack balance, perform each 'discovery' call only on programs of matching stack balance, Brute force is simple, but may demand very much patience (or faster hardware), The sky, not the skull is the limit what all we can do with Tcl:), classes can be defined, with variables and methods, objects are created as instances of a class, objects are called with messages to perform a method, or just as parts of a transparent value, with TOOT, a is the state in which they can be applied, b is the character that must be read from tape if this rule is to apply, D is the direction to move the tape after writing (R(ight) or L(eft)), e is the state to transition to after the rule was applied, Every animal is suitable for a pet, that loves to gaze at the moon, No animals are carnivorous, unless they prowl at night, No animals ever take to me, except what are in this house, Animals that prowl at night always love to gaze at the moon. 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