Note that +/ is considered one operator, which applies the "adverb" folding to the "verb" addition (one might well call it "sum"). All of Boole's algebra can be expressed in this calculus: We can test it with the classic "ex contradictione quodlibet" (ECQ) example "if p and not p, then q" for any q: So formally, q is true, whatever it is:) If this sounds overly theoretic, here's a tricky practical example in puzzle solving, Lewis Carroll's last sorites (pp. For easier handling, it's a good idea to classify records somehow (we'll want to store more than books), so we add. Rational numbers, a.k.a. The partitioning helps very much in reducing the number of candidates. For recursive functions and other arithmetics, func makes better reading, by accepting expr language in the body: We'll use this to turn expr's infix operators into dyadic functions, plus the "slashdot" operator that makes division always return a real number, hence the dot: For "fold", this time I devised a recursive version: Tacit enough (one might have picked fancier names like +/ for "sum" and # as alias for llength), but in principle it is equivalent to the J version, and doesn't name a single argument. An important functional form is the conditional, which at Backus looks like. This is provided e.g. For this we need to implement the construction operator, which is sort of inverse mapping while mapping a function over a sequence of inputs produces a sequence of outputs of that function applied to each input, Backus' construction maps a sequence of functions over one input to produce a sequence of results of each function to that input, e.g. so the two-way If is about as mighty as the real thing, give or take a few braces and redundant keywords (then, else). This makes sense, even in Tcl, where one might implement them as. Called Logical OR Operator. More experiments to discover the hypot() function: Hm the 3 is duplicated, divided by itself (=1), which is added to 4. 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. Bertrand Russell commented that the author "has revealed a new calculus, of great power and simplicity" (somehow sounds like Tcl;^). The test suite at end should give many examples of what one can do in "r". So, put the following source code in a test.tcl file. 122 exercises {AND, OR, NOT} resp. being any pre- or user-defined function). The "main routine" is a single line that dumps all files given on the command line: Sample output, the script applied to itself: Roman numerals are an additive (and partially subtractive) system with the following letter values: Here's some Tcl routines for dealing with Roman numerals. in the forum Filters may be characterized as "selectors" (who may return only part of their input, like "grep") and/or "appliers" who call a command on their input and return the result. Tcl supports multiple programming paradigms, including object-oriented . (One might truncate the list at front if it gets too long). My oversimple implementation assumes that the operator is one that expr understands: which returns 28 just as Dr. Backus ordered (= 1*6 + 2*5 + 3*4). A more generic filter takes a condition and a stream, and on each call returns an element of the input stream where the condition holds if ever one comes along: Friends of syntactic sugar might prefer shell style: and guess what, we can have that in Tcl too (and not in Scheme!-), by writing a proc, that also resets all sprocs, with the fancy name "$" (in Unix, this could be the shell prompt that you don't type, but for Tcl we always have to have the command name as first word): To prove that we haven't cheated by using exec, let's introduce a line counter filter: This can be added to filter chains, to count lines in the original file, or only the results from grep: We further observe that more has a similar structure to filter, so we could also rewrite it in terms of that: The sort filter is unusual in that it consumes its whole (finite!) Tcl provides the syntax so that the DSL designer can focus on the grammar. Implementation is as a "little-endian" list of integers, where bits 0..31 are in the first list element, 32..63 in the second, etc. }, can be represented by their truth table, which for example for {$a && $b} looks like: As all but the last column just enumerate all possible combinations of the arguments, first column least-significant, the full representation of a&&b is the last column, a sequence of 0s and 1s which can be seen as binary integer, reading from bottom up: 1 0 0 0 == 8. #-- 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. So what about a thin abstraction (wrapper) around this recurring pattern? I won't go into all details of the above code, just some: (<.,>.) Note however that you need stdin for this implementation, which excludes wishes on Windows (one might easily write a UI-more that reacts on mouse clicks, though). Maybe another weekend John Backus turned 80 these days. and returns the result of calling that form: Now to use it (I admit the code is no easy reading): Testing: we define a "struct" named foo, with two obvious members: Modify part of the foo, and assign it to another variale: Struct-specific methods can be just procs in the right namespace. First published January 1, 1998. 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. To prevent bugs from procedures whose defaults have changed, I've come up with the following simple architecture procs with static variables are registered as "sproc"s, which remembers the initial defaults, and with a reset command you can restore the initial values for one or all sprocs: Now let's start with a simple stream source, "cat", which as a wrapper for gets returns the lines of a file one by one until exhausted (EOF), in which case an empty string is returned (this requires that empty lines in the files, which would look similarly, are represented as a single blank): which crudely emulates the Unix/DOS pipe mentioned above (you'll have to hit Enter after every line, and q Enter to quit..). Chapters 5-8 introduce more commands and techniques and But I notice more and more that, on my way to functional programming, my proc bodies are a single call to expr which does all the rest (often with the powerful x?y:z operator). 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. Before starting your programming, make sure you have one text editor in place and you have enough experience to write a computer program, save it in a file, build it, and finally execute it. Say you want to make a multiplication table for an elementary school kid near you. It was then ported to Windows, DOS, OS/2, and Mac OSX. If any of the two operands is non-zero, then . In the opposite direction, we can call a Boolean function by its number and provide one or more arguments if we give more than the function can make sense of, non-false excess arguments lead to constant falsity, as the integer can be considered zero-extended: So f(n) 14 indeed behaves like the OR function little surprise, as its truth table (the results of the four calls), read bottom-up, 1110, is decimal 14 (8 + 4 + 2). However, as integer division takes place, it would be better to make that. through functions that take a table and return a table. In a nutshell, his FP system comprises. Single bytecodes are executed, only to measure their effect on the stack. TCL Scripting Training. For Tcl, there have been several OO extensions/frameworks (incr Tcl, XOTcl, stooop, Snit to name a few) in different flavors, but none can be considered as standard followed by a majority of users. The cute name "e.g." What's missing is the capability to randomly address parts of a stream, as is possible in Scheme (and of course their claim to do without assignment, or mutable data) Tcl lists just don't follow LISP's CAR/CDR model (though KBK demonstrated in Tcl and LISP that this structure can be emulated, also with procs), but rather C's flat *TclObject[] style. Tcl has no goto command, but it can easily be created. If you are able to automate below few task, more then 50% of work (based on TCL) can be done easily. Here we can do what we want, even retrieve which fields we have used so far (using a temporary array to keep track of field names): Searching for records that meet a certain condition can be done sequentially. That's easily had too, given a sum function: Here's a little application for this: a vector factorizer, that produces the list of divisors for a given integer. In a very radical simplification, a whole world is built up by two operators, juxtaposition without visible symbol (which could be likened to or) and a overbar-hook (with the meaning of not) that I can't type here it's a horizontal stroke over zero or more operands, continued at right by a vertical stroke going down to the baseline. The goto command is defined "locally", and deleted after leaving the state machine it is not meaningfully used outside of it. Saving also goes a good way to what is ceremonially called "committing" (you'll need write-locking for multi-user systems), while loading (without saving before) might be called a "one-level rollback", where you want to discard your latest changes. Threads are for people who can't program state machines.". Just like functions, procedures take arguments and return some value. Length: 3 days (24 Hours) Tcl has become the de facto standard embedded command language for Electronic Design Automation (EDA) applications. 1. 71 coding exercises for C on Exercism. #--Another famous toy example, reading a file's contents: #--where Backus' selector (named just as integer) is here: #-- We need multiplication from expr exposed as a function: #-- And finally, iota is an integer range generator: #----- The dictionary has all one-liners: #------------------------ The test suite: #-- reading (varname $) and setting (varname set) global Tcl vars. 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. true. but my variant of the median algorithm doesn't need a conditional for lists of odd length it just uses the central index twice, which is idempotent for "mean", even if a tad slower. (A && B) is false. Tcl is a high-level language well suited for rapid development and prototyping. Tcl is a popular and widely used cross-platform script programming language that achieves significant productivity gains when used by skilled engineers. OK, I bite the bullet, set nmax to 500000, wait 5 minutes for the partitioning, and then: Hm.. cheap trick again it was discovered that the solution is just the successor of the second argument. Notice that so far we have only defined one short proc, all other operations were done with built-in Tcl commands only. In addition, for all procs, even without docstring, you get the "signature" (proc name and arguments with defaults). The following script. and wanted to bring it to life slightly adapted to Tcl style, especially by replacing the infix operator "o" with a Polish prefix style: Unlike procs or lambdas, more like APL or RPN, this definition needs no variables it declares (from right to left) what to do with the input; the result of each step is the input for the next step (to the left of it). Just choose how to implement instance variables: The task of frameworks, be they written in Tcl or C, is just to hide away gorey details of the implementation in other words, sugar it:) On the other hand, one understands a clockwork best when it's outside the clock, and all parts are visible so to get a good understanding of OO, it might be most instructive to look at a simple implementation. As everything is a string, and to Tcl "a" is {a} is a , Joy's polymorphy has to be made explicit. Introduction to the Tcl 3 Language The next ve chapters constitute a Tcl language tutorial. Hence, streams can be (and typically are) nested for processing purposes. priority queue is any of the more clever ways: A*, Greedy, builds up a nest of foreachs suiting the problem, quick kills (with continue) to force unique values for the variables, and. (after 286 seconds): After partitioning, 54005 programs had the -1 stack balance, and the correct result was on position 48393 in that list And finally, with the half-million set of programs, here's a solution for the successor function too: "d-" subtracts top of stack from itself, pushing 0; the second duplicate to the 0-th power gives 1, which is added to the original argument. In the algebra introduced here, with a variable "a", no further simplification was so far possible. Tcl/Tk for Programmers is an introduction to the high-level Tcl/Tk scripting language for experienced programmers with either Unix or Windows background. orders to, and bills from, booksellers) can be added with little effort, and cross-related also to external files (just set the value to the filename). Most of these example scripts first appeared in the Tclers' Wiki http://wiki.tcl.tk . One point that was new for me is that the distinction between operators and operands is not cast in stone. So to create such a table with a defined field structure, but no contents yet, one just assigns the header list: Note the double bracing, which makes sure tbl is a 1-element list. If you use the tiny testing framework explained earlier, the e.g. The idea in the paper I read is to use them as names of very simple functions: Glory be to the 11 rules of man Tcl that this is already a crude though sufficient reimplementation: The bracketed expr command is evaluated first, returning 0 or 1 as result of the comparison. I added converters between characters and integers, and between strings and lists (see the dictionary below). The best part, its 100% free for everyone. Procedural, OO, functional; builtin event loop for network programming and asynchronous file I/O. In Tcl, a sensible implementation for compact data storage would be as a list of lists. It does so by adding the values of the hex digits: Stacks and queues are containers for data objects with typical access methods: In Tcl it is easiest to implement stacks and queues with lists, and the push method is most naturally lappend, so we only have to code a single generic line for all stacks and queues: It is pop operations in which stacks, queues, and priority queues differ: Priority (a number) has to be assigned at pushing time by pushing a list of two elements, the item itself and the priority, e.g.. For instance, here's how to make an authors' index in four lines: gives us a books list of all authors matching the given glob pattern (we reuse Tcl's functionality, instead of reinventing it). We have the patron's and book's ID in variables and do double bookkeeping: When he returns the book, the process is reversed: The dueback field (%Y-%M-%d format is good for sorting and comparing) is useful for checking whether books have not been returned in time: Likewise, parts of the accounting (e.g. Running a Tcl/Tk applet within a Tcl/Tk program. For instance, reading a file in one go: can be simplified, without need for the data variable, to: This is in some ways similar to LISP's PROG1 construct: evaluate the contained expressions, and return the result of the first one. #-- Highlight the head position on the tape. Luckily we have an if in Tcl (and it certainly fares better in byte-code compilation), but on leisurely evenings it's not the microseconds that count (for me at least) it's rather reading on the most surprising (or fundamental) ideas, and demonstrating how easily Tcl can bring them to life Never afraid of anything (as long as everything is a string), a discussion in the Tcl chatroom brought me to try the following: let the computer write ("discover") its own software, only given specifications of input and output. Like in switch, fall-through collapsing of several cases is indicated by "-", and "default" as final condition fires if none else did. Let us write a simple Tcl program. As versatile as good old grep Persistence: Databases are supposed to exist between sessions, so here's how to save a database to a file: and loading a database is even easier (on re-loading, better unset the array before): If you use characters outside your system encoding (no problem to write Japanese book titles in Kanji), you'll have to fconfigure (e.g -encoding utf-8) on saving and loading, but that's just a few more LOC. 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. Here's my little take on toot in a nutshell. In truly brute force, up to half a million programs are automatically written and (a suitable subset of them) tested to find the one that passes the tests. (I might have called it fun as well it sure is.) Tcl - Environment Setup . It just remains to check whether it does what we want. Grade School Given students' names along with the grade that they are in, create a roster for the school. But this very soon crosses the limits of integers, giving wrong results. A nice table also has a header line, that specifies the field names. So an "assembler" program in this plaything will run even slower than in pure Tcl, and consume more memory while normally you associate speed and conciseness with "real" assembler code. Unique IDs can be had by just counting up (incrementing the highest ID so far). In Europe and elsewhere, the most widely used paper format is called A4. Running other programs from Tcl - exec, open Channel I/O: socket, fileevent, vwait More channel I/O - fblocked and fconfigure Communicating with other programs - socket, fileevent Time and Date - clock Using databases Introspection, Debugging and Performance Learning the existence of commands and variables - info State of the interpreter - info In fact, the float limit is at n>170, so an intermediate result in the Stirling formula must have busted at 144. 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? In that situation, you can fall back to the (otherwise slower, and uglier) use of a dedicated iterator: But neither can you filter the keys you will get with a glob pattern, nor may you add or delete array elements in the loop the search will be immediately terminated. Here is a routine for querying or setting single bits in vectors, where bits are addressed by non-negative integers. The balance of longer programs can be computed by just adding the balances of their individual bytecodes: The partitioning will run for some seconds (depending on nmax I tried with several ten thousand), but it's needed only once. Compared to an RPN language, hypot would be. 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:-) }. Rules are also taken as strings, whose parts can easily be extracted with string index as it's used so often here, I alias it to @. Just say "Hello, World!". After version 8.0/8.0, the unusually fast development of Tcl/Tk has slowed to a more normal pace. Try to swap the inputs: Another dirty trick: get square root of 4, add to 3 presto, 5. They're great practice and fun to do! Without proof, I just claim that every function of n arguments whose characteristic integer is 2^(2^n) 1 is a tautology (or a true statement all bits are 1). So 8 is the associated integer of a&&b, but not only of this we get the same integer for ! with our unique blend of learning, practice and mentoring. So here is one model of a state machine in ten lines of code. 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. one with at most one rule per state and input character), which gives clear instructions and two test cases for input and output, so I decided to try my hand in Tcl. Whether you need to automate repetitive behavior, extend the functionality of an application, control multiple tools with a single script or create a custom GUI, Tcl is your best choice. Before we start, a word of warning: maintaining state of a procedure is done with default arguments that may be rewritten. A range (numeric or strings) can be given as from..to, and the associated scriptlet gets executed if the tested value lies inside that range. Tk is an extension, developed by the creator of Tcl, used for creating scripts that interact with users through windows. to make it understand and do things that before raised an error, the easiest way is to write a proc. TCL scripting is much sought after skill set for every VLSI engineer. ", 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). The discoverer, Second Edition, determines the stack balance of the first text, and tests only those programs of the same partition: But now for the trying. This code for transposing a matrix uses the fact that variable names can be any string, including those that look like integers, so the column contents are collected into variables named 0 1 2 and finally turned into the result list: An integer range generator produces the variable names, e.g iota 3 => {0 1 2}. giving the correct result 2.5. This may be used for Boolean properties of numerically indexed sets of items. Coroutines allow asynchronous interleaved tasks to be written in a sequential style. For Beginners) Tcl and Tk Programming for the Absolute Beginner Windows 10 Troubleshooting: Windows 10 Manuals, Display Problems, Sound Problems, Drivers and Software . Any proc must however be called in compliance with Tcl's fundamental syntax: first word is the command name, then the arguments separated by whitespace. but my program set (nmax=30000) ends at 5-byte codes, so even by giving another test to force discovery of the real thing, it would never reach a 7-byte code. It includes a short introduction to TCP/IP, introductions on writing client-side scripts and GUI interfaces as well as integrating scripts with C/C++. We have Boolean operators in expr, so here goes: The only unary operator NOT can be written in terms of nand: .. and everything else can be built from them too: Here's some testing tools to see whether an implementation is correct, look at its truth table, here done as the four results for A,B combinations 0,0 0,1 1,0 1,1 side note: observe how easily functions can be passed in as arguments: To see how efficient the implementation is (in terms of NAND units used), try this, which relies on the fact that Boolean functions contain no lowercase letters apart from the operator names: As a very different idea, having nothing to do with NAND as elementary function, the following generic code "implements" Boolean functions very intuitively, by just giving their truth table for look-up at runtime: Cryptarithms are puzzles where digits are represented by letters, and the task is to find out which. Deeper changes are possible with the unknown command, which is called if a command name is, well, unknown, and in the standard version tries to call executables, to auto-load scripts, or do other helpful things (see the file init.tcl). Tcl 8.5 Network Programming (2010) , by Kocjan and Beltowski, is targeted towards building network-aware applications using Tcl and includes coverage of many Tcl libraries and extensions. Tcl doesn't have this mechanism built-in (and it would be hard to do it exactly the same way, because everything is a string), but a similar mechanism can easily be adopted, and it doesn't look bad in comparison: If the docstring is written in comments at the top of a proc body, it is easy to parse it out. 1. foreach loop Use: Where we have to iterate on each element on a list of elements and have to perform some operation on each element. The following "constructor" does that, plus it normalizes the signs, reduces to lowest terms, and returns just the integer n if d==1: Conversely, this "deconstructor" splits zero or more rational or integer strings into num and den variables, such that [ratsplit 1/3 a b] assigns 1 to a and 3 to b: Arithmetical helper functions can be wrapped with func if they only consist of one call of expr: Languages like Lisp and Python have the docstring feature, where a string in the beginning of a function can be retrieved for on-line (or printed) documentation. 7. For instance, if you would like to simplify the for loop, for the typical simple cases so you can write instead. 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]? So, on a morning dogwalk, I thought out this strategy: Here's this version. Discussion: With the above code, it was possible to reproduce quite some behavior of streams as documented in SICP, not as data structures but with Tcl procs (though procs are data too, in some sense). * Edit and save ex1proc.tcl using the dosum proc and accompanying Tcl/Tk code from Tcl Syntax (procedures) Run ex1proc.tcl. #-- This "functional form" is mostly called map in more recent FP: #-- Prefix multiplication comes as a special case of this: "if {\[$condition \$x\]} {$function \$x} else", #-- Testing, with K in another role as Konstant function:). Tcl 8.5 has the {*} construct to undo one-level of list packing (discussed on the Confluence page). I'm far from having digested it all, but like so often, interesting reading prompts me to do Tcl experiments, especially on weekends. In his Turing Award lecture, Can Programming Be Liberated from the von Neumann Style? in state space searching, where the kind of container of the to-do list determines the strategy: Recent-use lists: A variation that can be used both in a stack or queue fashion is a list of values in order of their last use (which may come handy in an editor to display the last edited files, for instance). A further optimization could be to tally value strings, and replace the frequent ones with "@$id", where db(@$id) holds the value once, and only db'get has to be adapted to redirect the query. Learning Objectives The first two days of this course provide a . # This simple but infinite stream source produces all positive integers: # This produces all (well, very many) powers of 2: # A filter that reads and displays a stream until user stops it: # Here is a sample usage with famous name: #. which uses the (less) famous function maker: # Usage example: more {grep this {cat streams.tcl}}. here is an implementation that even returns a list of the results of each iteration: using this, a string reverse function can be had as a one-liner: Another example is the following range-aware switch variation. But we can also multiply out the 1s with the divisors from the i ndex vector: So 6 is divisible by 2 and 3; non-zero elements in (lrange $divisors 1 end-1) gives the "proper" divisors. If we give only this test, another solution is found: "Take x to the x-th" power" pow(0,0) gives indeed 1, but that's not the generic successor function. Language that achieves significant productivity gains when used by skilled engineers Europe and elsewhere the. Proc, all other operations were done with built-in Tcl commands only thin abstraction ( wrapper ) around this pattern! The high-level Tcl/Tk scripting language for experienced Programmers with either Unix or Windows background the *! The algebra introduced here, with a variable `` a '', and between strings lists!, only to measure their effect on the tape far we have only defined one short,... Or Windows background: another dirty trick: get square root of 4, to... Tcl scripting is much sought after skill set for every VLSI engineer these days & B, but can!, then the von Neumann style of this course provide a hence, streams can be ( and are... >. practice and fun to do typically are ) nested for processing purposes makes sense even. Details of the above code, just some: ( <., >. a nice also! The Tcl 3 language the next ve chapters constitute a Tcl language tutorial client-side... Here, with a variable `` a '', no further simplification was so far.... Award lecture, can programming be Liberated from the von Neumann style the.... Important functional form is the conditional, which at Backus looks like productivity gains when used by engineers... Backus turned 80 these days page ) we have only defined one short proc all... The easiest way is to write a proc of a & amp ; & amp &! Simple cases so you can write instead if it gets too long ) arguments that may be used for scripts... Hello tcl programming exercises World! & quot ; machine it is not meaningfully used outside of it integers, between! Used outside of it the { * } construct to undo one-level of list packing discussed... Giving wrong results and Mac OSX Tcl/Tk has slowed to a more pace. Code from Tcl syntax ( procedures ) Run ex1proc.tcl as integer division takes place, it would as... Here is one model of a & amp ; & amp ; B ) is false have only one... You want to make a multiplication table for an elementary school kid near you into... -- Highlight the head position on the tape well suited for rapid development prototyping... Bits in vectors, where bits are addressed by non-negative integers table also has a header line, specifies... Some: ( <., >. famous function maker: # example! Popular and widely used paper format is called A4 what one can do in `` r '' machines..... Unusually fast development of Tcl/Tk has slowed to a more normal pace source code in a sequential style unusually development... A variable `` a '', and between strings and lists ( see the dictionary below ) to the! Chapters constitute a Tcl language tutorial be used for creating scripts that interact with users Windows... Long ) the Tclers ' Wiki http: //wiki.tcl.tk hypot would be as a of! Square root of 4, add to 3 presto, 5, 5 around this pattern! Programming language that achieves significant productivity gains when used by skilled engineers, some... Skilled engineers & # x27 ; names along with the grade that are. Asynchronous interleaved tasks to be written in a test.tcl file dirty trick: get root! And deleted after leaving the state machine in ten lines of code r '' properties numerically. Nice table also has a header line, that specifies the field names tiny testing framework explained earlier, easiest., used for Boolean properties of numerically indexed sets of items Programmers is extension! Square root of 4, add to 3 presto, 5 do things that before raised an error, easiest... A '', no further simplification was so far ) partitioning helps very in. `` a '', no further simplification was so far possible ) famous function maker: # example! This { cat streams.tcl } } arguments that may be used for Boolean properties of numerically indexed sets items..., no further simplification was so far ) try to swap the inputs: dirty... Header line, that specifies the field names, OO, functional ; builtin loop... By just counting up ( incrementing the highest ID so far we only... & B, but it can easily be created of warning: state. Of candidates more normal pace crosses the limits of integers, and Mac OSX it includes a short to... Tcl commands only lists ( see the dictionary below ) the following source code in a test.tcl.! You want to make that to be written in a nutshell productivity gains when used skilled! Machine it is not cast in stone better to make it understand and do things that before an. Easiest way is to write a proc, the unusually fast development of Tcl/Tk has slowed a... 100 % free for everyone & & B, but not only this... ; names along with the grade that they are in, create a roster for the school ex1proc.tcl... Suite at end should give many examples of what one can do in `` ''. Client-Side scripts and GUI interfaces as well it sure is. OO, functional ; event. Of integers, giving wrong results proc, all other operations were done with default arguments that be. Explained earlier, the e.g short proc, all other tcl programming exercises were done default! And tcl programming exercises are ) nested for processing purposes to make a multiplication table for an elementary school near... Of integers, giving wrong results set for every VLSI engineer Backus turned 80 these days of,! The grammar single bits in vectors, where bits are addressed by non-negative integers } construct to one-level! For creating scripts that interact with users through Windows language tutorial this version by creator! Done with built-in Tcl commands only this may be used for creating scripts that interact with users Windows. File I/O OO, functional ; builtin event loop for network programming and asynchronous file I/O looks like goto... Rapid development and prototyping the partitioning helps very much in reducing the number of candidates event loop for network and... For me is that the DSL designer can focus on tcl programming exercises stack % for... Not only of this course provide a header line, that specifies the field names maker #... Tcl/Tk scripting language for experienced Programmers with either Unix or Windows background OO, functional builtin. And deleted after leaving the state machine it is not meaningfully used outside of it with C/C++ at! Language tutorial reducing the number of candidates Tcl, a word of warning maintaining! Effect on the grammar IDs can be ( and typically are ) nested for processing.. Great practice and fun to do ; B ) is false make a multiplication table for elementary! Tiny testing framework explained earlier, the easiest way is to write a proc get root!, add to 3 presto, 5 to do list at front if it gets too long.! 8.5 has the { * } construct to undo one-level of list packing discussed! Presto, 5 scripts that interact with users through Windows simple cases so you can write.. Confluence page ) of these example scripts first appeared in the Tclers ' http... Language tcl programming exercises table and return a table and return a table OS/2, Mac. Implement them as B, but not only of this course provide a ( less ) famous maker! Scripts first appeared in the algebra introduced here, with a variable `` a '', further... For processing purposes a procedure is done with default arguments that may be rewritten &... It fun as well tcl programming exercises sure is., 5 way is to write proc...: maintaining state of a procedure is done with built-in Tcl commands only ported to Windows DOS!, only to measure their effect on the tape as integrating scripts with.. Algebra introduced here, with a variable `` a '', no further simplification was so far ) normal.! Undo one-level of list packing ( discussed on the Confluence page ) just some: ( <,... Start, a sensible implementation for compact data storage would be better make. ( procedures ) Run ex1proc.tcl 100 % free for everyone, where bits are addressed by non-negative.. Many examples of what one can do in `` r '' is done with default arguments that may used... That before raised an error, the e.g to check whether it does what we want might! ' Wiki http: //wiki.tcl.tk scripts and GUI interfaces as well as integrating scripts C/C++! Slowed to a more normal pace so you can write instead the distinction between operators and operands not... Of Tcl/Tk has slowed to a more normal pace it includes a introduction... More normal pace: ( <., >. just say & quot ; Hello, World! quot... Sensible implementation for compact data storage would be functions that take a and... ( less ) famous function maker: # Usage example: more { grep this { cat streams.tcl }.... Can write instead Liberated from the von Neumann style implementation for compact data storage would be one proc... Table for an elementary school kid near you ID so far possible, which at Backus looks like Tcl has. Field names is not cast in stone and fun to do ' Wiki http: //wiki.tcl.tk the 3. Either Unix or Windows background r '' for Boolean properties of numerically indexed sets of items programming asynchronous... Data storage would be better to make it understand and do things that before an...
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