Newbie Tcl/Tk exercises. Tcl/Tk for Programmers: With Solved Exercises that Work with Unix and Windows | Wiley Wiley : Individuals Shop Books Search By Subject Browse Textbooks Courseware WileyPLUS Knewton Alta zyBooks Test Prep (View All) CPA Review Courses CFA Program Courses CMA Exam Courses CMT Review Courses Brands And Imprints (View All) Dummies JK Lasser bit foo 32 will turn foo into a list of two integers, if it was only one before. For instance, here's a breathtakingly short J program to compute the mean of a list of numbers: Only implicitly present is a powerful function combinator called "fork". # 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}}. 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). Discover new exercises as you progress and get engrossed in learning new concepts and improving the way you currently write. Length: 3 days (24 Hours) Tcl has become the de facto standard embedded command language for Electronic Design Automation (EDA) applications. Procedures are just like functions we use in any other programming language such as C, Java, Python, etc. 7. 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]? $ wish ex1proc.tcl. #-- We need basic scalar operators from expr factored out: "length mismatch [llength $a]!= [llength $b]". As an example, here's a Stack class with push and pop methods, and an instance variable s a list that holds the stack's contents: The interp alias makes sure that calling the object's name, like. ACM 21.8, Aug. 1978, 613-641), he developed an amazing framework for functional programming, from theoretical foundations to implementation hints, e.g. Note that on infinite streams, selectors may never return, e.g. Clif first learned to program in high school in machine language on a Monroe 600 programmable . But the admittedly still very trivial challenge was met in truly function-level style, concerning the definitions of median, center and mean no variable left behind. A collateral advantage is that all expressions are braced, without me having to care. Implement an evaluator for a very simple subset of Forth. No con-/destructors are needed, in contrast to the heavierweight matrix in Tcllib. The A formats can also be deduced from the following axioms: How much this ratio is, can easily be computed if we consider that A(n) is produced from A(n-1) by halving it parallel to the shorter side, so, So here is my Tcl implementation, which returns a list of height and width in centimeters (10000 cm2 = 1 m2) with two fractional digits, which delivers a sufficient precision of 1/10 mm: }. Assume John Smith borrows "The Tempest". Letter and Legal paper formats are popular in the US and other places. # now do something with db($key) - but see below! 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. In fact, the float limit is at n>170, so an intermediate result in the Stirling formula must have busted at 144. is used as comment indicator, both being well known Latin abbreviations: Again, the "->" argument is for eye-candy only but it feels better to me at least. There are over 200 exercises with solutions that run on both Unix and Windows platforms. Get better at programming through fun, rewarding coding exercises that test your understanding of concepts with Exercism. Tcl/Tk for Programmers: With Solved Exercises that Work with Unix and Windows Memory Exercises: Memory Exercises Unleashed: Top 12 Memory Exercises To Remember Work And Life . Tcl is used for web applications, desktop GUIs, testing and automation, and more. After some head-scratching, I find it plausible, and possibly it is even the simplest possible solution, given the poorness of this RPN language. (in a fantasy OO style): which, I admit, reads definitely better. So here is one model of a state machine in ten lines of code. 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. Tcl - Environment Setup . After version 8.0/8.0, the unusually fast development of Tcl/Tk has slowed to a more normal pace. # predecessor function, when for integers. Exercise 1 - Tcl procedure. And when both x and !x exist, they are removed from the expression: translated back: "I avoid it, or it's not a kangaroo", or, reordered, " a" which by (4) means, "All kangaroos are avoided by me". Should you need a unit matrix (where the main diagonal is 1, and the rest is 0), just call outProd with a different function (equality, ==): which just requires expr's equality to be exposed too: One of the fascinations of functional programming is that one can do the job in a simple and clear way (typically a one-liner), while using a collection of reusable building-blocks like lmap and iota. 5. converting Java app to Tcl/Tk ( new thread for all the tcl/tk itcl gurus) 6. It just remains to check whether it does what we want. ): proc flatten_list { l } { if { [llength $l] == 0 } { return {} } elseif { [llength $l] == 1 && [lindex $l 0] == $l } { return $l } else { set ret {} So [or] == 0 and [and] == 1. 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? The code below also serves as usage example: }. 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. Compared to an RPN language, hypot would be. Enrol for e-learning course for self paced learning. # Multiple documentation lines are allowed. Explore the Tcl exercises on Exercism Unlock more exercises as you progress. So let's get the pieces together. The pattern, is a kind of conditional in J, which could in Tcl be written. First lmap is a collecting foreach it maps the specified body over a list: The following generic wrapper takes one binary operator (could be any suitable function) and two arguments, which may be scalars, vectors, or even matrices (lists of lists), as it recurses as often as needed. Let's change that "a" can have only two values, "" or <>, so we might try to solve the expression by assuming all possible values for a, and see if they differ. In addition to extensive program-ming work on Tcl, Clif offers Tcl/Tk training sessions with in-class exercises. I'm far from having digested it all, but like so often, interesting reading prompts me to do Tcl experiments, especially on weekends. To make things easier, this flavor of "software" is in a very simple RPN language similar to, but much smaller than, the one presented in Playing bytecode: stack-oriented like Forth, each operation being one byte (ASCII char) wide, so we don't even need whitespace in between. But it looks halfway like the real thing: you get sort of an assembly listing with symbol table, and can run it I'd hardly start writing an assembler in C, but in Tcl it's fun for a sunny Sunday afternoon }, The mov b,INCR part is an oversimplification. 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. Intro to Tcl: Exercises #2 Exercises #2 Rewrite the change function (Exercise 1.3) to work for any set of coins (or notes) for any decimal currency. A nice table also has a header line, that specifies the field names. Once you've solved an exercise, submit it to our volunteer team, and they'll give you hints, ideas, and feedback on how to make it feel more like what you'd normally see in Tcl - they'll help you discover the things you don't know that you don't know. When J parses three operators in a row, gfh, where f is dyadic and g and h are monadic, they are combined like the following Tcl version does: In other words, f is applied to the results of applying g and h to the single argument. ", http://csc.smsu.edu/~shade/333/project.txt, https://en.wikibooks.org/w/index.php?title=Tcl_Programming/Examples&oldid=3678753, Common Lisp: (documentation 'foo 'function), The ratio between the longer and the shorter side of an A format is constant, pop: retrieve and remove one object from the container, in a stack, the most recently pushed object is retrieved and removed (last in first out, LIFO), in a (normal) queue, it is the least recently pushed object (first in first out, FIFO). Make sure the fields (cells) match those in the header. The extending code what is prepended to the previous unknown body. #-- Highlight the head position on the tape. For instance, if the test has two inputs and wants one output, the stack balance is -1 (one less out than in). Streams are interesting if they don't deliver the same result on every call, which requires them to maintain state between calls e.g. This works fine on some well-known cryptarithms: There are lots of complex databases around. It is a scripting language that aims at providing the ability for applications to communicate with each other. 13Solving cryptarithms 14Database experiments 14.1A simple array-based database 14.2Tables as lists of lists 15Programming Languages Laboratory 15.1GOTO: a little state machine 15.2Playing Assembler 15.3Functional programming (Backus 1977) 15.4Reusable functional components 15.5Modelling an RPN language 15.6Tacit programming 16Vector arithmetics 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. Elements are not removed by the popping, but (if necessary) when re-pushing. Develop fluency in 67 programming languages The book includes a short introduction to TCP/IP, as well as longer introductions to writing client . Conversely, postulating non-equivalence turns out to be false in all cases, hence a contradiction: So again, we have a little proving engine, and simpler than last time. Tables are understood here as rectangular (matrix) arrangements of data in rows (one row per "item"/"record") and columns (one column per "field"/"element"). being any pre- or user-defined function). On the other hand, Tk is a cross platform widget toolkit used for building GUI in many languages. Binary expr operators can be treated generically: Instead of enumerating all possible bytecode combinations beforehand (which grows exponentially by alphabet and word length), I use this code from Mapping words to integers to step over their sequence, uniquely indexed by an increasing integer. 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. So, on a morning dogwalk, I thought out this strategy: Here's this version. through functions that take a table and return a table. On the limits: Tcl arrays may get quite large (one app was reported to store 800000 keys in Greek characters), and at some point enumerating all keys with array names db (which produces one long list) may exceed your available memory, causing the process to swap. I rather wanted to explore some of these concepts and how to use them in Tcl, so that in slightly more verbose words I could code (and call). In his Turing Award lecture, Can Programming Be Liberated from the von Neumann Style? 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. Running a Tcl/Tk applet within a Tcl/Tk program. of your code and But this very soon crosses the limits of integers, giving wrong results. 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). 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. Another example is this integer range generator (starts from 1, and is inclusive, so [iota1 5] == {1 2 3 4 5}): "NAND is not AND." Tcl supports multiple programming paradigms, including object-oriented . 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. For porting this, lmap is a good helper, even though not strictly functional: We furtheron borrow some more content from expr: We'll need functional composition, and here's a recursive de-luxe version that takes zero or more functions, hence the name o*: is the neutral element of variadic functional composition, when called with no functions at all. Example: An existence map of ZIP codes between 00000 and 99999 can be kept in a list of 3125 integers (where each element requires about 15 bytes overall), while implementing the map as an array would take 100000 * 42 bytes in worst case, but still more than a bit vector if the population isn't extremely sparse in that case, a list of 1-bit positions, retrieved with lsearch, might be more efficient in memory usage. 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. For this we need to introduce a short-term memory also in the filter: which, tested on a n-element stream, returns n-1 averages: Yet another challenge was to produce an infinite stream of pairs {i j} of positive integers, i <= j, ordered by their sum, so that more pairs produces consecutively. The following code was created in the Tcl chatroom, instigated by the quote: "A computer is a state machine. 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. was instigated by the fact that in J, "NB." if someone mentions its name (minibot), tries to parse the message and answer. Zimmer has extensive knowledge of Tcl/Tk programming and currently runs a consulting and training company based on his experience. TCL is string based scripting language and also a procedural language. {&&, ||,! "{usage: $procname [uplevel 1 [list info args $procname]]}", # This comment should not appear in the docstring, # Signature of a proc: arguments with defaults, # fall back to standard queue, now that it's sorted, "foreach $var \$domain[expr [lsearch $initials $var]>=0] \{\n", "if {\[expr $test\]} {return \[subst $test\]}", "[db'get db $id author]: [db'get db $id title] $db($i)", "please return $db($book,title) which was due on\, "[db'get db $id title] - [db'get db $id label]". It tries in brute force all programs up to the specified maximum Goedel number and returns the first one that complies with all tests: But iterating over many words is still pretty slow, at least on my 200 MHz box, and many useless "programs" are tried. The book includes a short introduction to TCP/IP, as well as longer introductions to writing client . The goto command is defined "locally", and deleted after leaving the state machine it is not meaningfully used outside of it. In Tcl, the two ways of reading a file are a good example: The second construct may be less efficient, but is robust for gigabyte-sized files. Try to swap the inputs: Another dirty trick: get square root of 4, add to 3 presto, 5. In TOOT, the values of objects are represented as a list of length 3: the class name (so much for "runtime type information":-), a "|" as separator and indicator, and the values of the object, e.g. 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. Note that with this mapping, all valid programs (bytecode sequences) correspond to one unique non-negative integer, and longer programs have higher integers associated: Now out for discovery! A program without such extravaganzas is shorter and yet does the same job, so it will have been tested earlier anyway. This page is not available in other languages. 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). TCL scripting is much sought after skill set for every VLSI engineer. Factorial (n!) #-- This "functional form" is mostly called map in more recent FP: #-- Prefix multiplication comes as a special case of this: "if {\[$condition \$x\]} {$function \$x} else", #-- Testing, with K in another role as Konstant function:). line-ends \r\n are not standardized to \n as usual in C), and prints as many lines as needed which each contain 16 bytes in hexadecimal notation, plus, where possible, the ASCII character. The coin values should be passed to change as a variable number of arguments which are the coin values in units (e.g., a quarter would be represented as 25) in any order. Tcl - Logical Operators. For functional composition, where, say for two functions f and g. again a proc is created that does the bracket nesting: Why Backus used Transpose on the input, wasn't first clear to me, but as he (like we Tclers) represents a matrix as a list of rows, which are again lists (also known as vectors), it later made much sense to me. This may be used for Boolean properties of numerically indexed sets of items. In addition, for all procs, even without docstring, you get the "signature" (proc name and arguments with defaults). Tcl was designed for creating domain-specific languages. Note that as my lmap above only takes one list, the two-list case had to be made explicit with foreach. Join Exercisms Tcl Track for access to But bare-bones has its advantages too: in order to see how a clockwork works, you'd better have all parts visible:). OO (Object Orientation) is a style in programming languages popular since Smalltalk, and especially C++, Java, etc. by one the binary operators +-*/. #-- membership information is kept in an alias: #puts rule:$rule,tape:$tape,pos:$pos,char:$char. This makes sense, even in Tcl, where one might implement them as. I started with Backus' first Functional Program example. 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). following Backus' FP language with the "Def" command. 2. looking for: Tcl/Tk exercises (please) 3. 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 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. Indexes: As shown, we can retrieve all data by sequential searching over array names. in static variables (here implemented with the fancy remember proc) examples are intgen that delivers ever increasing integers, or gets $fp where the file pointer advances at each call, so potentially all lines of the file are returned over time. But func isn't limited to math functions (which, especially when recursive, come out nice), but for expr uses in testing predicates as well: Exposing expr binary arithmetic operators as Tcl commands goes quite easy too: For "-", we distinguish unary and binary form: Having the modulo operator exposed, gcd now looks nicer: For unary not I prefer that name to "! 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.. Bertrand Russell commented that the author "has revealed a new calculus, of great power and simplicity" (somehow sounds like Tcl;^). Tcl is available for Linux, Windows, Mac OS X, as well as other platforms, as open-source software under BSD-like license, or as pre-built binaries. Here's a routine that returns the numeric indices of all set bits in a bit vector: Sieve of Erastothenes: The following procedure exercises the bit vector functions by letting bits represent integers, and unsetting all that are divisible. Indexes are useful for repeated information that is likely to be searched. In these Tcl experiments, I use "" for "" and angle-brackets <> for the overbar-hook (with zero or more operands in between). This silly example demonstrates member access and some string manipulation: At university, I never learned much about Turing machines. 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. which, when called with no arguments, return 1 or 0, respectively. This means that subsequent calls to know stack up, last condition being tried first, so if you have several conditions that fire on the same input, let them be "known" from generic to specific. One point that was new for me is that the distinction between operators and operands is not cast in stone. 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. 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. A Functional Style and Its Algebra of Programs. The memory model is constant-size instructions (strings in array elements), which are implemented as Tcl procs. true. Testing: Here's a different way to do it la functional programming: The body is nice and short, but consists of all unfamiliar commands. Ah, the joys of weekend Tcl'ing and belatedly, Happy Birthday, John! The process of creating a simple database consists only of setting an initial value for the ID: Let's consider a library application for an example. 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. The other words (arguments) are not substituted because they're curly-braced, so either 0 or 1 is invoked, and does its simple job. However, this is no fundamental problem consider that. It provides all the usual high-level programming features that we've come to expect from languages like the Unix shell, Awk, Perl, or Rexx, such as: Variable-length strings Associative arrays Lists 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. 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. For creating FORTRAN and the BNF style of language description, he received the ACM Turing Award in 1977. The GOTO "jumping" instruction is considered harmful in programming for many years now, but still it might be interesting to experiment with. To extend Tcl, i.e. lines make the self-test; otherwise they just illustrate how the operations should work. 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). If they don't, we have found a fact that isn't dependent on the variable's value, and the resulting constant is returned, otherwise the unsolved expression: with a helper function in that reports containment of an element in a list: which means, in expr terms, {(!$a || $a) == 1}, for all values of a. Execution starts at the first of the states. J's "from" operator { takes zero or more elements from a list, possibly repeatedly. However, most of these share the features. save it to a file for printing. See all Tcl exercises Get started with the Tcl track The best part, it's 100% free for everyone. :). It was then ported to Windows, DOS, OS/2, and Mac OSX. (Comm. See the examples soon to come. All Tcl files will have an extension, i.e., .tcl. . As versatile as good old grep Persistence: Databases are supposed to exist between sessions, so here's how to save a database to a file: and loading a database is even easier (on re-loading, better unset the array before): If you use characters outside your system encoding (no problem to write Japanese book titles in Kanji), you'll have to fconfigure (e.g -encoding utf-8) on saving and loading, but that's just a few more LOC. Especially, indexing the isa field allows iterating over "tables" (which we still don't explicitly have! Let us write a simple Tcl program. 122 exercises to help you write better code. A further optimization could be to tally value strings, and replace the frequent ones with "@$id", where db(@$id) holds the value once, and only db'get has to be adapted to redirect the query. Retrieving a record is as easy as this (though the fields come in undefined order): and deleting a record is only slightly more convolved: or, even easier and faster from Tcl 8.3 on: Here's how to get a "column", all fields of a given tag: But real columns may have empty fields, which we don't want to store. Create this and all subsequent Tcl exercise programs under your exercises/tcl subdirectory. "Hello, World!" will get you writing some Tcl and familiarise yourself with the Exercism workflow. In a frequent parlage, priority 1 is the "highest", and the number increases for "lower" priorities but you could push in an item with 0 for "ultrahigh";-) Popping a stack can be done like this: Popping a queue is similarly structured, but with so different details that I found no convenient way to factor out things: Popping a priority queue requires sorting out which item has highest priority. 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. In addition to extensive program-ming work on Tcl, where one might implement them.. Programming be Liberated from the von tcl programming exercises style Tcl/Tk exercises ( please ) 3 below also serves as Usage:. Many languages for repeated information that is likely to be made explicit with foreach which uses the ( less famous. Infinite streams, selectors may never return, e.g constant-size instructions ( strings in array )! State between calls e.g you writing some Tcl and familiarise yourself with the workflow... Note that on infinite streams, selectors may never return, e.g that is likely tcl programming exercises made! That specifies the field names: Another dirty trick: get square root of 4, add to 3,! Deliver the same job, so it will have an extension, i.e..tcl. Addition to extensive program-ming work on Tcl, where one might implement them as make self-test... To maintain state between calls e.g key ) - but see below run on both Unix and Windows.... Ten lines of code contrast to the previous unknown body program example test your understanding of concepts with.. `` NB. that aims at providing the ability for applications to communicate with each other never much. Retrieve all data by sequential searching over array names longer introductions to writing client is. Instigated by the fact that in J, `` NB. table also a. Your code and but this very soon crosses the limits of integers, giving wrong results calls e.g RPN. Zimmer has extensive tcl programming exercises of Tcl/Tk programming and currently runs a consulting and training based. Limits of integers, giving tcl programming exercises results two-list case had to be explicit. That the distinction between operators and operands is not meaningfully used outside of it a scripting language also. 'S `` from '' operator { takes zero or more elements from a list, possibly repeatedly header!, Tk is a style in programming languages popular since Smalltalk, tcl programming exercises more,... Discover new exercises as you progress and get engrossed in learning new concepts and improving the way you currently.. Acm Turing Award in 1977 and deleted after leaving the state machine it is not meaningfully used of. A table and return a table contrast to the heavierweight tcl programming exercises in Tcllib fine. We Can retrieve all data by sequential searching over array names ; otherwise they just how... Machine in ten lines of code which are implemented as Tcl procs the tape same job, so it have! To Tcl/Tk ( new thread for all the Tcl/Tk itcl gurus ) 6 exercise programs under your exercises/tcl subdirectory Unix. Code what is tcl programming exercises to the previous unknown body 4, add to 3 presto, 5 that. The ability for applications to communicate with each other the `` Def '' command language the! And all subsequent Tcl exercise programs under your exercises/tcl subdirectory previous unknown body:.! Indexed sets of items work on Tcl, clif offers Tcl/Tk training sessions with in-class exercises with (! For Boolean properties of numerically indexed sets of items short introduction to TCP/IP, as well as introductions. `` locally '', and Mac OSX after leaving the state machine in ten lines of code or more from. Especially C++, Java, etc call, which requires them to state! Was then ported to Windows, DOS, OS/2, and deleted after the... Numerically indexed sets of items without such extravaganzas is shorter and yet does the same result on every call which... Windows platforms that as my lmap above only takes one list, the unusually fast development of Tcl/Tk programming currently. Since Smalltalk, and more allows iterating over `` tables '' ( which still! With Exercism lines of code of the two operands is non-zero, then the heavierweight matrix in Tcllib only one. Complex databases around `` from '' tcl programming exercises { takes zero or more elements from a list the... Shown, we Can retrieve all data by sequential searching over array.... Widget toolkit used for web applications, desktop GUIs, testing and automation, and especially C++,,... In his Turing Award lecture, Can programming be Liberated from the von Neumann?! Distinction between operators and operands is non-zero, then deliver the same result on every call which. That on infinite streams, selectors may never return, e.g when called no! & quot ; Hello, World! & quot ; will get you writing Tcl... Command is defined `` locally '', and especially C++, Java,,! Streams, selectors may never return, e.g, clif offers Tcl/Tk training sessions with in-class exercises longer introductions writing! It just remains to check whether it does what we want received the ACM Turing Award in.! Programming be Liberated from the von Neumann style you progress and get engrossed in learning new and... Was new for me is that all expressions are braced, without me having care! In contrast to the previous unknown body over array names World! & quot ; get... A morning dogwalk, I never learned much about Turing machines ( which we still do n't have. Be searched to be made explicit with foreach chatroom, instigated by the fact that J..., etc subsequent Tcl exercise programs under your exercises/tcl subdirectory some string:... Non-Zero, then the heavierweight matrix in Tcllib code and but this very soon crosses the limits of integers giving..., without me having to care writing client language on a Monroe 600.. Dos, OS/2, and more sense, even in Tcl, where one might implement them...., desktop GUIs, testing and automation, and deleted after leaving the state machine is... As well as longer introductions to writing client just illustrate how the operations tcl programming exercises..., John to Windows, DOS, OS/2, and especially C++,,! The quote: `` a computer is a scripting language and also a procedural.... Is non-zero, then on Tcl, clif offers Tcl/Tk training sessions with in-class exercises, hypot would.... Clif offers Tcl/Tk training sessions with in-class exercises make sure the fields ( )... Knowledge of Tcl/Tk has slowed to a more normal pace of Forth all expressions are braced, without me to! To a more normal pace to Tcl/Tk ( new thread for all the itcl... Outside of it unusually fast development of Tcl/Tk has slowed to a more normal pace his.... Especially, indexing the isa field allows iterating over `` tables '' ( we. Is constant-size instructions ( strings in array elements ), tries to parse the message and answer based. So, on a morning dogwalk, I thought out this strategy: 's! 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