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PODoes this language feature already exist?
 

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  1. PODoes this language feature already exist?
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    <p>I'm currently developing a new language for programming in a continuous environment (compare it to electrical engineering), and I've got some ideas on a certain language construction.</p> <p>Let me explain the feature by explanation and then by definition:</p> <pre><code>x = a U b; </code></pre> <p>Where <code>x</code> is a variable and <code>a</code> and <code>b</code> are other variables (or static values). This works like a union between <code>a</code> and <code>b</code>; no duplicates and no specific order.</p> <pre><code>with(x) { // regular 'with' usage; using the global interpretation of "x" x = 5; // effectively will do: // x = a U b U 5; // a = 5; // b = 5; // Thus, when "a" or "b" changes, "x" is still equal to "5". } with(x = a) { // this code block is executed when the "x" variable // has the "a" variable assigned. All references in // this code-block to "x" are references to "a". So saying: x = 5; // would only change the variable "a". If the variable "a" // later on changes, x still equals to 5, in this fashion: // 'x = a U b U 5;' // '[currentscope] = 5;' // thus, 'a = 5;' } with(x = b) { // same but with "b" } with(x != a) { // here the "x" variable refers to any variable // but "a"; thus saying x = 5; // is equal to the rewriting of // 'x = a U b U 5;' // 'b = 5;' (since it was the scope of this block) } with(x = (a U b)) { // guaranteed that "x" is 'a U b'; interacting with "x" // will interact with both "a" and "b". x = 5; // makes both "a" and "b" equal to 5; also the "x" variable // is updated to contain: // 'x = a U b U 5;' // '[currentscope] = 5;' // 'a U b = 5;' // and thus: 'a = 5; b = 5;'. } // etc. </code></pre> <p>In the above, all code-blocks are executed, but the "scope" changes in each block how <code>x</code> is interpreted. In the first block, <code>x</code> is guaranteed to be <code>a</code>: thus interacting with <code>x</code> inside that block will interact on <code>a</code>. The second and the third code-block are only equal in this situation (because <code>not a</code>: then there only remains <code>b</code>). The last block guarantees that <code>x</code> is at least <code>a</code> or <code>b</code>.</p> <p>Further more; <code>U</code> is not the "bitwise or operator", but I've called it the "and/or"-operator. Its definition is:</p> <pre><code>"U" = "and" U "or" </code></pre> <p>(On my blog, <a href="http://cplang.wordpress.com/2009/12/19/binop-and-or/" rel="noreferrer">http://cplang.wordpress.com/2009/12/19/binop-and-or/</a>, there is more (mathematical) background information on this operator. It's loosely based on sets. Using different syntax, changed it in this question.)</p> <p><strong>Update: more examples.</strong></p> <pre><code>print = "Hello world!" U "How are you?"; // this will print // both values, but the // order doesn't matter. // 'userkey' is a variable containing a key. with(userkey = "a") { print = userkey; // will only print "a". } with(userkey = ("shift" U "a")) { // pressed both "shift" and the "a" key. print = userkey; // will "print" shift and "a", even // if the user also pressed "ctrl": // the interpretation of "userkey" is changed, // such that it only contains the matched cases. } with((userkey = "shift") U (userkey = "a")) { // same as if-statement above this one, showing the distributivity. } x = 5 U 6 U 7; y = x + x; // will be: // y = (5 U 6 U 7) + (5 U 6 U 7) // = 10 U 11 U 12 U 13 U 14 somewantedkey = "ctrl" U "alt" U "space" with(userkey = somewantedkey) { // must match all elements of "somewantedkey" // (distributed the Boolean equals operated) // thus only executed when all the defined keys are pressed } with(somewantedkey = userkey) { // matches only one of the provided "somewantedkey" // thus when only "space" is pressed, this block is executed. } </code></pre> <p><strong>Update2: more examples and some more context.</strong></p> <pre><code>with(x = (a U b)) { // this } // can be written as with((x = a) U (x = b)) { // this: changing the variable like x = 5; // will be rewritten as: // a = 5 and b = 5 } </code></pre> <p><strong>Some background information:</strong> I'm building a language which is "time-independent", like Java is "platform-independant". Everything stated in the language is "as is", and is continuously actively executed. This means; the programmer does not know in which order (unless explicitly stated using constructions) elements are, nor when statements are executed. The language is completely separated from the "time"-concept, i.e. it's continuously executed:</p> <pre><code>with(true) { a = 0; // only runs once (lazy execution) } with(a &lt; 5) { a++; } // this is a loop-structure; // how and when it's executed isn't known however. with(a) { // everytime the "a" variable changes, this code-block is executed. with(true) { b = 3; // only 5 times (again lazy execution, but it's a sub-with) } with(b &lt; 2) { // dependent on "b" // runs only 3 times * 5 times = 15 times. } with(b &gt; 1) { // dependent on "b" b = b - 1; // runs 4 times * 5 times = 20 times. } } </code></pre> <p><strong>Update 3:</strong></p> <p>After pondering on the type of this language feature; it closely resemblances Netbeans Platform's Lookup, where each "with"-statement a synchronized agent is, working on it's specific "filter" of objects. Instead of type-based, this is variable-based (fundamentally quite the same; just a different way of identifiying objects).</p> <p>I greatly thank all of you for providing me with very insightful information and links/hints to great topics I can research. Thanks.</p> <p>I do not know if this construction already exists, so that's my question: <strong>does this language feature already exist?</strong></p>
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    1. COAND/OR is the same as OR, in a Boolean sense.
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      1. PODoes this language feature already exist?
      1. USPaul R
    2. COThis clearly is not Boolean algebra. Note the self-reference in the definition.
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    3. COUsing the "and/or" terminology is probably not such a great idea then - maybe you could use a term which is less ambiguous and gives some hint as to what you are actually trying to achieve ?
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      1. USPaul R
 

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