kopia lustrzana https://github.com/miklobit/TiddlyWiki5
104 wiersze
2.1 KiB
JavaScript
104 wiersze
2.1 KiB
JavaScript
/*\
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title: $:/core/modules/filters/range.js
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type: application/javascript
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module-type: filteroperator
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Filter operator for generating a numeric range.
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\*/
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(function(){
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/*jslint node: true, browser: true */
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/*global $tw: false */
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"use strict";
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/*
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Export our filter function
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*/
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exports.range = function(source,operator,options) {
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var results = [];
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// For backwards compatibility, if there is only one operand, try to split it using one of the delimiters
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var parts = operator.operands || [];
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if(parts.length === 1) {
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parts = operator.operand.split(/[,:;]/g);
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}
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// Process the parts
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var beg, end, inc, i, fixed = 0;
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for (i=0; i<parts.length; i++) {
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// Validate real number
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if(!/^\s*[+-]?((\d+(\.\d*)?)|(\.\d+))\s*$/.test(parts[i])) {
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return ["range: bad number \"" + parts[i] + "\""];
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}
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// Count digits; the most precise number determines decimal places in output.
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var frac = /\.\d+/.exec(parts[i]);
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if(frac) {
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fixed = Math.max(fixed,frac[0].length-1);
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}
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parts[i] = parseFloat(parts[i]);
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}
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switch(parts.length) {
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case 1:
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end = parts[0];
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if (end >= 1) {
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beg = 1;
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}
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else if (end <= -1) {
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beg = -1;
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}
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else {
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return [];
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}
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inc = 1;
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break;
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case 2:
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beg = parts[0];
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end = parts[1];
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inc = 1;
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break;
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case 3:
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beg = parts[0];
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end = parts[1];
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inc = Math.abs(parts[2]);
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break;
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}
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if(inc === 0) {
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return ["range: increment 0 causes infinite loop"];
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}
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// May need to count backwards
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var direction = ((end < beg) ? -1 : 1);
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inc *= direction;
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// Estimate number of resulting elements
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if((end - beg) / inc > 10000) {
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return ["range: too many steps (over 10K)"];
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}
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// Avoid rounding error on last step
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end += direction * 0.5 * Math.pow(0.1,fixed);
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var safety = 10010;
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// Enumerate the range
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if (end<beg) {
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for(i=beg; i>end; i+=inc) {
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results.push(i.toFixed(fixed));
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if(--safety<0) {
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break;
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}
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}
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} else {
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for(i=beg; i<end; i+=inc) {
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results.push(i.toFixed(fixed));
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if(--safety<0) {
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break;
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}
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}
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}
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if(safety<0) {
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return ["range: unexpectedly large output"];
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}
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// Reverse?
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if(operator.prefix === "!") {
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results.reverse();
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}
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return results;
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};
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})();
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