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Merge pull request #326 from Skeeve/listops

New list operations from @Skeeve
This commit is contained in:
Jeremy Ruston 2014-01-25 08:51:26 -08:00
commit 592ef257a2
2 changed files with 126 additions and 0 deletions

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@ -0,0 +1,116 @@
/*\
title: $:/core/modules/filters/listops.js
type: application/javascript
module-type: filteroperator
Filter operator for manipulating lists
\*/
(function(){
/*jslint node: true, browser: true */
/*global $tw: false */
"use strict";
/*
Export our filter function
*/
exports.reverse = function(source,operator,options) {
var results = [];
// Iterate through the source tiddlers
if($tw.utils.isArray(source)) {
$tw.utils.each(source,function(title) {
results.unshift(title);
});
} else {
$tw.utils.each(source,function(element,title) {
results.unshift(title);
});
}
return results;
};
exports.first = function(source,operator,options) {
var results = [];
var count = operator.operand || 1;
// Iterate through the source tiddlers
if($tw.utils.isArray(source)) {
results = source.slice(0, Math.min(count, source.length));
} else {
for(var title in source) {
if(count-- < 1) break;
results.push(title);
};
}
return results;
};
exports.last = function(source,operator,options) {
var results = [];
var count = operator.operand || 1;
// Iterate through the source tiddlers
if($tw.utils.isArray(source)) {
results = source.slice(-count);
} else {
for(var title in source) {
results.push(title);
};
results = results.slice(-count);
}
return results;
};
exports.rest = function(source,operator,options) {
var results = [];
var count = operator.operand || 1;
// Iterate through the source tiddlers
if($tw.utils.isArray(source)) {
results = source.slice(count);
} else {
for(var title in source) {
if(--count < 0) {
results.push(title);
}
};
}
return results;
};
exports.butfirst = exports.rest;
exports.bf = exports.rest;
exports.butlast = function(source,operator,options) {
var results = [];
var count = operator.operand || 1;
// Iterate through the source tiddlers
if($tw.utils.isArray(source)) {
results = source.slice(0,-count);
} else {
for(var title in source) {
results.push(title);
};
results = results.slice(0,-count);
}
return results;
};
exports.bl = exports.butlast;
exports.nth = function(source,operator,options) {
var results = [];
var count = operator.operand || 1;
// Iterate through the source tiddlers
if($tw.utils.isArray(source)) {
results = source.slice(count-1,count);
} else {
for(var title in source) {
--count;
if(count > 0) continue;
if(count < 0) break;
results.push(title);
break;
};
}
return results;
};
})();

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@ -59,6 +59,16 @@ A filter string consists of one or more runs of filter operators that each look
* ''sameday'': selects all the tiddlers falling into the same day as the provided date in the specified date field
* ''fields'': returns the names of the fields present on the selected tiddlers
* ''search'': returns all tiddlers that contain the specified text
* ''reverse'': reverses the list
* ''first'': selects the first tiddler of the list (or the first n if the operand is n)
* ''last'': selects the last tiddler of the list (or the last n if the operand is n)
* ''rest'': selects all but the first tiddler of the list (or all but the first n if the operand is n)
* ''butfirst'': synonym for ''rest''
* ''bf'': another synonym for ''rest''
* ''butlast'': selects all but the last tiddler of the list (or all but the last n if the operand is n)
* ''bl'': another synonym for ''butlast''
* ''nth'': selects the n-th tiddler of the list. Defaults to n = 1.
An operator can be negated with by preceding it with `!`, for example `[!tag[Tommy]]` selects the tiddlers that are not tagged with `Tommy`.