576 lines
33 KiB
HTML
576 lines
33 KiB
HTML
<!DOCTYPE html>
|
||
|
||
<html>
|
||
|
||
<head>
|
||
|
||
<meta charset="utf-8" />
|
||
<meta name="generator" content="pandoc" />
|
||
<meta http-equiv="X-UA-Compatible" content="IE=EDGE" />
|
||
|
||
<meta name="viewport" content="width=device-width, initial-scale=1" />
|
||
|
||
|
||
|
||
<title>Transformers</title>
|
||
|
||
<script>// Pandoc 2.9 adds attributes on both header and div. We remove the former (to
|
||
// be compatible with the behavior of Pandoc < 2.8).
|
||
document.addEventListener('DOMContentLoaded', function(e) {
|
||
var hs = document.querySelectorAll("div.section[class*='level'] > :first-child");
|
||
var i, h, a;
|
||
for (i = 0; i < hs.length; i++) {
|
||
h = hs[i];
|
||
if (!/^h[1-6]$/i.test(h.tagName)) continue; // it should be a header h1-h6
|
||
a = h.attributes;
|
||
while (a.length > 0) h.removeAttribute(a[0].name);
|
||
}
|
||
});
|
||
</script>
|
||
|
||
<style type="text/css">
|
||
code{white-space: pre-wrap;}
|
||
span.smallcaps{font-variant: small-caps;}
|
||
span.underline{text-decoration: underline;}
|
||
div.column{display: inline-block; vertical-align: top; width: 50%;}
|
||
div.hanging-indent{margin-left: 1.5em; text-indent: -1.5em;}
|
||
ul.task-list{list-style: none;}
|
||
</style>
|
||
|
||
|
||
|
||
<style type="text/css">
|
||
code {
|
||
white-space: pre;
|
||
}
|
||
.sourceCode {
|
||
overflow: visible;
|
||
}
|
||
</style>
|
||
<style type="text/css" data-origin="pandoc">
|
||
pre > code.sourceCode { white-space: pre; position: relative; }
|
||
pre > code.sourceCode > span { line-height: 1.25; }
|
||
pre > code.sourceCode > span:empty { height: 1.2em; }
|
||
.sourceCode { overflow: visible; }
|
||
code.sourceCode > span { color: inherit; text-decoration: inherit; }
|
||
div.sourceCode { margin: 1em 0; }
|
||
pre.sourceCode { margin: 0; }
|
||
@media screen {
|
||
div.sourceCode { overflow: auto; }
|
||
}
|
||
@media print {
|
||
pre > code.sourceCode { white-space: pre-wrap; }
|
||
pre > code.sourceCode > span { display: inline-block; text-indent: -5em; padding-left: 5em; }
|
||
}
|
||
pre.numberSource code
|
||
{ counter-reset: source-line 0; }
|
||
pre.numberSource code > span
|
||
{ position: relative; left: -4em; counter-increment: source-line; }
|
||
pre.numberSource code > span > a:first-child::before
|
||
{ content: counter(source-line);
|
||
position: relative; left: -1em; text-align: right; vertical-align: baseline;
|
||
border: none; display: inline-block;
|
||
-webkit-touch-callout: none; -webkit-user-select: none;
|
||
-khtml-user-select: none; -moz-user-select: none;
|
||
-ms-user-select: none; user-select: none;
|
||
padding: 0 4px; width: 4em;
|
||
color: #aaaaaa;
|
||
}
|
||
pre.numberSource { margin-left: 3em; border-left: 1px solid #aaaaaa; padding-left: 4px; }
|
||
div.sourceCode
|
||
{ }
|
||
@media screen {
|
||
pre > code.sourceCode > span > a:first-child::before { text-decoration: underline; }
|
||
}
|
||
code span.al { color: #ff0000; font-weight: bold; }
|
||
code span.an { color: #60a0b0; font-weight: bold; font-style: italic; }
|
||
code span.at { color: #7d9029; }
|
||
code span.bn { color: #40a070; }
|
||
code span.bu { color: #008000; }
|
||
code span.cf { color: #007020; font-weight: bold; }
|
||
code span.ch { color: #4070a0; }
|
||
code span.cn { color: #880000; }
|
||
code span.co { color: #60a0b0; font-style: italic; }
|
||
code span.cv { color: #60a0b0; font-weight: bold; font-style: italic; }
|
||
code span.do { color: #ba2121; font-style: italic; }
|
||
code span.dt { color: #902000; }
|
||
code span.dv { color: #40a070; }
|
||
code span.er { color: #ff0000; font-weight: bold; }
|
||
code span.ex { }
|
||
code span.fl { color: #40a070; }
|
||
code span.fu { color: #06287e; }
|
||
code span.im { color: #008000; font-weight: bold; }
|
||
code span.in { color: #60a0b0; font-weight: bold; font-style: italic; }
|
||
code span.kw { color: #007020; font-weight: bold; }
|
||
code span.op { color: #666666; }
|
||
code span.ot { color: #007020; }
|
||
code span.pp { color: #bc7a00; }
|
||
code span.sc { color: #4070a0; }
|
||
code span.ss { color: #bb6688; }
|
||
code span.st { color: #4070a0; }
|
||
code span.va { color: #19177c; }
|
||
code span.vs { color: #4070a0; }
|
||
code span.wa { color: #60a0b0; font-weight: bold; font-style: italic; }
|
||
</style>
|
||
<script>
|
||
// apply pandoc div.sourceCode style to pre.sourceCode instead
|
||
(function() {
|
||
var sheets = document.styleSheets;
|
||
for (var i = 0; i < sheets.length; i++) {
|
||
if (sheets[i].ownerNode.dataset["origin"] !== "pandoc") continue;
|
||
try { var rules = sheets[i].cssRules; } catch (e) { continue; }
|
||
var j = 0;
|
||
while (j < rules.length) {
|
||
var rule = rules[j];
|
||
// check if there is a div.sourceCode rule
|
||
if (rule.type !== rule.STYLE_RULE || rule.selectorText !== "div.sourceCode") {
|
||
j++;
|
||
continue;
|
||
}
|
||
var style = rule.style.cssText;
|
||
// check if color or background-color is set
|
||
if (rule.style.color === '' && rule.style.backgroundColor === '') {
|
||
j++;
|
||
continue;
|
||
}
|
||
// replace div.sourceCode by a pre.sourceCode rule
|
||
sheets[i].deleteRule(j);
|
||
sheets[i].insertRule('pre.sourceCode{' + style + '}', j);
|
||
}
|
||
}
|
||
})();
|
||
</script>
|
||
|
||
|
||
|
||
|
||
<style type="text/css">body {
|
||
background-color: #fff;
|
||
margin: 1em auto;
|
||
max-width: 700px;
|
||
overflow: visible;
|
||
padding-left: 2em;
|
||
padding-right: 2em;
|
||
font-family: "Open Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;
|
||
font-size: 14px;
|
||
line-height: 1.35;
|
||
}
|
||
#TOC {
|
||
clear: both;
|
||
margin: 0 0 10px 10px;
|
||
padding: 4px;
|
||
width: 400px;
|
||
border: 1px solid #CCCCCC;
|
||
border-radius: 5px;
|
||
background-color: #f6f6f6;
|
||
font-size: 13px;
|
||
line-height: 1.3;
|
||
}
|
||
#TOC .toctitle {
|
||
font-weight: bold;
|
||
font-size: 15px;
|
||
margin-left: 5px;
|
||
}
|
||
#TOC ul {
|
||
padding-left: 40px;
|
||
margin-left: -1.5em;
|
||
margin-top: 5px;
|
||
margin-bottom: 5px;
|
||
}
|
||
#TOC ul ul {
|
||
margin-left: -2em;
|
||
}
|
||
#TOC li {
|
||
line-height: 16px;
|
||
}
|
||
table {
|
||
margin: 1em auto;
|
||
border-width: 1px;
|
||
border-color: #DDDDDD;
|
||
border-style: outset;
|
||
border-collapse: collapse;
|
||
}
|
||
table th {
|
||
border-width: 2px;
|
||
padding: 5px;
|
||
border-style: inset;
|
||
}
|
||
table td {
|
||
border-width: 1px;
|
||
border-style: inset;
|
||
line-height: 18px;
|
||
padding: 5px 5px;
|
||
}
|
||
table, table th, table td {
|
||
border-left-style: none;
|
||
border-right-style: none;
|
||
}
|
||
table thead, table tr.even {
|
||
background-color: #f7f7f7;
|
||
}
|
||
p {
|
||
margin: 0.5em 0;
|
||
}
|
||
blockquote {
|
||
background-color: #f6f6f6;
|
||
padding: 0.25em 0.75em;
|
||
}
|
||
hr {
|
||
border-style: solid;
|
||
border: none;
|
||
border-top: 1px solid #777;
|
||
margin: 28px 0;
|
||
}
|
||
dl {
|
||
margin-left: 0;
|
||
}
|
||
dl dd {
|
||
margin-bottom: 13px;
|
||
margin-left: 13px;
|
||
}
|
||
dl dt {
|
||
font-weight: bold;
|
||
}
|
||
ul {
|
||
margin-top: 0;
|
||
}
|
||
ul li {
|
||
list-style: circle outside;
|
||
}
|
||
ul ul {
|
||
margin-bottom: 0;
|
||
}
|
||
pre, code {
|
||
background-color: #f7f7f7;
|
||
border-radius: 3px;
|
||
color: #333;
|
||
white-space: pre-wrap;
|
||
}
|
||
pre {
|
||
border-radius: 3px;
|
||
margin: 5px 0px 10px 0px;
|
||
padding: 10px;
|
||
}
|
||
pre:not([class]) {
|
||
background-color: #f7f7f7;
|
||
}
|
||
code {
|
||
font-family: Consolas, Monaco, 'Courier New', monospace;
|
||
font-size: 85%;
|
||
}
|
||
p > code, li > code {
|
||
padding: 2px 0px;
|
||
}
|
||
div.figure {
|
||
text-align: center;
|
||
}
|
||
img {
|
||
background-color: #FFFFFF;
|
||
padding: 2px;
|
||
border: 1px solid #DDDDDD;
|
||
border-radius: 3px;
|
||
border: 1px solid #CCCCCC;
|
||
margin: 0 5px;
|
||
}
|
||
h1 {
|
||
margin-top: 0;
|
||
font-size: 35px;
|
||
line-height: 40px;
|
||
}
|
||
h2 {
|
||
border-bottom: 4px solid #f7f7f7;
|
||
padding-top: 10px;
|
||
padding-bottom: 2px;
|
||
font-size: 145%;
|
||
}
|
||
h3 {
|
||
border-bottom: 2px solid #f7f7f7;
|
||
padding-top: 10px;
|
||
font-size: 120%;
|
||
}
|
||
h4 {
|
||
border-bottom: 1px solid #f7f7f7;
|
||
margin-left: 8px;
|
||
font-size: 105%;
|
||
}
|
||
h5, h6 {
|
||
border-bottom: 1px solid #ccc;
|
||
font-size: 105%;
|
||
}
|
||
a {
|
||
color: #0033dd;
|
||
text-decoration: none;
|
||
}
|
||
a:hover {
|
||
color: #6666ff; }
|
||
a:visited {
|
||
color: #800080; }
|
||
a:visited:hover {
|
||
color: #BB00BB; }
|
||
a[href^="http:"] {
|
||
text-decoration: underline; }
|
||
a[href^="https:"] {
|
||
text-decoration: underline; }
|
||
|
||
code > span.kw { color: #555; font-weight: bold; }
|
||
code > span.dt { color: #902000; }
|
||
code > span.dv { color: #40a070; }
|
||
code > span.bn { color: #d14; }
|
||
code > span.fl { color: #d14; }
|
||
code > span.ch { color: #d14; }
|
||
code > span.st { color: #d14; }
|
||
code > span.co { color: #888888; font-style: italic; }
|
||
code > span.ot { color: #007020; }
|
||
code > span.al { color: #ff0000; font-weight: bold; }
|
||
code > span.fu { color: #900; font-weight: bold; }
|
||
code > span.er { color: #a61717; background-color: #e3d2d2; }
|
||
</style>
|
||
|
||
|
||
|
||
|
||
</head>
|
||
|
||
<body>
|
||
|
||
|
||
|
||
|
||
<h1 class="title toc-ignore">Transformers</h1>
|
||
|
||
|
||
|
||
<p>Transformers allow you to apply functions to the glue input and
|
||
output, before and after evaluation. This allows you to write things
|
||
like <code>glue_sql()</code>, which automatically quotes variables for
|
||
you or add a syntax for automatically collapsing outputs.</p>
|
||
<p>The transformer functions simply take two arguments <code>text</code>
|
||
and <code>envir</code>, where <code>text</code> is the unparsed string
|
||
inside the glue block and <code>envir</code> is the execution
|
||
environment. Most transformers will then call
|
||
<code>eval(parse(text = text, keep.source = FALSE), envir)</code> which
|
||
parses and evaluates the code.</p>
|
||
<p>You can then supply the transformer function to glue with the
|
||
<code>.transformer</code> argument. In this way users can manipulate the
|
||
text before parsing and change the output after evaluation.</p>
|
||
<p>It is often useful to write a <code>glue()</code> wrapper function
|
||
which supplies a <code>.transformer</code> to <code>glue()</code> or
|
||
<code>glue_data()</code> and potentially has additional arguments. One
|
||
important consideration when doing this is to include
|
||
<code>.envir = parent.frame()</code> in the wrapper to ensure the
|
||
evaluation environment is correct.</p>
|
||
<p>Some example implementations of potentially useful transformers
|
||
follow. The aim right now is not to include most of these custom
|
||
functions within the <code>glue</code> package. Rather, users are
|
||
encouraged to create custom functions using transformers to fit their
|
||
individual needs.</p>
|
||
<div class="sourceCode" id="cb1"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb1-1"><a href="#cb1-1" tabindex="-1"></a><span class="fu">library</span>(glue)</span></code></pre></div>
|
||
<div id="collapse-transformer" class="section level3">
|
||
<h3>collapse transformer</h3>
|
||
<p>A transformer which automatically collapses any glue block ending
|
||
with <code>*</code>.</p>
|
||
<div class="sourceCode" id="cb2"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb2-1"><a href="#cb2-1" tabindex="-1"></a>collapse_transformer <span class="ot"><-</span> <span class="cf">function</span>(<span class="at">regex =</span> <span class="st">"[*]$"</span>, ...) {</span>
|
||
<span id="cb2-2"><a href="#cb2-2" tabindex="-1"></a> <span class="cf">function</span>(text, envir) {</span>
|
||
<span id="cb2-3"><a href="#cb2-3" tabindex="-1"></a> collapse <span class="ot"><-</span> <span class="fu">grepl</span>(regex, text)</span>
|
||
<span id="cb2-4"><a href="#cb2-4" tabindex="-1"></a> <span class="cf">if</span> (collapse) {</span>
|
||
<span id="cb2-5"><a href="#cb2-5" tabindex="-1"></a> text <span class="ot"><-</span> <span class="fu">sub</span>(regex, <span class="st">""</span>, text)</span>
|
||
<span id="cb2-6"><a href="#cb2-6" tabindex="-1"></a> }</span>
|
||
<span id="cb2-7"><a href="#cb2-7" tabindex="-1"></a> res <span class="ot"><-</span> <span class="fu">identity_transformer</span>(text, envir)</span>
|
||
<span id="cb2-8"><a href="#cb2-8" tabindex="-1"></a> <span class="cf">if</span> (collapse) {</span>
|
||
<span id="cb2-9"><a href="#cb2-9" tabindex="-1"></a> <span class="fu">glue_collapse</span>(res, ...) </span>
|
||
<span id="cb2-10"><a href="#cb2-10" tabindex="-1"></a> } <span class="cf">else</span> {</span>
|
||
<span id="cb2-11"><a href="#cb2-11" tabindex="-1"></a> res</span>
|
||
<span id="cb2-12"><a href="#cb2-12" tabindex="-1"></a> }</span>
|
||
<span id="cb2-13"><a href="#cb2-13" tabindex="-1"></a> }</span>
|
||
<span id="cb2-14"><a href="#cb2-14" tabindex="-1"></a>}</span>
|
||
<span id="cb2-15"><a href="#cb2-15" tabindex="-1"></a></span>
|
||
<span id="cb2-16"><a href="#cb2-16" tabindex="-1"></a><span class="fu">glue</span>(<span class="st">"{1:5*}</span><span class="sc">\n</span><span class="st">{letters[1:5]*}"</span>, <span class="at">.transformer =</span> <span class="fu">collapse_transformer</span>(<span class="at">sep =</span> <span class="st">", "</span>))</span>
|
||
<span id="cb2-17"><a href="#cb2-17" tabindex="-1"></a><span class="co">#> 1, 2, 3, 4, 5</span></span>
|
||
<span id="cb2-18"><a href="#cb2-18" tabindex="-1"></a><span class="co">#> a, b, c, d, e</span></span>
|
||
<span id="cb2-19"><a href="#cb2-19" tabindex="-1"></a></span>
|
||
<span id="cb2-20"><a href="#cb2-20" tabindex="-1"></a><span class="fu">glue</span>(<span class="st">"{1:5*}</span><span class="sc">\n</span><span class="st">{letters[1:5]*}"</span>, <span class="at">.transformer =</span> <span class="fu">collapse_transformer</span>(<span class="at">sep =</span> <span class="st">", "</span>, <span class="at">last =</span> <span class="st">" and "</span>))</span>
|
||
<span id="cb2-21"><a href="#cb2-21" tabindex="-1"></a><span class="co">#> 1, 2, 3, 4 and 5</span></span>
|
||
<span id="cb2-22"><a href="#cb2-22" tabindex="-1"></a><span class="co">#> a, b, c, d and e</span></span>
|
||
<span id="cb2-23"><a href="#cb2-23" tabindex="-1"></a></span>
|
||
<span id="cb2-24"><a href="#cb2-24" tabindex="-1"></a>x <span class="ot"><-</span> <span class="fu">c</span>(<span class="st">"one"</span>, <span class="st">"two"</span>)</span>
|
||
<span id="cb2-25"><a href="#cb2-25" tabindex="-1"></a><span class="fu">glue</span>(<span class="st">"{x}: {1:5*}"</span>, <span class="at">.transformer =</span> <span class="fu">collapse_transformer</span>(<span class="at">sep =</span> <span class="st">", "</span>))</span>
|
||
<span id="cb2-26"><a href="#cb2-26" tabindex="-1"></a><span class="co">#> one: 1, 2, 3, 4, 5</span></span>
|
||
<span id="cb2-27"><a href="#cb2-27" tabindex="-1"></a><span class="co">#> two: 1, 2, 3, 4, 5</span></span></code></pre></div>
|
||
</div>
|
||
<div id="shell-quoting-transformer" class="section level3">
|
||
<h3>Shell quoting transformer</h3>
|
||
<p>A transformer which automatically quotes variables for use in shell
|
||
commands, e.g. via <code>system()</code> or <code>system2()</code>.</p>
|
||
<div class="sourceCode" id="cb3"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb3-1"><a href="#cb3-1" tabindex="-1"></a>shell_transformer <span class="ot"><-</span> <span class="cf">function</span>(<span class="at">type =</span> <span class="fu">c</span>(<span class="st">"sh"</span>, <span class="st">"csh"</span>, <span class="st">"cmd"</span>, <span class="st">"cmd2"</span>)) {</span>
|
||
<span id="cb3-2"><a href="#cb3-2" tabindex="-1"></a> type <span class="ot"><-</span> <span class="fu">match.arg</span>(type)</span>
|
||
<span id="cb3-3"><a href="#cb3-3" tabindex="-1"></a> <span class="cf">function</span>(text, envir) {</span>
|
||
<span id="cb3-4"><a href="#cb3-4" tabindex="-1"></a> res <span class="ot"><-</span> <span class="fu">identity_transformer</span>(text, envir)</span>
|
||
<span id="cb3-5"><a href="#cb3-5" tabindex="-1"></a> <span class="fu">shQuote</span>(res)</span>
|
||
<span id="cb3-6"><a href="#cb3-6" tabindex="-1"></a> }</span>
|
||
<span id="cb3-7"><a href="#cb3-7" tabindex="-1"></a>}</span>
|
||
<span id="cb3-8"><a href="#cb3-8" tabindex="-1"></a></span>
|
||
<span id="cb3-9"><a href="#cb3-9" tabindex="-1"></a>glue_sh <span class="ot"><-</span> <span class="cf">function</span>(..., <span class="at">.envir =</span> <span class="fu">parent.frame</span>(), <span class="at">.type =</span> <span class="fu">c</span>(<span class="st">"sh"</span>, <span class="st">"csh"</span>, <span class="st">"cmd"</span>, <span class="st">"cmd2"</span>)) {</span>
|
||
<span id="cb3-10"><a href="#cb3-10" tabindex="-1"></a> .type <span class="ot"><-</span> <span class="fu">match.arg</span>(.type)</span>
|
||
<span id="cb3-11"><a href="#cb3-11" tabindex="-1"></a> <span class="fu">glue</span>(..., <span class="at">.envir =</span> .envir, <span class="at">.transformer =</span> <span class="fu">shell_transformer</span>(.type))</span>
|
||
<span id="cb3-12"><a href="#cb3-12" tabindex="-1"></a></span>
|
||
<span id="cb3-13"><a href="#cb3-13" tabindex="-1"></a>}</span>
|
||
<span id="cb3-14"><a href="#cb3-14" tabindex="-1"></a></span>
|
||
<span id="cb3-15"><a href="#cb3-15" tabindex="-1"></a>filename <span class="ot"><-</span> <span class="st">"test"</span></span>
|
||
<span id="cb3-16"><a href="#cb3-16" tabindex="-1"></a><span class="fu">writeLines</span>(<span class="at">con =</span> filename, <span class="st">"hello!"</span>)</span>
|
||
<span id="cb3-17"><a href="#cb3-17" tabindex="-1"></a></span>
|
||
<span id="cb3-18"><a href="#cb3-18" tabindex="-1"></a>command <span class="ot"><-</span> <span class="fu">glue_sh</span>(<span class="st">"cat {filename}"</span>)</span>
|
||
<span id="cb3-19"><a href="#cb3-19" tabindex="-1"></a>command</span>
|
||
<span id="cb3-20"><a href="#cb3-20" tabindex="-1"></a><span class="co">#> cat 'test'</span></span>
|
||
<span id="cb3-21"><a href="#cb3-21" tabindex="-1"></a><span class="fu">system</span>(command)</span></code></pre></div>
|
||
</div>
|
||
<div id="emoji-transformer" class="section level3">
|
||
<h3>emoji transformer</h3>
|
||
<p>A transformer which converts the text to the equivalent emoji.</p>
|
||
<div class="sourceCode" id="cb4"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb4-1"><a href="#cb4-1" tabindex="-1"></a>emoji_transformer <span class="ot"><-</span> <span class="cf">function</span>(text, envir) {</span>
|
||
<span id="cb4-2"><a href="#cb4-2" tabindex="-1"></a> <span class="cf">if</span> (<span class="fu">grepl</span>(<span class="st">"[*]$"</span>, text)) {</span>
|
||
<span id="cb4-3"><a href="#cb4-3" tabindex="-1"></a> text <span class="ot"><-</span> <span class="fu">sub</span>(<span class="st">"[*]$"</span>, <span class="st">""</span>, text)</span>
|
||
<span id="cb4-4"><a href="#cb4-4" tabindex="-1"></a> <span class="fu">glue_collapse</span>(<span class="fu">ji_find</span>(text)<span class="sc">$</span>emoji)</span>
|
||
<span id="cb4-5"><a href="#cb4-5" tabindex="-1"></a> } <span class="cf">else</span> {</span>
|
||
<span id="cb4-6"><a href="#cb4-6" tabindex="-1"></a> <span class="fu">ji</span>(text)</span>
|
||
<span id="cb4-7"><a href="#cb4-7" tabindex="-1"></a> }</span>
|
||
<span id="cb4-8"><a href="#cb4-8" tabindex="-1"></a>}</span>
|
||
<span id="cb4-9"><a href="#cb4-9" tabindex="-1"></a></span>
|
||
<span id="cb4-10"><a href="#cb4-10" tabindex="-1"></a>glue_ji <span class="ot"><-</span> <span class="cf">function</span>(..., <span class="at">.envir =</span> <span class="fu">parent.frame</span>()) {</span>
|
||
<span id="cb4-11"><a href="#cb4-11" tabindex="-1"></a> <span class="fu">glue</span>(..., <span class="at">.open =</span> <span class="st">":"</span>, <span class="at">.close =</span> <span class="st">":"</span>, <span class="at">.envir =</span> .envir, <span class="at">.transformer =</span> emoji_transformer)</span>
|
||
<span id="cb4-12"><a href="#cb4-12" tabindex="-1"></a>}</span>
|
||
<span id="cb4-13"><a href="#cb4-13" tabindex="-1"></a><span class="fu">glue_ji</span>(<span class="st">"one :heart:"</span>)</span>
|
||
<span id="cb4-14"><a href="#cb4-14" tabindex="-1"></a><span class="fu">glue_ji</span>(<span class="st">"many :heart*:"</span>)</span></code></pre></div>
|
||
</div>
|
||
<div id="sprintf-transformer" class="section level3">
|
||
<h3>sprintf transformer</h3>
|
||
<p>A transformer which allows succinct <code>sprintf</code> format
|
||
strings.</p>
|
||
<div class="sourceCode" id="cb5"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb5-1"><a href="#cb5-1" tabindex="-1"></a>sprintf_transformer <span class="ot"><-</span> <span class="cf">function</span>(text, envir) {</span>
|
||
<span id="cb5-2"><a href="#cb5-2" tabindex="-1"></a> m <span class="ot"><-</span> <span class="fu">regexpr</span>(<span class="st">":.+$"</span>, text)</span>
|
||
<span id="cb5-3"><a href="#cb5-3" tabindex="-1"></a> <span class="cf">if</span> (m <span class="sc">!=</span> <span class="sc">-</span><span class="dv">1</span>) {</span>
|
||
<span id="cb5-4"><a href="#cb5-4" tabindex="-1"></a> format <span class="ot"><-</span> <span class="fu">substring</span>(<span class="fu">regmatches</span>(text, m), <span class="dv">2</span>)</span>
|
||
<span id="cb5-5"><a href="#cb5-5" tabindex="-1"></a> <span class="fu">regmatches</span>(text, m) <span class="ot"><-</span> <span class="st">""</span></span>
|
||
<span id="cb5-6"><a href="#cb5-6" tabindex="-1"></a> res <span class="ot"><-</span> <span class="fu">identity_transformer</span>(text, envir)</span>
|
||
<span id="cb5-7"><a href="#cb5-7" tabindex="-1"></a> <span class="fu">do.call</span>(sprintf, <span class="fu">list</span>(<span class="fu">glue</span>(<span class="st">"%{format}"</span>), res))</span>
|
||
<span id="cb5-8"><a href="#cb5-8" tabindex="-1"></a> } <span class="cf">else</span> {</span>
|
||
<span id="cb5-9"><a href="#cb5-9" tabindex="-1"></a> <span class="fu">identity_transformer</span>(text, envir)</span>
|
||
<span id="cb5-10"><a href="#cb5-10" tabindex="-1"></a> }</span>
|
||
<span id="cb5-11"><a href="#cb5-11" tabindex="-1"></a>}</span>
|
||
<span id="cb5-12"><a href="#cb5-12" tabindex="-1"></a></span>
|
||
<span id="cb5-13"><a href="#cb5-13" tabindex="-1"></a>glue_fmt <span class="ot"><-</span> <span class="cf">function</span>(..., <span class="at">.envir =</span> <span class="fu">parent.frame</span>()) {</span>
|
||
<span id="cb5-14"><a href="#cb5-14" tabindex="-1"></a> <span class="fu">glue</span>(..., <span class="at">.transformer =</span> sprintf_transformer, <span class="at">.envir =</span> .envir)</span>
|
||
<span id="cb5-15"><a href="#cb5-15" tabindex="-1"></a>}</span>
|
||
<span id="cb5-16"><a href="#cb5-16" tabindex="-1"></a><span class="fu">glue_fmt</span>(<span class="st">"π = {pi:.3f}"</span>)</span>
|
||
<span id="cb5-17"><a href="#cb5-17" tabindex="-1"></a><span class="co">#> π = 3.142</span></span></code></pre></div>
|
||
</div>
|
||
<div id="signif-transformer" class="section level3">
|
||
<h3>signif transformer</h3>
|
||
<p>A transformer generator that represents numbers with a given number
|
||
of significant digits. This is useful if we want to represent all
|
||
numbers using the same significant digits</p>
|
||
<div class="sourceCode" id="cb6"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb6-1"><a href="#cb6-1" tabindex="-1"></a>signif_transformer <span class="ot"><-</span> <span class="cf">function</span>(<span class="at">digits =</span> <span class="dv">3</span>) {</span>
|
||
<span id="cb6-2"><a href="#cb6-2" tabindex="-1"></a> <span class="fu">force</span>(digits)</span>
|
||
<span id="cb6-3"><a href="#cb6-3" tabindex="-1"></a> <span class="cf">function</span>(text, envir) {</span>
|
||
<span id="cb6-4"><a href="#cb6-4" tabindex="-1"></a> x <span class="ot"><-</span> <span class="fu">identity_transformer</span>(text, envir)</span>
|
||
<span id="cb6-5"><a href="#cb6-5" tabindex="-1"></a> <span class="cf">if</span> (<span class="fu">is.numeric</span>(x)) {</span>
|
||
<span id="cb6-6"><a href="#cb6-6" tabindex="-1"></a> <span class="fu">signif</span>(x, <span class="at">digits =</span> digits)</span>
|
||
<span id="cb6-7"><a href="#cb6-7" tabindex="-1"></a> } <span class="cf">else</span> {</span>
|
||
<span id="cb6-8"><a href="#cb6-8" tabindex="-1"></a> x</span>
|
||
<span id="cb6-9"><a href="#cb6-9" tabindex="-1"></a> }</span>
|
||
<span id="cb6-10"><a href="#cb6-10" tabindex="-1"></a> }</span>
|
||
<span id="cb6-11"><a href="#cb6-11" tabindex="-1"></a>}</span>
|
||
<span id="cb6-12"><a href="#cb6-12" tabindex="-1"></a>glue_signif <span class="ot"><-</span> <span class="cf">function</span>(..., <span class="at">.envir =</span> <span class="fu">parent.frame</span>()) {</span>
|
||
<span id="cb6-13"><a href="#cb6-13" tabindex="-1"></a> <span class="fu">glue</span>(..., <span class="at">.transformer =</span> <span class="fu">signif_transformer</span>(<span class="dv">3</span>), <span class="at">.envir =</span> .envir)</span>
|
||
<span id="cb6-14"><a href="#cb6-14" tabindex="-1"></a>}</span>
|
||
<span id="cb6-15"><a href="#cb6-15" tabindex="-1"></a></span>
|
||
<span id="cb6-16"><a href="#cb6-16" tabindex="-1"></a><span class="fu">glue_signif</span>(<span class="st">"π = {pi}; 10π = {10*pi}; 100π = {100*pi}"</span>)</span>
|
||
<span id="cb6-17"><a href="#cb6-17" tabindex="-1"></a><span class="co">#> π = 3.14; 10π = 31.4; 100π = 314</span></span></code></pre></div>
|
||
</div>
|
||
<div id="safely-transformer" class="section level3">
|
||
<h3>safely transformer</h3>
|
||
<p>A transformer that acts like <code>purrr::safely()</code>, which
|
||
returns a value instead of an error.</p>
|
||
<div class="sourceCode" id="cb7"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb7-1"><a href="#cb7-1" tabindex="-1"></a>safely_transformer <span class="ot"><-</span> <span class="cf">function</span>(<span class="at">otherwise =</span> <span class="cn">NA</span>) {</span>
|
||
<span id="cb7-2"><a href="#cb7-2" tabindex="-1"></a> <span class="cf">function</span>(text, envir) {</span>
|
||
<span id="cb7-3"><a href="#cb7-3" tabindex="-1"></a> <span class="fu">tryCatch</span>(</span>
|
||
<span id="cb7-4"><a href="#cb7-4" tabindex="-1"></a> <span class="fu">identity_transformer</span>(text, envir),</span>
|
||
<span id="cb7-5"><a href="#cb7-5" tabindex="-1"></a> <span class="at">error =</span> <span class="cf">function</span>(e) <span class="cf">if</span> (<span class="fu">is.language</span>(otherwise)) <span class="fu">eval</span>(otherwise) <span class="cf">else</span> otherwise)</span>
|
||
<span id="cb7-6"><a href="#cb7-6" tabindex="-1"></a> }</span>
|
||
<span id="cb7-7"><a href="#cb7-7" tabindex="-1"></a>}</span>
|
||
<span id="cb7-8"><a href="#cb7-8" tabindex="-1"></a></span>
|
||
<span id="cb7-9"><a href="#cb7-9" tabindex="-1"></a>glue_safely <span class="ot"><-</span> <span class="cf">function</span>(..., <span class="at">.otherwise =</span> <span class="cn">NA</span>, <span class="at">.envir =</span> <span class="fu">parent.frame</span>()) {</span>
|
||
<span id="cb7-10"><a href="#cb7-10" tabindex="-1"></a> <span class="fu">glue</span>(..., <span class="at">.transformer =</span> <span class="fu">safely_transformer</span>(.otherwise), <span class="at">.envir =</span> .envir)</span>
|
||
<span id="cb7-11"><a href="#cb7-11" tabindex="-1"></a>}</span>
|
||
<span id="cb7-12"><a href="#cb7-12" tabindex="-1"></a></span>
|
||
<span id="cb7-13"><a href="#cb7-13" tabindex="-1"></a><span class="co"># Default returns missing if there is an error</span></span>
|
||
<span id="cb7-14"><a href="#cb7-14" tabindex="-1"></a><span class="fu">glue_safely</span>(<span class="st">"foo: {xyz}"</span>)</span>
|
||
<span id="cb7-15"><a href="#cb7-15" tabindex="-1"></a><span class="co">#> foo: NA</span></span>
|
||
<span id="cb7-16"><a href="#cb7-16" tabindex="-1"></a></span>
|
||
<span id="cb7-17"><a href="#cb7-17" tabindex="-1"></a><span class="co"># Or an empty string</span></span>
|
||
<span id="cb7-18"><a href="#cb7-18" tabindex="-1"></a><span class="fu">glue_safely</span>(<span class="st">"foo: {xyz}"</span>, <span class="at">.otherwise =</span> <span class="st">"Error"</span>)</span>
|
||
<span id="cb7-19"><a href="#cb7-19" tabindex="-1"></a><span class="co">#> foo: Error</span></span>
|
||
<span id="cb7-20"><a href="#cb7-20" tabindex="-1"></a></span>
|
||
<span id="cb7-21"><a href="#cb7-21" tabindex="-1"></a><span class="co"># Or output the error message in red</span></span>
|
||
<span id="cb7-22"><a href="#cb7-22" tabindex="-1"></a><span class="fu">library</span>(crayon)</span>
|
||
<span id="cb7-23"><a href="#cb7-23" tabindex="-1"></a><span class="fu">glue_safely</span>(<span class="st">"foo: {xyz}"</span>, <span class="at">.otherwise =</span> <span class="fu">quote</span>(<span class="fu">glue</span>(<span class="st">"{red}Error: {conditionMessage(e)}{reset}"</span>)))</span>
|
||
<span id="cb7-24"><a href="#cb7-24" tabindex="-1"></a><span class="co">#> foo: Error: Failed to evaluate glue component {xyz}</span></span>
|
||
<span id="cb7-25"><a href="#cb7-25" tabindex="-1"></a><span class="co">#> Caused by error:</span></span>
|
||
<span id="cb7-26"><a href="#cb7-26" tabindex="-1"></a><span class="co">#> ! object 'xyz' not found</span></span></code></pre></div>
|
||
</div>
|
||
<div id="variables-and-values-transformer" class="section level3">
|
||
<h3>“Variables and Values” transformer</h3>
|
||
<p>A transformer that expands input of the form <code>{var_name=}</code>
|
||
into <code>var_name = var_value</code>, i.e. a shorthand for exposing
|
||
variable names with their values. This is inspired by an <a href="https://docs.python.org/3.8/whatsnew/3.8.html#f-strings-now-support-for-quick-and-easy-debugging">f-strings
|
||
feature coming in Python 3.8</a>. It’s actually more general: you can
|
||
use it with an expression input such as <code>{expr=}</code>.</p>
|
||
<div class="sourceCode" id="cb8"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb8-1"><a href="#cb8-1" tabindex="-1"></a>vv_transformer <span class="ot"><-</span> <span class="cf">function</span>(text, envir) {</span>
|
||
<span id="cb8-2"><a href="#cb8-2" tabindex="-1"></a> regex <span class="ot"><-</span> <span class="st">"=$"</span></span>
|
||
<span id="cb8-3"><a href="#cb8-3" tabindex="-1"></a> <span class="cf">if</span> (<span class="sc">!</span><span class="fu">grepl</span>(regex, text)) {</span>
|
||
<span id="cb8-4"><a href="#cb8-4" tabindex="-1"></a> <span class="fu">return</span>(<span class="fu">identity_transformer</span>(text, envir))</span>
|
||
<span id="cb8-5"><a href="#cb8-5" tabindex="-1"></a> }</span>
|
||
<span id="cb8-6"><a href="#cb8-6" tabindex="-1"></a></span>
|
||
<span id="cb8-7"><a href="#cb8-7" tabindex="-1"></a> text <span class="ot"><-</span> <span class="fu">sub</span>(regex, <span class="st">""</span>, text)</span>
|
||
<span id="cb8-8"><a href="#cb8-8" tabindex="-1"></a> res <span class="ot"><-</span> <span class="fu">identity_transformer</span>(text, envir)</span>
|
||
<span id="cb8-9"><a href="#cb8-9" tabindex="-1"></a> n <span class="ot"><-</span> <span class="fu">length</span>(res)</span>
|
||
<span id="cb8-10"><a href="#cb8-10" tabindex="-1"></a> res <span class="ot"><-</span> <span class="fu">glue_collapse</span>(res, <span class="at">sep =</span> <span class="st">", "</span>)</span>
|
||
<span id="cb8-11"><a href="#cb8-11" tabindex="-1"></a> <span class="cf">if</span> (n <span class="sc">></span> <span class="dv">1</span>) {</span>
|
||
<span id="cb8-12"><a href="#cb8-12" tabindex="-1"></a> res <span class="ot"><-</span> <span class="fu">c</span>(<span class="st">"["</span>, res, <span class="st">"]"</span>)</span>
|
||
<span id="cb8-13"><a href="#cb8-13" tabindex="-1"></a> }</span>
|
||
<span id="cb8-14"><a href="#cb8-14" tabindex="-1"></a> <span class="fu">glue_collapse</span>(<span class="fu">c</span>(text, <span class="st">" = "</span>, res))</span>
|
||
<span id="cb8-15"><a href="#cb8-15" tabindex="-1"></a>}</span></code></pre></div>
|
||
<div class="sourceCode" id="cb9"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb9-1"><a href="#cb9-1" tabindex="-1"></a><span class="fu">set.seed</span>(<span class="dv">1234</span>)</span>
|
||
<span id="cb9-2"><a href="#cb9-2" tabindex="-1"></a>description <span class="ot"><-</span> <span class="st">"some random"</span></span>
|
||
<span id="cb9-3"><a href="#cb9-3" tabindex="-1"></a>numbers <span class="ot"><-</span> <span class="fu">sample</span>(<span class="dv">100</span>, <span class="dv">4</span>)</span>
|
||
<span id="cb9-4"><a href="#cb9-4" tabindex="-1"></a>average <span class="ot"><-</span> <span class="fu">mean</span>(numbers)</span>
|
||
<span id="cb9-5"><a href="#cb9-5" tabindex="-1"></a>sum <span class="ot"><-</span> <span class="fu">sum</span>(numbers)</span>
|
||
<span id="cb9-6"><a href="#cb9-6" tabindex="-1"></a></span>
|
||
<span id="cb9-7"><a href="#cb9-7" tabindex="-1"></a><span class="fu">glue</span>(<span class="st">"For {description} {numbers=}, {average=}, {sum=}."</span>, <span class="at">.transformer =</span> vv_transformer)</span>
|
||
<span id="cb9-8"><a href="#cb9-8" tabindex="-1"></a><span class="co">#> For some random numbers = [28, 80, 22, 9], average = 34.75, sum = 139.</span></span>
|
||
<span id="cb9-9"><a href="#cb9-9" tabindex="-1"></a></span>
|
||
<span id="cb9-10"><a href="#cb9-10" tabindex="-1"></a>a <span class="ot"><-</span> <span class="dv">3</span></span>
|
||
<span id="cb9-11"><a href="#cb9-11" tabindex="-1"></a>b <span class="ot"><-</span> <span class="fl">5.6</span></span>
|
||
<span id="cb9-12"><a href="#cb9-12" tabindex="-1"></a><span class="fu">glue</span>(<span class="st">"{a=}</span><span class="sc">\n</span><span class="st">{b=}</span><span class="sc">\n</span><span class="st">{a * 9 + b * 2=}"</span>, <span class="at">.transformer =</span> vv_transformer)</span>
|
||
<span id="cb9-13"><a href="#cb9-13" tabindex="-1"></a><span class="co">#> a = 3</span></span>
|
||
<span id="cb9-14"><a href="#cb9-14" tabindex="-1"></a><span class="co">#> b = 5.6</span></span>
|
||
<span id="cb9-15"><a href="#cb9-15" tabindex="-1"></a><span class="co">#> a * 9 + b * 2 = 38.2</span></span></code></pre></div>
|
||
</div>
|
||
|
||
|
||
|
||
<!-- code folding -->
|
||
|
||
|
||
<!-- dynamically load mathjax for compatibility with self-contained -->
|
||
<script>
|
||
(function () {
|
||
var script = document.createElement("script");
|
||
script.type = "text/javascript";
|
||
script.src = "https://mathjax.rstudio.com/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML";
|
||
document.getElementsByTagName("head")[0].appendChild(script);
|
||
})();
|
||
</script>
|
||
|
||
</body>
|
||
</html>
|