# Recipes

## Introduction

This vignette walks the user through some applications of linne.

## Shiny Inputs

Shiny developers often want to customise how shiny inputs look and feel, which can be a bother. Let’s say we want to change the label color of the textInput shiny input.

shiny::textInput(inputId = "text", "Label") 
cat(as.character(shiny::textInput(inputId = "text", "Label")))
#> <div class="form-group shiny-input-container">
#>   <label class="control-label" for="text">Label</label>
#>   <input id="text" type="text" class="form-control" value=""/>
#> </div>

One might be tempted to only use sel_id('text'), as demonstrated above, this would not work. We could instead use on of the infix operators select the child tag “label” of the input.

Linne$new()$
rule(
sel_id("text") %child% sel_tag("label"),
color = "#f4a717"
)$show_css() #> #text label{ #> color:#f4a717; #> } Now, just to demonstrate what is possible with CSS, say we want to change the font size of a specific option in a selectInput. shiny::selectInput("select", "Select one:", choices = letters[1:3])  cat(as.character(shiny::selectInput("select", "Select one:", choices = letters[1:3]))) #> <div class="form-group shiny-input-container"> #> <label class="control-label" for="select">Select one:</label> #> <div> #> <select id="select"><option value="a" selected>a</option> #> <option value="b">b</option> #> <option value="c">c</option></select> #> <script type="application/json" data-for="select" data-nonempty="">{}</script> #> </div> #> </div> We can again use a combination of selectors to select say, option “b”, to a different size. Linne$new()$rule( sel_id("select") # inputId = "select" %child% sel_attr("value", "b"), # value = 'b' color = "#f4a717" )$show_css()
#> #select [value='b']{
#>  color:#f4a717;
#> }

A good way to conceptualise the %child% operator is to think of it like one uses the pipe in the rvest package or how one might use the pipe in purrr: to gradually but surely go down the tree until the right node is selected.