README
¶
Plush
Plush is the templating system that Go both needs and deserves. Powerful, flexible, and extendable, Plush is there to make writing your templates that much easier.
Installation
$ go get -u github.com/gobuffalo/plush
Usage
Plush allows for the embedding of dynamic code inside of your templates. Take the following example:
<!-- input -->
<p><%= "plush is great" %></p>
<!-- output -->
<p>plush is great</p>
Controlling Output
By using the <%= %> tags we tell Plush to dynamically render the inner content, in this case the string plush is great, into the template between the <p></p> tags.
If we were to change the example to use <% %> tags instead the inner content will be evaluated and executed, but not injected into the template:
<!-- input -->
<p><% "plush is great" %></p>
<!-- output -->
<p></p>
By using the <% %> tags we can create variables (and functions!) inside of templates to use later:
<!-- does not print output -->
<%
let h = {name: "mark"}
let greet = fn(n) {
return "hi " + n
}
%>
<!-- prints output -->
<h1><%= greet(h["name"]) %></h1>
Full Example:
html := `<html>
<%= if (names && len(names) > 0) { %>
<ul>
<%= for (n) in names { %>
<li><%= capitalize(n) %></li>
<% } %>
</ul>
<% } else { %>
<h1>Sorry, no names. :(</h1>
<% } %>
</html>`
ctx := plush.NewContext()
ctx.Set("names", []string{"john", "paul", "george", "ringo"})
s, err := plush.Render(html, ctx)
if err != nil {
log.Fatal(err)
}
fmt.Print(s)
// output: <html>
// <ul>
// <li>John</li>
// <li>Paul</li>
// <li>George</li>
// <li>Ringo</li>
// </ul>
// </html>
Comments
You can add comments like this:
<%# This is a comment %>
You can also add line comments within a code section
<%
# this is a comment
not_a_comment()
%>
If/Else Statements
The basic syntax of if/else if/else statements is as follows:
<%
if (true) {
# do something
} else if (false) {
# do something
} else {
# do something else
}
%>
When using if/else statements to control output, remember to use the <%= %> tag to output the result of the statement:
<%= if (true) { %>
<!-- some html here -->
<% } else { %>
<!-- some other html here -->
<% } %>
Operators
Complex if statements can be built in Plush using "common" operators:
==- checks equality of two expressions!=- checks that the two expressions are not equal~=- checks a string against a regular expression (foo ~= "^fo")<- checks the left expression is less than the right expression<=- checks the left expression is less than or equal to the right expression>- checks the left expression is greater than the right expression>=- checks the left expression is greater than or equal to the right expression&&- requires both the left and right expression to be true||- requires either the left or right expression to be true
Grouped Expressions
<%= if ((1 < 2) && (someFunc() == "hi")) { %>
<!-- some html here -->
<% } else { %>
<!-- some other html here -->
<% } %>
Maps
Maps in Plush will get translated to the Go type map[string]interface{} when used. Creating, and using maps in Plush is not too different than in JSON:
<% let h = {key: "value", "a number": 1, bool: true} %>
Would become the following in Go:
map[string]interface{}{
"key": "value",
"a number": 1,
"bool": true,
}
Accessing maps is just like access a JSON object:
<%= h["key"] %>
Using maps as options to functions in Plush is incredibly powerful. See the sections on Functions and Helpers to see more examples.
Arrays
Arrays in Plush will get translated to the Go type []interface{} when used.
<% let a = [1, 2, "three", "four", h] %>
[]interface{}{ 1, 2, "three", "four", h }
For Loops
There are three different types that can be looped over: maps, arrays/slices, and iterators. The format for them all looks the same:
<%= for (key, value) in expression { %>
<%= key %> <%= value %>
<% } %>
You can also continue to the next iteration of the loop:
for (i,v) in [1, 2, 3,4,5,6,7,8,9,10] {
if (i > 0) {
continue
}
return v
}
You can terminate the for loop with break:
for (i,v) in [1, 2, 3,4,5,6,7,8,9,10] {
if (i > 5) {
break
}
return v
}
The values inside the () part of the statement are the names you wish to give to the key (or index) and the value of the expression. The expression can be an array, map, or iterator type.
Arrays
Using Index and Value
<%= for (i, x) in someArray { %>
<%= i %> <%= x %>
<% } %>
Using Just the Value
<%= for (val) in someArray { %>
<%= val %>
<% } %>
Maps
Using Index and Value
<%= for (k, v) in someMap { %>
<%= k %> <%= v %>
<% } %>
Using Just the Value
<%= for (v) in someMap { %>
<%= v %>
<% } %>
Iterators
type ranger struct {
pos int
end int
}
func (r *ranger) Next() interface{} {
if r.pos < r.end {
r.pos++
return r.pos
}
return nil
}
func betweenHelper(a, b int) Iterator {
return &ranger{pos: a, end: b - 1}
}
html := `<%= for (v) in between(3,6) { return v } %>`
ctx := plush.NewContext()
ctx.Set("between", betweenHelper)
s, err := plush.Render(html, ctx)
if err != nil {
log.Fatal(err)
}
fmt.Print(s)
// output: 45
Default helpers
Plush ships with a comprehensive list of helpers to make your life easier. For more info check the helpers package.
Custom Helpers
html := `<p><%= one() %></p>
<p><%= greet("mark")%></p>
<%= can("update") { %>
<p>i can update</p>
<% } %>
<%= can("destroy") { %>
<p>i can destroy</p>
<% } %>
`
ctx := NewContext()
// one() #=> 1
ctx.Set("one", func() int {
return 1
})
// greet("mark") #=> "Hi mark"
ctx.Set("greet", func(s string) string {
return fmt.Sprintf("Hi %s", s)
})
// can("update") #=> returns the block associated with it
// can("adsf") #=> ""
ctx.Set("can", func(s string, help HelperContext) (template.HTML, error) {
if s == "update" {
h, err := help.Block()
return template.HTML(h), err
}
return "", nil
})
s, err := Render(html, ctx)
if err != nil {
log.Fatal(err)
}
fmt.Print(s)
// output: <p>1</p>
// <p>Hi mark</p>
// <p>i can update</p>
Special Thanks
This package absolutely 100% could not have been written without the help of Thorsten Ball's incredible book, Writing an Interpeter in Go.
Not only did the book make understanding the process of writing lexers, parsers, and asts, but it also provided the basis for the syntax of Plush itself.
If you have yet to read Thorsten's book, I can't recommend it enough. Please go and buy it!
Documentation
¶
Index ¶
- Variables
- func BuffaloRenderer(input string, data map[string]interface{}, helpers map[string]interface{}) (string, error)
- func CacheSet(key string, t *Template)
- func GroupByHelper(size int, underlying interface{}) (*groupBy, error)
- func PartialHelper(name string, data map[string]interface{}, help HelperContext) (template.HTML, error)
- func Render(input string, ctx hctx.Context) (string, error)
- func RenderR(input io.Reader, ctx hctx.Context) (string, error)
- func RunScript(input string, ctx hctx.Context) error
- type Context
- type ErrUnknownIdentifier
- type HTMLer
- type HelperContext
- type Iterator
- type PartialFeeder
- type Template
Examples ¶
Constants ¶
This section is empty.
Variables ¶
var CacheEnabled bool
var DefaultTimeFormat = "January 02, 2006 15:04:05 -0700"
DefaultTimeFormat is the default way of formatting a time.Time type. This a **GLOBAL** variable, so if you change it, it will change for templates rendered through the `plush` package. If you want to set a specific time format for a particular call to `Render` you can set the `TIME_FORMAT` in the context.
ctx.Set("TIME_FORMAT", "2006-02-Jan")
s, err = Render(input, ctx)
var Helpers = helpers.NewMap(map[string]interface{}{})
Helpers contains all of the default helpers for These will be available to all templates. You should add any custom global helpers to this list.
Functions ¶
func BuffaloRenderer ¶
func BuffaloRenderer(input string, data map[string]interface{}, helpers map[string]interface{}) (string, error)
BuffaloRenderer implements the render.TemplateEngine interface allowing velvet to be used as a template engine for Buffalo
func GroupByHelper ¶
func PartialHelper ¶
func Render ¶
Render a string using the given the context.
Example ¶
ExampleRender using `if`, `for`, `else`, functions, etc...
html := `<html>
<%= if (names && len(names) > 0) { %>
<ul>
<%= for (n) in names { %>
<li><%= capitalize(n) %></li>
<% } %>
</ul>
<% } else { %>
<h1>Sorry, no names. :(</h1>
<% } %>
</html>`
ctx := plush.NewContext()
ctx.Set("names", []string{"john", "paul", "george", "ringo"})
s, err := plush.Render(html, ctx)
if err != nil {
log.Fatal(err)
}
fmt.Print(s)
Output: <html> <ul> <li>John</li> <li>Paul</li> <li>George</li> <li>Ringo</li> </ul> </html>
Example (CustomHelperFunctions) ¶
html := `<p><%= one() %></p>
<p><%= greet("mark")%></p>
<%= can("update") { %>
<p>i can update</p>
<% } %>
<%= can("destroy") { %>
<p>i can destroy</p>
<% } %>
`
ctx := plush.NewContext()
ctx.Set("one", func() int {
return 1
})
ctx.Set("greet", func(s string) string {
return fmt.Sprintf("Hi %s", s)
})
ctx.Set("can", func(s string, help plush.HelperContext) (template.HTML, error) {
if s == "update" {
h, err := help.Block()
return template.HTML(h), err
}
return "", nil
})
s, err := plush.Render(html, ctx)
if err != nil {
log.Fatal(err)
}
fmt.Print(s)
Output: <p>1</p> <p>Hi mark</p> <p>i can update</p>
Example (ForIterator) ¶
html := `<%= for (v) in between(3,6) { %><%=v%><% } %>`
s, err := plush.Render(html, plush.NewContext())
if err != nil {
log.Fatal(err)
}
fmt.Print(s)
Output: 45
Example (ScripletTags) ¶
html := `<%
let h = {name: "mark"}
let greet = fn(n) {
return "hi " + n
}
%>
<h1><%= greet(h["name"]) %></h1>`
s, err := plush.Render(html, plush.NewContext())
if err != nil {
log.Fatal(err)
}
fmt.Print(s)
Output: <h1>hi mark</h1>
Types ¶
type Context ¶
Context holds all of the data for the template that is being rendered.
func NewContextWith ¶
NewContextWith returns a fully formed context using the data provided.
func NewContextWithContext ¶
NewContextWithContext returns a new plush.Context given another context
func NewContextWithOuter ¶
NewContextWith returns a fully formed context using the data provided and setting the outer context with the passed seccond argument.
func (*Context) New ¶
New context containing the current context. Values set on the new context will not be set onto the original context, however, the original context's values will be available to the new context.
type ErrUnknownIdentifier ¶
func (*ErrUnknownIdentifier) Error ¶
func (e *ErrUnknownIdentifier) Error() string
type HelperContext ¶
HelperContext is an optional last argument to helpers that provides the current context of the call, and access to an optional "block" of code that can be executed from within the helper.
func (HelperContext) Block ¶
func (h HelperContext) Block() (string, error)
Block executes the block of template associated with the helper, think the block inside of an "if" or "each" statement.
func (HelperContext) BlockWith ¶
func (h HelperContext) BlockWith(hc hctx.Context) (string, error)
BlockWith executes the block of template associated with the helper, think the block inside of an "if" or "each" statement, but with it's own context.
func (HelperContext) HasBlock ¶
func (h HelperContext) HasBlock() bool
HasBlock returns true if a block is associated with the helper function
type Iterator ¶
type Iterator interface {
Next() interface{}
}
Iterator type can be implemented and used by the `for` command to build loops in templates
type PartialFeeder ¶
PartialFeeder is callback function should implemented on application side.
type Template ¶
type Template struct {
Input string
// contains filtered or unexported fields
}
Template represents an input and helpers to be used to evaluate and render the input.
func NewTemplate ¶
NewTemplate from the input string. Adds all of the global helper functions from "Helpers", this function does not cache the template.
func (*Template) Clone ¶
Clone a template. This is useful for defining helpers on per "instance" of the template.
Source Files
Directories