FET

FET is a golang template engine that can tranlate smarty like template code into golang html/template.

Why FET

FET means Friendly, Easily for Template code. The official golang package html/template is a fully functional template engine, but it has a few defects with user experience, so you need FET.

Features

• Expression logics
• Use incldue with defined variables scopes
• Use extends inherit base template with defined variables scopes
• Limited support for for and capture

Document

Document

中文文档

Usage

it's more likely to the php template engine smarty.

• inherit

  {%extends "base.html"%}

• blocks for inherit

  {%block "header"%}
    <div>some code here</div>
  {%/block%}

• include

  {%include file="header.html" var=1%}

• loop, do not support keyword break continue

  // for Gofet mode
  {%for item,key in list%}
    // output
  {%/for%}
  
  {%for i = 0, j = 10; i < j; i++%}
    // output
  {%/for%}
  // for Smarty mode
  {%foreach $list as $key => $item%}
    // output
  {%/foreach%}
  // for
  {%for $i = 0, $j = 10; $i < $j; $i++%}
    // output
  {%/for%}

• if condition

  {%if $num > 100%}
  
  {%elseif $num < 50%}
  
  {%else%}
  
  {%/if%}

• output

  {%$item.url%}

• pipe funcs

  {%$item.title|truncate:30%}

• variable define

  {%$title = "this is a title"%}

• capture

  {%capture "hello"%}hello{%/capture%}
  {%if true%}
    {%$fet.capture.hello%},wolrd!
  {%else%}
    just {%$fet.capture.hello%}!
  {%/if%}

• static variables

  {%$fet.capture.xxx%}
  {%$fet.config.leftDelimiter%}
  {%$fet.config.rightDelimiter%}
  {%$fet.config.templateDir%}
  {%$fet.config.compileDir%}
  {%$fet.now%}
  {%$fet.debug%} // will output all the variables that assigned in the template<include variables that difined in the template by yourself> to the js devtools's Console panel.

• special variables

  {%$ROOT%}  // will output $
  {%$fet%} // will output .

Expression

1. operators: You can either use the keyword operator or the punctuation.

   keyword	punctuation	example
   and	&&	1 && 2 <=> 1 and 2
   or	||	1 || 2 <=> 1 or 2
   not	!	!a <=> not a
   eq	==	a == b <=> a eq b
   ne	!=	a != b <=> a ne b
   gt	>	a > b <=> a gt b
   ge	>=	a >= b <=> a ge b
   lt	<	a < b <=> a lt b
   le	<=	a <= b <=> a le b
   bitor	-	a bitor b
   -	&	a & b
   -	^	a ^ b
   -	+	a + b
   -	-	a - b
   -	*	a * b
   -	/	a / b
   -	%	a % b
   -	**	a ** b

   Be careful of the and and or operators, they don't have short circuit with conditions.

2. pipe
   | pipeline funcs
   : set parameters for pipeline funcs

3. numbers
   hex: 0xffff
   octal: 0o777
   binary: 0b1000
   scientific notation 1e10

String concat

{% $sayHello = "world" %}
{% "hello `$sayHello`"%} // output "hello world"

use `` for variable or expression in strings. do not use +.

Func Maps

• Math
  min max floor ceil

• Formats
  number_format

• Strings truncate concat ucwords

• Assert
  empty

• Length
  count

• Output
  safe

• view more in funcs.go

Config types.Mode

• types.Smarty
  the variable and field must begin with $, use foreach tag for loops.

• types.Gofet
  the variable and field mustn't begin with $, use for tag for loops.

In development

# install command line tool `fetc`
go get -v github.com/fefit/fetc
# then init the config, will make a config file `fet.config.json`
fetc init
# then watch the file change, compile your fet template file immediately
fetc watch

Demo code

package main

import (
  "os"
  "github.com/fefit/fet"
  "github.com/fefit/fet/types"
)

func main(){
  conf := &fet.Config{
    LeftDelimiter: "{%", // default "{%"
    RightDelimiter: "%}", // default "%}"
    TemplateDir: "tmpls", //  default "templates"
    CompileDir: "views", // default "templates_c",
    Ignores: []string{"inc/*"}, // ignore compile,paths and files that will be included and extended. use filepath.Match() method.
    UcaseField: false, // default false, if true will auto uppercase field name to uppercase.
    CompileOnline: false, // default false, you should compile your template files offline
    Glob: false, // default false, if true, will add {{define "xxx"}}{{end}} to wrap the compiled content,"xxx" is the relative pathname base on your templateDir, without the file extname.
    AutoRoot: false, // default false,if true, if the variable is not assign in the scope, will treat it as the root field of template data, otherwise you need use '$ROOT' to index the data field.
    Mode: types.Smarty, // default types.Smarty, also can be "types.Gofet"
  }
  fet, _ := fet.New(conf)
  // assign data
  data := map[string]interface{}{
    "Hello": "World"
  }
  // the index.html {%$ROOT.Hello%}
  // Display
  fet.Display("index.html", data, os.Stdout)
  // will output: World
}

API

static methods

• fet.LoadConf(configFile string) (*types.FetConfig, error)

  if you use the command line fetc build a config file fet.config.json, then you can use fet.LoadConf to get the config.

• fet.New(config *types.FetConfig) (instance *Fet, error)

  get a fet instance.

instance methods

• instance.Compile(tpl string, createFile bool) (result string, err error)

  compile a template file, if createFile is true, will create the compiled file.

• instance.CompileAll() error

  compile all files need to compile.

• instance.Display(tpl string, data interface{}, output io.Wirter) error

  render the parsed html code into output.

• instance.Fetch(tpl string, data interface{}) (result string, err error)

  just get the parsed string code, it always use CompileOnline mode.

Use in project

1. compile mode

   just use fet compile your template files offline, and add the FuncMap lib/funcs/funcs.go to your project.

2. install mode

   install fet,and use fet.Display(tpl, data, io.Writer) to render the template file.

License

MIT License.