pongo2

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 Go to latest Published: Oct 28, 2014 License: MIT Imports: 18 Imported by: 1

README

pongo2

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pongo2 is the successor of pongo, a Django-syntax like templating-language.

Install/update using go get (no dependencies required by pongo2):

go get -u github.com/flosch/pongo2

Please use the issue tracker if you're encountering any problems with pongo2 or if you need help with implementing tags or filters (create a ticket!). If possible, please use playground to create a short test case on what's wrong and include the link to the snippet in your issue.

New: Try pongo2 out in the pongo2 playground.

First impression of a template

<html><head><title>Our admins and users</title></head>
{# This is a short example to give you a quick overview of pongo2's syntax. #}

{% macro user_details(user, is_admin=false) %}
	<div class="user_item">
		<!-- Let's indicate a user's good karma -->
		<h2 {% if (user.karma >= 40) || (user.karma > calc_avg_karma(userlist)+5) %}
			class="karma-good"{% endif %}>
			
			<!-- This will call user.String() automatically if available: -->
			{{ user }}
		</h2>

		<!-- Will print a human-readable time duration like "3 weeks ago" -->
		<p>This user registered {{ user.register_date|naturaltime }}.</p>
		
		<!-- Let's allow the users to write down their biography using markdown;
		     we will only show the first 15 words as a preview -->
		<p>The user's biography:</p>
		<p>{{ user.biography|markdown|truncatewords_html:15 }}
			<a href="/user/{{ user.id }}/">read more</a></p>
		
		{% if is_admin %}<p>This user is an admin!</p>{% endif %}
	</div>
{% endmacro %}

<body>
	<!-- Make use of the macro defined above to avoid repetitive HTML code
	     since we want to use the same code for admins AND members -->
	
	<h1>Our admins</h1>
	{% for admin in adminlist %}
		{{ user_details(admin, true) }}
	{% endfor %}
	
	<h1>Our members</h1>
	{% for user in userlist %}
		{{ user_details(user) }}
	{% endfor %}
</body>
</html>

Development status

Latest stable release: v1.0 (go get -u gopkg.in/flosch/pongo2.v1 / v1-branch) [read the announcement]

Current development: v1.1 (master-branch)

Topic Status
Django version compatibility: 1.7
Missing (planned) filters: none (hints)
Missing (planned) tags: none (hints)

Please also have a look on the caveats and on the official add-ons.

Features (and new in pongo2)

Recent API changes within pongo2

If you're using the master-branch of pongo2, you might be interested in this section. Since pongo2 is still in development (even though there is a first stable release!), there could be (backwards-incompatible) API changes over time. To keep track of these and therefore make it painless for you to adapt your codebase, I'll list them here.

  • Function signature for tag and filter parsing/execution changed (error return type changed to *Error).
  • INodeEvaluator has been removed and got replaced by IEvaluator. You can change your existing tags/filters by simply replacing the interface.
  • Two new helper functions: RenderTemplateFile() and RenderTemplateString().
  • Template.ExecuteRW() is now Template.ExecuteWriter()
  • Template.Execute*() functions do now take a pongo2.Context directly (no pointer anymore).

How you can help

  • Write filters / tags (see tutorial) by forking pongo2 and sending pull requests
  • Write/improve code tests (use the following command to see what tests are missing: go test -v -cover -covermode=count -coverprofile=cover.out && go tool cover -html=cover.out)
  • Write/improve template tests (see the template_tests/ directory)
  • Write middleware, libraries and websites using pongo2. :-)

Documentation

For a documentation on how the templating language works you can head over to the Django documentation. pongo2 aims to be compatible with it.

You can access pongo2's API documentation on godoc.

Blog post series

Caveats

Filters
  • date / time: The date and time filter are taking the Golang specific time- and date-format (not Django's one) currently. Take a look on the format here.
  • stringformat: stringformat does not take Python's string format syntax as a parameter, instead it takes Go's. Essentially {{ 3.14|stringformat:"pi is %.2f" }} is fmt.Sprintf("pi is %.2f", 3.14).
  • escape / force_escape: Unlike Django's behaviour, the escape-filter is applied immediately. Therefore there is no need for a force_escape-filter yet.
Tags
  • for: All the forloop fields (like forloop.counter) are written with a capital letter at the beginning. For example, the counter can be accessed by forloop.Counter and the parentloop by forloop.Parentloop.
  • now: takes Go's time format (see date and time-filter).
Misc
  • not in-operator: You can check whether a map/struct/string contains a key/field/substring by using the in-operator (or the negation of it): {% if key in map %}Key is in map{% else %}Key not in map{% endif %} or {% if !(key in map) %}Key is NOT in map{% else %}Key is in map{% endif %}.

Add-ons, libraries and helpers

Official

  • ponginae - A web-framework for Go (using pongo2).
  • pongo2-addons - Official additional filters/tags for pongo2 (for example a markdown-filter). They are in their own repository because they're relying on 3rd-party-libraries.

3rd-party

Please add your project to this list and send me a pull request when you've developed something nice for pongo2.

API-usage examples

Please see the documentation for a full list of provided API methods.

A tiny example (template string)

// Compile the template first (i. e. creating the AST)
tpl, err := pongo2.FromString("Hello {{ name|capfirst }}!")
if err != nil {
	panic(err)
}
// Now you can render the template with the given 
// pongo2.Context how often you want to.
out, err := tpl.Execute(pongo2.Context{"name": "florian"})
if err != nil {
	panic(err)
}
fmt.Println(out) // Output: Hello Florian!

Example server-usage (template file)

package main

import (
	"github.com/flosch/pongo2"
	"net/http"
)

// Pre-compiling the templates at application startup using the
// little Must()-helper function (Must() will panic if FromFile()
// or FromString() will return with an error - that's it).
// It's faster to pre-compile it anywhere at startup and only
// execute the template later.
var tplExample = pongo2.Must(pongo2.FromFile("example.html"))

func examplePage(w http.ResponseWriter, r *http.Request) {
	// Execute the template per HTTP request
	err := tplExample.ExecuteWriter(pongo2.Context{"query": r.FormValue("query")}, w)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
	}
}

func main() {
	http.HandleFunc("/", examplePage)
	http.ListenAndServe(":8080", nil)
}

Benchmark

The benchmarks have been run on the my machine (Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz) using the command:

go test -bench . -cpu 1,2,4,8

All benchmarks are compiling (depends on the benchmark) and executing the template_tests/complex.tpl template.

The results are:

BenchmarkExecuteComplexWithSandboxActive                50000             60450 ns/op
BenchmarkExecuteComplexWithSandboxActive-2              50000             56998 ns/op
BenchmarkExecuteComplexWithSandboxActive-4              50000             60343 ns/op
BenchmarkExecuteComplexWithSandboxActive-8              50000             64229 ns/op
BenchmarkCompileAndExecuteComplexWithSandboxActive      10000            164410 ns/op
BenchmarkCompileAndExecuteComplexWithSandboxActive-2    10000            156682 ns/op
BenchmarkCompileAndExecuteComplexWithSandboxActive-4    10000            164821 ns/op
BenchmarkCompileAndExecuteComplexWithSandboxActive-8    10000            171806 ns/op
BenchmarkParallelExecuteComplexWithSandboxActive        50000             60428 ns/op
BenchmarkParallelExecuteComplexWithSandboxActive-2      50000             31887 ns/op
BenchmarkParallelExecuteComplexWithSandboxActive-4     100000             22810 ns/op
BenchmarkParallelExecuteComplexWithSandboxActive-8     100000             18820 ns/op
BenchmarkExecuteComplexWithoutSandbox                   50000             56942 ns/op
BenchmarkExecuteComplexWithoutSandbox-2                 50000             56168 ns/op
BenchmarkExecuteComplexWithoutSandbox-4                 50000             57838 ns/op
BenchmarkExecuteComplexWithoutSandbox-8                 50000             60539 ns/op
BenchmarkCompileAndExecuteComplexWithoutSandbox         10000            162086 ns/op
BenchmarkCompileAndExecuteComplexWithoutSandbox-2       10000            159771 ns/op
BenchmarkCompileAndExecuteComplexWithoutSandbox-4       10000            163826 ns/op
BenchmarkCompileAndExecuteComplexWithoutSandbox-8       10000            169062 ns/op
BenchmarkParallelExecuteComplexWithoutSandbox           50000             57152 ns/op
BenchmarkParallelExecuteComplexWithoutSandbox-2         50000             30276 ns/op
BenchmarkParallelExecuteComplexWithoutSandbox-4        100000             22065 ns/op
BenchmarkParallelExecuteComplexWithoutSandbox-8        100000             18034 ns/op

Benchmarked on October 2nd 2014.

Documentation

Overview

A Django-syntax like template-engine

Blog posts about pongo2 (including introduction and migration): https://www.florian-schlachter.de/?tag=pongo2

Complete documentation on the template language: https://docs.djangoproject.com/en/dev/topics/templates/

Try out pongo2 live in the pongo2 playground: https://www.florian-schlachter.de/pongo2/

Make sure to read README.md in the repository as well.

A tiny example with template strings:

(Snippet on playground: https://www.florian-schlachter.de/pongo2/?id=1206546277) 

// Compile the template first (i. e. creating the AST)
tpl, err := pongo2.FromString("Hello {{ name|capfirst }}!")
if err != nil {
    panic(err)
}
// Now you can render the template with the given
// pongo2.Context how often you want to.
out, err := tpl.Execute(pongo2.Context{"name": "fred"})
if err != nil {
    panic(err)
}
fmt.Println(out) // Output: Hello Fred!

Index

Constants

View Source 
const (
	TokenError = iota
	EOF

	TokenHTML

	TokenKeyword
	TokenIdentifier
	TokenString
	TokenNumber
	TokenSymbol
)
View Source 
const Version = "v2"

Version string

Variables

View Source 
var (

	// Available symbols in pongo2 (within filters/tag)
	TokenSymbols = []string{

		"==", ">=", "<=", "&&", "||", "{{", "}}", "{%", "%}", "!=", "<>",

		"(", ")", "+", "-", "*", "<", ">", "/", "^", ",", ".", "!", "|", ":", "=", "%",
	}

	// Available keywords in pongo2
	TokenKeywords = []string{"in", "and", "or", "not", "true", "false", "as", "export"}
)
View Source 
var (

	// Creating a default set
	DefaultSet = NewSet("default")

	// Methods on the default set
	FromString           = DefaultSet.FromString
	FromFile             = DefaultSet.FromFile
	FromCache            = DefaultSet.FromCache
	RenderTemplateString = DefaultSet.RenderTemplateString
	RenderTemplateFile   = DefaultSet.RenderTemplateFile

	// Globals for the default set
	Globals = DefaultSet.Globals
)

Functions

func ApplyFilter 

func ApplyFilter(name string, value *Value, param *Value) (*Value, *Error)

Applies a filter to a given value using the given parameters. Returns a *pongo2.Value or an error.

func RegisterFilter 

func RegisterFilter(name string, fn FilterFunction)

Registers a new filter. If there's already a filter with the same name, RegisterFilter will panic. You usually want to call this function in the filter's init() function: http://golang.org/doc/effective_go.html#init

See http://www.florian-schlachter.de/post/pongo2/ for more about writing filters and tags.

func RegisterTag 

func RegisterTag(name string, parserFn TagParser)

Registers a new tag. If there's already a tag with the same name, RegisterTag will panic. You usually want to call this function in the tag's init() function: http://golang.org/doc/effective_go.html#init

See http://www.florian-schlachter.de/post/pongo2/ for more about writing filters and tags.

func ReplaceFilter 

func ReplaceFilter(name string, fn FilterFunction)

Replaces an already registered filter with a new implementation. Use this function with caution since it allows you to change existing filter behaviour.

func ReplaceTag 

func ReplaceTag(name string, parserFn TagParser)

Replaces an already registered tag with a new implementation. Use this function with caution since it allows you to change existing tag behaviour.

Types

type Context 

type Context map[string]interface{}

Use this Context type to provide constants, variables, instances or functions to your template.

pongo2 automatically provides meta-information or functions through the "pongo2"-key. Currently, context["pongo2"] contains the following keys:

  1. version: returns the version string

Template examples for accessing items from your context: 

{{ myconstant }}
{{ myfunc("test", 42) }}
{{ user.name }}
{{ pongo2.version }}

func (Context) Update 

func (c Context) Update(other Context) Context

type Error 

type Error struct {
	Template *Template
	Filename string
	Line     int
	Column   int
	Token    *Token
	Sender   string
	ErrorMsg string
}

This Error type is being used to address an error during lexing, parsing or execution. If you want to return an error object (for example in your own tag or filter) fill this object with as much information as you have. Make sure "Sender" is always given (if you're returning an error within a filter, make Sender equals 'filter:yourfilter'; same goes for tags: 'tag:mytag'). It's okay if you only fill in ErrorMsg if you don't have any other details at hand.

func (*Error) Error 

func (e *Error) Error() string

Returns a nice formatted error string.

func (*Error) RawLine 

func (e *Error) RawLine() (line string, available bool)

Returns the affected line from the original template, if available.

type ExecutionContext 

type ExecutionContext struct {
	Autoescape bool
	Public     Context
	Private    Context
	Shared     Context
	// contains filtered or unexported fields
}

If you're writing a custom tag, your tag's Execute()-function will have access to the ExecutionContext. This struct stores anything about the current rendering process's Context including the Context provided by the user (field Public). You can safely use the Private context to provide data to the user's template (like a 'forloop'-information). The Shared-context is used to share data between tags. All ExecutionContexts share this context.

Please be careful when accessing the Public data. PLEASE DO NOT MODIFY THE PUBLIC CONTEXT (read-only).

To create your own execution context within tags, use the NewChildExecutionContext(parent) function.

func NewChildExecutionContext 

func NewChildExecutionContext(parent *ExecutionContext) *ExecutionContext

func (*ExecutionContext) Error 

func (ctx *ExecutionContext) Error(msg string, token *Token) *Error

func (*ExecutionContext) Logf 

func (ctx *ExecutionContext) Logf(format string, args ...interface{})

type Expression 

type Expression struct {
	// contains filtered or unexported fields
}

func (*Expression) Evaluate 

func (expr *Expression) Evaluate(ctx *ExecutionContext) (*Value, *Error)

func (*Expression) Execute 

func (expr *Expression) Execute(ctx *ExecutionContext, buffer *bytes.Buffer) *Error

func (*Expression) FilterApplied 

func (expr *Expression) FilterApplied(name string) bool

func (*Expression) GetPositionToken 

func (expr *Expression) GetPositionToken() *Token

type FilterFunction 

type FilterFunction func(in *Value, param *Value) (out *Value, err *Error)

type IEvaluator 

type IEvaluator interface {
	INode
	GetPositionToken() *Token
	Evaluate(*ExecutionContext) (*Value, *Error)
	FilterApplied(name string) bool
}

type INode 

type INode interface {
	Execute(*ExecutionContext, *bytes.Buffer) *Error
}

type INodeTag 

type INodeTag interface {
	INode
}

type NodeWrapper 

type NodeWrapper struct {
	Endtag string
	// contains filtered or unexported fields
}

func (*NodeWrapper) Execute 

func (wrapper *NodeWrapper) Execute(ctx *ExecutionContext, buffer *bytes.Buffer) *Error

type Parser 

type Parser struct {
	// contains filtered or unexported fields
}

The parser provides you a comprehensive and easy tool to work with the template document and arguments provided by the user for your custom tag.

The parser works on a token list which will be provided by pongo2. A token is a unit you can work with. Tokens are either of type identifier, string, number, keyword, HTML or symbol.

(See Token's documentation for more about tokens)

func (*Parser) Consume 

func (p *Parser) Consume()

Consume one token. It will be gone forever.

func (*Parser) ConsumeN 

func (p *Parser) ConsumeN(count int)

Consume N tokens. They will be gone forever.

func (*Parser) Count 

func (p *Parser) Count() int

Returns the total token count.

func (*Parser) Current 

func (p *Parser) Current() *Token

Returns the current token.

func (*Parser) Error 

func (p *Parser) Error(msg string, token *Token) *Error

Produces a nice error message and returns an error-object. The 'token'-argument is optional. If provided, it will take the token's position information. If not provided, it will automatically use the CURRENT token's position information.

func (*Parser) Get 

func (p *Parser) Get(i int) *Token

Returns tokens[i] or NIL (if i >= len(tokens))

func (*Parser) GetR 

func (p *Parser) GetR(shift int) *Token

Returns tokens[current-position + shift] or NIL (if (current-position + i) >= len(tokens))

func (*Parser) Match 

func (p *Parser) Match(typ TokenType, val string) *Token

Returns the CURRENT token if the given type AND value matches. Consumes this token on success.

func (*Parser) MatchOne 

func (p *Parser) MatchOne(typ TokenType, vals ...string) *Token

Returns the CURRENT token if the given type AND *one* of the given values matches. Consumes this token on success.

func (*Parser) MatchType 

func (p *Parser) MatchType(typ TokenType) *Token

Returns the CURRENT token if the given type matches. Consumes this token on success.

func (*Parser) ParseExpression 

func (p *Parser) ParseExpression() (IEvaluator, *Error)

func (*Parser) Peek 

func (p *Parser) Peek(typ TokenType, val string) *Token

Returns the CURRENT token if the given type AND value matches. It DOES NOT consume the token.

func (*Parser) PeekN 

func (p *Parser) PeekN(shift int, typ TokenType, val string) *Token

Returns the tokens[current position + shift] token if the given type AND value matches for that token. DOES NOT consume the token.

func (*Parser) PeekOne 

func (p *Parser) PeekOne(typ TokenType, vals ...string) *Token

Returns the CURRENT token if the given type AND *one* of the given values matches. It DOES NOT consume the token.

func (*Parser) PeekType 

func (p *Parser) PeekType(typ TokenType) *Token

Returns the CURRENT token if the given type matches. It DOES NOT consume the token.

func (*Parser) PeekTypeN 

func (p *Parser) PeekTypeN(shift int, typ TokenType) *Token

Returns the tokens[current position + shift] token if the given type matches. DOES NOT consume the token for that token.

func (*Parser) Remaining 

func (p *Parser) Remaining() int

Returns the UNCONSUMED token count.

func (*Parser) WrapUntilTag 

func (p *Parser) WrapUntilTag(names ...string) (*NodeWrapper, *Parser, *Error)

Wraps all nodes between starting tag and "{% endtag %}" and provides one simple interface to execute the wrapped nodes. It returns a parser to process provided arguments to the tag.

type TagParser 

type TagParser func(doc *Parser, start *Token, arguments *Parser) (INodeTag, *Error)

This is the function signature of the tag's parser you will have to implement in order to create a new tag.

'doc' is providing access to the whole document while 'arguments' is providing access to the user's arguments to the tag: 

{% your_tag_name some "arguments" 123 %}

start_token will be the *Token with the tag's name in it (here: your_tag_name).

Please see the Parser documentation on how to use the parser. See RegisterTag()'s documentation for more information about writing a tag as well.

type Template 

type Template struct {
	// contains filtered or unexported fields
}

func Must 

func Must(tpl *Template, err *Error) *Template

Helper function which panics, if a Template couldn't successfully parsed. This is how you would use it: 

var baseTemplate = pongo2.Must(pongo2.FromFile("templates/base.html"))

func (*Template) Execute 

func (tpl *Template) Execute(context Context) (string, *Error)

Executes the template and returns the rendered template as a string

func (*Template) ExecuteBytes 

func (tpl *Template) ExecuteBytes(context Context) ([]byte, *Error)

Executes the template and returns the rendered template as a []byte

func (*Template) ExecuteWriter 

func (tpl *Template) ExecuteWriter(context Context, writer io.Writer) *Error

Executes the template with the given context and writes to writer (io.Writer) on success. Context can be nil. Nothing is written on error; instead the error is being returned.

type TemplateSet 

type TemplateSet struct {

	// Globals will be provided to all templates created within this template set
	Globals Context

	// If debug is true (default false), ExecutionContext.Logf() will work and output to STDOUT. Furthermore,
	// FromCache() won't cache the templates. Make sure to synchronize the access to it in case you're changing this
	// variable during program execution (and template compilation/execution).
	Debug bool

	// Sandbox features
	// - Limit access to directories (using SandboxDirectories)
	// - Disallow access to specific tags and/or filters (using BanTag() and BanFilter())
	//
	// You can limit file accesses (for all tags/filters which are using pongo2's file resolver technique)
	// to these sandbox directories. All default pongo2 filters/tags are respecting these restrictions.
	// For example, if you only have your base directory in the list, a {% ssi "/etc/passwd" %} will not work.
	// No items in SandboxDirectories means no restrictions at all.
	//
	// For efficiency reasons you can ban tags/filters only *before* you have added your first
	// template to the set (restrictions are statically checked). After you added one, it's not possible anymore
	// (for your personal security).
	//
	// SandboxDirectories can be changed at runtime. Please synchronize the access to it if you need to change it
	// after you've added your first template to the set. You *must* use this match pattern for your directories:
	// http://golang.org/pkg/path/filepath/#Match
	SandboxDirectories []string
	// contains filtered or unexported fields
}

A template set allows you to create your own group of templates with their own global context (which is shared among all members of the set), their own configuration (like a specific base directory) and their own sandbox. It's useful for a separation of different kind of templates (e. g. web templates vs. mail templates).

func NewSet 

func NewSet(name string) *TemplateSet

Create your own template sets to separate different kind of templates (e. g. web from mail templates) with different globals or other configurations (like base directories).

func (*TemplateSet) BanFilter 

func (set *TemplateSet) BanFilter(name string)

Ban a specific filter for this template set. See more in the documentation for TemplateSet.

func (*TemplateSet) BanTag 

func (set *TemplateSet) BanTag(name string)

Ban a specific tag for this template set. See more in the documentation for TemplateSet.

func (*TemplateSet) BaseDirectory 

func (set *TemplateSet) BaseDirectory() string

func (*TemplateSet) FromCache 

func (set *TemplateSet) FromCache(filename string) (*Template, *Error)

FromCache() is a convenient method to cache templates. It is thread-safe and will only compile the template associated with a filename once. If TemplateSet.Debug is true (for example during development phase), FromCache() will not cache the template and instead recompile it on any call (to make changes to a template live instantaneously). Like FromFile(), FromCache() takes a relative path to a set base directory. Sandbox restrictions apply (if given).

func (*TemplateSet) FromFile 

func (set *TemplateSet) FromFile(filename string) (*Template, *Error)

Loads a template from a filename and returns a Template instance. If a base directory is set, the filename must be either relative to it or be an absolute path. Sandbox restrictions (SandboxDirectories) apply if given.

func (*TemplateSet) FromString 

func (set *TemplateSet) FromString(tpl string) (*Template, *Error)

Loads a template from string and returns a Template instance.

func (*TemplateSet) RenderTemplateFile 

func (set *TemplateSet) RenderTemplateFile(fn string, ctx Context) string

Shortcut; renders a template file directly. Panics when providing a malformed template or an error occurs during execution.

func (*TemplateSet) RenderTemplateString 

func (set *TemplateSet) RenderTemplateString(s string, ctx Context) string

Shortcut; renders a template string directly. Panics when providing a malformed template or an error occurs during execution.

func (*TemplateSet) SetBaseDirectory 

func (set *TemplateSet) SetBaseDirectory(name string) error

Use this function to set your template set's base directory. This directory will be used for any relative path in filters, tags and From*-functions to determine your template.

type Token 

type Token struct {
	Filename string
	Typ      TokenType
	Val      string
	Line     int
	Col      int
}

func (*Token) String 

func (t *Token) String() string

type TokenType 

type TokenType int

type Value 

type Value struct {
	// contains filtered or unexported fields
}

func AsSafeValue 

func AsSafeValue(i interface{}) *Value

Like AsValue, but does not apply the 'escape' filter.

func AsValue 

func AsValue(i interface{}) *Value

Converts any given value to a pongo2.Value Usually being used within own functions passed to a template through a Context or within filter functions.

Example: 

AsValue("my string")

func MustApplyFilter 

func MustApplyFilter(name string, value *Value, param *Value) *Value

Like ApplyFilter, but panics on an error

func (*Value) Bool 

func (v *Value) Bool() bool

Returns the underlying value as bool. If the value is not bool, false will always be returned. If you're looking for true/false-evaluation of the underlying value, have a look on the IsTrue()-function.

func (*Value) CanSlice 

func (v *Value) CanSlice() bool

Checks whether the underlying value is of type array, slice or string. You normally would use CanSlice() before using the Slice() operation.

func (*Value) Contains 

func (v *Value) Contains(other *Value) bool

Checks whether the underlying value (which must be of type struct, map, string, array or slice) contains of another Value (e. g. used to check whether a struct contains of a specific field or a map contains a specific key).

Example: 

AsValue("Hello, World!").Contains(AsValue("World")) == true

func (*Value) EqualValueTo 

func (v *Value) EqualValueTo(other *Value) bool

Checks whether two values are containing the same value or object.

func (*Value) Float 

func (v *Value) Float() float64

Returns the underlying value as a float (converts the underlying value, if necessary). If it's not possible to convert the underlying value, it will return 0.0.

func (*Value) Index 

func (v *Value) Index(i int) *Value

Get the i-th item of an array, slice or string. Otherwise it will return NIL.

func (*Value) Integer 

func (v *Value) Integer() int

Returns the underlying value as an integer (converts the underlying value, if necessary). If it's not possible to convert the underlying value, it will return 0.

func (*Value) Interface 

func (v *Value) Interface() interface{}

Gives you access to the underlying value.

func (*Value) IsBool 

func (v *Value) IsBool() bool

Checks whether the underlying value is a bool

func (*Value) IsFloat 

func (v *Value) IsFloat() bool

Checks whether the underlying value is a float

func (*Value) IsInteger 

func (v *Value) IsInteger() bool

Checks whether the underlying value is an integer

func (*Value) IsNil 

func (v *Value) IsNil() bool

Checks whether the underlying value is NIL

func (*Value) IsNumber 

func (v *Value) IsNumber() bool

Checks whether the underlying value is either an integer or a float.

func (*Value) IsString 

func (v *Value) IsString() bool

Checks whether the underlying value is a string

func (*Value) IsTrue 

func (v *Value) IsTrue() bool

Tries to evaluate the underlying value the Pythonic-way:

Returns TRUE in one the following cases:

  • int != 0
  • uint != 0
  • float != 0.0
  • len(array/chan/map/slice/string) > 0
  • bool == true
  • underlying value is a struct

Otherwise returns always FALSE.

func (*Value) Iterate 

func (v *Value) Iterate(fn func(idx, count int, key, value *Value) bool, empty func())

Iterates over a map, array, slice or a string. It calls the function's first argument for every value with the following arguments: 

idx      current 0-index
count    total amount of items
key      *Value for the key or item
value    *Value (only for maps, the respective value for a specific key)

If the underlying value has no items or is not one of the types above, the empty function (function's second argument) will be called.

func (*Value) IterateOrder 

func (v *Value) IterateOrder(fn func(idx, count int, key, value *Value) bool, empty func(), reverse bool)

Like Value.Iterate, but can iterate through an array/slice/string in reverse. Does not affect the iteration through a map because maps don't have any particular order.

func (*Value) Len 

func (v *Value) Len() int

Returns the length for an array, chan, map, slice or string. Otherwise it will return 0.

func (*Value) Negate 

func (v *Value) Negate() *Value

Tries to negate the underlying value. It's mainly used for the NOT-operator and in conjunction with a call to return_value.IsTrue() afterwards.

Example: 

AsValue(1).Negate().IsTrue() == false

func (*Value) Slice 

func (v *Value) Slice(i, j int) *Value

Slices an array, slice or string. Otherwise it will return an empty []int.

func (*Value) String 

func (v *Value) String() string

Returns a string for the underlying value. If this value is not of type string, pongo2 tries to convert it. Currently the following types for underlying values are supported:

  1. string
  2. int/uint (any size)
  3. float (any precision)
  4. bool
  5. time.Time
  6. String() will be called on the underlying value if provided

NIL values will lead to an empty string. Unsupported types are leading to their respective type name.

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