Documentation
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Overview ¶
Package extensions defines custom extensions to the go text templating language. This package serves primarily as a lightweight wrapper on top of text/template to ensure a consistent set of extensions across the application by providing some validate functions to ensure that a minimal set of keywords are supported.
Index ¶
- Constants
- func DefaultEnv(env string) string
- func DefaultJoin(sep string, src interface{}) (string, error)
- func DefaultJsonify(val interface{}) (string, error)
- func DefaultSplit(sep, str string) []string
- func RememberCalls(list *[]string, returnvalue interface{}) interface{}
- func StubTemplateFunc(...string) (string, error)
- func Unimplemented(name string) interface{}
- type LanguageExtension
- func (l *LanguageExtension) Join(toAdd *LanguageExtension) *LanguageExtension
- func (l *LanguageExtension) On(keyword string, action interface{}) *LanguageExtension
- func (l *LanguageExtension) Render(dotValues interface{}, name, toRender string) (bytes.Buffer, error)
- func (l *LanguageExtension) Validate() (missingKeywords []string, extraKeywords []string, valid bool)
Constants ¶
const RefFuncName string = "lookup"
RefFuncName is the name of the function to reference exported values from other nodes. It is a const defined here to make it easily changeable to avoid bikeshedding
Variables ¶
This section is empty.
Functions ¶
func DefaultEnv ¶
DefaultEnv provides a default implementation for the env function in text templates. It operates by determining whether an environment variable exists; if so, returns its value, otherwise returns an empty string.
func DefaultJoin ¶
DefaultJoin provides a default implementation for the join function in text templates. It operates by simply reversing the arguments to split so that it works in a reasonable manner when dealing with piped output.
func DefaultJsonify ¶
DefaultJsonify just marshals a value to string
func DefaultSplit ¶
DefaultSplit provides a default implementation for the split function in text templates. It operates by simply reversing the arguments to split so that it works in a reasonable manner when dealing with piped input.
func RememberCalls ¶
func RememberCalls(list *[]string, returnvalue interface{}) interface{}
RememberCalls is a utility function to instert calls into a list. RememberCalls takes a pointer to a list of strings, and a default. It returns a variadic function that when called from gotemplate will take the indexed argument and append it to the provided list.
func StubTemplateFunc ¶
StubTemplateFunc is the NOP function for template parsing
func Unimplemented ¶
func Unimplemented(name string) interface{}
Unimplemented returns a function that will raise an error with the fact that the keyword is unimplemented.
Types ¶
type LanguageExtension ¶
LanguageExtension is a type wrapper around a template.FuncMap to allow us to encapsulate more context in the future.
func DefaultLanguage ¶
func DefaultLanguage() *LanguageExtension
DefaultLanguage provides a default language extension. It creates default implementations of context-free and non-dependency-generating functions (e.g. split) and provides a unimplemented function for functions that must be supplied with context or which may register dependencies.
func EmptyLanguage ¶
func EmptyLanguage() *LanguageExtension
EmptyLanguage will create an empty language
func MakeLanguage ¶
func MakeLanguage() *LanguageExtension
MakeLanguage provides an empty language that implements a nil operation for all known keywords.
func MinimalLanguage ¶
func MinimalLanguage() *LanguageExtension
MinimalLanguage provides a language extension where all known extensions are associated with NOP functions- as with MakeLanguage()- except that arity, input, and output types are respected and pure transformations are implemented. It is less featureful than DefaultLanguage but will not introduce template errors that may be present when using an unmodified MakeLanguage.
func (*LanguageExtension) Join ¶
func (l *LanguageExtension) Join(toAdd *LanguageExtension) *LanguageExtension
Join adds the keywords from toAdd that do not exist in l and adds them
func (*LanguageExtension) On ¶
func (l *LanguageExtension) On(keyword string, action interface{}) *LanguageExtension
On provides a mechanism for defining an activity that will take place on encountering a keyword. It inserts the key and value pair into the language and returns a reference to the language. The language is mutated and the returned version is simply to allow method chaning, e.g.:
language = MakeLanguage().On("foo", foo).On("bar", bar).On("baz", baz)
func (*LanguageExtension) Render ¶
func (l *LanguageExtension) Render(dotValues interface{}, name, toRender string) (bytes.Buffer, error)
Render provides a lightweight interface over template.New and template.Execute, it creates a new template given the name and input string, renders it with the currently defined language extensions, and writes the output into the provided io.Writer. If any error is returned at any point it is passed on to the user.
func (*LanguageExtension) Validate ¶
func (l *LanguageExtension) Validate() (missingKeywords []string, extraKeywords []string, valid bool)
Validate checks the defined language against the known keywords and returns the deltas, if any. It returns true if the language exactly matches the known keyword list and false, with deltas, otherwise.
Source Files
Directories