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vendor/github.com/Masterminds/sprig/README.md

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+# Sprig: Template functions for Go templates
+[![Stability: Sustained](https://masterminds.github.io/stability/sustained.svg)](https://masterminds.github.io/stability/sustained.html)
+[![Build Status](https://travis-ci.org/Masterminds/sprig.svg?branch=master)](https://travis-ci.org/Masterminds/sprig)
+
+The Go language comes with a [built-in template
+language](http://golang.org/pkg/text/template/), but not
+very many template functions. Sprig is a library that provides more than 100 commonly
+used template functions.
+
+It is inspired by the template functions found in
+[Twig](http://twig.sensiolabs.org/documentation) and in various
+JavaScript libraries, such as [underscore.js](http://underscorejs.org/).
+
+## Usage
+
+**Template developers**: Please use Sprig's [function documentation](http://masterminds.github.io/sprig/) for
+detailed instructions and code snippets for the >100 template functions available.
+
+**Go developers**: If you'd like to include Sprig as a library in your program,
+our API documentation is available [at GoDoc.org](http://godoc.org/github.com/Masterminds/sprig).
+
+For standard usage, read on.
+
+### Load the Sprig library
+
+To load the Sprig `FuncMap`:
+
+```go
+
+import (
+  "github.com/Masterminds/sprig"
+  "html/template"
+)
+
+// This example illustrates that the FuncMap *must* be set before the
+// templates themselves are loaded.
+tpl := template.Must(
+  template.New("base").Funcs(sprig.FuncMap()).ParseGlob("*.html")
+)
+
+
+```
+
+### Calling the functions inside of templates
+
+By convention, all functions are lowercase. This seems to follow the Go
+idiom for template functions (as opposed to template methods, which are
+TitleCase). For example, this:
+
+```
+{{ "hello!" | upper | repeat 5 }}
+```
+
+produces this:
+
+```
+HELLO!HELLO!HELLO!HELLO!HELLO!
+```
+
+## Principles Driving Our Function Selection
+
+We followed these principles to decide which functions to add and how to implement them:
+
+- Use template functions to build layout. The following
+  types of operations are within the domain of template functions:
+  - Formatting
+  - Layout
+  - Simple type conversions
+  - Utilities that assist in handling common formatting and layout needs (e.g. arithmetic)
+- Template functions should not return errors unless there is no way to print
+  a sensible value. For example, converting a string to an integer should not
+  produce an error if conversion fails. Instead, it should display a default
+  value.
+- Simple math is necessary for grid layouts, pagers, and so on. Complex math
+  (anything other than arithmetic) should be done outside of templates.
+- Template functions only deal with the data passed into them. They never retrieve
+  data from a source.
+- Finally, do not override core Go template functions.