gobuffalo/velvet

package velvet

// Context holds all of the data for the template that is being rendered.
type Context struct {
    data    map[string]interface{}
    options map[string]interface{}
    outer   *Context
}

func (c *Context) export() map[string]interface{} {
    m := map[string]interface{}{}
    if c.outer != nil {
        for k, v := range c.outer.export() {
            m[k] = v
        }
    }
    for k, v := range c.data {
        m[k] = v
    }
    if c.options != nil {
        for k, v := range c.options {
            m[k] = v
        }
    }

    return m
}

// 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.
func (c *Context) New() *Context {
    cc := NewContext()
    cc.outer = c
    return cc
}

// Set a value onto the context
func (c *Context) Set(key string, value interface{}) {
    c.data[key] = value
}

// Get a value from the context, or it's parent's context if one exists.
func (c *Context) Get(key string) interface{} {
    if v, ok := c.data[key]; ok {
        return v
    }
    if c.outer != nil {
        return c.outer.Get(key)
    }
    return nil
}

// Has checks the existence of the key in the context.
func (c *Context) Has(key string) bool {
    return c.Get(key) != nil
}

// Options are the values passed into a helper.
func (c *Context) Options() map[string]interface{} {
    return c.options
}

// NewContext returns a fully formed context ready to go
func NewContext() *Context {
    return &Context{
        data:    map[string]interface{}{},
        options: map[string]interface{}{},
        outer:   nil,
    }
}

// NewContextWith returns a fully formed context using the data
// provided.
func NewContextWith(data map[string]interface{}) *Context {
    c := NewContext()
    c.data = data
    return c
}