`where` template function's internal condition check function doesn't
check boolean values and always returns `false` silently.
This adds missing boolean value comparison to the function.
`where Values ".Param.key" true` like clause can be used.
Only "=", "==", "eq", "!=", "<>", "ne" operators are allowed to be used
with a boolean value. If an other operator is passed with it, the
condition check function returns `false` like before.
'sort' template function used to accept only each element's struct field
name, method name and map key name as its second argument. This extends
it to accept a field/method/key chaining key string like
'Params.foo.bar' as the argument. It evaluates sub elements of each
array or map elements and sorts by them.
Typical use case would be sorting pages by user defined front matter
value. For example, sorting pages by 'Params.foo.bar' is possible by
writing the following template code
{{ range sort .Data.Pages "Params.foo.bar" }}
{{ .Content }}
{{ end }}
It ignores all leading and trailing dots so "Params.foo.bar" can be
written in ".Params.foo.bar"
This also fixes the issue that 'sort' cannot evaluate a pointer value.
Fix#1330
sort template function returns `[]interface{}` type slice value
regardless of its original element type.
This fixes it to keep the original element type. For example, if it
sorts `map[string]int` type value, it returns `[]int` slice value
instead of `[]interface{}` slice value.
`where` template function's internal condition check function always
returns `false` when a target value doesn't exist or it's nil value but
this behavior makes it difficult to filter values which doesn't have a
particular parameter.
To solve it, this adds nil value comparison to the function.
`where Values ".Param.key" nil` like clause can be used for the case
above.
Only "=", "==", "eq", "!=", "<>", "ne" operators are allowed to be used
with `nil`. If an other operator is passed with `nil`, the condition
check function returns `false` like before.
Fix#1232
