templating.ps1

$map = @{
    color  = 'red'
    person = @{
        firstname = 'Bob'
        lastname  = 'Smith'
    }
    gender = 'his'
}

$template = @'
This a block of text. Here is a color {{ color }}.
{{ person.firstname }} {{ person.lastname }} should be able to read this with {{ gender }} name in it.
'@

[regex]::Replace($template, '\{{\s*(\S+)\s*\}}', {
    param($s)

    foreach ($i in $s.Groups[1].Value.Split('.')) {
        $map = $map[$i]
    }
    $map
})