yq/path_parser.go

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2015-10-03 05:10:29 +00:00
package main
func parsePath(path string) []string {
return parsePathAccum([]string{}, path)
}
func parsePathAccum(paths []string, remaining string) []string {
head, tail := nextYamlPath(remaining)
if tail == "" {
return append(paths, head)
}
return parsePathAccum(append(paths, head), tail)
}
func nextYamlPath(path string) (pathElement string, remaining string) {
switch path[0] {
case '[':
// e.g [0].blah.cat -> we need to return "0" and "blah.cat"
return search(path[1:len(path)], []uint8{']'}, true)
case '"':
// e.g "a.b".blah.cat -> we need to return "a.b" and "blah.cat"
return search(path[1:len(path)], []uint8{'"'}, true)
default:
// e.g "a.blah.cat" -> return "a" and "blah.cat"
return search(path[0:len(path)], []uint8{'.', '['}, false)
}
}
func search(path string, matchingChars []uint8, skipNext bool) (pathElement string, remaining string) {
for i := 0; i < len(path); i++ {
var char = path[i]
if contains(matchingChars, char) {
var remainingStart = i + 1
if skipNext {
remainingStart = remainingStart + 1
} else if !skipNext && char != '.' {
remainingStart = i
}
if remainingStart > len(path) {
remainingStart = len(path)
}
return path[0:i], path[remainingStart:len(path)]
}
}
return path, ""
}
func contains(matchingChars []uint8, candidate uint8) bool {
for _, a := range matchingChars {
if a == candidate {
return true
}
}
return false
}