func extractVars()

in internal/pkg/agent/transpiler/vars.go [233:297]

• 61 lines of code
• 22 McCabe index (conditional complexity)

func extractVars(i string, defaultProvider string) ([]varI, error) {
	const out = rune(0)

	quote := out
	constant := false
	escape := false
	is := make([]rune, 0, len(i))
	res := make([]varI, 0)
	for _, r := range i {
		if r == '|' {
			if escape {
				return nil, fmt.Errorf(`variable pipe cannot be escaped; remove \ before |`)
			}
			if quote == out {
				if constant {
					res = append(res, &constString{string(is)})
				} else if len(is) > 0 {
					if is[len(is)-1] == '.' {
						return nil, fmt.Errorf("variable cannot end with '.'")
					}
					res = append(res, &varString{maybeAddDefaultProvider(string(is), defaultProvider)})
				}
				is = is[:0] // slice to zero length; to keep allocated memory
				constant = false
			} else {
				is = append(is, r)
			}
			continue
		}
		if !escape && (r == '"' || r == '\'') {
			if quote == out {
				// start of unescaped quote
				quote = r
				constant = true
			} else if quote == r {
				// end of unescaped quote
				quote = out
			} else {
				is = append(is, r)
			}
			continue
		}
		// escape because of backslash (\); except when it is the second backslash of a pair
		escape = !escape && r == '\\'
		if r == '\\' {
			if !escape {
				is = append(is, r)
			}
		} else if quote != out || !unicode.IsSpace(r) {
			is = append(is, r)
		}
	}
	if quote != out {
		return nil, fmt.Errorf(`starting %s is missing ending %s`, string(quote), string(quote))
	}
	if constant {
		res = append(res, &constString{string(is)})
	} else if len(is) > 0 {
		if is[len(is)-1] == '.' {
			return nil, fmt.Errorf("variable cannot end with '.'")
		}
		res = append(res, &varString{maybeAddDefaultProvider(string(is), defaultProvider)})
	}
	return res, nil
}