Function parseAtom

docopt.go:319–353

(tokens *tokenList, options *patternList)

}

func parseAtom(tokens *tokenList, options *patternList) (patternList, error) {
	// atom ::= '(' expr ')' | '[' expr ']' | 'options' | long | shorts | argument | command ;
	tok := tokens.current()
	result := patternList{}
	if tokens.current().match(false, "(", "[") {
		tokens.move()
		var matching string
		pl, err := parseExpr(tokens, options)
		if err != nil {
			return nil, err
		}
		if tok.eq("(") {
			matching = ")"
			result = patternList{newRequired(pl...)}
		} else if tok.eq("[") {
			matching = "]"
			result = patternList{newOptional(pl...)}
		}
		moved := tokens.move()
		if !moved.eq(matching) {
			return nil, tokens.errorFunc("unmatched '%s', expected: '%s' got: '%s'", tok, matching, moved)
		}
		return result, nil
	} else if tok.eq("options") {
		tokens.move()
		return patternList{newOptionsShortcut()}, nil
	} else if tok.hasPrefix("--") && !tok.eq("--") {
		return parseLong(tokens, options)
	} else if tok.hasPrefix("-") && !tok.eq("-") && !tok.eq("--") {
		return parseShorts(tokens, options)
	} else if tok.hasPrefix("<") && tok.hasSuffix(">") || tok.isUpper() {
		return patternList{newArgument(tokens.move().String(), nil)}, nil
	}
	return patternList{newCommand(tokens.move().String(), false)}, nil
}

func parseLong(tokens *tokenList, options *patternList) (patternList, error) {
	// long ::= '--' chars [ ( ' ' | '=' ) chars ] ;