all non-<a href="#Blank_identifier">blank</a> names in the signature
must be <a href="#Uniqueness_of_identifiers">unique</a>.
If absent, each type stands for one item of that type.
Parameter and result
lists are always parenthesized except that if there is exactly
one unnamed result it may be written as an unparenthesized type.
</p>

<p>
The final incoming parameter in a function signature may have

			case token.TYPE:
				// types are handled individually
				if len(d.Specs) == 1 && !d.Lparen.IsValid() {
					// common case: single declaration w/o parentheses
					// (if a single declaration is parenthesized,
					// create a new fake declaration below, so that
					// go/doc type declarations always appear w/o
					// parentheses)
					if s, ok := d.Specs[0].(*ast.TypeSpec); ok {
						r.readType(d, s)
					}

	case *syntax.ExprStmt:
		// spec: "With the exception of specific built-in functions,
		// function and method calls and receive operations can appear
		// in statement context. Such statements may be parenthesized."
		var x operand
		kind := check.rawExpr(nil, &x, s.X, nil, false)
		var msg string
		var code Code
		switch x.mode {
		default:
			if kind == statement {
				return
			}

	case *ast.ExprStmt:
		// spec: "With the exception of specific built-in functions,
		// function and method calls and receive operations can appear
		// in statement context. Such statements may be parenthesized."
		var x operand
		kind := check.rawExpr(nil, &x, s.X, nil, false)
		var msg string
		var code Code
		switch x.mode {
		default:
			if kind == statement {
				return
			}

	// This test checks nextStdChunk's behavior directly,
	// instead of needing to test it only indirectly through Parse/Format.

	// markChunks returns format with each detected
	// 'format chunk' parenthesized.
	// For example showChunks("2006-01-02") == "(2006)-(01)-(02)".
	markChunks := func(format string) string {
		// Note that NextStdChunk and StdChunkNames
		// are not part of time's public API.

 * side, this yields nine basic types of ranges, enumerated below. (Notation: a square bracket
 * ({@code [ ]}) indicates that the range is closed on that side; a parenthesis ({@code ( )}) means
 * it is either open or unbounded. The construct {@code {x | statement}} is read "the set of all
 * <i>x</i> such that <i>statement</i>.")
 *
 * <blockquote>
 *
 * <table>

 * side, this yields nine basic types of ranges, enumerated below. (Notation: a square bracket
 * ({@code [ ]}) indicates that the range is closed on that side; a parenthesis ({@code ( )}) means
 * it is either open or unbounded. The construct {@code {x | statement}} is read "the set of all
 * <i>x</i> such that <i>statement</i>.")
 *
 * <blockquote>
 *
 * <table>

		// digits?
		for s.accept(decimalDigits + "_") {
		}
	}
	return string(s.buf)
}

// complexTokens returns the real and imaginary parts of the complex number starting here.
// The number might be parenthesized and has the format (N+Ni) where N is a floating-point
// number and there are no spaces within.
func (s *ss) complexTokens() (real, imag string) {
	// TODO: accept N and Ni independently?
	parens := s.accept("(")

	case *parse.ChainNode:
		return s.evalChainNode(dot, n, cmd.Args, final)
	case *parse.IdentifierNode:
		// Must be a function.
		return s.evalFunction(dot, n, cmd, cmd.Args, final)
	case *parse.PipeNode:
		// Parenthesized pipeline. The arguments are all inside the pipeline; final must be absent.
		s.notAFunction(cmd.Args, final)
		return s.evalPipeline(dot, n)
	case *parse.VariableNode:
		return s.evalVariableNode(dot, n, cmd.Args, final)

	"az": {"alignof ", 1, precUnary},
	"cc": {"const_cast", 2, precPostfix},
	"cl": {"()", 2, precPostfix},
	// cp is not in the ABI but is used by clang "when the call
	// would use ADL except for being parenthesized."
	"cp": {"()", 2, precPostfix},
	"cm": {",", 2, precComma},
	"co": {"~", 1, precUnary},
	"dV": {"/=", 2, precAssign},
	"dX": {"[...]=", 3, precAssign},
	"da": {"delete[] ", 1, precUnary},