case ' ', '(', ')', '[', ']', '{', '}', ',':
		return false
	default:
		return !unicode.IsSpace(r) && unicode.IsPrint(r)
	}
}

// Comment assignment.
// We build two lists of all subexpressions, preorder and postorder.
// The preorder list is ordered by start location, with outer expressions first.
// The postorder list is ordered by end location, with outer expressions last.

	for i, lorig := range nl {
		l, r := lorig, nr[i]

		// Do not generate 'x = x' during return. See issue 4014.
		if op == ir.ORETURN && ir.SameSafeExpr(l, r) {
			continue
		}

		// Save subexpressions needed on left side.
		// Drill through non-dereferences.
		for {
			// If an expression has init statements, they must be evaluated
			// before any of its saved sub-operands (#45706).

//  - an additional conditional can be provided after the match pattern with "&&".
// on the generated side
//  - the type of the top-level expression is the same as the one on the left-hand side.
//  - the type of any subexpressions must be specified explicitly (or
//    be specified in the op's type field).
//  - auxint will be 0 if not specified.
//  - aux will be nil if not specified.

// blocks are specified using the following format:

	{"insert resched checks", "lower"},
	{"insert resched checks", "tighten"},

	// prove relies on common-subexpression elimination for maximum benefits.
	{"generic cse", "prove"},
	// deadcode after prove to eliminate all new dead blocks.
	{"prove", "generic deadcode"},
	// common-subexpression before dead-store elim, so that we recognize
	// when two address expressions are the same.
	{"generic cse", "dse"},

)

func f() int {
	d++
	return d
}
</pre>

<p>
the initialization order is <code>d</code>, <code>b</code>, <code>c</code>, <code>a</code>.
Note that the order of subexpressions in initialization expressions is irrelevant:
<code>a = c + b</code> and <code>a = b + c</code> result in the same initialization
order in this example.
</p>

<p>

)

func f() int {
	d++
	return d
}
</pre>

<p>
the initialization order is <code>d</code>, <code>b</code>, <code>c</code>, <code>a</code>.
Note that the order of subexpressions in initialization expressions is irrelevant:
<code>a = c + b</code> and <code>a = b + c</code> result in the same initialization
order in this example.
</p>

<p>