}
		st.advance(1)
	}
}

// An operator is the demangled name, and the number of arguments it
// takes in an expression.
type operator struct {
	name string
	args int
	prec precedence
}

// The operators map maps the mangled operator names to information
// about them.
var operators = map[string]operator{
	"aN": {"&=", 2, precAssign},
	"aS": {"=", 2, precAssign},

}

// Operator is an operator.
type Operator struct {
	Name       string
	precedence precedence
}

func (op *Operator) print(ps *printState) {
	ps.writeString("operator")
	if isLower(op.Name[0]) {
		ps.writeByte(' ')
	}
	n := op.Name
	n = strings.TrimSuffix(n, " ")
	ps.writeString(n)
}

func (op *Operator) Traverse(fn func(AST) bool) {
	fn(op)

func (check *Checker) op(m opPredicates, x *operand, op syntax.Operator) bool {
	if pred := m[op]; pred != nil {
		if !pred(x.typ) {
			check.errorf(x, UndefinedOp, invalidOp+"operator %s not defined on %s", op, x)
			return false
		}
	} else {
		check.errorf(x, InvalidSyntaxTree, "unknown operator %s", op)
		return false
	}
	return true
}

// opPos returns the position of the operator if x is an operation;

abi.RF_EXHAUSTED = 3 // iterator function call, e.g. f(func(x t){...}), returned so the sequence is "exhausted".

abi.RF_MISSING_PANIC = 4 // used to report errors.

The value of #stateK transitions
(1) before calling the iterator function,

	var #stateN = abi.RF_READY

(2) after the iterator function call returns,

	if #stateN == abi.RF_PANIC {

Multiplication operators bind strongest, followed by addition
operators, comparison operators, <code>&amp;&amp;</code> (logical AND),
and finally <code>||</code> (logical OR):
</p>

<pre class="grammar">
Precedence    Operator
    5             *  /  %  &lt;&lt;  &gt;&gt;  &amp;  &amp;^
    4             +  -  |  ^
    3             ==  !=  &lt;  &lt;=  &gt;  &gt;=

	switch p.tok {
	case _Lbrace:
		return p.blockStmt("")

	case _Operator, _Star:
		switch p.op {
		case Add, Sub, Mul, And, Xor, Not:
			return p.simpleStmt(nil, 0) // unary operators
		}

	case _Literal, _Func, _Lparen, // operands
		_Lbrack, _Struct, _Map, _Chan, _Interface, // composite types
		_Arrow: // receive operator
		return p.simpleStmt(nil, 0)

	case _For:
		return p.forStmt()

know the location of every pointer to Go memory. Because of this,
there are restrictions on passing pointers between Go and C.

In this section the term Go pointer means a pointer to memory
allocated by Go (such as by using the & operator or calling the
predefined new function) and the term C pointer means a pointer to
memory allocated by C (such as by a call to C.malloc). Whether a
pointer is a Go pointer or a C pointer is a dynamic property

- [All](/pkg/slices#All) returns an iterator over slice indexes and values.
- [Values](/pkg/slices#Values) returns an iterator over slice elements.
- [Backward](/pkg/slices#Backward) returns an iterator that loops over
  a slice backward.
- [Collect](/pkg/slices#Collect) collects values from an iterator into
  a new slice.
- [AppendSeq](/pkg/slices#AppendSeq) appends values from an iterator to
  an existing slice.

The "range" clause in a "for-range" loop now accepts iterator functions of the following types

	func(func() bool)
	func(func(K) bool)
	func(func(K, V) bool)

as range expressions.
Calls of the iterator argument function produce the iteration values for the "for-range" loop.
For details see the [language spec](/ref/spec#For_statements).

		return typ

	case *syntax.MapType:
		typ := new(Map)
		setDefType(def, typ)

		typ.key = check.varType(e.Key)
		typ.elem = check.varType(e.Value)

		// spec: "The comparison operators == and != must be fully defined
		// for operands of the key type; thus the key type must not be a
		// function, map, or slice."
		//
		// Delay this check because it requires fully setup types;