}

// SubexpIndex returns the index of the first subexpression with the given name,
// or -1 if there is no subexpression with that name.
//
// Note that multiple subexpressions can be written using the same name, as in
// (?P<bob>a+)(?P<bob>b+), which declares two subexpressions named "bob".
// In this case, SubexpIndex returns the index of the leftmost such subexpression
// in the regular expression.

//
// The blocks of the CFG contain all the function's non-control
// statements.  The CFG does not contain control statements such as If,
// Switch, Select, and Branch, but does contain their subexpressions;
// also, each block records the control statement (Block.Stmt) that
// gave rise to it and its relationship (Block.Kind) to that statement.
//
// For example, this source code:
//
//	if x := f(); x != nil {

	}
	(*flags)[start] = f
	(*flags)[last] |= flagOff // maybe start==last
}

// calcFlags calculates the flags to print around each subexpression in re,
// storing that information in (*flags)[sub] for each affected subexpression.
// The first time an entry needs to be written to *flags, calcFlags allocates the map.
// calcFlags also calculates the flags that must be active or can't be active

	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.

		//     u	standard unspecified behavior -- errors not counted
		//     v	REG_CLASS_ESCAPE	\ special inside [...]
		//     w	REG_NOSUB		no subexpression match array
		//     x	REG_LENIENT		let some errors slide
		//     y	REG_LEFT		regexec() implicit ^...
		//     z	REG_NULL		NULL subexpressions ok
		//     $	                        expand C \c escapes in fields 2 and 3
		//     /	                        field 2 is a regsubcomp() expression

	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).

		strflags = iflags
	}
	sub = out

	// Round 2: Factor out common simple prefixes,
	// just the first piece of each concatenation.
	// This will be good enough a lot of the time.
	//
	// Complex subexpressions (e.g. involving quantifiers)
	// are not safe to factor because that collapses their
	// distinct paths through the automaton, which affects
	// correctness in some cases.
	start = 0
	out = sub[:0]

//  - 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"},

// or a function call.
type PrimaryTerm struct {
	Value         *LitValue   `parser:"  @@"`
	JPathExpr     *JSONPath   `parser:"| @@"`
	ListExpr      *ListExpr   `parser:"| @@"`
	SubExpression *Expression `parser:"| \"(\" @@ \")\""`
	// Include function expressions here.
	FuncCall *FuncExpr `parser:"| @@"`
}

// FuncExpr represents a function call
type FuncExpr struct {