Method expandMacro

parser/parser.go:959–991

(exprID int64, function string, target ast.Expr, args ...ast.Expr)

}

func (p *parser) expandMacro(exprID int64, function string, target ast.Expr, args ...ast.Expr) (ast.Expr, bool) {
	macro, found := p.macros[makeMacroKey(function, len(args), target != nil)]
	if !found {
		macro, found = p.macros[makeVarArgMacroKey(function, target != nil)]
		if !found {
			return nil, false
		}
	}
	eh := exprHelperPool.Get().(*exprHelper)
	defer exprHelperPool.Put(eh)
	eh.parserHelper = p.helper
	eh.id = exprID
	expr, err := macro.Expander()(eh, target, args)
	// An error indicates that the macro was matched, but the arguments were not well-formed.
	if err != nil {
		loc := err.Location
		if loc == nil {
			loc = p.helper.getLocation(exprID)
		}
		p.helper.deleteID(exprID)
		return p.reportError(loc, "%s", err.Message), true
	}
	// A nil value from the macro indicates that the macro implementation decided that
	// an expansion should not be performed.
	if expr == nil {
		return nil, false
	}
	if p.populateMacroCalls {
		p.helper.addMacroCall(expr.ID(), function, target, args...)
	}
	p.helper.deleteID(exprID)
	return expr, true
}

func (p *parser) checkAndIncrementRecursionDepth() {
	p.recursionDepth++