bug: high memory usage when calling compile()

[Mido-sys]

Description

Description

We noticed high memory usage for this function under compiler.go: due to converting bytes to string.

func (c *compiler) compile() (string, error) {
	bb := &bytes.Buffer{}

	for _, stmt := range c.program.Statements {
		var res interface{}
		var err error

		switch node := stmt.(type) {
		case *ast.ReturnStatement:
			res, err = c.evalReturnStatement(node)

		case *ast.ExpressionStatement:
			if h, ok := node.Expression.(*ast.HTMLLiteral); ok {
				res = template.HTML(h.Value)
			} else {
				_, err = c.evalExpression(node.Expression)
			}
		case *ast.LetStatement:
			res, err = c.evalLetStatement(node)
		}

		if err != nil {
			s := stmt
			if c.curStmt != nil {
				s = c.curStmt
			}
			return "", fmt.Errorf("line %d: %w", s.T().LineNumber, err)
		}

		c.write(bb, res)
	}

	return bb.String(), nil
}

The bytes.Buffer to string conversion requires memory allocation. A better solution is to drop bytes.Buffer and just use strings.Builder instead. strings.Builder uses a more optimized code to convert to string

[Mido-sys]

Hello @paganotoni , I pushed a fix.