The action taken by the assembler when it replaces a variable symbol with a value , for example , during the expansion of a macro definition.
汇编程序采用的一种动作，例如在宏定义展开时，它用一个值来代替一个变量符号。
3
The exploitation and consumption of tour souvenir constitutes a symbol communication system, which is closely related with designer, producer, merchant, consumer macro-economic policy and so on.