1. A method, comprising: implementing a function not present in a compiler for a first language-using a compiler for a second language, the implementing further comprising: generating, by the compiler for the first language, a first abstract syntax tree; converting the first abstract syntax tree to a second abstract syntax tree of the compiler for the second language using a conversion table; when a compilation error occurs in the compiler for the second language, generating therein a special node for error processing in the second abstract syntax tree and storing an error token indicating information of the compilation error in the special node; and when unparsing by the compiler for the second language, outputting the error token stored in the special node.