Java代写代考

grammar ArithLang; // Grammar of this Programming Language // – grammar rules start with lowercase program returns [Program ast] : e=exp { $ast = new Program($e.ast); } ; exp returns [Exp ast]: n=numexp { $ast = $n.ast; } | a=addexp { $ast = $a.ast; } | s=subexp { $ast = $s.ast; } | m=multexp {

package typelang; import org.antlr.v4.runtime.Lexer; import typelang.AST.*; import typelang.parser.*; import java.io.BufferedReader; import java.io.FileReader; import java.io.IOException; import java.io.InputStreamReader; public class Reader { public Program read() throws IOException { String programText = readNextProgram(getProgramDirectory()); return parse(programText); } public Program parse(String programText) { Lexer l = getLexer(new org.antlr.v4.runtime.ANTLRInputStream(programText)); TypeLangParser p = getParser(new org.antlr.v4.runtime.CommonTokenStream(l)); Program program = p.program().ast; return program; }