ANTLR 4. Programming Assignment #3

Transcription

1 ANTLR 4 Programming Assignment #3

2 C++ auto keyword C++03: variable s type must be specified explicitly Since C++11: definition of variable with an explicit initialization can use the auto keyword Type inference C++11 auto some_int = 5; C++03 int some_int = 5; 2

3 C++ auto keyword (cont d) Syntax auto variable initializer auto function (since C++11) (since C++14) Example auto.cpp #include <iostream> using namespace std; auto add(int a, int b) { return a + b; $ g++ std=c++14 o auto auto.cpp $./auto int main( ) { auto a = ; auto b = add(2, 3); cout<<a<<endl; cout<<b<<endl; return 0; 3

4 C++ auto keyword (cont d) Syntax auto variable initializer auto function (since C++11) (since C++14) Example auto.cpp #include <iostream> using namespace std; auto add(int a, int b) { return a + b; int main( ) { auto a = ; auto b = add(2, 3); cout<<a<<endl; cout<<b<<endl; return 0; $ g++ std=c++14 o auto auto.cpp $./auto

5 C auto keyword Storage class specifier auto, extern, static, register keyword auto are rarely used variable inside a function is automatic by default Not datatype int main( ) { auto int a; int main( ) { int a; 5

6 Compiler auto datatype Use gcc/g++ version 4.9 or higher auto.c #include <stdio.h> auto add(int a, int b) { return a + b; int main( ) { auto a = ; auto b = add(2, 3); printf( %f \n, a); printf( %d \n, b); return 0; $ gcc std=c11 auto.c auto.c: error or warning $ g++ std=c++14 auto.c $./a.out

7 PA#3 AutoC2CApp implement auto datatype C source-to-ansi C source compiler output is source code which uses ANSI C datatype (covers int, float, void, char) Based on the PA#2 (C2CApp) Use ANTLR Visitor (not Listener) 7

8 PA#3 (cont d) Make variable & function symbol table Implement type checking (type inference) Use static scoping int i; auto a; auto b; a = ; type checking var/func datatype i int a auto float b auto 8

9 PA#3 Listener (cont d) program function #include <stdio.h> void main( ) { auto g; auto A(int a) { g = 3 + a; g = 1; A(3); // g = 6 declaration function assignstmt callstmt DFS g = 1? assignstmt wrong type checking can cause enterprogram enterfunction enterdeclaration auto g; exitdeclaration auto g; enterfunction enterassignstmt g = 3 + a; exitassignstmt g = 3 + a; exitfunction enterassignstmt g = 1; exitassignstmt g = 1; entercallstmt exitcallstmt exitfunction exitprogram 9

10 PA#3 Visitor (cont d) program visitx( ) function #include <stdio.h> declaration function assignstmt callstmt void main( ) { auto g; auto A(int a) { g = 3 + a; g = 1; A(3); // g = 6 assignstmt can visit any node g = 6 visitprogram visitfunction visitdeclaration auto g; visitassignstmt g = 1; visitcallstmt visitfunction visitassignstmt g = 3 + a; 10

11 PA#3 (cont d) Input & Output auto.c #include <stdio.h> void main( ) { auto g; auto A(int a) { g = 3 + a; g = 1; A(3); gcc compile X output_auto.c #include <stdio.h> void main( ) { int g; void A(int a) { g = 3 + a; g = 1; A(3); gcc compile O 11

12 PA#3 AutoC grammar 12 grammar AutoC; (cont d) program : inclist? decllist? funclist? ; stmt : assignstmt callstmt retstmt whilestmt forstmt ifstmt switchstmt compoundstmt ; expr : Unop expr expr Unop expr expr Addiop expr expr Multop expr expr Relaop expr expr Eqltop expr call Intnum Floatnum Id Id '[' expr ']' '(' expr ')' StringLiteral ; Type : int float void char auto ; compoundstmt : { decllist? funclist? stmtlist ;...

13 PA#3 (cont d) Skeleton code AutoC2CApp.java class C2CVisitor extends CBaseVisitor<Integer> { Stack<StringBuilder> out = new Stack<StringBuilder>(); public Integer visitdirectivedefinition(@notnull CParser.DirectiveDefinitionContext ctx) { if(ctx.getparent() instanceof CParser.IncListContext) for (int i=0; i< ctx.getchildcount(); i++) out.peek().append(ctx.getchild(i).gettext()+"\n"); return public Integer visitfunction(@notnull CParser.FunctionContext ctx) { for (int i=0; i < ctx.getchildcount(); i++) if (ctx.getchild(i) instanceof TerminalNode) out.peek().append(ctx.getchild(i).gettext()+" "); return public Integer visitterminal(terminalnode node) { if(node.getparent().getparent().getparent() instanceof CParser.ProgramContext==false) out.peek().append(node.gettext()+'\n'); return null; public class AutoC2CApp { public static void main(string[] args) throws IOException { // Input file if (args.length!= 1){ System.err.println("Input C file"); System.exit(1); String filename = args[0]; System.setIn(new FileInputStream(filename)); InputStream input = System.in; // Get lexer CLexer lexer = new CLexer(new ANTLRInputStream(input)); // Get a list of matched tokens CommonTokenStream tokens = new CommonTokenStream(lexer); // Pass tokens to parser CParser parser = new CParser(tokens); // ParseTree ParseTree tree = parser.program(); // our visitor C2CVisitor visitor = new C2CVisitor(); // visit Cparser visitor.visit(tree); // Output file FileOutputStream output = new FileOutputStream(new File("output_"+args[0])); System.out.println("Output file name: output_"+args[0]); output.write(visitor.out.peek().tostring().getbytes()); output.flush(); output.close(); 13

14 Summary PA#3 auto datatype C source-to-ansi C source compiler use Visitor only implement your own type checking methods with static scoping output source code must be compiled by gcc due by 6 June All 3 PAs can be resubmitted until final exam(16 June) maximum 5 points resubmission via (sspark@arcs.skku.edu) 14