Add try catch mechanism (#13)

* Add try, catch, finally in the syntax

* Add throw, try, catch, finally mechanism in the interpreter

parse.leg

@@ -18,7 +18,7 @@
     _DO(PreDecVariable) _DO(PreDecMember) _DO(PreDecIndex)                                                      \
     _DO(PostDecVariable) _DO(PostDecMember) _DO(PostDecIndex)                                                   \
     _DO(GetVariable) _DO(GetMember) _DO(SetMember) _DO(GetIndex) _DO(SetIndex)                                  \
-    _DO(Return) _DO(Break) _DO(Continue) _DO(Throw)                                                             \
+    _DO(Return) _DO(Break) _DO(Continue) _DO(Throw) _DO(Try)                                                    \
     _DO(Quasiquote) _DO(Unquote)
 
 typedef enum {
@@ -73,7 +73,9 @@ oop globals= 0;
      DO_PROTOS() _DO(__proto__) _DO(__name__) _DO(__default__) _DO(__arguments__)                               \
     _DO(name) _DO(body) _DO(param) _DO(key) _DO(value) _DO(condition) _DO(consequent) _DO(alternate)            \
     _DO(lhs) _DO(rhs) _DO(scope) _DO(args) _DO(expression) _DO(labels) _DO(statements) _DO(initialise)          \
-    _DO(update) _DO(this) _DO(fixed) _DO(operator) _DO(map) _DO(func) _DO(__line__) _DO(__file__)
+    _DO(update) _DO(this) _DO(fixed) _DO(operator) _DO(map) _DO(func)                                           \
+    _DO(try) _DO(catch) _DO(finally) _DO(exception)                                                             \
+    _DO(__line__) _DO(__file__)
 
 #define _DO(NAME) oop NAME##_symbol;
 DO_SYMBOLS()
@@ -544,6 +546,16 @@ oop newContinue(void)
     return obj;
 }
 
+oop newTry(oop try, oop exception, oop catch, oop finally)
+{
+    oop obj = newObject(Try_proto);
+    map_set(obj, try_symbol, try);
+    map_set(obj, exception_symbol, exception);
+    map_set(obj, catch_symbol, catch);
+    map_set(obj, finally_symbol, finally);
+    return obj;
+}
+
 oop fold(oop ast);
 
 #define YY_INPUT(buf, result, max_size)        \
@@ -608,6 +620,7 @@ exp     =   VAR l:ident                        ASSIGN e:exp  { $$ = newDeclarati
         |   BREAK                                            { $$ = newBreak() }
         |   CONTINUE                                         { $$ = newContinue() }
         |   THROW                                    e:exp   { $$ = newUnary(Throw_proto, e) }
+        |   t:try                                            { $$ = t }
         |   l:IDENT                       o:assignOp e:exp   { $$ = newAssign(Assign_proto,    l,    o, e) }
         |   l:postfix DOT   i:IDENT       o:assignOp e:exp   { $$ = newSetMap(SetMember_proto, l, i, o, e) }
         |   l:postfix LBRAC i:exp   RBRAC o:assignOp e:exp   { $$ = newSetMap(SetIndex_proto,  l, i, o, e) }
@@ -620,6 +633,12 @@ ident   =   l:IDENT                                          { $$ = l }
 syntax2  = < [a-zA-Z_][a-zA-Z0-9_]* >
            &{ null != getSyntaxId(2, intern(yytext)) }   -   { $$ = getSyntaxId(2, intern(yytext)) }
 
+try     =   TRY                           t:stmt              i:null c:null f:null
+            ( CATCH LPAREN i:IDENT RPAREN c:stmt ) ?
+            ( FINALLY                     f:stmt ) ?         { $$ = newTry(t, i, c, f) }
+
+null    =                                                    { $$ = null }
+
 assignOp = ASSIGN                 { $$= null }
          | ASSIGNADD              { $$= Add_symbol }
          | ASSIGNSUB              { $$= Sub_symbol }
@@ -769,7 +788,8 @@ eol     =  ( "\n""\r"*
 comment =  "//"  ( ![\n\r] . )*
         |  "/*"  ( !"*/"   . )* "*/"
 
-keyword = FUN | SYNTAX | VAR | SWITCH | CASE | DEFAULT | DO | FOR | WHILE | IF | ELSE | NULL | RETURN | BREAK | CONTINUE | THROW
+keyword = FUN | SYNTAX | VAR | SWITCH | CASE | DEFAULT | DO | FOR | WHILE | IF | ELSE | NULL | RETURN | BREAK | CONTINUE
+        | THROW | TRY | CATCH | FINALLY
 
 IDENT   =    !keyword < [a-zA-Z_][a-zA-Z0-9_]* >   -   { $$ = intern(yytext) }
 
@@ -795,6 +815,9 @@ RETURN  =    'return'   ![a-zA-Z0-9_] -
 BREAK   =    'break'    ![a-zA-Z0-9_] -
 CONTINUE =   'continue' ![a-zA-Z0-9_] -
 THROW   =    'throw'    ![a-zA-Z0-9_] -
+TRY     =    'try'      ![a-zA-Z0-9_] -
+CATCH   =    'catch'    ![a-zA-Z0-9_] -
+FINALLY =    'finally'  ![a-zA-Z0-9_] -
 IMPORT  =    'import'   ![a-zA-Z0-9_] -
 HASH    =    '#'                      -
 LOGOR   =    '||'                     -
@@ -1383,6 +1406,62 @@ oop eval(oop scope, oop ast)
         jbs->result = eval(scope, map_get(ast, rhs_symbol));
         siglongjmp(jbs->jb, j_throw);
     }
+    case t_Try: {
+        oop try = map_get(ast, try_symbol);
+        oop exception = map_get(ast, exception_symbol);
+        oop catch = map_get(ast, catch_symbol);
+        oop finally = map_get(ast, finally_symbol);
+
+        jbRecPush();
+        int jbt = sigsetjmp(jbs->jb, 0);
+        switch (jbt) {
+            case j_return: {
+                runtimeError(ast, "return outside of a function");
+            }
+            case j_break: {
+                runtimeError(ast, "break outside of a loop or switch");
+            }
+            case j_continue: {
+                runtimeError(ast, "continue outside of a loop");
+            }
+            case j_throw: {
+                oop e= jbs->result;
+                jbRecPop();
+                jbs->result= e;
+                // that should only be set in the catch local scope
+                setVariable(scope, exception, e);
+                jbRecPush();
+                jbt = sigsetjmp(jbs->jb, 0);
+                switch (jbt) {
+                    case j_return: {
+                        runtimeError(ast, "return outside of a function");
+                    }
+                    case j_break: {
+                        runtimeError(ast, "break outside of a loop or switch");
+                    }
+                    case j_continue: {
+                        runtimeError(ast, "continue outside of a loop");
+                    }
+                    case j_throw: {
+                        // transfer exception
+                        oop e= jbs->result;
+                        jbRecPop();
+                        jbs->result= e;
+
+                        eval(scope, finally);
+                        siglongjmp(jbs->jb, j_throw);
+                    }
+                }
+                oop catchRes= eval(scope, catch);
+                eval(scope, finally);
+                jbRecPop();
+                return catchRes;
+            }
+        }
+        oop res = eval(scope, try);
+        jbRecPop();
+        return res;
+    }
     case t_Block: {
         oop statements = map_get(ast, statements_symbol);
         int i = 0;
@@ -1766,6 +1845,13 @@ oop prim_print(oop params)
     return params;
 }
 
+oop prim_println(oop params)
+{
+    oop res= prim_print(params);
+    printf("\n");
+    return res;
+}
+
 oop evalArgs(oop scope, oop args)
 {
    int i = 0;
@@ -1788,7 +1874,7 @@ void readEvalPrint(char *fileName) {
 
     if (0 == jbt) {
         while (inputStack && yyparse()) {
-            if (opt_v > 1) printf("%s:%i: ", inputStack->name, inputStack->lineNumber);
+            if (opt_v > 1) printf("%s:%i: ", get(inputStack->name, String, value), inputStack->lineNumber);
             if (!yylval) {
                 fclose(inputStack->file);
                 inputStackPop();
@@ -1854,16 +1940,17 @@ int main(int argc, char **argv)
     symbol_table= makeMap();
     globals= makeMap();
 
-    map_set(globals, intern("exit")  , makeFunction(prim_exit,   intern("exit"),   null, null, globals, null));
-    map_set(globals, intern("keys")  , makeFunction(prim_keys,   intern("keys"),   null, null, globals, null));
-    map_set(globals, intern("values"), makeFunction(prim_values, intern("values"), null, null, globals, null));
-    map_set(globals, intern("length"), makeFunction(prim_length, intern("length"), null, null, globals, null));
-    map_set(globals, intern("print") , makeFunction(prim_print,  intern("print"),  null, null, globals, null));
-    map_set(globals, intern("invoke"), makeFunction(prim_invoke, intern("invoke"), null, null, globals, null));
-    map_set(globals, intern("apply") , makeFunction(prim_apply,  intern("apply"),  null, null, globals, null));
-    map_set(globals, intern("clone") , makeFunction(prim_clone,  intern("clone"),  null, null, globals, null));
-    map_set(globals, intern("import"), makeFunction(prim_import, intern("import"), null, null, globals, null));
-    map_set(globals, intern("millis"), makeFunction(prim_millis, intern("millis"), null, null, globals, null));
+    map_set(globals, intern("exit")   , makeFunction(prim_exit,    intern("exit"),    null, null, globals, null));
+    map_set(globals, intern("keys")   , makeFunction(prim_keys,    intern("keys"),    null, null, globals, null));
+    map_set(globals, intern("values") , makeFunction(prim_values,  intern("values"),  null, null, globals, null));
+    map_set(globals, intern("length") , makeFunction(prim_length,  intern("length"),  null, null, globals, null));
+    map_set(globals, intern("print")  , makeFunction(prim_print,   intern("print"),   null, null, globals, null));
+    map_set(globals, intern("println"), makeFunction(prim_println, intern("println"), null, null, globals, null));
+    map_set(globals, intern("invoke") , makeFunction(prim_invoke,  intern("invoke"),  null, null, globals, null));
+    map_set(globals, intern("apply")  , makeFunction(prim_apply,   intern("apply"),   null, null, globals, null));
+    map_set(globals, intern("clone")  , makeFunction(prim_clone,   intern("clone"),   null, null, globals, null));
+    map_set(globals, intern("import") , makeFunction(prim_import,  intern("import"),  null, null, globals, null));
+    map_set(globals, intern("millis") , makeFunction(prim_millis,  intern("millis"),  null, null, globals, null));
 
     #define _DO(NAME) NAME##_symbol=intern(#NAME);
     DO_SYMBOLS()

test-try-catch.txt

@@ -0,0 +1,18 @@
+try {
+    try {
+        println("hello")
+        throw "ERROR 12";
+        println("that should not be executed");
+    } catch (e) {
+        println("catch!")
+        println("inner: ", e)
+        throw "pizza"
+        print("after pizza")
+    } finally {
+        println("finally...")
+        throw "oh no"
+        println("after oh no")
+    }
+} catch (e) {
+    println("outer: ", e);
+}