stop eval in a switch statement from confusing parsing (Fix #845)

ChangeLog

@@ -29,6 +29,7 @@
             Fix negative Date to string code (fix #854)
             Convert type warnings to exceptions (to provide stack traces for problems)
             Add uncaughtException event (fix #846)
+            Stop eval in a switch statement from confusing parsing (Fix #845)
 
      1v85 : Ensure HttpServerResponse.writeHead actually sends the header right away
              - enables WebSocket Server support from JS

src/jsparse.c

@@ -2499,7 +2499,8 @@ JsVar *jspEvaluateVar(JsVar *str, JsVar *scope, uint16_t lineNumberOffset) {
   jslSetLex(oldLex);
 
   // restore state and execInfo
-  oldExecInfo.execute = execInfo.execute; // JSP_RESTORE_EXECUTE has made this ok.
+  JsExecFlags mask = EXEC_FOR_INIT|EXEC_IN_LOOP|EXEC_IN_SWITCH;
+  oldExecInfo.execute = (oldExecInfo.execute & mask) | (execInfo.execute & ~mask); 
   execInfo = oldExecInfo;
 
   // It may have returned a reference, but we just want the value...

src/jsparse.h

@@ -77,8 +77,8 @@ JsVar *jspGetPrototypeOwner(JsVar *proto);
 typedef enum  {
   EXEC_NO = 0,
   EXEC_YES = 1,
-  EXEC_BREAK = 2,
-  EXEC_CONTINUE = 4,
+  EXEC_BREAK = 2,     // Have we had a 'break' keyword (so should skip to end of loop and exit)
+  EXEC_CONTINUE = 4,  // Have we had a 'continue' keywrord (so should skip to end of loop and restart)
 
   EXEC_INTERRUPTED = 8, // true if execution has been interrupted
   EXEC_EXCEPTION = 16, // we had an exception, so don't execute until we hit a try/catch block

tests/test_eval_switch.js

@@ -0,0 +1,16 @@
+// https://github.com/espruino/Espruino/issues/845
+
+function test(){
+ switch ("a"){
+  case "a":
+   eval(1);
+   break;
+ }
+}
+
+try {
+  test();
+  result = 1;
+} catch (e) {
+  result = 0;
+}