Fixed issue 19 - incorrect method declarations for listener.

Author: johnholliday

package-lock.json

@@ -53,8 +53,8 @@
     "@types/commander": "^2.12.2",
     "@types/ejs": "^2.6.0",
     "@types/lodash": "^4.14.116",
-    "@types/node": "^10.7.1",
+    "@types/node": "^10.11.3",
     "tslint": "^5.11.0",
-    "typescript": "^3.0.1"
+    "typescript": "^3.1.1"
   }
 }

package.json

@@ -37,14 +37,18 @@ export class AntlrCompiler {
         return dest;
     }
 
+    capitalize = (s: string) => {
+        return s.charAt(0).toUpperCase() + s.slice(1);
+    }
+
     compileTypeScriptListener(grammar: string, parser: any) {
         const className = `${grammar}Listener`;
         const dest = `${this.outputDirectory}/${className}.d.ts`;
         const template = fs.readFileSync(`${__dirname}/templates/listener.d.ts.ejs`).toString();
         const map = parserUtil.ruleToContextTypeMap(parser);
 
         const methods = _.flatten(_.map(parser.ruleNames, (rule) => {
-            return [`${rule}Enter(ctx: ${map.get(rule)}): void;`, `${rule}Exit(ctx: ${map.get(rule)}): void;`];
+            return [`enter${this.capitalize(rule)}(ctx: ${map.get(rule)}): void;`, `exit${this.capitalize(rule)}(ctx: ${map.get(rule)}): void;`];
         }));
 
         const imports = _.flatten(_.map(parser.ruleNames, (rule) => {