Add location reporting to compiler errors

package.json

@@ -1,6 +1,6 @@
 {
   "name": "loot-ml",
-  "version": "0.0.7",
+  "version": "0.0.8",
   "description": "A language for creating loot tables",
   "main": "index.js",
   "author": "Rob Grindeland",

src/Compiler.ts

@@ -92,7 +92,7 @@ class Compiler {
                     this.compileSelector(obj as SelectorObject);
                     break;
                 default:
-                    throw new Error(`Invalid parser object type ${obj.type}`);
+                    this.compileError(`Invalid parser object type ${obj.type}`, obj.location);
             }
         }
 
@@ -163,7 +163,7 @@ class Compiler {
                 weights
             },
             (err: string) => {
-                throw new Error(err);
+                throw this.compileError(`${sel.identifier}: ${err}`, selector.location);
             }
         );
 
@@ -206,6 +206,20 @@ class Compiler {
     public buildRepeater(fn: string, count: string): string {
         return `()=>((i,n,o)=>{for(;i<n;i++)o.push((${fn})());return o})(0,${count},[])`;
     }
+
+    /**
+     * Throws a compile error
+     * @param message Error message
+     * @param location Error location
+     */
+    public compileError(message: string, location: { line: number; column: number } | null) {
+        if (location) {
+            const { line, column } = location;
+            throw new Error(`${message} (at ${line}:${column})`);
+        } else {
+            throw new Error(message);
+        }
+    }
 }
 
 export default Compiler;

src/Parser.ts

@@ -208,7 +208,7 @@ class Parser {
         }
 
         if (!this._aliasObjects.hasOwnProperty(token.value)) {
-            this._aliasObjects[token.value] = new AliasObject(token.value, alias!);
+            this._aliasObjects[token.value] = new AliasObject(token.value, alias!, token.location);
         }
 
         return this._aliasObjects[token.value];
@@ -229,22 +229,23 @@ class Parser {
 
         const list = this.parseIdentifierList();
 
-        return new SelectorObject(selector!, args, list);
+        return new SelectorObject(selector!, args, list, token.location);
     }
 
     /**
      * Parses an item
      */
     public parseItem(): ItemObject {
-        this.expectToken(TOKEN_TYPE.IDENTIFIER, true, 'item');
+        const token = this.expectToken(TOKEN_TYPE.IDENTIFIER, true, 'item');
+
         this.expectToken(TOKEN_TYPE.LEFT_BRACKET, true);
 
         const type = this.parseString();
         const amount = this.matchToken(TOKEN_TYPE.COMMA, true) ? this.parseAmount() : 1;
 
         this.expectToken(TOKEN_TYPE.RIGHT_BRACKET, true);
 
-        return new ItemObject(type, amount);
+        return new ItemObject(type, amount, token.location);
     }
 
     /**

src/parserObjects/AliasObject.ts

@@ -7,7 +7,8 @@ class AliasObject implements ParserObject {
 
     constructor(
         public name: string,
-        public identifier: ParserObject
+        public identifier: ParserObject,
+        public location: { line: number, column: number }
     ) {}
 }
 

src/parserObjects/ItemObject.ts

@@ -7,7 +7,8 @@ class ItemObject implements ParserObject {
 
     constructor(
         public name: string,
-        public amount: number | number[]
+        public amount: number | number[],
+        public location: { line: number, column: number }
     ) {}
 }
 

src/parserObjects/SelectorObject.ts

@@ -8,7 +8,8 @@ class SelectorObject implements ParserObject {
     constructor(
         public selector: Selector,
         public args: Argument[],
-        public list: WeightedIdentifier[]
+        public list: WeightedIdentifier[],
+        public location: { line: number, column: number }
     ) {}
 }
 

src/selectors/repeat.ts

@@ -8,15 +8,15 @@ const RepeatSelector: Selector = {
 
     compile({ list, args, compiledList }, err) {
         if (args.length < 1) {
-            err(`repeat: Expected 1 argument but got ${args.length}`);
+            err(`Expected 1 argument but got ${args.length}`);
         }
 
         if ('string' === typeof args[0]) {
-            err(`repeat: First argument must be number or range`);
+            err(`First argument must be number or range`);
         }
 
         if (list.length !== 1) {
-            err('repeat: Must have exactly one element in the list');
+            err('Must have exactly one element in the list');
         }
 
         const amount: number | number[] = args[0] as any;

src/selectors/someOf.ts

@@ -8,11 +8,11 @@ const SomeOfSelector: Selector = {
 
     compile({ list, args, compiledList, isWeighted, totalWeights, weights }, err) {
         if (args.length < 1) {
-            err(`oneOf: Expected 1 argument but got ${args.length}`);
+            err(`Expected 1 argument but got ${args.length}`);
         }
 
         if ('string' === typeof args[0]) {
-            err(`oneOf: First argument must be number or range`);
+            err(`First argument must be number or range`);
         }
 
         const amount: number | number[] = args[0] as any;

src/types.d.ts

@@ -25,6 +25,7 @@ export interface ItemResult {
 export interface ParserObject {
     type: PARSER_OBJECT_TYPE;
     compiled: string;
+    location: { line: number, column: number };
 }
 
 /**