Parser now uses context to store details of the computation

app/imports/parser/parser.js

@@ -6,3 +6,31 @@ const nearleyGrammar = nearley.Grammar.fromCompiled(grammar);
 export default function parser(){
   return new nearley.Parser(nearleyGrammar);
 }
+
+export class CompilationContext {
+  constructor(){
+    this.errors = [];
+    this.rolls = [];
+  }
+  storeError(e){
+    this.errors.push(e);
+  }
+  storeRoll(r){
+    this.rolls.push(r);
+  }
+}
+
+export function parse(string){
+  let parser = new nearley.Parser(nearleyGrammar);
+  parser.feed(string);
+  let results = parser.results;
+  if (results.length === 1){
+    return results[0];
+  } else if (results.length === 0){
+    // Valid parsing up until now, but need more. Unexpected end of input.
+    return null;
+  } else {
+    console.warn('Grammar is ambiguous!', {string, results});
+    return results[0];
+  }
+}