Began implementing dice rolls in the maths parser

app/imports/api/creature/computation/afterComputation/evaluateAndRollString.js

@@ -0,0 +1,77 @@
+import math from '/imports/math.js';
+import bareSymbolSubtitutor from '/imports/api/creature/computation/utility/bareSymbolSubtitutor.js';
+import substituteRollsWithFunctions from '/imports/api/creature/computation/afterComputation/substituteRollsWithFunctions.js'
+
+export default function evaluateAndRollString(string, scope){
+  let errors = [];
+  if (!string){
+    errors.push('No string provided');
+    return {result: string, errors};
+  }
+
+  if (!scope) errors.push('No scope provided');
+
+  // Parse the string using mathjs
+  let calc;
+  try {
+    calc = math.parse(string);
+  } catch (e) {
+    errors.push(e);
+    return {result: string, errors};
+  }
+
+  // Replace all bare symbols with symbol.value
+  let transformedCalc = calc.transform(bareSymbolSubtitutor(scope));
+  // Replace all rolls with the function to call them
+  transformedCalc = calc.transform(substituteRollsWithFunctions);
+
+  // Evaluate the expression to a number or return with substitutions
+  try {
+    let result = transformedCalc.evaluate(scope);
+    return {result, errors};
+  } catch (e1){
+    errors.push(e1);
+    try {
+      let result = simplifyWithAccessors(transformedCalc, scope).toHTML();
+      return {result, errors};
+    } catch (e2){
+      errors.push(e2);
+      return {result: transformedCalc.toHTML(), errors};
+    }
+  }
+}
+
+function simplifyWithAccessors(calc, scope){
+  let noAccessorCalc = calc.transform(substituteAccessors(scope));
+  return math.simplify(noAccessorCalc);
+}
+
+// returns a function to replace all accessors with either their resolved value
+// or a symbol to simplify with
+function substituteAccessors(scope){
+  return function(node){
+    if (node.isAccessorNode){
+      try {
+        return evaluateAccessor(node, scope);
+      } catch (e) {
+        return replaceAccessorWithSymbol(node);
+      }
+    } else {
+      return node;
+    }
+  }
+}
+
+// Throws error if symbol is undefined in scope
+function evaluateAccessor(node, scope){
+  let value = node.evaluate(scope);
+  if (value === undefined){
+    throw 'Undefined symbol'
+  }
+  return new math.ConstantNode(value);
+}
+
+function replaceAccessorWithSymbol(node){
+  let symbolNode = new math.SymbolNode(node.toString());
+  return symbolNode;
+}