Expressions with expr-eval added

README.md

@@ -80,6 +80,7 @@ for (let i=0; i< testData.length; i++) {
 ```
 
 ## More Examples
+### Initiate and compile in separate steps
 ```js
 // create an instance direct..
 let table = new Table(testTable);
@@ -88,4 +89,60 @@ let table = new Table(testTable);
 let table = new Table();
 table.compile(testTable);
 ```
-
+### Formular expressions in input
+```js
+let testTable = {
+    description: 'Simple table',
+    hitPolicy: 'Unique',
+    input: {
+        'x': {
+            description: 'Input x',
+            type: 'number'
+        },
+        'y': {
+            description: 'Input y',
+            type: 'number',
+            default: 2
+        },
+        'a': {
+            description: 'Formula Input',
+            type: 'expression',        // optional
+            expression: '2 * x + y'    // check expr-eval for syntax
+        }
+    },
+    output: {
+        'z': {},
+        't': {}
+    },
+    rules: {
+        'First rule': {
+            'x': '< 5, [20..30]',
+            'y': '> 6,[30..40]',
+            'a': '< 15',                // uses the calculated value
+            'z': '7',
+            't': 'first'
+        },
+        'Second rule': {
+            'x': '> 5',
+            'a': '> 15',
+            'z': '2',
+            't': 'second'
+        }
+    }
+};
+```
+### Set default values for input (if value is not provided in data sets)
+```js
+    input: {
+        'x': {
+            description: 'Input x',
+            type: 'number',
+            default: '0'                // 0 must be in quotes
+        },
+        'y': {
+            description: 'Input y',
+            type: 'number',
+            default: 2                  // with or without quotes
+        }
+    }
+```

lib/table.js

@@ -2,7 +2,8 @@
 
 const compiler = require('checkcond').Compiler;
 const check = require('checkcond').Check;
-
+const Parser = require('expr-eval').Parser;
+const parser = new Parser();
 
 class Table {
     constructor(table) {
@@ -14,9 +15,24 @@ class Table {
         let compiled = [];
         let inputs = [];
         let outputs = [];
+        table.calculate = [];
+        table.defaults = {};
 
         if (table.input) {
-            Object.keys(table.input).forEach(function(key) {inputs.push(key)});
+            Object.keys(table.input).forEach(function(key) {
+                inputs.push(key);
+                // input parameter calculated based on expressions
+                if (table.input[key].expression) {
+                    let calc = [];
+                    calc[0] = key;
+                    calc[1] = parser.parse(table.input[key].expression);
+                    table.calculate.push(calc);
+                };
+                // default values for input parameter
+                if (table.input[key].default) {
+                    table.defaults[key] = table.input[key].default; 
+                };
+            });
         };
         if (table.output) {
             Object.keys(table.output).forEach(function(key) {outputs.push(key)});
@@ -28,6 +44,7 @@ class Table {
             rule.output = [];
             rule.desc = desc;
 
+            // bild array of input variables with the assigned compiled(!) condition for this rule
             let addInput = function(item) {
                 let input = [];
                 let condString = table.rules[desc][item];
@@ -40,10 +57,9 @@ class Table {
             }
             inputs.forEach(addInput);
 
+            // build array of output variables for this rule
             let addOutput = function(item) {
-                let output = [];
-                output[item] = table.rules[desc][item];
-                rule.output = output;
+                rule.output[item] = table.rules[desc][item];
             }
             outputs.forEach(addOutput);
 
@@ -63,6 +79,17 @@ class Table {
         let self = this;
         let res = data;
         let output = {};
+
+        // assign default values
+        Object.keys(this._table.defaults).forEach(function(key) {
+            if (!data[key]) data[key] = self._table.defaults[key];
+        });
+
+        // calculate expressions
+        let calcExpr = function(calc) {
+            data[calc[0]] = calc[1].evaluate(data);
+        };
+        this._table.calculate.forEach(calcExpr);
 
         if (this._table.output) {
             Object.keys(this._table.output).forEach(function(key) {res[key] = null});

package.json

@@ -1,6 +1,6 @@
 {
   "name": "cond-table",
-  "version": "0.0.2",
+  "version": "0.0.3",
   "description": "decision table",
   "main": "index.js",
   "scripts": {
@@ -12,7 +12,8 @@
     "url": "git+https://github.com/al66/cond-table.git"
   },
   "keywords": [
-    "rule", "rules",
+    "rule",
+    "rules",
     "rules-engine",
     "decision",
     "decision-engine",
@@ -36,6 +37,7 @@
     "test": "test"
   },
   "dependencies": {
-    "checkcond": "0.0.5"
+    "checkcond": "0.0.5",
+    "expr-eval": "1.0.0"
   }
 }

test/test.js

@@ -70,7 +70,12 @@ describe('Test table 1', function() {
             'y': {
                 description: 'Input y',
                 type: 'number',
-                default: 2
+                default: '0'
+            },
+            'a': {
+                description: 'Formula Input',
+                type: 'expression',
+                expression: '2 * x + y'
             }
         },
         output: {
@@ -83,10 +88,12 @@ describe('Test table 1', function() {
             'First rule': {
                 'x': '< 5, [20..30]',
                 'y': '> 6,[30..40]',
+                'a': '< 15',
                 'z': '7'
             },
             'Second rule': {
                 'x': '> 5',
+                'a': '> 15',
                 'z': '2'
             }
         }
@@ -176,6 +183,65 @@ describe('Test table 2', function() {
     }
 });
 
+describe('Multiple output', function() {
+    let testTable = {
+        description: 'Simple table',
+        hitPolicy: 'Unique',
+        input: {
+            'x': {
+                description: 'Input x',
+                type: 'number'
+            },
+            'y': {
+                description: 'Input y',
+                type: 'number',
+                default: 2
+            },
+            'a': {
+                description: 'Formula Input',
+                type: 'expression',
+                expression: '2 * x + y'
+            }
+        },
+        output: {
+            'z': {},
+            't': {}
+        },
+        rules: {
+            'First rule': {
+                'x': '< 5, [20..30]',
+                'y': '> 6,[30..40]',
+                'a': '< 15',
+                'z': '7',
+                't': 'first'
+            },
+            'Second rule': {
+                'x': '> 5',
+                'a': '> 15',
+                'z': '2',
+                't': 'second'
+            }
+        }
+    };
+    let testData = [
+        { 'x': '3', 'y':'2', 'z':null, 't':null},
+        { 'x': '3', 'y':'7', 'z':'7', 't':'first'},
+        { 'x': '6', 'y':'7', 'z':'2', 't':'second'},
+        { 'x': '20', 'y':'37', 'z':'7', 't':'first'},
+        { 'x': '6', 'z':'2', 't':'second'}
+    ];
+
+    let table = new Table();
+    table.compile(testTable);
+    for (let i=0; i< testData.length; i++) {
+        it('Test data line ' + i, function(done){
+            let result = table.result(testData[i]);
+            expect(result.z).to.be.equals(testData[i].z);
+            expect(result.t).to.be.equals(testData[i].t);
+            done();
+        });
+    }
+});
 
 describe('Incomplete Table', function() {
     let testTable = {