From 5dec7604525f0f7e21bf8bcff371448e1b17f3a0 Mon Sep 17 00:00:00 2001
From: Stefan Zermatten <stefanzermatten@gmail.com>
Date: Thu, 10 Sep 2020 11:38:28 +0200
Subject: [PATCH] Parser now works with variables passed into scope

---
 app/imports/parser/grammar.js                | 18 +++++---
 app/imports/parser/grammar.ne                | 14 ++++--
 app/imports/parser/parseTree/AccessorNode.js | 46 ++++++++++++++++++++
 app/imports/parser/parseTree/IfNode.js       |  7 ++-
 app/imports/parser/parseTree/SymbolNode.js   | 23 ++++++++--
 app/imports/ui/pages/Parser.vue              |  2 +-
 6 files changed, 93 insertions(+), 17 deletions(-)
 create mode 100644 app/imports/parser/parseTree/AccessorNode.js

diff --git a/app/imports/parser/grammar.js b/app/imports/parser/grammar.js
index 310a2ad8..289327de 100644
--- a/app/imports/parser/grammar.js
+++ b/app/imports/parser/grammar.js
@@ -2,6 +2,7 @@
 // http://github.com/Hardmath123/nearley
 function id(x) { return x[0]; }
 
+  import AccessorNode from '/imports/parser/parseTree/AccessorNode.js';
   import ArrayNode from '/imports/parser/parseTree/ArrayNode.js';
 	import CallNode from '/imports/parser/parseTree/CallNode.js';
 	import ConstantNode from '/imports/parser/parseTree/ConstantNode.js';
@@ -23,7 +24,7 @@ function id(x) { return x[0]; }
     name: {
       match: /[a-zA-Z]+\w*?/,
       type: moo.keywords({
-        'keywords': ['if', 'else', 'd'],
+        'keywords': ['d'],
       }),
     },
     space: {
@@ -32,6 +33,7 @@ function id(x) { return x[0]; }
     },
     separator: [',', ';'],
     period: ['.'],
+    ternaryOperator: ['?', ':'],
     multiplicativeOperator: ['*', '/'],
     exponentOperator: ['^'],
     additiveOperator: ['+', '-'],
@@ -56,8 +58,8 @@ function id(x) { return x[0]; }
 let Lexer = lexer;
 let ParserRules = [
     {"name": "expression", "symbols": ["ifStatement"], "postprocess": d => d[0]},
-    {"name": "ifStatement", "symbols": ["_", "expression", "_", {"literal":"?"}, "_", "expression", "_", {"literal":":"}, "_", "expression"], "postprocess": 
-        d => new IfNode({condition: d[4], consequent: d[8], alternative: d[12]})
+    {"name": "ifStatement", "symbols": ["_", "equalityExpression", "_", {"literal":"?"}, "_", "equalityExpression", "_", {"literal":":"}, "_", "ifStatement"], "postprocess": 
+        d => new IfNode({condition: d[1], consequent: d[5], alternative: d[9]})
           },
     {"name": "ifStatement", "symbols": ["equalityExpression"], "postprocess": id},
     {"name": "equalityExpression", "symbols": ["equalityExpression", "_", (lexer.has("equalityOperator") ? {type: "equalityOperator"} : equalityOperator), "_", "relationalExpression"], "postprocess": d => operator(d, 'equality')},
@@ -100,11 +102,17 @@ let ParserRules = [
     {"name": "arrayExpression$ebnf$2$subexpression$1", "symbols": ["_", (lexer.has("separator") ? {type: "separator"} : separator), "_", "expression"], "postprocess": d => d[3]},
     {"name": "arrayExpression$ebnf$2", "symbols": ["arrayExpression$ebnf$2", "arrayExpression$ebnf$2$subexpression$1"], "postprocess": function arrpush(d) {return d[0].concat([d[1]]);}},
     {"name": "arrayExpression", "symbols": [{"literal":"["}, "_", "arrayExpression$ebnf$1", "arrayExpression$ebnf$2", "_", {"literal":"]"}], "postprocess": 
-        d => new ArrayNode({values: [d[2], ...d[3]]})
+        d => new ArrayNode({values: d[2] ? [d[2], ...d[3]] : []})
           },
     {"name": "arrayExpression", "symbols": ["parenthesizedExpression"], "postprocess": id},
     {"name": "parenthesizedExpression", "symbols": [{"literal":"("}, "_", "expression", "_", {"literal":")"}], "postprocess": d => new ParenthesisNode({content: d[2]})},
-    {"name": "parenthesizedExpression", "symbols": ["valueExpression"], "postprocess": id},
+    {"name": "parenthesizedExpression", "symbols": ["accessorExpression"], "postprocess": id},
+    {"name": "accessorExpression$ebnf$1$subexpression$1", "symbols": [{"literal":"."}, "name"], "postprocess": d => d[1].name},
+    {"name": "accessorExpression$ebnf$1", "symbols": ["accessorExpression$ebnf$1$subexpression$1"]},
+    {"name": "accessorExpression$ebnf$1$subexpression$2", "symbols": [{"literal":"."}, "name"], "postprocess": d => d[1].name},
+    {"name": "accessorExpression$ebnf$1", "symbols": ["accessorExpression$ebnf$1", "accessorExpression$ebnf$1$subexpression$2"], "postprocess": function arrpush(d) {return d[0].concat([d[1]]);}},
+    {"name": "accessorExpression", "symbols": ["name", "accessorExpression$ebnf$1"], "postprocess": d=> new AccessorNode({name: d[0], path: d[1]})},
+    {"name": "accessorExpression", "symbols": ["valueExpression"], "postprocess": id},
     {"name": "valueExpression", "symbols": ["name"], "postprocess": id},
     {"name": "valueExpression", "symbols": ["number"], "postprocess": id},
     {"name": "valueExpression", "symbols": ["string"], "postprocess": id},
diff --git a/app/imports/parser/grammar.ne b/app/imports/parser/grammar.ne
index 4e199c11..bac66f8a 100644
--- a/app/imports/parser/grammar.ne
+++ b/app/imports/parser/grammar.ne
@@ -1,5 +1,6 @@
 @preprocessor esmodule
 @{%
+  import AccessorNode from '/imports/parser/parseTree/AccessorNode.js';
   import ArrayNode from '/imports/parser/parseTree/ArrayNode.js';
 	import CallNode from '/imports/parser/parseTree/CallNode.js';
 	import ConstantNode from '/imports/parser/parseTree/ConstantNode.js';
@@ -21,7 +22,7 @@
     name: {
       match: /[a-zA-Z]+\w*?/,
       type: moo.keywords({
-        'keywords': ['if', 'else', 'd'],
+        'keywords': ['d'],
       }),
     },
     space: {
@@ -30,6 +31,7 @@
     },
     separator: [',', ';'],
     period: ['.'],
+    ternaryOperator: ['?', ':'],
     multiplicativeOperator: ['*', '/'],
     exponentOperator: ['^'],
     additiveOperator: ['+', '-'],
@@ -60,8 +62,8 @@ expression ->
   ifStatement {% d => d[0] %}
 
 ifStatement ->
-  _ expression _ "?" _ expression _ ":" _ expression {%
-     d => new IfNode({condition: d[4], consequent: d[8], alternative: d[12]})
+  _ equalityExpression _ "?" _ equalityExpression _ ":" _ ifStatement {%
+     d => new IfNode({condition: d[1], consequent: d[5], alternative: d[9]})
   %}
 | equalityExpression {% id %}
 
@@ -118,12 +120,16 @@ indexExpression ->
 
 arrayExpression ->
   "[" _ (expression {% d => d[0] %}):? ( _ %separator _ expression {% d => d[3] %} ):* _ "]" {%
-    d => new ArrayNode({values: [d[2], ...d[3]]})
+    d => new ArrayNode({values: d[2] ? [d[2], ...d[3]] : []})
   %}
 | parenthesizedExpression {% id %}
 
 parenthesizedExpression ->
   "(" _ expression _ ")" {% d => new ParenthesisNode({content: d[2]}) %}
+| accessorExpression {% id %}
+
+accessorExpression ->
+  name ( "." name {% d => d[1].name %} ):+ {% d=> new AccessorNode({name: d[0], path: d[1]}) %}
 | valueExpression {% id %}
 
 valueExpression ->
diff --git a/app/imports/parser/parseTree/AccessorNode.js b/app/imports/parser/parseTree/AccessorNode.js
new file mode 100644
index 00000000..a406af09
--- /dev/null
+++ b/app/imports/parser/parseTree/AccessorNode.js
@@ -0,0 +1,46 @@
+import ParseNode from '/imports/parser/parseTree/ParseNode.js';
+import ErrorNode from '/imports/parser/parseTree/ErrorNode.js';
+import ConstantNode from '/imports/parser/parseTree/ConstantNode.js';
+
+export default class AccessorNode extends ParseNode {
+  constructor({name, path}) {
+    super(...arguments);
+    this.name = name;
+    this.path = path;
+  }
+  compile(scope){
+    let value = scope && scope[this.name];
+    // For objects, get their value
+    this.path.forEach(name => {
+      if (value === undefined) return;
+      value = value[name];
+    });
+    let type = typeof value;
+    if (type === 'string' || type === 'number' || type === 'boolean'){
+      return new ConstantNode({value, type, previousNodes: [this]});
+    } else if (type === 'undefined'){
+      return new AccessorNode({
+        name: this.name,
+        path: this.path,
+        previousNodes: [this],
+      });
+    } else {
+      throw new Meteor.Error(`Unexpected case: ${this.name} resolved to ${value}`);
+    }
+  }
+  reduce(scope){
+    let result = this.compile(scope);
+    if (result instanceof AccessorNode){
+      return new ErrorNode({
+        node: result,
+        error: `${this.toString()} could not be resolved`,
+        previousNodes: [result],
+      });
+    } else {
+      return result;
+    }
+  }
+  toString(){
+    return `${this.name}.${this.path.join('.')}`;
+  }
+}
diff --git a/app/imports/parser/parseTree/IfNode.js b/app/imports/parser/parseTree/IfNode.js
index 66334d84..7f1c9178 100644
--- a/app/imports/parser/parseTree/IfNode.js
+++ b/app/imports/parser/parseTree/IfNode.js
@@ -22,13 +22,12 @@ export default class IfNode extends ParseNode {
   }
   resolve(fn, scope){
     let condition = this.condition[fn](scope);
-    let consequent = this.consequent[fn](scope);
-    let alternative = this.alternative[fn](scope);
-    this.resolve(condition, consequent, alternative);
     if (condition.value){
+      let consequent = this.consequent[fn](scope);
       consequent.inheritDetails([condition, this]);
-      return consequent;
+      return this.consequent[fn](scope);
     } else {
+      let alternative = this.alternative[fn](scope);
       alternative.inheritDetails([condition, this]);
       return alternative;
     }
diff --git a/app/imports/parser/parseTree/SymbolNode.js b/app/imports/parser/parseTree/SymbolNode.js
index 35c2ffab..73becc6f 100644
--- a/app/imports/parser/parseTree/SymbolNode.js
+++ b/app/imports/parser/parseTree/SymbolNode.js
@@ -13,15 +13,32 @@ export default class SymbolNode extends ParseNode {
   compile(scope){
     let value = scope && scope[this.name];
     let type = typeof value;
+    // For objects, get their value
+    if (type === 'object'){
+      value = value.value;
+      type = typeof value;
+    }
     if (type === 'string' || type === 'number' || type === 'boolean'){
       return new ConstantNode({value, type, previousNodes: [this]});
     } else if (type === 'undefined'){
-      return new ErrorNode({
-        node: this,
-        error: `${this.name} could not be resolved`,
+      return new SymbolNode({
+        name: this.name,
+        previousNodes: [this],
       });
     } else {
       throw new Meteor.Error(`Unexpected case: ${this.name} resolved to ${value}`);
     }
   }
+  reduce(scope){
+    let result = this.compile(scope);
+    if (result instanceof SymbolNode){
+      return new ErrorNode({
+        node: result,
+        error: `${this.toString()} could not be resolved`,
+        previousNodes: [result],
+      });
+    } else {
+      return result;
+    }
+  }
 }
diff --git a/app/imports/ui/pages/Parser.vue b/app/imports/ui/pages/Parser.vue
index ba8d7683..cb3ddd92 100644
--- a/app/imports/ui/pages/Parser.vue
+++ b/app/imports/ui/pages/Parser.vue
@@ -59,7 +59,7 @@ export default {
       this.output = JSON.stringify(output, null, 2);
       if (!output) return;
       this.string = output;
-      let scope = {cat: 1, dog: 2, mouse: 3};
+      let scope = {strength: {value: 16}, hitpoints: {value: 32, currentValue: 8}, mouse: 3};
       this.compiled = output.compile(scope);
       this.rolled = output.roll(scope);
       this.reduced = output.reduce(scope);