Refactor to commands

lib/commands.js

@@ -0,0 +1,32 @@
+
+function ExpressionCommand(expr) {
+    this.execute = function (ctx) {
+        expr.evaluate(ctx);
+    };
+}
+
+function CompositeCommand(cmds) {
+    this.execute = function (ctx) {
+        cmds.forEach(function (cmd) {
+            cmd.execute(ctx);
+        });
+    };
+}
+
+function ProgramCommand(cmds) {
+    this.execute = function (ctx) {
+        ctx.set('$program', new CompositeCommand(cmds));
+    };
+}
+
+function ProcedureCommand(name, argnames, cmds) {
+    this.execute = function (ctx) {
+        ctx.set(name, new CompositeCommand(cmds));
+    };
+}
+
+module.exports = {
+    expression: function (expr) { return new ExpressionCommand(expr); },
+    program: function (cmds) { return new ProgramCommand(cmds); },
+    procedure: function (name, argnames, cmds) { return new ProcedureCommand(name, argnames, cmds); }
+};

lib/parsers.js

@@ -2,32 +2,7 @@
 var expressions = require('./expressions');
 var lexers = require('./lexers');
 var TokenType = lexers.TokenType;
-
-function ExpressionCommand(expr) {
-    this.execute = function (ctx) {
-        expr.evaluate(ctx);
-    };
-}
-
-function CompositeCommand(cmds) {
-    this.execute = function (ctx) {
-        cmds.forEach(function (cmd) {
-            cmd.execute(ctx);
-        });
-    };
-}
-
-function ProgramCommand(cmds) {
-    this.execute = function (ctx) {
-        ctx.set('$program', new CompositeCommand(cmds));
-    };
-}
-
-function ProcedureCommand(name, argnames, cmds) {
-    this.execute = function (ctx) {
-        ctx.set(name, new CompositeCommand(cmds));
-    };
-}
+var commands = require('./commands');
 
 function Parser(text) {
     var lexer = lexers.lexer(text);
@@ -54,7 +29,7 @@ function Parser(text) {
 
         tryGetToken(';', TokenType.Delimiter);
 
-        return new ExpressionCommand(expr);
+        return commands.expression(expr);
     };
 
     this.parseExpression = function () {
@@ -130,7 +105,7 @@ function Parser(text) {
 
         getToken('}', TokenType.Delimiter);
 
-        return new ProgramCommand(cmds);
+        return commands.program(cmds);
     }
 
     function parseProcedure() {
@@ -155,7 +130,7 @@ function Parser(text) {
 
         getToken('}', TokenType.Delimiter);
 
-        return new ProcedureCommand(name, argnames, cmds);
+        return commands.procedure(name, argnames, cmds);
     }
 }