Add option to extract constant tables, fix string.start

AspectedRouting/IO/LuaSkeleton/LuaSkeleton.Expressions.cs

@@ -218,6 +218,7 @@ namespace AspectedRouting.IO.LuaSkeleton
 
         public string MappingToLua(Mapping m)
         {
+            var isConstant = true;
             var contents = m.StringToResultFunctions.Select(kv =>
                 {
                     var (key, expr) = kv;
@@ -228,13 +229,23 @@ namespace AspectedRouting.IO.LuaSkeleton
                         left = key;
                     }
 
-                    return left + " = " + ToLua(expr, key);
+                    var luaExpr = ToLua(expr, key);
+                    if (luaExpr.Contains("tags")) {
+                        isConstant = false;
+                    }
+                    return left + " = " + luaExpr ;
                 }
             );
-            return
+            var mapping =
                 "{\n    " +
                 string.Join(",\n    ", contents) +
                 "\n}";
+            if (_staticTables && isConstant) {
+                return AddConstant(mapping);
+            }
+
+            return mapping;
+
         }
 
         /// <summary>

AspectedRouting/IO/LuaSkeleton/LuaSkeleton.cs

@@ -1,30 +1,38 @@
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using AspectedRouting.Language;
 
 namespace AspectedRouting.IO.LuaSkeleton
 {
-    
     /// <summary>
-    /// The 'LuaSkeleton' is a class which is used in Lua generation of profiles.
+    ///     The 'LuaSkeleton' is a class which is used in Lua generation of profiles.
-    ///
+    ///     The lua skeleton basically keeps track of dependencies, and added functions.
-    /// The lua skeleton basically keeps track of dependencies, and added functions.
+    ///     Once done, all these can be retrieved as code.
-    /// Once done, all these can be retrieved as code.
+    ///     E.g. if an expression is turned into lua with 'ToExpression', then the dependencies will be automatically added.
-    ///
-    /// E.g. if an expression is turned into lua with 'ToExpression', then the dependencies will be automatically added.
-    /// 
     /// </summary>
     public partial class LuaSkeleton
     {
+        private readonly HashSet<string> _alreadyAddedFunctions = new HashSet<string>();
+
+        private readonly List<string> _constants = new List<string>();
         private readonly Context _context;
 
         private readonly HashSet<string> _dependencies = new HashSet<string>();
         private readonly List<string> _functionImplementations = new List<string>();
-        private readonly HashSet<string> _alreadyAddedFunctions = new HashSet<string>();
 
-        public LuaSkeleton(Context context)
+        /// <summary>
+        ///     It turns out that creating lua tables is a huge performance overhead.
+        ///     Lots of functions however need a constant table to be invoked. Creating this table over and over is performance
+        ///     issue.
+        ///     If this flag is set, those constant tables are exported so they are created only once
+        /// </summary>
+        private readonly bool _staticTables;
+
+        public LuaSkeleton(Context context, bool staticTables = false)
         {
             _context = context;
+            _staticTables = staticTables;
         }
 
         internal void AddDep(string name)
@@ -41,19 +49,15 @@ namespace AspectedRouting.IO.LuaSkeleton
         {
             return _alreadyAddedFunctions.Contains(name);
         }
-        
+
         public void AddDependenciesFor(IExpression e)
         {
             var (_, functionNames) = e.InList().DirectlyAndInderectlyCalled(_context);
-            foreach (var functionName in functionNames)
+            foreach (var functionName in functionNames) {
-            {
+                if (_context.DefinedFunctions.TryGetValue(functionName, out var aspectMeta)) {
-
+                    AddFunction(aspectMeta);
-                if (_context.DefinedFunctions.TryGetValue(functionName, out var aspectemeta))
-                {
-                    AddFunction(aspectemeta);
                 }
-                else
+                else {
-                {
                     AddDep(functionName);
                 }
             }
@@ -63,21 +67,28 @@ namespace AspectedRouting.IO.LuaSkeleton
         {
             var imps = new List<string>();
 
-            foreach (var name in _dependencies)
+            foreach (var name in _dependencies) {
-            {
                 var path = $"IO/lua/{name}.lua";
-                if (File.Exists(path))
+                if (File.Exists(path)) {
-                {
                     imps.Add(File.ReadAllText(path));
                 }
-                else
+                else {
-                {
                     throw new FileNotFoundException(path);
                 }
             }
 
             return imps;
         }
-        
+
+        public string AddConstant(string luaExpression)
+        {
+            _constants.Add(luaExpression);
+            return "c" + (_constants.Count - 1);
+        }
+
+        public IEnumerable<string> GenerateConstants()
+        {
+            return _constants.Select((c, i) => $"c{i} = {c}");
+        }
     }
 }

AspectedRouting/IO/itinero1/LuaPrinter1.cs

@@ -1,4 +1,3 @@
-using System;
 using System.Collections.Generic;
 using System.Linq;
 using AspectedRouting.Language;
@@ -88,6 +87,7 @@ namespace AspectedRouting.IO.itinero1
                 functions,
                 "---------------------- UTILS ------------------------".InList(),
                 dependencies,
+                _skeleton.GenerateConstants().ToList(),
                 "----------------------- TESTS ------------------------".InList(),
                 tests.InList(),
                 GenerateLegacyTail().InList()

AspectedRouting/IO/itinero2/LuaPrinter2.cs

@@ -9,33 +9,30 @@ using AspectedRouting.Tests;
 namespace AspectedRouting.IO.itinero2
 {
     /// <summary>
-    /// Lua printer for itinero2-lua format
+    ///     Lua printer for itinero2-lua format
-    ///
+    ///     The itinero 2.0 lua profile is a whole lot simpler then the 1.0 format,
-    /// The itinero 2.0 lua profile is a whole lot simpler then the 1.0 format,
+    ///     as a single profile there only describes a single behaviour of a vehicle:
-    /// as a single profile there only describes a single behaviour of a vehicle:
+    ///     It has:
-    ///
+    ///     - name: string, e.g. 'bicycle.fastest'
-    /// It has:
+    ///     - factor(attributes, result): void, where 'attributes' are all the tags of the way,
-    /// - name: string, e.g. 'bicycle.fastest'
+    ///     and result must contain (after calling):
-    /// - factor(attributes, result): void, where 'attributes' are all the tags of the way,
+    ///     - 'forward_speed', a double describing the forward speed (in km/h)
-    /// and result must contain (after calling):
+    ///     - 'backward_speed', the speed when travelling in the opposite direction (0 if not possible)
-    /// - 'forward_speed', a double describing the forward speed (in km/h)
+    ///     - 'forward', a double describing the forwardfactor
-    /// - 'backward_speed', the speed when travelling in the opposite direction (0 if not possible)
+    ///     - 'backward', the backward factor
-    /// - 'forward', a double describing the forwardfactor
+    ///     - 'canstop', a boolean indicating if stopping along the road is possible
-    /// - 'backward', the backward factor
-    /// - 'canstop', a boolean indicating if stopping along the road is possible
-    /// 
     /// </summary>
     public partial class LuaPrinter2
     {
-        private readonly ProfileMetaData _profile;
-        private readonly string _behaviourName;
-        private readonly Context _context;
         private readonly List<AspectTestSuite> _aspectTests;
+        private readonly string _behaviourName;
         private readonly IEnumerable<BehaviourTestSuite> _behaviourTestSuite;
+        private readonly Context _context;
         private readonly DateTime _lastChangeTime;
+        private readonly LuaParameterPrinter _parameterPrinter;
+        private readonly ProfileMetaData _profile;
 
         private readonly LuaSkeleton.LuaSkeleton _skeleton;
-        private readonly LuaParameterPrinter _parameterPrinter;
 
 
         public LuaPrinter2(ProfileMetaData profile, string behaviourName,
@@ -43,7 +40,7 @@ namespace AspectedRouting.IO.itinero2
             List<AspectTestSuite> aspectTests, IEnumerable<BehaviourTestSuite> behaviourTestSuite,
             DateTime lastChangeTime)
         {
-            _skeleton = new LuaSkeleton.LuaSkeleton(context);
+            _skeleton = new LuaSkeleton.LuaSkeleton(context, false);
             _profile = profile;
             _behaviourName = behaviourName;
             _context = context;
@@ -55,23 +52,21 @@ namespace AspectedRouting.IO.itinero2
 
         public string ToLua()
         {
-        var profileDescr =    _profile.Behaviours[_behaviourName]["description"].Evaluate(_context).ToString();
+            var profileDescr = _profile.Behaviours[_behaviourName]["description"].Evaluate(_context).ToString();
             var header =
-                new List<string>
+                new List<string> {
-                {
                     $"name = \"{_profile.Name}.{_behaviourName}\"",
                     $"generationDate = \"{_lastChangeTime:s}\"",
                     $"description = \"{profileDescr} ({_profile.Description})\""
                 };
 
             var testPrinter = new LuaTestPrinter(_skeleton,
-                new List<string>() {"unitTestProfile2"});
+                new List<string> {"unitTestProfile2"});
             var tests = testPrinter.GenerateFullTestSuite(
-                _behaviourTestSuite.ToList(), 
+                _behaviourTestSuite.ToList(),
                 new List<AspectTestSuite>(),
                 true);
-            var all = new List<string>
+            var all = new List<string> {
-            {
                 header.Lined(),
                 "",
                 GenerateMainFunction(),
@@ -85,9 +80,11 @@ namespace AspectedRouting.IO.itinero2
                 "",
                 string.Join("\n\n", _skeleton.GenerateDependencies()), // Should be AFTER generating the main function!
                 "",
+                string.Join("\n\n", _skeleton.GenerateConstants()),
+                "",
                 tests,
                 "",
-                
+
                 "if (itinero == nil) then",
                 "    itinero = {}",
                 "    itinero.log = print",

AspectedRouting/IO/lua/remove_relation_prefix.lua

@@ -1,4 +1,4 @@
-function string.start(strt, s)
+function string_start(strt, s)
     return string.sub(s, 1, string.len(strt)) == strt
 end
 
@@ -9,7 +9,7 @@ function remove_relation_prefix(tags, name)
     local new_tags = {}
     for k, v in pairs(tags) do
         local prefix = "_relation:" .. name .. ":";
-        if (string.start(prefix, k)) then
+        if (string_start(prefix, k)) then
             local new_key = "_relation:" .. string.sub(k, string.len(prefix) + 1) -- plus 1: sub uses one-based indexing to select the start
             new_tags[new_key] = v
         else