From fada8eea237f9206ad8714b613ca40df294da19c Mon Sep 17 00:00:00 2001
From: Harald Wolff <h.wolff@Haralds-Mac-Pro.local>
Date: Thu, 14 Feb 2019 16:44:33 +0100
Subject: [PATCH] WIP

---
 Expression.cs       | 175 ++++++++++++++++++++++++++++++++++----------
 Template.cs         |   6 +-
 TemplateProvider.cs |   4 +-
 TemplateReader.cs   |   1 +
 ln.templates.csproj |   1 -
 5 files changed, 146 insertions(+), 41 deletions(-)

diff --git a/Expression.cs b/Expression.cs
index d2a731f..b35a72d 100644
--- a/Expression.cs
+++ b/Expression.cs
@@ -3,6 +3,8 @@ using System.Reflection;
 using System.IO;
 using System.Text;
 using System.Collections.Generic;
+using System.Collections.Specialized;
+using System.Linq;
 namespace ln.templates
 {
     delegate bool ConditionDelegate(char ch);
@@ -34,54 +36,99 @@ namespace ln.templates
 
         private void Compile()
         {
-            StringReader reader = new StringReader(Source);
-            List<Token> tokens = new List<Token>();
-            while (reader.Peek() != -1)
-                ReadToken(reader, tokens);
-            TopEval = BuildEval(tokens);
+            try
+            {
+                StringReader reader = new StringReader(Source);
+                List<Token> tokens = new List<Token>();
+                while (reader.Peek() != -1)
+                    ReadToken(reader, tokens);
+
+                Queue<Token> qtokens = new Queue<Token>(tokens);
+
+                TopEval = BuildExpression(qtokens);
+            } catch (Exception e)
+            {
+                throw new Exception(String.Format("Failed to compile expression: {0}", Source), e);
+            }
         }
 
-        private Eval BuildEval(List<Token> tokens)
+
+        private Eval BuildName(Token nameToken,Eval parent,Queue<Token> tokens)
         {
-            Eval currentEval = null;
+            if ((tokens.Count > 0) && (tokens.Peek().TokenType == TokenType.OPENLIST))
+            {
+                tokens.Dequeue();
+
+                List<Eval> pl = new List<Eval>();
+                while (tokens.Peek().TokenType != TokenType.ENDLIST)
+                {
+                    pl.Add(BuildExpression(tokens));
+
+                    if (tokens.Peek().TokenType == TokenType.ENDLIST)
+                        break;
+
+                    if (tokens.Peek().TokenType != TokenType.COMMA)
+                        throw new FormatException("Expected ',' between parameters to call statement");
+
+                    tokens.Dequeue();
+                }
+
+                tokens.Dequeue();
+
+                return new MethodCall(parent, nameToken.Value, pl.ToArray());
+            }
+            else
+            {
+                return new Name(parent, nameToken.Value);
+            }
+        }
+
+        private Eval BuildPath(Queue<Token> tokens)
+        {
+            Eval currentEval = BuildName(tokens.Dequeue(), null, tokens);
 
             while (tokens.Count > 0)
             {
-                Token token = tokens[0];
-                tokens.RemoveAt(0);
-
+                Token token = tokens.Peek();
                 switch (token.TokenType)
                 {
                     case TokenType.DOT:
-                        token = tokens[0];
-                        tokens.RemoveAt(0);
-                        if (token.TokenType != TokenType.NAME)
-                            throw new ArgumentException("missing fieldname after .");
-                        currentEval = new Name(currentEval, token.Value);
+                        tokens.Dequeue();
+                        currentEval = BuildName(tokens.Dequeue(), currentEval, tokens);
                         break;
-                    case TokenType.NAME:
-                        currentEval = new Name(currentEval, token.Value);
-                        break;
-                    case TokenType.NUMBER:
-                        currentEval = new Number(token.Value);
-                        break;
-                    case TokenType.STRING:
-                        currentEval = new CString(token.Value);
-                        break;
-                    case TokenType.BRACKET:
-                        if (token.Value.Equals("["))
-                        {
-                            currentEval = new Indexer(currentEval, BuildEval(tokens));
-                        } else if (token.Value.Equals("]"))
-                        {
-                            return currentEval;
-                        }
+                    case TokenType.OPENINDEXER:
+                        tokens.Dequeue();
+                        Eval index = BuildExpression(tokens);
+                        token = tokens.Dequeue();
+                        if (token.TokenType != TokenType.ENDINDEXER)
+                            throw new FormatException("Expected ']'");
+                        currentEval = new Indexer(currentEval, index);
                         break;
+                    default:
+                        return currentEval;
                 }
             }
             return currentEval;
         }
 
+
+        private Eval BuildExpression(Queue<Token> tokens)
+        {
+            Token next = tokens.Peek();
+
+            switch (next.TokenType)
+            {
+                case TokenType.NAME:
+                    return BuildPath(tokens);
+                case TokenType.NUMBER:
+                    return new Number(tokens.Dequeue().Value);
+                case TokenType.STRING:
+                    return new CString(tokens.Dequeue().Value);
+            }
+
+            throw new FormatException(String.Format("unexpected Token: {0}", next.Value));
+        }
+
         private void ReadToken(TextReader reader, List<Token> tokens)
         {
             if (reader.Peek() == -1)
@@ -91,7 +138,7 @@ namespace ln.templates
             {
                 reader.Read();
             }
-            else if (char.IsLetter(ch))
+            else if (char.IsLetter(ch) || (ch == '_'))
             {
                 ReadName(reader, tokens);
             }
@@ -108,10 +155,30 @@ namespace ln.templates
                 reader.Read();
                 tokens.Add(new Token(TokenType.DOT, "."));
             }
-            else if ((ch == '[')| (ch == ']'))
+            else if (ch == '[')
             {
                 reader.Read();
-                tokens.Add(new Token(TokenType.BRACKET, new string(new char[] { ch })));
+                tokens.Add(new Token(TokenType.OPENINDEXER, new string(new char[] { ch })));
+            }
+            else if (ch == ']')
+            {
+                reader.Read();
+                tokens.Add(new Token(TokenType.ENDINDEXER, new string(new char[] { ch })));
+            }
+            else if (ch == '(')
+            {
+                reader.Read();
+                tokens.Add(new Token(TokenType.OPENLIST, new string(new char[] { ch })));
+            }
+            else if (ch == ')')
+            {
+                reader.Read();
+                tokens.Add(new Token(TokenType.ENDLIST, new string(new char[] { ch })));
+            }
+            else if (ch == ',')
+            {
+                reader.Read();
+                tokens.Add(new Token(TokenType.COMMA, new string(new char[] { ch })));
             }
             else
             {
@@ -122,7 +189,7 @@ namespace ln.templates
         {
             StringBuilder sb = new StringBuilder();
             int ch = 0;
-            while (char.IsLetterOrDigit((char)(ch = reader.Peek())))
+            while (char.IsLetterOrDigit((char)(ch = reader.Peek())) || (ch == '_'))
             {
                 sb.Append((char)reader.Read());
             }
@@ -176,7 +243,7 @@ namespace ln.templates
         }
 
 
-        enum TokenType { NAME, DOT, NUMBER, STRING, BRACKET }
+        enum TokenType { NAME, DOT, NUMBER, STRING, OPENINDEXER, ENDINDEXER, OPENLIST, ENDLIST, COMMA }
         class Token
         {
             public TokenType TokenType;
@@ -336,6 +403,40 @@ namespace ln.templates
             }
         }
 
+        class MethodCall : Eval
+        {
+            Eval[] Parameters;
+            String Name;
+
+            public MethodCall(Eval parent, String name,params Eval[] p)
+                : base(parent)
+            {
+                Name = name;
+                Parameters = p;
+            }
+
+            public override object Evaluate(Context context)
+            {
+                object p = Parent.Evaluate(context);
+
+                object[] pvalues = new object[Parameters.Length];
+                Type[] ptypes = new Type[Parameters.Length];
+
+                for (int i=0;i<pvalues.Length;i++)
+                {
+                    pvalues[i] = Parameters[i].Evaluate(context);
+                    if (pvalues[i] == null)
+                        ptypes[i] = null;
+                    else
+                        ptypes[i] = pvalues[i].GetType();
+                }
+
+                MethodInfo methodInfo = p.GetType().GetRuntimeMethod(Name, ptypes);
+
+                return methodInfo.Invoke(p, pvalues);
+            }
+        }
+
         class Number : Eval
         {
             object value;
diff --git a/Template.cs b/Template.cs
index becc0c8..7261587 100644
--- a/Template.cs
+++ b/Template.cs
@@ -70,7 +70,11 @@ namespace ln.templates
 
             if (FrameExpression != null)
             {
-                Template frame = context.Provider.FindTemplate(FrameExpression.Evaluate(null) as string);
+                Template frame = context.Provider.FindTemplate(FrameExpression.Evaluate(context.ExpressionContext) as string);
+                if (frame == null)
+                {
+                    throw new NullReferenceException(String.Format("FindTemplate() returned null for {0}",FrameExpression.Source));
+                }
                 return frame.Generate(new Context(context, writer.ToString()));
             }
             return writer.ToString();
diff --git a/TemplateProvider.cs b/TemplateProvider.cs
index 2d2f95b..158191b 100644
--- a/TemplateProvider.cs
+++ b/TemplateProvider.cs
@@ -1,8 +1,8 @@
 using System;
 namespace ln.templates
 {
-    public abstract class TemplateProvider
+    public interface TemplateProvider
     {
-        public abstract Template FindTemplate(string templatePath);
+        Template FindTemplate(string templatePath);
     }
 }
diff --git a/TemplateReader.cs b/TemplateReader.cs
index 4adf78e..c1254bd 100644
--- a/TemplateReader.cs
+++ b/TemplateReader.cs
@@ -34,6 +34,7 @@ namespace ln.templates
                 {
                     t = Source;
                     op = null;
+                    Source = "";
                 }
                 else
                 {
diff --git a/ln.templates.csproj b/ln.templates.csproj
index 42f94c4..789a4b3 100644
--- a/ln.templates.csproj
+++ b/ln.templates.csproj
@@ -29,7 +29,6 @@
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="System.Xml" />
-    <Reference Include="System.Web" />
   </ItemGroup>
   <ItemGroup>
     <Compile Include="Properties\AssemblyInfo.cs" />