C#: add step8_macros

4 files changed, 277 insertions, 3 deletions

diff --git a/cs/Makefile b/cs/Makefile
index 012c503..e105786 100644
--- a/cs/Makefile
+++ b/cs/Makefile
@@ -3,14 +3,15 @@
 TESTS =
 
 SOURCES = readline.cs types.cs reader.cs printer.cs env.cs core.cs \
-	  step7_quote.cs
+	  step8_macros.cs
 
 OTHER_SOURCES = getline.cs
 
 #####################
 
 SRCS = step0_repl.cs step1_read_print.cs step2_eval.cs step3_env.cs \
-       step4_if_fn_do.cs step5_tco.cs step6_file.cs step7_quote.cs
+       step4_if_fn_do.cs step5_tco.cs step6_file.cs step7_quote.cs \
+       step8_macros.cs
 
 LIB_SRCS = $(filter-out step%,$(OTHER_SOURCES) $(SOURCES))
 
diff --git a/cs/core.cs b/cs/core.cs
index 0ebc3ef..c5b9e10 100644
--- a/cs/core.cs
+++ b/cs/core.cs
@@ -36,6 +36,9 @@ namespace Mal {
         static public MalFunction list_Q = new MalFunction(
             a => a[0].GetType() == typeof(MalList) ? True : False);
 
+        static MalFunction nth = new MalFunction(
+            a => ((MalList)a[0])[ ((MalInteger)a[1]).getValue() ]);
+
         static MalFunction cons = new MalFunction(
             a => {
                 var lst = new List<MalVal>();
@@ -80,7 +83,8 @@ namespace Mal {
 
             {"cons", cons},
             {"concat", concat},
-            {"first", new MalFunction(a => ((MalList)a[0]).nth(0))},
+            {"nth", nth},
+            {"first", new MalFunction(a => ((MalList)a[0])[0])},
             {"rest",  new MalFunction(a => ((MalList)a[0]).rest())},
             {"empty?", new MalFunction(
                 a => ((MalList)a[0]).size() == 0 ? True : False)},
diff --git a/cs/step8_macros.cs b/cs/step8_macros.cs
new file mode 100644
index 0000000..fe085f9
--- /dev/null
+++ b/cs/step8_macros.cs
@@ -0,0 +1,265 @@
+using System;
+using System.IO;
+using System.Collections;
+using System.Collections.Generic;
+using Mal;
+using MalVal = Mal.types.MalVal;
+using MalString = Mal.types.MalString;
+using MalSymbol = Mal.types.MalSymbol;
+using MalInteger = Mal.types.MalInteger;
+using MalList = Mal.types.MalList;
+using MalVector = Mal.types.MalVector;
+using MalHashMap = Mal.types.MalHashMap;
+using MalFunction = Mal.types.MalFunction;
+using Env = Mal.env.Env;
+
+namespace Mal {
+    class step4_if_fn_do {
+        // read
+        static MalVal READ(string str) {
+            return reader.read_str(str);
+        }
+
+        // eval
+        public static bool is_pair(MalVal x) {
+            return x is MalList && ((MalList)x).size() > 0;
+        }
+
+        public static MalVal quasiquote(MalVal ast) {
+            if (!is_pair(ast)) {
+                return new MalList(new MalSymbol("quote"), ast);
+            } else {
+                MalVal a0 = ((MalList)ast)[0];
+                if ((a0 is MalSymbol) &&
+                    (((MalSymbol)a0).getName() == "unquote")) {
+                    return ((MalList)ast)[1];
+                } else if (is_pair(a0)) {
+                    MalVal a00 = ((MalList)a0)[0];
+                    if ((a00 is MalSymbol) &&
+                        (((MalSymbol)a00).getName() == "splice-unquote")) {
+                        return new MalList(new MalSymbol("concat"),
+                                           ((MalList)a0)[1],
+                                           quasiquote(((MalList)ast).rest()));
+                    }
+                }
+                return new MalList(new MalSymbol("cons"),
+                                   quasiquote(a0),
+                                   quasiquote(((MalList)ast).rest()));
+            }
+        }
+
+        public static bool is_macro_call(MalVal ast, Env env) {
+            if (ast is MalList) {
+                MalVal a0 = ((MalList)ast)[0];
+                if (a0 is MalSymbol &&
+                    env.find(((MalSymbol)a0).getName()) != null) {
+                    MalVal mac = env.get(((MalSymbol)a0).getName());
+                    if (mac is MalFunction &&
+                        ((MalFunction)mac).isMacro()) {
+                        return true;
+                    }
+                }
+            }
+            return false;
+        }
+
+        public static MalVal macroexpand(MalVal ast, Env env) {
+            while (is_macro_call(ast, env)) {
+                MalSymbol a0 = (MalSymbol)((MalList)ast)[0];
+                MalFunction mac = (MalFunction) env.get(a0.getName());
+                ast = mac.apply(((MalList)ast).rest());
+            }
+            return ast;
+        }
+
+        static MalVal eval_ast(MalVal ast, Env env) {
+            if (ast is MalSymbol) {
+                MalSymbol sym = (MalSymbol)ast;
+                return env.get(sym.getName());
+            } else if (ast is MalList) {
+                MalList old_lst = (MalList)ast;
+                MalList new_lst = ast.list_Q() ? new MalList()
+                                            : (MalList)new MalVector();
+                foreach (MalVal mv in old_lst.getValue()) {
+                    new_lst.conj_BANG(EVAL(mv, env));
+                }
+                return new_lst;
+            } else if (ast is MalHashMap) {
+                var new_dict = new Dictionary<string, MalVal>();
+                foreach (var entry in ((MalHashMap)ast).getValue()) {
+                    new_dict.Add(entry.Key, EVAL((MalVal)entry.Value, env));
+                }
+                return new MalHashMap(new_dict);
+            } else {
+                return ast;
+            }
+        }
+
+
+        static MalVal EVAL(MalVal orig_ast, Env env) {
+            MalVal a0, a1, a2, res;
+            MalList el;
+
+            while (true) {
+
+            //System.out.println("EVAL: " + printer._pr_str(orig_ast, true));
+            if (!orig_ast.list_Q()) {
+                return eval_ast(orig_ast, env);
+            }
+
+            // apply list
+            MalVal expanded = macroexpand(orig_ast, env);
+            if (!expanded.list_Q()) { return expanded; } 
+            MalList ast = (MalList) expanded;
+
+            if (ast.size() == 0) { return ast; }
+            a0 = ast[0];
+
+            String a0sym = a0 is MalSymbol ? ((MalSymbol)a0).getName()
+                                           : "__<*fn*>__";
+
+            switch (a0sym) {
+            case "def!":
+                a1 = ast[1];
+                a2 = ast[2];
+                res = EVAL(a2, env);
+                env.set(((MalSymbol)a1).getName(), res);
+                return res;
+            case "let*":
+                a1 = ast[1];
+                a2 = ast[2];
+                MalSymbol key;
+                MalVal val;
+                Env let_env = new Env(env);
+                for(int i=0; i<((MalList)a1).size(); i+=2) {
+                    key = (MalSymbol)((MalList)a1)[i];
+                    val = ((MalList)a1)[i+1];
+                    let_env.set(key.getName(), EVAL(val, let_env));
+                }
+                return EVAL(a2, let_env);
+            case "quote":
+                return ast[1];
+            case "quasiquote":
+                return EVAL(quasiquote(ast[1]), env);
+            case "defmacro!":
+                a1 = ast[1];
+                a2 = ast[2];
+                res = EVAL(a2, env);
+                ((MalFunction)res).setMacro();
+                env.set(((MalSymbol)a1).getName(), res);
+                return res;
+            case "macroexpand":
+                a1 = ast[1];
+                return macroexpand(a1, env);
+            case "do":
+                eval_ast(ast.slice(1, ast.size()-1), env);
+                orig_ast = ast[ast.size()-1];
+                break;
+            case "if":
+                a1 = ast[1];
+                MalVal cond = EVAL(a1, env);
+                if (cond == Mal.types.Nil || cond == Mal.types.False) {
+                    // eval false slot form
+                    if (ast.size() > 3) {
+                        orig_ast = ast[3];
+                    } else {
+                        return Mal.types.Nil;
+                    }
+                } else {
+                    // eval true slot form
+                    orig_ast = ast[2];
+                }
+                break;
+            case "fn*":
+                MalList a1f = (MalList)ast[1];
+                MalVal a2f = ast[2];
+                Env cur_env = env;
+                return new MalFunction(a2f, env, a1f,
+                    args => EVAL(a2f, new Env(cur_env, a1f, args)) );
+            default:
+                el = (MalList)eval_ast(ast, env);
+                var f = (MalFunction)el[0];
+                MalVal fnast = f.getAst();
+                if (fnast != null) {
+                    orig_ast = fnast;
+                    env = f.genEnv(el.rest());
+                } else {
+                    return f.apply(el.rest());
+                }
+                break;
+            }
+
+            }
+        }
+
+        // print
+        static string PRINT(MalVal exp) {
+            return printer._pr_str(exp, true);
+        }
+
+        // REPL
+        static MalVal RE(Env env, string str) {
+            return EVAL(READ(str), env);
+        }
+        public static Env _ref(Env env, string name, MalVal mv) {
+            return env.set(name, mv);
+        }
+
+
+        static void Main(string[] args) {
+            string prompt = "user> ";
+            
+            var repl_env = new Mal.env.Env(null);
+            foreach (var entry in Mal.core.ns) {
+                _ref(repl_env, entry.Key, entry.Value);
+            }
+            _ref(repl_env, "read-string", new MalFunction(
+                    a => reader.read_str(((MalString)a[0]).getValue())));
+            _ref(repl_env, "eval", new MalFunction(
+                    a => EVAL(a[0], repl_env)));
+            _ref(repl_env, "slurp", new MalFunction(
+                    a => new MalString(File.ReadAllText(
+                            ((MalString)a[0]).getValue()))));
+
+            RE(repl_env, "(def! not (fn* (a) (if a false true)))");
+            RE(repl_env, "(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))");
+
+            int fileIdx = 0;
+            if (args.Length > 0 && args[0] == "--raw") {
+                Mal.readline.mode = Mal.readline.Mode.Raw;
+                fileIdx = 1;
+            }
+            if (args.Length > fileIdx) {
+                for(int i=fileIdx; i<args.Length; i++) {
+                    RE(repl_env, "(load-file \"" + args[i] + "\")");
+                }
+                return;
+            }
+            while (true) {
+                string line;
+                try {
+                    line = Mal.readline.Readline(prompt);
+                    if (line == null) { break; }
+                } catch (IOException e) {
+                    Console.WriteLine("IOException: " + e.Message);
+                    break;
+                }
+                try {
+                    Console.WriteLine(PRINT(RE(repl_env, line)));
+                } catch (Mal.types.MalContinue) {
+                    continue;
+                } catch (Mal.reader.ParseError e) {
+                    Console.WriteLine(e.Message);
+                    continue;
+                } catch (Mal.types.MalException e) {
+                    Console.WriteLine("Error: " + e.getValue());
+                    continue;
+                } catch (Exception e) {
+                    Console.WriteLine("Error: " + e.Message);
+                    Console.WriteLine(e.StackTrace);
+                    continue;
+                }
+            }
+        }
+    }
+}
diff --git a/cs/types.cs b/cs/types.cs
index 442a2b2..cd94f94 100644
--- a/cs/types.cs
+++ b/cs/types.cs
@@ -295,6 +295,7 @@ namespace Mal {
             MalVal ast = null;
             Mal.env.Env env = null;
             MalList fparams;
+            bool macro = false;
             public MalFunction(Func<MalList, MalVal> fn) {
                 this.fn = fn;
             }
@@ -325,6 +326,9 @@ namespace Mal {
             public Mal.env.Env genEnv(MalList args) {
                 return new Mal.env.Env(env, fparams, args);
             }
+            public bool isMacro() { return macro; }
+            public void setMacro() { macro = true; }
+
         }
     }
 }