Version submited to the language jam

AstGenerator.cs

@@ -15,7 +15,8 @@ public static class AstGenerator {
 
         Variant("Val",
           Case("int", "Int"),
-          Case("string", "String")),
+          Case("string", "String"),
+          Case("bool", "Bool")),
 
         Variant("ParserResult",
           Case("(MixFix.Annotation, ParserResult)", "Annotated"),

DefaultGrammar.cs

@@ -13,7 +13,7 @@ public static class DefaultGrammar {
       .WithOperator("int",      LiteralInt,     NonAssociative, S.Int)
       .WithOperator("additive", Unsupported, LeftAssociative, "int|terminal|multiplicative", S.Plus, "int|terminal|multiplicative")
       .WithOperator("multiplicative", Unsupported, LeftAssociative, "int|terminal", S.Times, "int|terminal")
-      .WithOperator("terminal", Unsupported, NonAssociative, S.Ident)
+      .WithOperator("terminal", EnvLookup, NonAssociative, S.Ident)
       // This is the root set of operators
       // TODO: this needs aliases
       .WithOperator("prog",  And, LeftAssociative, "equality|terminal", S.And, "equality|terminal")

Evaluator.cs

@@ -7,9 +7,13 @@ using static Global;
 
 public class Evaluator {
   public static string EvaluateWrap(Ast.AstNode source)
-    => Evaluate(source, ImmutableDictionary<string, Ast.Val>.Empty).Match(
+    => Evaluate(source, new Dictionary<string, Ast.Val> {
+      { "true", Ast.Val.Bool(true) },
+      { "false", Ast.Val.Bool(false) }
+    }.ToImmutableDictionary()).Match(
          Int: i => i.ToString(),
-         String: s => s);
+         String: s => s,
+         Bool: b => b ? "true" : "false");
 
   public static Ast.Val Evaluate(Ast.AstNode source, ImmutableDictionary<string, Ast.Val> env)
     // => Log(source.Str(), ()
@@ -23,6 +27,16 @@ public class Evaluator {
           // TODO: check that the last token is indeed Program
           return Evaluate(o.Item2.ElementAt(1), env);
         },
+        EnvLookup: () =>
+          o.Item2
+            .Single()
+            .ElseThrow(
+              new RuntimeErrorException("EnvLookup should contain a single lexeme"))
+            .AsTerminal
+            .ElseThrow(
+              new RuntimeErrorException("EnvLookup's contents should be a lexeme"))
+            .lexeme
+            .Pipe(x => env[x]),
         And: () => {
           if (o.Item2.Count() != 3) {
             throw new RuntimeErrorException("The And operator should contain three parts");
@@ -30,7 +44,12 @@ public class Evaluator {
           // TODO: check that the last token is indeed Program
           var a = Evaluate(o.Item2.ElementAt(0), env);
           var b = Evaluate(o.Item2.ElementAt(2), env);
-          return Ast.Val.Int(999);
+          return
+            Ast.Val.Bool(
+              a.AsBool.ElseThrow(new RuntimeErrorException("type error: and requires two bools"))
+              &&
+              b.AsBool.ElseThrow(new RuntimeErrorException("type error: and requires two bools"))
+            );
         },
         LiteralInt: () =>
           o.Item2

MixFixGenerator.cs

@@ -59,6 +59,7 @@ public static class ParserGenerator {
           Case("LiteralInt"),
           Case("LiteralString"),
           Case("And"),
+          Case("EnvLookup"),
           Case("Unsupported")),
 
         Variant("Part",

Tests/004-foo42.e

@@ -1 +1 @@
-"foo"42
+"foo42"

Tests/005-42foo.e

@@ -1 +1 @@
-42"foo"
+"42foo"

Tests/007-bool.e

@@ -0,0 +1 @@
+true && false

Tests/007-bool.o

@@ -0,0 +1 @@
+false

Tests/008-eq2.e

@@ -0,0 +1 @@
+40 + 2 == 40 + 1 + 1 && true

Tests/008-eq2.o

@@ -0,0 +1 @@
+true

main.cs

@@ -90,8 +90,9 @@ public static class MainClass {
         Console.WriteLine("  Expression =");
         Console.WriteLine("    Int");
         Console.WriteLine("  | String");
-        Console.WriteLine("  | Variable");
+        Console.WriteLine("  | true");
-        Console.WriteLine("  | Pattern \"->\" Expression");
+        Console.WriteLine("  | false");
+        Console.WriteLine("  | Expression && Expression");
         Console.WriteLine("");
         Console.WriteLine("I'll run the tests for you in the meanwhile.");
         Console.WriteLine("");