14 files changed, 152 insertions, 43 deletions

diff --git a/ast/src/main/java/lv/enes/orang/ast/ExpressionVisitor.java b/ast/src/main/java/lv/enes/orang/ast/ExpressionVisitor.java
index 60ec3c2..410512f 100644
--- a/ast/src/main/java/lv/enes/orang/ast/ExpressionVisitor.java
+++ b/ast/src/main/java/lv/enes/orang/ast/ExpressionVisitor.java
@@ -17,6 +17,7 @@ public interface ExpressionVisitor<R, E extends OrangException> {
         R visitIfElseExpression(IfElseExpression expr) throws E;
         R visitIntLiteral(IntLiteral expr) throws E;
         R visitLetInExpression(LetInExpression expr) throws E;
+        R visitMap(MapExpression expr) throws E;
         R visitStringLiteral(StringLiteral expr) throws E;
         R visitTupleExpression(TupleExpression expr) throws E;
         R visitUnaryExpression(UnaryExpression expr) throws E;
diff --git a/ast/src/main/java/lv/enes/orang/ast/MapExpression.java b/ast/src/main/java/lv/enes/orang/ast/MapExpression.java
new file mode 100644
index 0000000..c758788
--- /dev/null
+++ b/ast/src/main/java/lv/enes/orang/ast/MapExpression.java
@@ -0,0 +1,13 @@
+package lv.enes.orang.ast;
+
+import lv.enes.orang.core.OrangException;
+
+import java.util.List;
+
+public record MapExpression(List<MapPair> entries) implements Expression {
+        public record MapPair(Expression from, Expression to) {}
+        @Override
+        public <R, E extends OrangException> R accept(ExpressionVisitor<R, E> visitor) throws E {
+                return visitor.visitMap(this);
+        }
+}
diff --git a/checker/src/main/java/lv/enes/orang/checker/Checker.java b/checker/src/main/java/lv/enes/orang/checker/Checker.java
index 1c7303e..f035e41 100644
--- a/checker/src/main/java/lv/enes/orang/checker/Checker.java
+++ b/checker/src/main/java/lv/enes/orang/checker/Checker.java
@@ -141,6 +141,15 @@ public class Checker implements ExpressionVisitor<Void, CheckerException>, State
         }
 
         @Override
+        public Void visitMap(MapExpression expr) throws CheckerException {
+                for (var entry : expr.entries()) {
+                        visit(entry.from());
+                        visit(entry.to());
+                }
+                return null;
+        }
+
+        @Override
         public Checker visitProgram(Program program) throws CheckerException {
                 var checker = this;
                 for (var stmt : program.statements()) {
diff --git a/evaluator/src/main/java/lv/enes/orang/evaluator/Array.java b/evaluator/src/main/java/lv/enes/orang/evaluator/Array.java
index ab0d896..265bbd9 100644
--- a/evaluator/src/main/java/lv/enes/orang/evaluator/Array.java
+++ b/evaluator/src/main/java/lv/enes/orang/evaluator/Array.java
@@ -46,7 +46,7 @@ public record Array(List<Value> items) implements Value {
                         newItems.addAll(rhsi);
                         return new Array(Collections.unmodifiableList(newItems));
                 } else {
-                        throw new OrangRuntimeException(STR."add not implemented for Array and \{rhs.typeName()}");
+                        return Value.super.add(rhs);
                 }
         }
 
@@ -58,7 +58,7 @@ public record Array(List<Value> items) implements Value {
                         }
                         return items.get(i);
                 } else {
-                        throw new OrangRuntimeException(STR."array access not implemented for Array and \{idx.typeName()}");
+                        return Value.super.arrayAccess(idx);
                 }
         }
 
@@ -71,7 +71,7 @@ public record Array(List<Value> items) implements Value {
                         }
                         return new Array(Collections.unmodifiableList(newItems));
                 } else {
-                        throw new OrangRuntimeException(STR."multiply not implemented for Array and \{rhs.typeName()}");
+                        return Value.super.multiply(rhs);
                 }
         }
 }
diff --git a/evaluator/src/main/java/lv/enes/orang/evaluator/Evaluator.java b/evaluator/src/main/java/lv/enes/orang/evaluator/Evaluator.java
index 69c03e8..8fd61e8 100644
--- a/evaluator/src/main/java/lv/enes/orang/evaluator/Evaluator.java
+++ b/evaluator/src/main/java/lv/enes/orang/evaluator/Evaluator.java
@@ -120,6 +120,17 @@ public record Evaluator(Map<String, Value> scope, Value lastResult) implements E
         }
 
         @Override
+        public Value visitMap(MapExpression expr) throws OrangRuntimeException {
+                var map = new HashMap<Value, Value>();
+                for (var entry : expr.entries()) {
+                        var from = visit(entry.from());
+                        var to = visit(entry.to());
+                        map.put(from, to);
+                }
+                return new OrangMap(Collections.unmodifiableMap(map));
+        }
+
+        @Override
         public Evaluator visitProgram(Program prog) throws OrangRuntimeException {
                 var evaluator = this;
                 for (var statement : prog.statements()) {
diff --git a/evaluator/src/main/java/lv/enes/orang/evaluator/OrangBoolean.java b/evaluator/src/main/java/lv/enes/orang/evaluator/OrangBoolean.java
index 3564a9c..46c887c 100644
--- a/evaluator/src/main/java/lv/enes/orang/evaluator/OrangBoolean.java
+++ b/evaluator/src/main/java/lv/enes/orang/evaluator/OrangBoolean.java
@@ -5,8 +5,8 @@ import lv.enes.orang.core.OrangRuntimeException;
 
 @EqualsAndHashCode
 public final class OrangBoolean implements Value {
-        public final static OrangBoolean TRUE = new OrangBoolean(true);
-        public final static OrangBoolean FALSE = new OrangBoolean(false);
+        public static final OrangBoolean TRUE = new OrangBoolean(true);
+        public static final OrangBoolean FALSE = new OrangBoolean(false);
 
         private final boolean value;
 
@@ -45,11 +45,11 @@ public final class OrangBoolean implements Value {
         }
 
         @Override
-        public OrangBoolean or(Value rhs) throws OrangRuntimeException {
+        public Value or(Value rhs) throws OrangRuntimeException {
                 if (rhs instanceof OrangBoolean rhsb) {
                         return new OrangBoolean(value || rhsb.value);
                 } else {
-                        throw new OrangRuntimeException(STR."or is not implemented for Boolean and \{rhs.typeName()}");
+                        return Value.super.or(rhs);
                 }
         }
 }
diff --git a/evaluator/src/main/java/lv/enes/orang/evaluator/OrangInteger.java b/evaluator/src/main/java/lv/enes/orang/evaluator/OrangInteger.java
index 90de0b5..872fce2 100644
--- a/evaluator/src/main/java/lv/enes/orang/evaluator/OrangInteger.java
+++ b/evaluator/src/main/java/lv/enes/orang/evaluator/OrangInteger.java
@@ -24,47 +24,47 @@ public record OrangInteger(int value) implements Value {
         }
 
         @Override
-        public OrangInteger add(Value rhs) throws OrangRuntimeException {
+        public Value add(Value rhs) throws OrangRuntimeException {
                 if (rhs instanceof OrangInteger(int rhsi)) {
                         return new OrangInteger(value + rhsi);
                 } else {
-                        throw new OrangRuntimeException(STR."add is not implemented for Integer and \{rhs.typeName()}");
+                        return Value.super.add(rhs);
                 }
         }
 
         @Override
-        public OrangInteger divide(Value rhs) throws OrangRuntimeException {
+        public Value divide(Value rhs) throws OrangRuntimeException {
                 if (rhs instanceof OrangInteger(int rhsi)) {
                         return new OrangInteger(value / rhsi);
                 } else {
-                        throw new OrangRuntimeException(STR."divide is not implemented for Integer and \{rhs.typeName()}");
+                        return Value.super.divide(rhs);
                 }
         }
 
         @Override
-        public OrangInteger multiply(Value rhs) throws OrangRuntimeException {
+        public Value multiply(Value rhs) throws OrangRuntimeException {
                 if (rhs instanceof OrangInteger(int rhsi)) {
                         return new OrangInteger(value * rhsi);
                 } else {
-                        throw new OrangRuntimeException(STR."multiply is not implemented for Integer and \{rhs.typeName()}");
+                        return Value.super.multiply(rhs);
                 }
         }
 
         @Override
-        public OrangInteger subtract(Value rhs) throws OrangRuntimeException {
+        public Value subtract(Value rhs) throws OrangRuntimeException {
                 if (rhs instanceof OrangInteger(int rhsi)) {
                         return new OrangInteger(value - rhsi);
                 } else {
-                        throw new OrangRuntimeException(STR."subtract is not implemented for Integer and \{rhs.typeName()}");
+                        return Value.super.subtract(rhs);
                 }
         }
 
         @Override
-        public OrangBoolean greaterThan(Value rhs) throws OrangRuntimeException {
+        public Value greaterThan(Value rhs) throws OrangRuntimeException {
                 if (rhs instanceof OrangInteger(int rhsi)) {
                         return OrangBoolean.of(value > rhsi);
                 } else {
-                        throw new OrangRuntimeException(STR."greaterThan is not implemented for Integer and \{rhs.typeName()}");
+                        return Value.super.greaterThan(rhs);
                 }
         }
 }
diff --git a/evaluator/src/main/java/lv/enes/orang/evaluator/OrangMap.java b/evaluator/src/main/java/lv/enes/orang/evaluator/OrangMap.java
new file mode 100644
index 0000000..27f9f35
--- /dev/null
+++ b/evaluator/src/main/java/lv/enes/orang/evaluator/OrangMap.java
@@ -0,0 +1,42 @@
+package lv.enes.orang.evaluator;
+
+import lv.enes.orang.core.OrangRuntimeException;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public record OrangMap(Map<Value, Value> map) implements Value {
+        @Override
+        public String typeName() {
+                return "Map";
+        }
+
+        @Override
+        public String stringify() {
+                var sb = new StringBuilder("{ ");
+                for (var entry : map.entrySet()) {
+                        sb.append(entry.getKey().stringify()).append(" -> ").append(entry.getValue().stringify()).append(", ");
+                }
+                return sb.append("}").toString();
+        }
+
+        @Override
+        public Value add(Value rhs) throws OrangRuntimeException {
+                if (rhs instanceof OrangMap(var rhsm)) {
+                        var newMap = new HashMap<>(map);
+                        newMap.putAll(rhsm);
+                        return new OrangMap(newMap);
+                } else {
+                        return Value.super.add(rhs);
+                }
+        }
+
+        @Override
+        public Value arrayAccess(Value idx) throws OrangRuntimeException {
+                if (map.containsKey(idx)) {
+                        return map.get(idx);
+                } else {
+                        throw new OrangRuntimeException(STR."No value associated with key \{idx.stringify()} in \{stringify()}");
+                }
+        }
+}
diff --git a/evaluator/src/main/java/lv/enes/orang/evaluator/OrangString.java b/evaluator/src/main/java/lv/enes/orang/evaluator/OrangString.java
index 5c38842..fe03c1f 100644
--- a/evaluator/src/main/java/lv/enes/orang/evaluator/OrangString.java
+++ b/evaluator/src/main/java/lv/enes/orang/evaluator/OrangString.java
@@ -30,11 +30,11 @@ public record OrangString(String value) implements Value {
         }
 
         @Override
-        public OrangString add(Value rhs) throws OrangRuntimeException {
+        public Value add(Value rhs) throws OrangRuntimeException {
                 if (rhs instanceof OrangString(String rhss)) {
                         return new OrangString(value + rhss);
                 } else {
-                        throw new OrangRuntimeException(STR."add is not implemented for Integer and \{rhs.typeName()}");
+                        return Value.super.add(rhs);
                 }
         }
 
@@ -43,7 +43,7 @@ public record OrangString(String value) implements Value {
                 if (rhs instanceof OrangInteger(var repeat)) {
                         return new OrangString(value.repeat(Math.max(0, repeat)));
                 } else {
-                        throw new OrangRuntimeException(STR."multiply not implemented for Array and \{rhs.typeName()}");
+                        return Value.super.multiply(rhs);
                 }
         }
 }
diff --git a/evaluator/src/main/java/lv/enes/orang/evaluator/Value.java b/evaluator/src/main/java/lv/enes/orang/evaluator/Value.java
index 35af35b..da44a19 100644
--- a/evaluator/src/main/java/lv/enes/orang/evaluator/Value.java
+++ b/evaluator/src/main/java/lv/enes/orang/evaluator/Value.java
@@ -3,7 +3,7 @@ package lv.enes.orang.evaluator;
 import lv.enes.orang.core.OrangRuntimeException;
 
 public sealed interface Value
-                permits Array, BuiltinFunction, Function, OrangBoolean, OrangInteger, OrangString,
+                permits Array, BuiltinFunction, Function, OrangBoolean, OrangInteger, OrangMap, OrangString,
                 PartialBuiltinFunction, PartialFunction, Tuple, Undefined {
         String typeName();
         String stringify();
@@ -56,19 +56,19 @@ public sealed interface Value
         }
 
 
-        default OrangBoolean greaterThan(Value rhs) throws OrangRuntimeException {
+        default Value greaterThan(Value rhs) throws OrangRuntimeException {
                 throw new OrangRuntimeException(STR."greater than is not implemented for \{typeName()} and \{rhs.typeName()}");
         }
 
-        default OrangBoolean greaterThanOrEqual(Value rhs) throws OrangRuntimeException {
+        default Value greaterThanOrEqual(Value rhs) throws OrangRuntimeException {
                 return greaterThan(rhs).or(orangEquals(rhs));
         }
 
-        default OrangBoolean lessThan(Value rhs) throws OrangRuntimeException {
+        default Value lessThan(Value rhs) throws OrangRuntimeException {
                 return greaterThanOrEqual(rhs).not();
         }
 
-        default OrangBoolean lessThanOrEqual(Value rhs) throws OrangRuntimeException {
+        default Value lessThanOrEqual(Value rhs) throws OrangRuntimeException {
                 return greaterThan(rhs).not();
         }
 
diff --git a/grammar.bnf b/grammar.bnf
index 3dcb1c6..d798f9d 100644
--- a/grammar.bnf
+++ b/grammar.bnf
@@ -3,10 +3,13 @@
 program ::= (statement ';'?)*;
 statement ::= definition;
 definition ::= 'def' def-spec '=' expression
-             | 'def' '_' '=' expression;
+             | 'def' '_' '=' expression
+             ;
+
 def-spec ::= IDENTIFIER arg-spec*;
 arg-spec ::= '(' arg-spec ')' | IDENTIFIER | arg-spec-tuple | '_';
 arg-spec-tuple ::= '(' ')' | '(' arg-spec ',' arg-spec (',' arg-spec)* ','? ')';
+
 expression ::= binary-expression | unary-expression;
 unary-expression ::= unop+ simple-expression;
 binary-expression ::= call-expression (binop call-expression)*;
@@ -21,23 +24,27 @@ simple-expression ::= '(' expression ')'
                     | IDENTIFIER
                     | STRING
                     | array
+                    | map
                     | tuple
+                    | do-expression
+                    | fn-expression
                     | if-else-expression
                     | let-in-expression
-                    | fn-expression
-                    | do-expression;
+                    ;
 
 array ::= '[' ']' | '[' expression (',' expression)* ','? ']';
+map ::= '{' '}' | '{' expression '->' expression (',' expression '->' expression) ','? '}';
 // Note that tuples always have either zero or at least two elements
 // A tuple with only one element is just '(' expression ')' -- a parenthese-wrapped expression
 // Also '(' expression ',' ')' is illegal
 tuple ::= '(' ')' | '(' expression ',' expression (',' expression)* ','? ')';
 
+do-expression ::= 'do' expression (';' expression)* 'end';
+fn-expression ::= 'fn' arg-spec+ '->' expression
+                | 'fn' arg-spec+ do-expression
+                ;
 if-else-expression ::= 'if' expression 'then' expression 'else' expression;
 let-in-expression ::= 'let' def-spec '=' expression ('and' def-spec '=' expression)* 'in' expression;
-fn-expression ::= 'fn' arg-spec+ '->' expression
-                | 'fn' arg-spec+ do-expression;
-do-expression ::= 'do' expression (';' expression)* 'end';
 
 repl-program ::= (repl-statement ';'?)* '\n'; // currently, hard-limited by the newline :sweat_smile:
 repl-statement ::= statement | expression;
diff --git a/lexer/src/main/java/lv/enes/orang/lexer/Lexer.java b/lexer/src/main/java/lv/enes/orang/lexer/Lexer.java
index 5cea0a3..f0e1ece 100644
--- a/lexer/src/main/java/lv/enes/orang/lexer/Lexer.java
+++ b/lexer/src/main/java/lv/enes/orang/lexer/Lexer.java
@@ -65,6 +65,8 @@ public class Lexer implements Iterator<Token> {
 
                         case '*' -> new Token(Token.Type.ASTERISK, input.next());
                         case '!' -> new Token(Token.Type.BANG, input.next());
+                        case '{' -> new Token(Token.Type.BRACE_LEFT, input.next());
+                        case '}' -> new Token(Token.Type.BRACE_RIGHT, input.next());
                         case '[' -> new Token(Token.Type.BRACKET_LEFT, input.next());
                         case ']' -> new Token(Token.Type.BRACKET_RIGHT, input.next());
                         case ',' -> new Token(Token.Type.COMMA, input.next());
diff --git a/lexer/src/main/java/lv/enes/orang/lexer/Token.java b/lexer/src/main/java/lv/enes/orang/lexer/Token.java
index 65e0f1d..d00aecd 100644
--- a/lexer/src/main/java/lv/enes/orang/lexer/Token.java
+++ b/lexer/src/main/java/lv/enes/orang/lexer/Token.java
@@ -42,6 +42,8 @@ public record Token(Type type, String literal) {
                 // Special chars
                 ASTERISK,
                 BANG,
+                BRACE_LEFT,
+                BRACE_RIGHT,
                 BRACKET_LEFT,
                 BRACKET_RIGHT,
                 COMMA,
diff --git a/parser/src/main/java/lv/enes/orang/parser/Parser.java b/parser/src/main/java/lv/enes/orang/parser/Parser.java
index 3d1d42b..55da6fb 100644
--- a/parser/src/main/java/lv/enes/orang/parser/Parser.java
+++ b/parser/src/main/java/lv/enes/orang/parser/Parser.java
@@ -116,16 +116,15 @@ public class Parser {
 
         private ArrayExpression parseArray() throws ParserException {
                 consumeToken(Token.Type.BRACKET_LEFT);
-                if (maybeConsumeToken(Token.Type.BRACKET_RIGHT)) {
-                        return new ArrayExpression(List.of());
-                }
-
                 var items = new ArrayList<Expression>();
-                do {
+                while (!maybeConsumeToken(Token.Type.BRACKET_RIGHT)) {
                         items.add(parseExpression());
-                } while (maybeConsumeToken(Token.Type.COMMA));
-                consumeToken(Token.Type.BRACKET_RIGHT);
-
+                        if (!maybeConsumeToken(Token.Type.COMMA)) {
+                                consumeToken(Token.Type.BRACKET_RIGHT);
+                                break;
+                        }
+                }
+                items.trimToSize();
                 return new ArrayExpression(Collections.unmodifiableList(items));
         }
 
@@ -298,6 +297,24 @@ public class Parser {
                 return new LetInExpression(Collections.unmodifiableList(bindings), body);
         }
 
+        private MapExpression parseMap() throws ParserException {
+                consumeToken(Token.Type.BRACE_LEFT);
+                var entries = new ArrayList<MapExpression.MapPair>();
+                while (!maybeConsumeToken(Token.Type.BRACE_RIGHT)) {
+                        var from = parseExpression();
+                        consumeToken(Token.Type.MINUS_GREATER);
+                        var to = parseExpression();
+                        entries.add(new MapExpression.MapPair(from, to));
+
+                        if (!maybeConsumeToken(Token.Type.COMMA)) {
+                                consumeToken(Token.Type.BRACE_RIGHT);
+                                break;
+                        }
+                }
+                entries.trimToSize();
+                return new MapExpression(Collections.unmodifiableList(entries));
+        }
+
         private Expression parseMemberAccessExpression() throws ParserException {
                 var expr = parseSimpleExpression();
                 while (maybeConsumeToken(Token.Type.PERIOD_BRACKET_LEFT)) {
@@ -335,17 +352,19 @@ public class Parser {
                         case IDENTIFIER -> new VariableExpression(input.next().literal());
                         case STRING -> parseString();
                         case BRACKET_LEFT -> parseArray();
+                        case BRACE_LEFT -> parseMap();
+                        case DO -> parseDoExpression();
+                        case FN -> parseFnExpression();
                         case IF -> parseIfElseExpression();
                         case LET -> parseLetInExpression();
-                        case FN -> parseFnExpression();
-                        case DO -> parseDoExpression();
                         default -> throw new ParserException(STR."Unexpected token \{input.peek()}");
                 };
         }
 
         private boolean couldStartSimpleExpression(Token.Type type) {
                 return switch (type) {
-                        case PAREN_LEFT, TRUE, FALSE, INTEGER, IDENTIFIER, STRING, BRACKET_LEFT, IF, LET, FN, DO -> true;
+                        case PAREN_LEFT, TRUE, FALSE, INTEGER, IDENTIFIER, STRING, BRACKET_LEFT, BRACE_LEFT, DO, FN, IF, LET
+                                        -> true;
                         default -> false;
                 };
         }
@@ -382,7 +401,10 @@ public class Parser {
                 exprs.add(first);
                 do {
                         exprs.add(parseExpression());
-                        maybeConsumeToken(Token.Type.COMMA);
+                        if (!maybeConsumeToken(Token.Type.COMMA)) {
+                                consumeToken(Token.Type.PAREN_RIGHT);
+                                break;
+                        }
                 } while (!maybeConsumeToken(Token.Type.PAREN_RIGHT));
                 exprs.trimToSize();
                 return new TupleExpression(exprs);