From a824ff273d1fce93b866c3a8169f95ba94df43a8 Mon Sep 17 00:00:00 2001
From: PaddiM8 <hi@bakk.dev>
Date: Thu, 10 Oct 2024 22:52:10 +0200
Subject: [PATCH] Use parser example for integration tests

---
 examples/parser/ast.elk       |  4 +++-
 examples/parser/evaluator.elk |  5 +++++
 examples/parser/lexer.elk     |  2 +-
 examples/parser/parser.elk    | 15 +++++++++++++++
 examples/parser/tests.elk     |  7 +++++++
 tests/IntegrationTests.cs     |  1 +
 6 files changed, 32 insertions(+), 2 deletions(-)
 create mode 100644 examples/parser/tests.elk

diff --git a/examples/parser/ast.elk b/examples/parser/ast.elk
index 475920e..3fad007 100644
--- a/examples/parser/ast.elk
+++ b/examples/parser/ast.elk
@@ -2,4 +2,6 @@ pub struct Token(kind, value)
 
 pub struct BinaryExpr(left, op, right)
 
-pub struct LiteralExpr(value)
\ No newline at end of file
+pub struct LiteralExpr(value)
+
+pub struct GroupExpr(value)
\ No newline at end of file
diff --git a/examples/parser/evaluator.elk b/examples/parser/evaluator.elk
index f630fd8..5f2be28 100644
--- a/examples/parser/evaluator.elk
+++ b/examples/parser/evaluator.elk
@@ -7,6 +7,7 @@ pub fn evaluate(ast) {
 fn next(expr) {
     return nextBinary(expr) if expr | isType(BinaryExpr)
     return nextLiteral(expr) if expr | isType(LiteralExpr)
+    return nextGroup(expr) if expr | isType(GroupExpr)
 }
 
 fn nextBinary(expr) {
@@ -21,4 +22,8 @@ fn nextBinary(expr) {
 
 fn nextLiteral(expr) {
     expr->value->value | into::float
+}
+
+fn nextGroup(expr) {
+    expr->value | next
 }
\ No newline at end of file
diff --git a/examples/parser/lexer.elk b/examples/parser/lexer.elk
index 918be60..261b436 100644
--- a/examples/parser/lexer.elk
+++ b/examples/parser/lexer.elk
@@ -30,7 +30,7 @@ fn next() {
 
     return nil if c == nil
 
-    if c in ["+", "-", "*", "/"] {
+    if c in ["+", "-", "*", "/", "(", ")"] {
         advance
         return new Token(c, c)
     }
diff --git a/examples/parser/parser.elk b/examples/parser/parser.elk
index 6647893..5d8db43 100644
--- a/examples/parser/parser.elk
+++ b/examples/parser/parser.elk
@@ -8,6 +8,7 @@ let index = 0
 pub fn parse(input) {
     tokens = lexer::lex(input)
     index = 0
+    return nil if len(tokens) == 0
 
     expr()
 }
@@ -28,6 +29,13 @@ fn match(kinds...) {
     kinds | iter::anyOf => kind { kind == current()->kind }
 }
 
+fn expect(kind) {
+    return advance() if match(kind)
+
+    throw new ParseError("Expected '${kind}'") if current() == nil
+    throw new ParseError("Expected '${kind}' but got '${current()->kind}'")
+}
+
 fn expr() {
     additive()
 }
@@ -61,6 +69,13 @@ fn primary() {
         return new LiteralExpr(advance())
     }
 
+    if match("(") {
+        advance()
+        let group = new GroupExpr(expr())
+        expect(")")
+        return group
+    }
+
     throw new ParseError("Unexpected end of expression") if current() != nil
     throw new ParseError("Unexpected token: '${current()->kind}'")
 }
diff --git a/examples/parser/tests.elk b/examples/parser/tests.elk
new file mode 100644
index 0000000..9339311
--- /dev/null
+++ b/examples/parser/tests.elk
@@ -0,0 +1,7 @@
+with parse from ./parser
+with evaluate from ./evaluator
+
+parse("2 + 3 * 4") | evaluate | assertEqual(14)
+parse("(3 + 3 * 4) / 3") | evaluate | assertEqual(5)
+parse("2") | evaluate | assertEqual(2)
+parse("") | evaluate | assertEqual(nil)
\ No newline at end of file
diff --git a/tests/IntegrationTests.cs b/tests/IntegrationTests.cs
index d585988..9345276 100644
--- a/tests/IntegrationTests.cs
+++ b/tests/IntegrationTests.cs
@@ -46,6 +46,7 @@ public static IEnumerable<string> ElkFiles()
             Directory.GetFiles(dataPath, "*.elk", SearchOption.AllDirectories),
             Directory.GetFiles(Path.Combine(examplesPath, "advent-of-code-2022"), "*.elk", SearchOption.AllDirectories),
             Directory.GetFiles(Path.Combine(examplesPath, "advent-of-code-2023"), "*.elk", SearchOption.AllDirectories),
+            Directory.GetFiles(Path.Combine(examplesPath, "parser"), "*.elk", SearchOption.AllDirectories),
         }.SelectMany(x => x);
     }
 }
\ No newline at end of file